CA2356617A1 - Transponder receiver - Google Patents
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- CA2356617A1 CA2356617A1 CA 2356617 CA2356617A CA2356617A1 CA 2356617 A1 CA2356617 A1 CA 2356617A1 CA 2356617 CA2356617 CA 2356617 CA 2356617 A CA2356617 A CA 2356617A CA 2356617 A1 CA2356617 A1 CA 2356617A1
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Abstract
A transponder (tag) monitoring method (300) and apparatus (250), preferably for vehicular tire monitoring systems, which automatically changes the system's database (267, TIRE_DB) to correct the association between transponders and transponder/tire (202/204) positions (205) whenever a known tag (202) is replaced by an unknown (foreign) tag. The tags are assumed to transmit a data stream which includes a unique tag ID. The data streams detected (received) by the receiver (266) are continually monitored.
If a data stream from a known tag is not seen for a TIMEOUT amount of time, then the position is labeled in the database as "REMOVED", and the tag ID associated with that tire position is nulled, thereby removing it from the list of known tags. Whenever an unknown ID is detected while any tire position is labeled as "REMOVED", it is recorded in a single field (MRR_FOREIGN_TAG_ID) which holds only the most recently received foreign tag ID.
That field is monitored to time (MRR_TIMER) the length of time for which the field maintains the same foreign tag ID, and if the time exceeds a TIMEOUT value then the foreign tag ID is automatically made known by associating it with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED"
to "NOT REMOVED ".
If a data stream from a known tag is not seen for a TIMEOUT amount of time, then the position is labeled in the database as "REMOVED", and the tag ID associated with that tire position is nulled, thereby removing it from the list of known tags. Whenever an unknown ID is detected while any tire position is labeled as "REMOVED", it is recorded in a single field (MRR_FOREIGN_TAG_ID) which holds only the most recently received foreign tag ID.
That field is monitored to time (MRR_TIMER) the length of time for which the field maintains the same foreign tag ID, and if the time exceeds a TIMEOUT value then the foreign tag ID is automatically made known by associating it with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED"
to "NOT REMOVED ".
Description
TR.AN5PONDER RECEIVER
TECHNICAL FIELD OF THE INVErTTION
The present invention relates to receivers for radio frequency transponders, and, more particularly, to methods of controlling RF transponder receivers, and/or for receivers in vehicular tire monitoring systems.
BACKGROUND OF THE INVENTION
Safe, efFcient and economical operation of a motor vehicle depends, to a significant degree, on maintaining correct air pressure in all (each) of the tires of the motor vehicle.
Operating the vehicle with low tire pressure may result in excessive tire wear, steering difficulties, poor mad-handling, and poor gasoline mileage, all of which are exacerbated when the tire pressure goes to zero in the case of a "flat" tire.
The need to monitor tire pressure when the tire is in use is highlighted in the context of "run-flat" (driven deflated) tires, tires which are capable of being used in a completely deflated condition. Such run-flat tires, as disclosed for example in commonly-owned USP
5,368,082, incorporated in its entirety by reference herein, may incorporate reinforced sidewalls, mechanisms for securing the tire bead to the rim, and a non-pneumatic tire (donut) within the pneumatic tire to enable a driver to maintain control over the vehicle after a catastrophic pressure loss, and are evolving to the point where it is becoming less and less noticeable to the driver that the tire has become deflated. The broad purpose behind using run-flat tires is to enable a driver of a vehicle to continue driving on a deflated pneumatic tire for a limited distance (e. g. , 50 miles, or 80 kilometers) prior to getting the tire repaired, rather than stopping on the side of the road to repair the deflated tire.
Hence, it is generally desirable to provide a low tire pressure warning system within in the vehicle to alert (e.g., via a light or a buzzer) the driver to the loss of air pressure in a pneumatic tire.
To this end, a number of electronic devices and systems are known for monitoring the pressure of pneumatic tires, and providing the operator of the vehicle with either an indication of the current tire pressure or alerting the operator when the pressure has dropped below a predetermined threshold level. It is known that the air pressure within any closed space such as a pneumatic tire (with a relatively fixed volume) varies with the temperature of the air according to the "ideal gas law" . Therefore, many tire pressure monitoring systems incorporate means of measuring the temperature within the tire and then utilize that temperature measurement to adjust the pressure measurement appropriately. The adjustment, or temperature compensation, of the pressure measurement may be done by the transponder before reporting (transmitting) the temperature-compensated pressure reading to a monitoring system receiver, or else both the temperature and pressure readings are reported to the receiver. In the latter case, the monitoring system receiver may perform the temperature-compensation, or it may simply record and/or report the temperature reading along with the pressure readings.
It is also known to monitor tire pressure with an electronic device which is not merely a passive resonant circuit, but rather is capable of transmitting a radio frequency (RFC signal indicative of the tire pressure to a remotely-located receiver.
Such a "transmitting device" may have its own power supply and may be activated only when the pressure drops below a predetermined threshold. Alternatively, the transmitting device may be activated ("turned ON") by an RF signal from the remotely-located receiver, in which case the receiver is considered to be an "interrogator" . Additionally, the transmitting device may be powered by an RF signal from the interrogator. Additionally, the electronic device which monitors the tire pressure may have the capability of receiving information from the interrogator, in which case the electronic device is referred to as a "transponder".
As used herein, a "transponder" is an electronic device capable of receiving and transmitting radio frequency signals, and impressing variable information (data) in a suitable format upon the transmitted signal indicative of a measured condition (e. g. , tire pressure) or conditions (e.g., tire pressure, temperature, revolutions), as well as optionally impressing fixed information (e. g. , tire ID) on the transmitted signal, as well as optionally responding to information which may be present on the received signal. The typical condition of paramount interest for pneumatic tires is tire pressure. "Passive"
transponders are transponders powered by the energy of a signal received from the interrogator.
"Active"
transponders are transponders having their own power supply (e.g., a battery), and include active transponders which remain in a "sleep" mode, using nninimal power, until "woken 3 0 up" by a signal from an interrogator, or by an internal periodic timer, or by an attached device. As used herein, the term "tag" refers either to a transponder having transmitting and receiving capability, or to a device that has only transmitting capability. Generally, tags which are transponders are preferred in the system of the present invention. As used herein, the term "tire-pressure monitoring system" (TPMS) or even more simply a vehicular "tire monitoring system" indicates an overall system comprising tags within the tires and a receiver which may be an interrogator disposed within the vehicle.
It is known to mount a tag, and associated condition sensor (e.g., pressure sensor) within each tire of a vehicle, and to collect information from each of these transponders with a common single interrogator (or receiver), and to alert a driver of the vehicle to a low tire pressure condition requiring correction (e. g. , replacing the tire). For example, U. S .
Patent No. 5,540,092 (Handheld, et al.; 1996), incorporated in its entirety by reference herein, discloses a system and method for monitoring a pneumatic tire. Figure 1 therein illustrates a pneumatic tire monitoring system (20) comprising a transponder (22) and a receiving unit (24). Each transponder has an identification code and is programmed to identify which wheel of the vehicle it is installed upon. A service tool (420, Figure 14) is disclosed which may be used to reprogram a transponder located within a vehicle tire after the location of the tire has been changed.
Other examples of transponder systems including RF transponders suitable for installation in a pneumatic tire are disclosed in U.S. Patent No. 5,451,959 (Schuermann;
09/95), U.S. Patent No. 5,661,651 (Geschke, et al.; 08/9'x, and U.S. Patent No. 5,581,023 (Handheld, et al.; 12/96), all incorporated in their entirety by reference herein. The described transponder systems include interrogation units, pressure sensors and/or temperature sensors associated with the transponder, and various techniques for establishing the identity of the tire/transponder in multiple transponder systems. For example, Schuermann discloses tags he calls responder units (12) which are to be individually addressed and interrogated using the interrogation unit (10). Fach responder unit has a memory (168) with data fixedly stored therein and said data are uniquely assigned to the responder unit. For Schuermann's system to be used in a vehicular monitoring system presumably either the interrogation unit would need to be programmed to associate unique data from each responder unit with the appropriate tire position, or the responder units would have to have their unique data appropriately programmed as described in Handfield (see USP 5,540,092 above). In another example, Geschke discloses tags he calls transmitters with parameter sensors (20) which transmit to a centrally located receiver (40).
Each transmitter transmits an lZF signal having a carrier frequency falling within at least one predefined frequency range centered at or about a nominal frequency (f~. The transmitted RF signals [and thus the identification of the corresponding transmitter] may be distinguished by the frequency of the respective transmitted RF signals.
In order to transport bulk materials, such as coal, iron ore and other minerals, the mining industry uses Off The-Road (OTR) vehicles that typically weigh up to 250 tons when fully loaded, with the result that exceedingly high internal stresses are imposed on the tires of such vehicles in the course of their daily use. Such internal stresses, which are primarily attributable to a number of factors including driving at excessive speeds, are so destructive of such tires that it is not uncommon to have to replace the tires. On the other hand, in order to maximize the productivity of OTR vehicles, they are normally driven as fast as possible until a user perceives that the internal physical condition of any given tire is marginal. Whereupon, the operator either stops, in the case of a loss of tire pressure, or reduces the speed of the vehicle, in the case of an excessive temperature condition, to relieve the internal stresses giving rise to the marginal condition, thereby prolonging the life of the tires. Thus the speed of an OTR vehicle is controlled on the basis of the operator's perception of the condition of the tires at any given time. And, if the operator's perception is erroneous, the productivity of the vehicle is unnecessarily reduced.
Accordingly, a long-standing need of the mining industry has been to ensure that the operators of OTR vehicles are provided with accurate information concerning various conditions of the tires of such vehicles, with a view to maximizing the productivity of the vehicles.
Various attempts have been made in the prior art to meet the aforesaid need, most recently by mounting integrated circuits within each of the tires of an OTR
vehicle, for detecting respective conditions related to an imminent failure of each tire and providing the OTR vehicle operators with timely information concerning such conditions.
For example, U.S. Patent No. 5,562,787, issued to Koch et al., incorporated in its entirety by reference herein, discloses a method and apparatus for monitoring respective conditions in the tires of vehicles. The apparatus comprises a monitoring device that is connectable to the interior of a tire and includes an integrated circuit having a transmitter. In addition, the monitoring device includes a plurality of sensors connected to the integrated circuit. The sensors continuously detect respective conditions of the tire and provide corresponding signals to the integrated circuit. The integrated circuit is programmed to periodically sample the tire condition signals, to compare the respective samples to respective standards, to generate respective tire condition signals based on the comparisons, and to provide an information signal to the aperator of the vehicle when any tire condition signal is indicative of a marginal condition of the tire. In addition, the integrated circuit is programmed to be normally dormant but to transmit information signals concerning the then 5 current tire condition signal to the operator in response to receiving a wake-up signal from the operator. Moreover, the integrated circuit may also be programmed to store data corresponding to periodic tire condition signals for historical, record keeping, purposes, and to cause the transmitter to transmit such historical data in response to receiving another wake-up signal.
Off the road vehicles often have more than 4 tires in use on a vehicle. For example, there may be one front tire on each of the left and right sides for steering, but two or even three tires on each side of the rear, load-bearing, porkion of the OTR
vehicle. A typical tire monitoring system for such a vehicle will have a receiver with one or more, preferably one centrally-located, antennas for receiving (optionally after interrogating) signals from the tags in each of the tires on the vehicle. In order to report (and/or alarm) tire conditions which are properly identified with each of the tires on the vehicle, the monitoring system receiver must be able to determine which tire that each of the tag RF signals is coming from. For monitoring systems where there isn't a separate antenna for each tire position, this problem has been solved by storing in each tag a unique identifying code (ID) and then having the tag include its 1D within a data stream transmitted by the tag, usually along with the tire condition data. The ID may be a simple serial number, or may include other identifying information about the tire and/or the tag. The receiver must "know" the ID for each tire position on the vehicle, and thereby is able to correctly associate the tire condition data of each received data stream with the appropriate tire position and thus the appropriate tire.
The present invention addresses additional problems with tire monitoring systems using tags with ID's which are associated with tire positions, such as described above for OTR vehicles. These additional problems have to do with data handling for "foreign" tags, i.e., tags which are not "known" by the monitoring system, but may be detected (by the receiver) when a tire and/or a tire tag is replaced, or when a tagged tire not installed on the 3 0 vehicle happens to be close enough to the vehicle to be detected (e. g. , on another nearby vehicle). In the first case, the foreign tag is a new tag which needs to be entered into the monitoring system database in place of the replaced tag and properly associated with its tire position. In the latter case, the foreign tag is truly foreign and must be ignored by the tire monitoring system.
BRIEF SUNFVIARY OF THE INVENTION
The present invention concerns a method for associating transponders (202) with tire positions (205) for a vehicular tire monitoring system (250) which comprises a transponder receiver (266) mounted on a vehicle (252), the receiver having an antenna (260) for receiving signals from the transponders which are mounted in each of the vehicle's multiple tires (204) which are to be monitored, and each transponder having a unique ID
(TAG ID) which is included as part of a data stream which is periodically transmitted from the transponder to the receiver. The method is characterized by the steps of:
1. Maintaining a database (267, TIRE DB) including ID's known to the tire monitoring system for the vehicle, wherein each specific known ID (TAG ID) is associated with a specific tire position (205, POS) on the vehicle, and labeling as "NOT
REMOVED" each tire position which has an associated known ID.
2. Whenever the specific ID associated with the specific tire position is not detected by the receiver, labeling the specific tire position as "REMOVED" .
3. Whenever an unknown specific ID (MRR FOREIGN TAG ID) is detected while any tire position is labeled as "REMOVED", automatically associating the unlaiown specific B7 with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED ".
According to the invention, the method further comprises enabling an operator to manually make a specific ID known and associated with a specific tire position on the vehicle.
According to the invention, the method further comprises including flags in the database wherein a specific flag is associated with each specific tire position in the database, and using a value of each specific flag to indicate each specific tire position which is expected to have a transponder with a known specific ID associated with the specific tire position.
According to the invention, the method further comprises in step 2: nulling the \specific B7 associated with the specific tire position, thereby removing it from the list of known ID's.
According to the invention, the method further comprises in step 2: utilizing a time period for attempting detection of the specific ID associated with the specific tire position;
and waiting until after the time period ends before labeling the specific tire position as "REMOVED" if the specific ID was not detected during the time period.
According to the invention, the method further comprises in step 3: utilizing a memory field to store o33nly a single most recently received unknown specific ID;
recording the length of time for which the memory field maintains the same foreign tag 117;
and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific tire position labeled as "REMOVED", and changing the specific tire position label from °'REMOVED" to "NOT
REMOVED ".
According to the invention, the method further comprises in step 3: using the specific tire position labeled as "REMOVED" which is first in the database.
According to the invention, the method is further characterized by: ignoring each specific tire position which is not expected to have a transponder with a known specific ID
associated with the specific tire position.
The present invention also concerns a transponder monitoring system which comprises a transponder receiver having an antenna for receiving signals from a plurality of transponders which are mounted in a plurality of positions which are to be monitored, each transponder having a unique ID which is included as part of a data stream which is periodically transmitted from the transponder to the receiver. The monitoring system is characterized by:
4. a database (267, TIRE DB) including ID's known to the monitoring system, wherein each specific known ID (TAG 117) is associated with a specific position (205, POS), and each position which has an associated known ID is labeled as "NOT REMOVED";
5. means for labeling the specific position as "REMOVED" whenever the specific ID
associated with the specific position is not detected by the receiver; and 6. means for automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED"
to "NOT REMOVED ", whenever an unknown specific ID (MRR FOREIGN TAG ID) is detected while any position is labeled as "REMOVED".
According to the invention, the system further comprises: means for enabling an operator to manually make a specific m lrnown and associated with a specific position on the vehicle.
According to the invention, the system further comprises: flags included in the database wherein a specific flag is associated with each specific position in the database, so that a value of each specific flag is used to indicate each specific position which is expected to have a transponder with a known specific m associated with the specific position.
According to the invention, the system further comprises in item 4: nulling the specific ID associated with the specific position, thereby removing it from the list of known ID's.
According to the invention, the system further comprises in item 4: a time period for attempting detection of the specific ID associated with the specific position;
and waiting until after the time period ends before labeling the specific position as "REMOVED" if the specific ID was not detected during the time period.
According to the invention, the system further comprises in item 6: a memory field used to store only a single most recently received unknown specific iD;
recording the length of time for which the memory field maintains the same foreign tag ID; and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "RFNiOVED" to "NOT REMOVED ".
According to the invention, the system further comprises in item 6: using the specific position labeled as "REMOVED" which is first in the database.
According to the invention, the system is further characterized by means for ignoring each specific position which is not expected to have a transponder with a known specific iD associated with the specific position.
More generally, the invention concerns a method for associating transponders with positions for a monitoring system which comprises a transponder receiver having an antenna for receiving signals from the transponders which are mounted in positions which are to be monitored, each transponder having a unique ID which is included as art of a data stream which is periodically transmitted from the transponder to the receiver. The method is characterized by the steps of:
7. maintaining a database including ID's known to the monitoring system, wherein each specific known ID is associated with a specific position, and labeling as "NOT
REMOVED" each position which has an associated known D7;
$. whenever the specific ID associated with the specific position is not detected by the receiver, labeling the specific position as "REMOVED"; and 9. whenever an unknown specific m is detected while any position is labeled as "REMOVED", automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED"
to "NOT REMOVED "
Other objects, features and advantages of the invention will become apparent in light of the following description thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. The figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these preferred embodiments, it should be understood that it is not intended to limit the spirit and scope of the invention to these particular embodiments.
Certain elements in selected ones of the drawings may be illustrated not-to-scale, for illustrative clarity. The cross-sectional views, if any, presented herein may be in the form of "slices", or "near-sighted" cross-sectional views, omitting certain background lines which would otherwise be visible in a true cross-sectional view, for illustrative clarity.
Elements of the figures are typically numbered as follows. The most significant digit (hundreds) of the reference number corresponds to the figure number.
Elements of Figure 1 are typically numbered in the range of 100-199. Elements of Figure 2 are typically numbered in the range of 200-299. Similar elements throughout the drawings may be referred to by similar reference numerals. For example, the element 199 in a figure may be similar, and possibly identical to the element 299 in an other figure. In some cases, similar (including identical) elements may be referred to with similar numbers in a single drawing. For example, each of a plurality of elements 199 may be referred to individually as 199a, 199b, 199c, etc. Such relationships, if any, between similar elements in the same or different figures will become apparent throughout the specification, including, if applicable, in the claims and abstract.
The stricture, operation, and advantages of the present preferred embodiment of the invention will become further apparent upon consideration of the following description taken in conjunction with the accompanying drawings, wherein:
Figure 1 is a block diagram of a typical tire pressure monitoring system (TPMS), according to the prior art;
Figure 2 is a block diagram of a tire pressure monitoring system, according to the invention; and Figures 3A, 3B, and 3C are a flow chart of a transponder ID association method 5 according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 illustrates a typical tire pressure monitoring system (TPMS) 150 of the prior art installed on a vehicle 152 (shown in dashed lines), such as a typical passenger vehicle having four pneumatic tires 104a, 104b, 104c and 104d (104) installed on four 10 respective wheels (not shown).
Each of the four tires 104a..104d (104) is equipped with an electronic module ("tag") 102a..102d (102), respectively, and associated sensor (not shown, well known) capable of monitoring one or more conditions such as air pressure and/or air temperature within the tire, and transmitting a radio frequency (RF) signal indicative of the monitored conditions) within the respective vehicle tire 104. The tags 102 are suitably transponders, but may alternatively simply comprise one or more condition sensors and a radio frequency transmitter. For the purposes of this detailed description, the terms "tag"
and "transponder"
will be used interchangeably and are intended to refer to the electronic devices) (e.g., 102) mounted in or on tires (e.g., 104) for monitoring systems (e.g., 150) such as those described herein.
The system 150 comprises a single reader/interrogator 166 ("receiver") and an associated display unit 162. One or more antennas 160a..160d (160) may be disposed on the vehicle chassis 152 to receive RF transmissions from the tags 102 and, optionally, to interrogate and/or power the tags 102. In this example of a prior art system, four antennas 160 are illustrated, each antenna being disposed at a fixed position on the vehicle adjacent a respective one of the tires 104, within the near field of the respective tag 102. As is known, the use of near field transmission has many distinct advantages over transmitting an inherently greater distance from each tire 104 to a centrally located antenna on the vehicle 152. In particular as it relates to the present invention, this system 150 having dedicated antennas 160 facilitates simple and positive association between tire position and tag signals.
There is no need to program the tags 102 or the receiver 166 to establish this association, and the association remains correct even if the tires 104 and/or the tags 102 are rotated or replaced.
The use of an antenna 160 adjacent each wheel is entirely optional and is well known, for example, as disclosed in USP 3,553,060; USP 3,810,090; USP
4,220,907; USP
5,541,574; and USP 5,774,047, all of which are incorporated in their entirety by reference herein.
In this manner, monitored condition information carned by the RF signals from the respective tags 102 can be decoded (e.g., demodulated) for subsequent display (162) to the operator of the vehicle 152. The "display" 162 may include suitable discernible visual and/or audible warnings at the option of the vehicle manufacturer.
The aforementioned TPMS 150 is presented merely as an example of an overall system installed on a vehicle, and should not be construed as limiting the present invention to a particular implementation, such as having an antenna at each of the wheel wells.
Alternatively, as illustrated in Figure 2, for example, the TPMS 250 may employ a single antenna 260 disposed in a suitable location to receive the transmissions of all of the tags 202.
Figure 2 illustrates a monitoring system 250 which was improved to test as a preferred embodiment of the present invention. Before improvement by the inventive method and system software, the monitoring system 250 is representative of prior art systems typically installed on OTR vehicles 252, typically having more than four tires 204, with corresponding tags 202. Each tire 204 and tag 202 is identified by a tire position label such as "left front tire" , as determined by a tire position 205 where the tire 204 is mounted.
For example, the tire positions 205 and corresponding tires 204 are: a left front (L.F.) tire 205a (tire 204a), a right front (R.F.) tire 205b (tire 204b), a left rear outer (L.R.O.) tire 205c (tire 204c), a left rear inner (L,.R.L) tire 205e (tire 204e), a right rear outer (R.R.O.) tire 205d (tire 204d), and a right rear inner (R.R.L) tire 205f (tire 204f).
Thus tires 204 are identified by their tire position 205 on the vehicle 252.
There is a single receiver 266 and an associated optional display unit 262. At least one antenna 260 is centrally disposed on the vehicle chassis 252 to receive RF
transmissions from the tags 202 and, optionally, to interrogate and/or power the tags 202.
There may be a secondary, backup antenna (not shown) but there is no attempt to dedicate separate antennas to each tire position 205. Instead, each tag 202 transmits a data stream which includes a unique identifying code (ID) stored in each tag 202 as detailed in the background hereinabove. The receiver 266 will receive, via the antennas) 260, signals from all of the tags 202. Various techniques are applied to separate the signals, for example by having each tag 202 transmit at periodic and/or pseudo-random intervals and/or at frequencies which vary within a specified range. Once the receiver 266 has distinguished separate received signals, each containing a data stream from one of the tags 202, the receiver must be able to associate the data stream with a tire position 205. Therefore the receiver 266 must "know" the D7 for each tire position 205 on the vehicle, and thereby is able to correctly associate the tire condition data contained within each received data stream with the appropriate tire position 205 and thus the appropriate tire 204. The association is typically performed by maintaining a database table of 1D's known to be relevant to the tire monitoring system 250 for the vehicle 252, wherein each known m is associated with a specific tire position 205 on the vehicle. The receiver 266 generally comprises some form of radio receiver (possibly with its own microcontroller) and a microprocessor having software for overall system control, plus a memory area which is capable of storing data such as a database 267 table of m/tire positions. A remote device 270, such as a portable computer or even a centralized control system mainframe computer, can be connected 271 to the receiver 266 when needed by way of a serial line, Ethernet line, radio link, etc. The remote device can be used to initially enter, or later modify, the database table 267. There may also be provided means to check and modify the database 267 by way of the optional display 262, if present. The table that is entered into the database 267 must, at a minimum, store proper tag 202 m's in memory locations which are associated with the tire position 205 corresponding to that tag 202. For example, the unique ID for the tag 202b must be stored in a way which associates it with the R.F. tire position 205b.
Furthermore, if the tire 204b and/or the tag 202b is replaced by a replacement tire 204b' (not shown) having a replacement tag 202b' (not shown) with a different m, then the database 267 must be modified to associate the ID of the tag 202b' with the R.F. tire position 205b.
The present invention seeks to improve the prior art monitoring systems such as system 250, in order to simplify its use by providing an automated tag association method, and a system which implements that inventive method. The inventive method performs all the functions described hereinabove for the monitoring system 250, including rejecting data stream signals from "foreign" tags (i.e., tags not installed in a valid tire position 205 on the vehicle 252), and additionally automatically modifies the database 267 whenever a tire 204 is removed or replaced, thereby generally eliminating the need under those circumstances for human action by way of manual database modification via, for example, the remote device 270 or display 262.
The inventive method 300 is illustrated by a flow chart in Figure 3. For a preferred embodiment the method 300 has been programmed in the C programming language and implemented in a "Data Logger RPC-220" computer which forms part of the receiver 266 of an OTR tire monitoring system 250. It will be seen that the inventive method 300 can be programmed in any suitable machine control language and implemented in any suitable programmable controller, PC, microcontroller, etc. The following description is simplified to its essential non-obvious elements, therefore details which are part of normal software engineering practice are omitted, such as handling of timing roll-over for timers which are "left running", for example.
The pre-existing receiver software had a database 267 "TIRE DB" structured to hold all relevant data in a set of fields comprising one record for each of 26 possible tire positions 205 (limited by a parameter which sets the actual number of tire positions 205 in the actual system 250 on a vehicle 252). Fields important to this discussion include tag ID
code "TAG ID" and tag tire position 205 "POS". Other fields include stored real-time data such as the most recent temperature and pressure readings, alarm flags, and ASCII strings for displaying the temperature and pressure readings. Only data coming from a tag 205 having an D7 matching the TAG ID field would be entered into the data fields of the TIRE DB record containing the TAG ID code, and this data would then be displayed (and/or data-logged, and/or alarmed) for the tire position 205 contained in the POS field of the same TIRE DB record. If a data stream was received which had a tag ID not included in any of the TAG ID fields of the TIRE DB records, the data stream was ignored ("rejected"), and the tag which transmitted that data stream was assumed to be foreign. If a tag 202 was replaced on the vehicle, it would be considered foreign and ignored until the replacement tag's ID was manually entered into the appropriate TAG m field of the TIRE DB database 267.
To implement the inventive method 300 certain flag values have been added to a "FLAGS" field in each TIRE DB record. A "TIRE POS USED" flag bit is set if the tire position 205 recorded in the POS field is intended to have a tire 204 mounted in the position 205 and monitored by a tag 202. A "TIRE REMOVED" flag bit is cleared ("false") if the tire position 205 recorded in the POS field is determined to be occupied by a tire 204 having a tag 202 with an ID which matches the TAG ID field in the same record.
Another added field is a "RECEIVE TI1V1ER" field which holds an indicator of time passed since the last new data was received from the tag 202 with an ID which matches the TAG ID
field in the same record.
Several other flags and variables have been added for storage in memory but not part of the TIRE DB database 267. An "ANY TIRE REMOVED" flag bit is used to indicate whether or not arty of the TIRE REMOVED flags are set (but only checking in TIRE DB records having a true TIRE POS USED flag). There are also fields for tracking foreign tags which are detected by the receiver 266. Any received data stream containing a tag ID which does not match any of the TAG ID fields in the TIRE DB records flagged as TIRE POS USED, is considered to be a data stream transmitted by a foreign tag, i.e., not installed in a valid (in-use) tire position 205 on the vehicle 252. An "MRR FOREIGN TAG ID" field is used to store the most recently received foreign tag ID. An "MRR TINIER" field holds an indicator of time passed since the MRR FOREIGN TAG ID field was last changed.
It should be noted that the inventive method 300 still requires that the TIRE
DB
database 267 must be initialized with the proper values for all of the fields, including each tag 204 ID which must be entered into the TAG ID field correctly associated with its tire position 205 as recorded in the POS field of the same record. As stated above, the initialization is generally performed manually by means of the remote device 270.
A summary overview of the method 300 is as follows:
a) The database 267 (TIRE DB) includes a table of ID's for tags 202 which are known (non-foreign) to the tire monitoring system 250 for the vehicle 252. In the database 267, each known ID (TAG 1D) is associated with a specific tire position 205 (POS) which is being used (POS IN USE) on the vehicle 252. Each tire position 205 which has an associated 1D is labeled (flagged) as "NOT REMOVED".
b) The data streams detected (received) by the receiver 266 are continually monitored. If a data stream from a known tag is not seen for a TINIEOUT amount of time, then the tire position 205 is labeled as "REMOVED", and the tag ID associated with that tire position 205 is nulled, thereby removing it from the list of known tags 202.
c) Whenever an unknown ID is detected while any tire position 205 is labeled as "REMOVED", it is recorded in a single field (MRR FOREIGN TAG 1D) which holds only the most recently received foreign tag ID. That field is monitored to time (MRR_TIIVIER) the length of time for which the field maintains the same foreign tag ID, and if the time exceeds a TIMEOUT value (which may be the same or different 5 from the TTI1VVIEOUT value for known tags) then the foreign tag ID is automatically made known by associating it with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED
". If more than one used tire position 205 is labeled "REMOVED", then the first such tire position 205 in the database 267 is used as the specific tire position.
10 The inventive method 300 will now be described with reference to the flow chart illustrated in Figures 3A, 3B and 3C. In Figure 3B it can be seen that the method 300 is run continuously (step 330), that it utilizes information from other concurrent processes such as the receiver and its signal processing which provides a tag ID and transponder measurement data which has been parsed from a new (most recently received) data stream 15 (step 390), and that the method 300 also calls on subroutines such as the TIRE TIMEOUT CHECK subroutine (step 310) which is continued in Figure 3A. The step 350 entitled "A" also indicates a branch of the flow chart which continues from Figure 3B to Figure 3C. Several branches of the method 300 flow chart lead to a step 331 entitled "continue" which is intended to signify essentially a looping back to the equivalent step 330 entitled "run continuously".
The TIRE TIIvIEOUT CHECK subroutine (step 310) as illustrated in Figure 3A
performs the (b) process of the method 300 summarized hereinabove, watching for removed tags 202 (and therefore tires 204) and updating the database 267 accordingly.
The subroutine 310 proceeds to step 312 which indicates that the subroutine 310 is nm periodically. The next step 314 indicates that for each periodic running of the subroutine 310, each of the tire position records (records in the TIRE DB database 267) is processed in turn by the steps 316 to 328 (as appropriate) and then looping back to step 314 for the next record. Although not shown by an arrow, the "for each... record" step 314 is generally assumed to be run once for each record after which program control exits the loop (i.e., halts) until the step 314 is re-started after a period of time by the "iun periodically"
step 312. Thus, for an individual "current" tire position record, the next step 316 checks if the tire position is used, i.e., is the TIRE 1?OS USED flag for the current record set (true)?
If not, the record is effectively out of consideration, and program flow loops back to step 314 to point to the next record. If yes, then step 318 checks if the tire is removed, i. e. , is the TIRE REMOVED flag for the current record set? If yes, then step 326 sets the ANY_TIRE REMOVED flag, and then program flow loops back to step 314. If no, then step 322 checks the value in the RECEIVE TI1V1ER field for the current record.
If the RECEIVE TI1VIER value is greater than the TI1VVIEOUT parameter value, then it has been too long since a data stream has been received from the tag having the TAG ID
for the current record. (Note that the RECEIVE TINIER value is reset to zero and restarted (step 336) whenever a data stream is received from the tag having the TAG ID for the current record.) The method 300 software assumes that the associated tag 202 (and tire 204) has been removed, and updates the appropriate fields. The overall ANY TIRE REMOVED
flag is set, and the fields of the current record are changed as follows: the TAG ID field is set to null (zero) to indicate no known tag. The tire data fields are pulled out, the TIRE REMOVED flag is set, and the RECEIVE TINIER is effectively stopped. From step 328 program flow loops back to step 314. If step 322 has determined that the RECEIVE TTI1VVIER value is not greater than the TiMEOUT parameter value, then the current record has been updated recently enough, and step 324 increments the RECEIVE TINIER before looping program flow back to step 314 for processing of the next record.
Processes (a) and (c) of the summarized method 300 are executed concurrently with the TIRE TIMEOUT CHECK subroutine 310, and are illustrated by the flow chart in Figures 3B and 3C. Starting in Figure 3B, the continuous running of step 330 flows through step 390 which presents a tire ID and other associated monitoring data which have been parsed from a new received data stream (most recently received, therefore "current").
It should be understood that the process of step 390 includes means for rejecting data streams which duplicate within a window of time, and that only new received data streams are presented in the step 390, so that program flow will not proceed through step 390 to the next step 332 until and unless such "new" ID-plus-data are presented. In the next step 332, the records of the TIRE DB database 267 are searched to attempt to match a known 3 0 TIRE ID field value with the value of the current ID, i. e. , is the current ID in the database 267? If yes, then the current data stream has been received from a known tag 202 and a matched record has been found which contains the TIRE ID field which matches the current ID, therefore step 334 updates the data fields in the matched record with the current data. Since the matched record's tag has just been heard from, and therefore confirmed as known, the next step 336 restarts the receive timer by zeroing the value of the RECEIVE TIMER for the matched record. Program flow then continues (step 331).
If, in step 332, it is determined that the current ID is not in the database 267, then the data stream is from a presently-unknown tag, and a set of steps beginning with step 338 is performed to deal appropriately with this fact. In step 338, the ANY TIRE
REMOVED
flag is checked. If the ANY TIRE REMOVED flag is not true, then the unknown tag must be truly foreign because all of the "used" tire positions 205 have tires 204 with known tags 202 in those positions 205. Therefore, the foreign tag is not relevant to the monitoring system 250 and can be ignored (step 346) while the program flow loops back to continue at step 330. If, on the other hand, the ANY_TIRE REMOVED flag is true, then the unknown tag may either be foreign, or it may have been installed in whichever tire position 205 has had its tire 204 and/or tag 202 removed. The next step 348, checks to see if the current ID has been received before, by comparing it with the most recently received foreign tag ID (MRR FOREIGN TAG ID). If they do not match, then the current tag and ID are new, and step 342 replaces the value in the MRR FOREIGN TAG m field with the current tag ID to make it the new most recently received foreign tag ID. Then, in step 344 the MRR TIMER is restarted at zero before the program flow continues (step 331). As can be seen in subsequent steps described hereinbelow, the MRR TI1VIFR tracks the amount of time elapsed from the first detection of a repeatedly received unlrnown (and therefore potentially foreign) tag ° s data stream .
If in step 348 the current ID does match the value in the MRR FOREIGN TAG ID
field, then that means that this is at least the second consecutive receipt of a data stream from the same unknown tag. In this case, program flow proceeds via continuation step "A"
(350) to step 352 in Figure 3C. Step 352 checks to see if the consecutive repeating of the current ID has proceeded long enough (as defined by the value of the TI1VIEOUT
parameter) to justify an assumption that the tag with the current ID (which matches the MRR FOREIGN TAG ID) has been installed on the vehicle 252. Note that this is a possibility because at least one tire is removed as determined by the preceding step 338. If the foreign tag timer has a value in the MRR TI1VIER field which does not exceed the TllVIEOUT value, then the current ID has not been repeating long enough to justify the assumption of installation, and the MRR TIMER value is incremented in step 362 before the program flow continues (step 331). On the other hand, if the answer to decision step 352 is "yes", then program flow proceeds to step 354 where the possibility of the current tag being installed is given an extra check, by searching the TIRE DB database 267 for the first occurrence (in case there are more than one) of a tire position record which has both of its TIRE POS USED and TIRE REMOVED flags set (true). If no such record is found, then no further action is taken (step 364) before continuing (step 331).
However, if such a record is found, then step 356 modifies several fields of the found record:
The TAG ID
field is changed to the value of the current ID (which matches the MRR FOREIGN TAG ID), thereby making the current m known to the monitoring system 250; the RECEIVE TIMER value is set to zero to start timing the interval until the next receipt of a data stream from the TAG 1D tag 202; and the TIRE REMOVED
flag is cleared (to false). In addition, step 356 changes the ANY-TIRE REMOVED flag to false (cleared). Note that if there happens to be a second tire position 205 which is used but has its tire 204 and/or tag 202 removed, the concurrently rumiing TIRE TllVIEOUT
CHECK
subroutine 310 will soon detect this fact and will set the ANY TIRE REMOVED
flag back to its correct value of true (steps 316, 318, and 326). Finally, step 358 resets the MRR
fields to prepare them for tracking other unlmown tags: the MRR FOREIGN TAG ID
is cleared to a null value; and the MRR TI1V1ER value is reset to zero and effectively stopped (until program flow returns to step 362 to increment it again). After step 358, program flow continues in step 331, effectively looping back to the run continuously step 330.
Thus is disclosed a preferred embodiment of a method 300 for automatically associating tags (transponders) 202 with appropriate tire positions 205 on a vehicle 252 which has a tire monitoring system 250 for implementing the inventive method 300. The inventive system 250 and method 300 have the advantage of automating the tag/position association process in the case where tags are removed and/or replaced one at a time as typically happens frequently during the life of a vehicular tire monitoring system 250. In the prior art systems, the tag/position association generally had to be manually performed whenever a tire or tag change occurred on the vehicle 252.
Although the preferred embodiment of the invention is described in conjunction with monitoring systems 250 which are mounted on vehicles 252 for the purpose of monitoring conditions in pneumatic tires 204 which are mounted on the vehicle 252, it should be noted that the scope of the inventive method 300 is broad enough to encompass other systems which monitor a plurality of transponder/tags wherein the location of each tag must be associated with a self reported m for each tag.
Although the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character - it being understood that only preferred embodiments have been shown and described, and that all changes and modifications that come within the spirit of the invention are desired to be protected. Undoubtedly, many other "variations" on the "themes" set forth hereinabove will occur to one having ordinary skill in the art to which the present invention most nearly pertains, and such variations are intended to be within the scope of the invention, as disclosed herein.
TECHNICAL FIELD OF THE INVErTTION
The present invention relates to receivers for radio frequency transponders, and, more particularly, to methods of controlling RF transponder receivers, and/or for receivers in vehicular tire monitoring systems.
BACKGROUND OF THE INVENTION
Safe, efFcient and economical operation of a motor vehicle depends, to a significant degree, on maintaining correct air pressure in all (each) of the tires of the motor vehicle.
Operating the vehicle with low tire pressure may result in excessive tire wear, steering difficulties, poor mad-handling, and poor gasoline mileage, all of which are exacerbated when the tire pressure goes to zero in the case of a "flat" tire.
The need to monitor tire pressure when the tire is in use is highlighted in the context of "run-flat" (driven deflated) tires, tires which are capable of being used in a completely deflated condition. Such run-flat tires, as disclosed for example in commonly-owned USP
5,368,082, incorporated in its entirety by reference herein, may incorporate reinforced sidewalls, mechanisms for securing the tire bead to the rim, and a non-pneumatic tire (donut) within the pneumatic tire to enable a driver to maintain control over the vehicle after a catastrophic pressure loss, and are evolving to the point where it is becoming less and less noticeable to the driver that the tire has become deflated. The broad purpose behind using run-flat tires is to enable a driver of a vehicle to continue driving on a deflated pneumatic tire for a limited distance (e. g. , 50 miles, or 80 kilometers) prior to getting the tire repaired, rather than stopping on the side of the road to repair the deflated tire.
Hence, it is generally desirable to provide a low tire pressure warning system within in the vehicle to alert (e.g., via a light or a buzzer) the driver to the loss of air pressure in a pneumatic tire.
To this end, a number of electronic devices and systems are known for monitoring the pressure of pneumatic tires, and providing the operator of the vehicle with either an indication of the current tire pressure or alerting the operator when the pressure has dropped below a predetermined threshold level. It is known that the air pressure within any closed space such as a pneumatic tire (with a relatively fixed volume) varies with the temperature of the air according to the "ideal gas law" . Therefore, many tire pressure monitoring systems incorporate means of measuring the temperature within the tire and then utilize that temperature measurement to adjust the pressure measurement appropriately. The adjustment, or temperature compensation, of the pressure measurement may be done by the transponder before reporting (transmitting) the temperature-compensated pressure reading to a monitoring system receiver, or else both the temperature and pressure readings are reported to the receiver. In the latter case, the monitoring system receiver may perform the temperature-compensation, or it may simply record and/or report the temperature reading along with the pressure readings.
It is also known to monitor tire pressure with an electronic device which is not merely a passive resonant circuit, but rather is capable of transmitting a radio frequency (RFC signal indicative of the tire pressure to a remotely-located receiver.
Such a "transmitting device" may have its own power supply and may be activated only when the pressure drops below a predetermined threshold. Alternatively, the transmitting device may be activated ("turned ON") by an RF signal from the remotely-located receiver, in which case the receiver is considered to be an "interrogator" . Additionally, the transmitting device may be powered by an RF signal from the interrogator. Additionally, the electronic device which monitors the tire pressure may have the capability of receiving information from the interrogator, in which case the electronic device is referred to as a "transponder".
As used herein, a "transponder" is an electronic device capable of receiving and transmitting radio frequency signals, and impressing variable information (data) in a suitable format upon the transmitted signal indicative of a measured condition (e. g. , tire pressure) or conditions (e.g., tire pressure, temperature, revolutions), as well as optionally impressing fixed information (e. g. , tire ID) on the transmitted signal, as well as optionally responding to information which may be present on the received signal. The typical condition of paramount interest for pneumatic tires is tire pressure. "Passive"
transponders are transponders powered by the energy of a signal received from the interrogator.
"Active"
transponders are transponders having their own power supply (e.g., a battery), and include active transponders which remain in a "sleep" mode, using nninimal power, until "woken 3 0 up" by a signal from an interrogator, or by an internal periodic timer, or by an attached device. As used herein, the term "tag" refers either to a transponder having transmitting and receiving capability, or to a device that has only transmitting capability. Generally, tags which are transponders are preferred in the system of the present invention. As used herein, the term "tire-pressure monitoring system" (TPMS) or even more simply a vehicular "tire monitoring system" indicates an overall system comprising tags within the tires and a receiver which may be an interrogator disposed within the vehicle.
It is known to mount a tag, and associated condition sensor (e.g., pressure sensor) within each tire of a vehicle, and to collect information from each of these transponders with a common single interrogator (or receiver), and to alert a driver of the vehicle to a low tire pressure condition requiring correction (e. g. , replacing the tire). For example, U. S .
Patent No. 5,540,092 (Handheld, et al.; 1996), incorporated in its entirety by reference herein, discloses a system and method for monitoring a pneumatic tire. Figure 1 therein illustrates a pneumatic tire monitoring system (20) comprising a transponder (22) and a receiving unit (24). Each transponder has an identification code and is programmed to identify which wheel of the vehicle it is installed upon. A service tool (420, Figure 14) is disclosed which may be used to reprogram a transponder located within a vehicle tire after the location of the tire has been changed.
Other examples of transponder systems including RF transponders suitable for installation in a pneumatic tire are disclosed in U.S. Patent No. 5,451,959 (Schuermann;
09/95), U.S. Patent No. 5,661,651 (Geschke, et al.; 08/9'x, and U.S. Patent No. 5,581,023 (Handheld, et al.; 12/96), all incorporated in their entirety by reference herein. The described transponder systems include interrogation units, pressure sensors and/or temperature sensors associated with the transponder, and various techniques for establishing the identity of the tire/transponder in multiple transponder systems. For example, Schuermann discloses tags he calls responder units (12) which are to be individually addressed and interrogated using the interrogation unit (10). Fach responder unit has a memory (168) with data fixedly stored therein and said data are uniquely assigned to the responder unit. For Schuermann's system to be used in a vehicular monitoring system presumably either the interrogation unit would need to be programmed to associate unique data from each responder unit with the appropriate tire position, or the responder units would have to have their unique data appropriately programmed as described in Handfield (see USP 5,540,092 above). In another example, Geschke discloses tags he calls transmitters with parameter sensors (20) which transmit to a centrally located receiver (40).
Each transmitter transmits an lZF signal having a carrier frequency falling within at least one predefined frequency range centered at or about a nominal frequency (f~. The transmitted RF signals [and thus the identification of the corresponding transmitter] may be distinguished by the frequency of the respective transmitted RF signals.
In order to transport bulk materials, such as coal, iron ore and other minerals, the mining industry uses Off The-Road (OTR) vehicles that typically weigh up to 250 tons when fully loaded, with the result that exceedingly high internal stresses are imposed on the tires of such vehicles in the course of their daily use. Such internal stresses, which are primarily attributable to a number of factors including driving at excessive speeds, are so destructive of such tires that it is not uncommon to have to replace the tires. On the other hand, in order to maximize the productivity of OTR vehicles, they are normally driven as fast as possible until a user perceives that the internal physical condition of any given tire is marginal. Whereupon, the operator either stops, in the case of a loss of tire pressure, or reduces the speed of the vehicle, in the case of an excessive temperature condition, to relieve the internal stresses giving rise to the marginal condition, thereby prolonging the life of the tires. Thus the speed of an OTR vehicle is controlled on the basis of the operator's perception of the condition of the tires at any given time. And, if the operator's perception is erroneous, the productivity of the vehicle is unnecessarily reduced.
Accordingly, a long-standing need of the mining industry has been to ensure that the operators of OTR vehicles are provided with accurate information concerning various conditions of the tires of such vehicles, with a view to maximizing the productivity of the vehicles.
Various attempts have been made in the prior art to meet the aforesaid need, most recently by mounting integrated circuits within each of the tires of an OTR
vehicle, for detecting respective conditions related to an imminent failure of each tire and providing the OTR vehicle operators with timely information concerning such conditions.
For example, U.S. Patent No. 5,562,787, issued to Koch et al., incorporated in its entirety by reference herein, discloses a method and apparatus for monitoring respective conditions in the tires of vehicles. The apparatus comprises a monitoring device that is connectable to the interior of a tire and includes an integrated circuit having a transmitter. In addition, the monitoring device includes a plurality of sensors connected to the integrated circuit. The sensors continuously detect respective conditions of the tire and provide corresponding signals to the integrated circuit. The integrated circuit is programmed to periodically sample the tire condition signals, to compare the respective samples to respective standards, to generate respective tire condition signals based on the comparisons, and to provide an information signal to the aperator of the vehicle when any tire condition signal is indicative of a marginal condition of the tire. In addition, the integrated circuit is programmed to be normally dormant but to transmit information signals concerning the then 5 current tire condition signal to the operator in response to receiving a wake-up signal from the operator. Moreover, the integrated circuit may also be programmed to store data corresponding to periodic tire condition signals for historical, record keeping, purposes, and to cause the transmitter to transmit such historical data in response to receiving another wake-up signal.
Off the road vehicles often have more than 4 tires in use on a vehicle. For example, there may be one front tire on each of the left and right sides for steering, but two or even three tires on each side of the rear, load-bearing, porkion of the OTR
vehicle. A typical tire monitoring system for such a vehicle will have a receiver with one or more, preferably one centrally-located, antennas for receiving (optionally after interrogating) signals from the tags in each of the tires on the vehicle. In order to report (and/or alarm) tire conditions which are properly identified with each of the tires on the vehicle, the monitoring system receiver must be able to determine which tire that each of the tag RF signals is coming from. For monitoring systems where there isn't a separate antenna for each tire position, this problem has been solved by storing in each tag a unique identifying code (ID) and then having the tag include its 1D within a data stream transmitted by the tag, usually along with the tire condition data. The ID may be a simple serial number, or may include other identifying information about the tire and/or the tag. The receiver must "know" the ID for each tire position on the vehicle, and thereby is able to correctly associate the tire condition data of each received data stream with the appropriate tire position and thus the appropriate tire.
The present invention addresses additional problems with tire monitoring systems using tags with ID's which are associated with tire positions, such as described above for OTR vehicles. These additional problems have to do with data handling for "foreign" tags, i.e., tags which are not "known" by the monitoring system, but may be detected (by the receiver) when a tire and/or a tire tag is replaced, or when a tagged tire not installed on the 3 0 vehicle happens to be close enough to the vehicle to be detected (e. g. , on another nearby vehicle). In the first case, the foreign tag is a new tag which needs to be entered into the monitoring system database in place of the replaced tag and properly associated with its tire position. In the latter case, the foreign tag is truly foreign and must be ignored by the tire monitoring system.
BRIEF SUNFVIARY OF THE INVENTION
The present invention concerns a method for associating transponders (202) with tire positions (205) for a vehicular tire monitoring system (250) which comprises a transponder receiver (266) mounted on a vehicle (252), the receiver having an antenna (260) for receiving signals from the transponders which are mounted in each of the vehicle's multiple tires (204) which are to be monitored, and each transponder having a unique ID
(TAG ID) which is included as part of a data stream which is periodically transmitted from the transponder to the receiver. The method is characterized by the steps of:
1. Maintaining a database (267, TIRE DB) including ID's known to the tire monitoring system for the vehicle, wherein each specific known ID (TAG ID) is associated with a specific tire position (205, POS) on the vehicle, and labeling as "NOT
REMOVED" each tire position which has an associated known ID.
2. Whenever the specific ID associated with the specific tire position is not detected by the receiver, labeling the specific tire position as "REMOVED" .
3. Whenever an unknown specific ID (MRR FOREIGN TAG ID) is detected while any tire position is labeled as "REMOVED", automatically associating the unlaiown specific B7 with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED ".
According to the invention, the method further comprises enabling an operator to manually make a specific ID known and associated with a specific tire position on the vehicle.
According to the invention, the method further comprises including flags in the database wherein a specific flag is associated with each specific tire position in the database, and using a value of each specific flag to indicate each specific tire position which is expected to have a transponder with a known specific ID associated with the specific tire position.
According to the invention, the method further comprises in step 2: nulling the \specific B7 associated with the specific tire position, thereby removing it from the list of known ID's.
According to the invention, the method further comprises in step 2: utilizing a time period for attempting detection of the specific ID associated with the specific tire position;
and waiting until after the time period ends before labeling the specific tire position as "REMOVED" if the specific ID was not detected during the time period.
According to the invention, the method further comprises in step 3: utilizing a memory field to store o33nly a single most recently received unknown specific ID;
recording the length of time for which the memory field maintains the same foreign tag 117;
and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific tire position labeled as "REMOVED", and changing the specific tire position label from °'REMOVED" to "NOT
REMOVED ".
According to the invention, the method further comprises in step 3: using the specific tire position labeled as "REMOVED" which is first in the database.
According to the invention, the method is further characterized by: ignoring each specific tire position which is not expected to have a transponder with a known specific ID
associated with the specific tire position.
The present invention also concerns a transponder monitoring system which comprises a transponder receiver having an antenna for receiving signals from a plurality of transponders which are mounted in a plurality of positions which are to be monitored, each transponder having a unique ID which is included as part of a data stream which is periodically transmitted from the transponder to the receiver. The monitoring system is characterized by:
4. a database (267, TIRE DB) including ID's known to the monitoring system, wherein each specific known ID (TAG 117) is associated with a specific position (205, POS), and each position which has an associated known ID is labeled as "NOT REMOVED";
5. means for labeling the specific position as "REMOVED" whenever the specific ID
associated with the specific position is not detected by the receiver; and 6. means for automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED"
to "NOT REMOVED ", whenever an unknown specific ID (MRR FOREIGN TAG ID) is detected while any position is labeled as "REMOVED".
According to the invention, the system further comprises: means for enabling an operator to manually make a specific m lrnown and associated with a specific position on the vehicle.
According to the invention, the system further comprises: flags included in the database wherein a specific flag is associated with each specific position in the database, so that a value of each specific flag is used to indicate each specific position which is expected to have a transponder with a known specific m associated with the specific position.
According to the invention, the system further comprises in item 4: nulling the specific ID associated with the specific position, thereby removing it from the list of known ID's.
According to the invention, the system further comprises in item 4: a time period for attempting detection of the specific ID associated with the specific position;
and waiting until after the time period ends before labeling the specific position as "REMOVED" if the specific ID was not detected during the time period.
According to the invention, the system further comprises in item 6: a memory field used to store only a single most recently received unknown specific iD;
recording the length of time for which the memory field maintains the same foreign tag ID; and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "RFNiOVED" to "NOT REMOVED ".
According to the invention, the system further comprises in item 6: using the specific position labeled as "REMOVED" which is first in the database.
According to the invention, the system is further characterized by means for ignoring each specific position which is not expected to have a transponder with a known specific iD associated with the specific position.
More generally, the invention concerns a method for associating transponders with positions for a monitoring system which comprises a transponder receiver having an antenna for receiving signals from the transponders which are mounted in positions which are to be monitored, each transponder having a unique ID which is included as art of a data stream which is periodically transmitted from the transponder to the receiver. The method is characterized by the steps of:
7. maintaining a database including ID's known to the monitoring system, wherein each specific known ID is associated with a specific position, and labeling as "NOT
REMOVED" each position which has an associated known D7;
$. whenever the specific ID associated with the specific position is not detected by the receiver, labeling the specific position as "REMOVED"; and 9. whenever an unknown specific m is detected while any position is labeled as "REMOVED", automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED"
to "NOT REMOVED "
Other objects, features and advantages of the invention will become apparent in light of the following description thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. The figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these preferred embodiments, it should be understood that it is not intended to limit the spirit and scope of the invention to these particular embodiments.
Certain elements in selected ones of the drawings may be illustrated not-to-scale, for illustrative clarity. The cross-sectional views, if any, presented herein may be in the form of "slices", or "near-sighted" cross-sectional views, omitting certain background lines which would otherwise be visible in a true cross-sectional view, for illustrative clarity.
Elements of the figures are typically numbered as follows. The most significant digit (hundreds) of the reference number corresponds to the figure number.
Elements of Figure 1 are typically numbered in the range of 100-199. Elements of Figure 2 are typically numbered in the range of 200-299. Similar elements throughout the drawings may be referred to by similar reference numerals. For example, the element 199 in a figure may be similar, and possibly identical to the element 299 in an other figure. In some cases, similar (including identical) elements may be referred to with similar numbers in a single drawing. For example, each of a plurality of elements 199 may be referred to individually as 199a, 199b, 199c, etc. Such relationships, if any, between similar elements in the same or different figures will become apparent throughout the specification, including, if applicable, in the claims and abstract.
The stricture, operation, and advantages of the present preferred embodiment of the invention will become further apparent upon consideration of the following description taken in conjunction with the accompanying drawings, wherein:
Figure 1 is a block diagram of a typical tire pressure monitoring system (TPMS), according to the prior art;
Figure 2 is a block diagram of a tire pressure monitoring system, according to the invention; and Figures 3A, 3B, and 3C are a flow chart of a transponder ID association method 5 according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 illustrates a typical tire pressure monitoring system (TPMS) 150 of the prior art installed on a vehicle 152 (shown in dashed lines), such as a typical passenger vehicle having four pneumatic tires 104a, 104b, 104c and 104d (104) installed on four 10 respective wheels (not shown).
Each of the four tires 104a..104d (104) is equipped with an electronic module ("tag") 102a..102d (102), respectively, and associated sensor (not shown, well known) capable of monitoring one or more conditions such as air pressure and/or air temperature within the tire, and transmitting a radio frequency (RF) signal indicative of the monitored conditions) within the respective vehicle tire 104. The tags 102 are suitably transponders, but may alternatively simply comprise one or more condition sensors and a radio frequency transmitter. For the purposes of this detailed description, the terms "tag"
and "transponder"
will be used interchangeably and are intended to refer to the electronic devices) (e.g., 102) mounted in or on tires (e.g., 104) for monitoring systems (e.g., 150) such as those described herein.
The system 150 comprises a single reader/interrogator 166 ("receiver") and an associated display unit 162. One or more antennas 160a..160d (160) may be disposed on the vehicle chassis 152 to receive RF transmissions from the tags 102 and, optionally, to interrogate and/or power the tags 102. In this example of a prior art system, four antennas 160 are illustrated, each antenna being disposed at a fixed position on the vehicle adjacent a respective one of the tires 104, within the near field of the respective tag 102. As is known, the use of near field transmission has many distinct advantages over transmitting an inherently greater distance from each tire 104 to a centrally located antenna on the vehicle 152. In particular as it relates to the present invention, this system 150 having dedicated antennas 160 facilitates simple and positive association between tire position and tag signals.
There is no need to program the tags 102 or the receiver 166 to establish this association, and the association remains correct even if the tires 104 and/or the tags 102 are rotated or replaced.
The use of an antenna 160 adjacent each wheel is entirely optional and is well known, for example, as disclosed in USP 3,553,060; USP 3,810,090; USP
4,220,907; USP
5,541,574; and USP 5,774,047, all of which are incorporated in their entirety by reference herein.
In this manner, monitored condition information carned by the RF signals from the respective tags 102 can be decoded (e.g., demodulated) for subsequent display (162) to the operator of the vehicle 152. The "display" 162 may include suitable discernible visual and/or audible warnings at the option of the vehicle manufacturer.
The aforementioned TPMS 150 is presented merely as an example of an overall system installed on a vehicle, and should not be construed as limiting the present invention to a particular implementation, such as having an antenna at each of the wheel wells.
Alternatively, as illustrated in Figure 2, for example, the TPMS 250 may employ a single antenna 260 disposed in a suitable location to receive the transmissions of all of the tags 202.
Figure 2 illustrates a monitoring system 250 which was improved to test as a preferred embodiment of the present invention. Before improvement by the inventive method and system software, the monitoring system 250 is representative of prior art systems typically installed on OTR vehicles 252, typically having more than four tires 204, with corresponding tags 202. Each tire 204 and tag 202 is identified by a tire position label such as "left front tire" , as determined by a tire position 205 where the tire 204 is mounted.
For example, the tire positions 205 and corresponding tires 204 are: a left front (L.F.) tire 205a (tire 204a), a right front (R.F.) tire 205b (tire 204b), a left rear outer (L.R.O.) tire 205c (tire 204c), a left rear inner (L,.R.L) tire 205e (tire 204e), a right rear outer (R.R.O.) tire 205d (tire 204d), and a right rear inner (R.R.L) tire 205f (tire 204f).
Thus tires 204 are identified by their tire position 205 on the vehicle 252.
There is a single receiver 266 and an associated optional display unit 262. At least one antenna 260 is centrally disposed on the vehicle chassis 252 to receive RF
transmissions from the tags 202 and, optionally, to interrogate and/or power the tags 202.
There may be a secondary, backup antenna (not shown) but there is no attempt to dedicate separate antennas to each tire position 205. Instead, each tag 202 transmits a data stream which includes a unique identifying code (ID) stored in each tag 202 as detailed in the background hereinabove. The receiver 266 will receive, via the antennas) 260, signals from all of the tags 202. Various techniques are applied to separate the signals, for example by having each tag 202 transmit at periodic and/or pseudo-random intervals and/or at frequencies which vary within a specified range. Once the receiver 266 has distinguished separate received signals, each containing a data stream from one of the tags 202, the receiver must be able to associate the data stream with a tire position 205. Therefore the receiver 266 must "know" the D7 for each tire position 205 on the vehicle, and thereby is able to correctly associate the tire condition data contained within each received data stream with the appropriate tire position 205 and thus the appropriate tire 204. The association is typically performed by maintaining a database table of 1D's known to be relevant to the tire monitoring system 250 for the vehicle 252, wherein each known m is associated with a specific tire position 205 on the vehicle. The receiver 266 generally comprises some form of radio receiver (possibly with its own microcontroller) and a microprocessor having software for overall system control, plus a memory area which is capable of storing data such as a database 267 table of m/tire positions. A remote device 270, such as a portable computer or even a centralized control system mainframe computer, can be connected 271 to the receiver 266 when needed by way of a serial line, Ethernet line, radio link, etc. The remote device can be used to initially enter, or later modify, the database table 267. There may also be provided means to check and modify the database 267 by way of the optional display 262, if present. The table that is entered into the database 267 must, at a minimum, store proper tag 202 m's in memory locations which are associated with the tire position 205 corresponding to that tag 202. For example, the unique ID for the tag 202b must be stored in a way which associates it with the R.F. tire position 205b.
Furthermore, if the tire 204b and/or the tag 202b is replaced by a replacement tire 204b' (not shown) having a replacement tag 202b' (not shown) with a different m, then the database 267 must be modified to associate the ID of the tag 202b' with the R.F. tire position 205b.
The present invention seeks to improve the prior art monitoring systems such as system 250, in order to simplify its use by providing an automated tag association method, and a system which implements that inventive method. The inventive method performs all the functions described hereinabove for the monitoring system 250, including rejecting data stream signals from "foreign" tags (i.e., tags not installed in a valid tire position 205 on the vehicle 252), and additionally automatically modifies the database 267 whenever a tire 204 is removed or replaced, thereby generally eliminating the need under those circumstances for human action by way of manual database modification via, for example, the remote device 270 or display 262.
The inventive method 300 is illustrated by a flow chart in Figure 3. For a preferred embodiment the method 300 has been programmed in the C programming language and implemented in a "Data Logger RPC-220" computer which forms part of the receiver 266 of an OTR tire monitoring system 250. It will be seen that the inventive method 300 can be programmed in any suitable machine control language and implemented in any suitable programmable controller, PC, microcontroller, etc. The following description is simplified to its essential non-obvious elements, therefore details which are part of normal software engineering practice are omitted, such as handling of timing roll-over for timers which are "left running", for example.
The pre-existing receiver software had a database 267 "TIRE DB" structured to hold all relevant data in a set of fields comprising one record for each of 26 possible tire positions 205 (limited by a parameter which sets the actual number of tire positions 205 in the actual system 250 on a vehicle 252). Fields important to this discussion include tag ID
code "TAG ID" and tag tire position 205 "POS". Other fields include stored real-time data such as the most recent temperature and pressure readings, alarm flags, and ASCII strings for displaying the temperature and pressure readings. Only data coming from a tag 205 having an D7 matching the TAG ID field would be entered into the data fields of the TIRE DB record containing the TAG ID code, and this data would then be displayed (and/or data-logged, and/or alarmed) for the tire position 205 contained in the POS field of the same TIRE DB record. If a data stream was received which had a tag ID not included in any of the TAG ID fields of the TIRE DB records, the data stream was ignored ("rejected"), and the tag which transmitted that data stream was assumed to be foreign. If a tag 202 was replaced on the vehicle, it would be considered foreign and ignored until the replacement tag's ID was manually entered into the appropriate TAG m field of the TIRE DB database 267.
To implement the inventive method 300 certain flag values have been added to a "FLAGS" field in each TIRE DB record. A "TIRE POS USED" flag bit is set if the tire position 205 recorded in the POS field is intended to have a tire 204 mounted in the position 205 and monitored by a tag 202. A "TIRE REMOVED" flag bit is cleared ("false") if the tire position 205 recorded in the POS field is determined to be occupied by a tire 204 having a tag 202 with an ID which matches the TAG ID field in the same record.
Another added field is a "RECEIVE TI1V1ER" field which holds an indicator of time passed since the last new data was received from the tag 202 with an ID which matches the TAG ID
field in the same record.
Several other flags and variables have been added for storage in memory but not part of the TIRE DB database 267. An "ANY TIRE REMOVED" flag bit is used to indicate whether or not arty of the TIRE REMOVED flags are set (but only checking in TIRE DB records having a true TIRE POS USED flag). There are also fields for tracking foreign tags which are detected by the receiver 266. Any received data stream containing a tag ID which does not match any of the TAG ID fields in the TIRE DB records flagged as TIRE POS USED, is considered to be a data stream transmitted by a foreign tag, i.e., not installed in a valid (in-use) tire position 205 on the vehicle 252. An "MRR FOREIGN TAG ID" field is used to store the most recently received foreign tag ID. An "MRR TINIER" field holds an indicator of time passed since the MRR FOREIGN TAG ID field was last changed.
It should be noted that the inventive method 300 still requires that the TIRE
DB
database 267 must be initialized with the proper values for all of the fields, including each tag 204 ID which must be entered into the TAG ID field correctly associated with its tire position 205 as recorded in the POS field of the same record. As stated above, the initialization is generally performed manually by means of the remote device 270.
A summary overview of the method 300 is as follows:
a) The database 267 (TIRE DB) includes a table of ID's for tags 202 which are known (non-foreign) to the tire monitoring system 250 for the vehicle 252. In the database 267, each known ID (TAG 1D) is associated with a specific tire position 205 (POS) which is being used (POS IN USE) on the vehicle 252. Each tire position 205 which has an associated 1D is labeled (flagged) as "NOT REMOVED".
b) The data streams detected (received) by the receiver 266 are continually monitored. If a data stream from a known tag is not seen for a TINIEOUT amount of time, then the tire position 205 is labeled as "REMOVED", and the tag ID associated with that tire position 205 is nulled, thereby removing it from the list of known tags 202.
c) Whenever an unknown ID is detected while any tire position 205 is labeled as "REMOVED", it is recorded in a single field (MRR FOREIGN TAG 1D) which holds only the most recently received foreign tag ID. That field is monitored to time (MRR_TIIVIER) the length of time for which the field maintains the same foreign tag ID, and if the time exceeds a TIMEOUT value (which may be the same or different 5 from the TTI1VVIEOUT value for known tags) then the foreign tag ID is automatically made known by associating it with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED
". If more than one used tire position 205 is labeled "REMOVED", then the first such tire position 205 in the database 267 is used as the specific tire position.
10 The inventive method 300 will now be described with reference to the flow chart illustrated in Figures 3A, 3B and 3C. In Figure 3B it can be seen that the method 300 is run continuously (step 330), that it utilizes information from other concurrent processes such as the receiver and its signal processing which provides a tag ID and transponder measurement data which has been parsed from a new (most recently received) data stream 15 (step 390), and that the method 300 also calls on subroutines such as the TIRE TIMEOUT CHECK subroutine (step 310) which is continued in Figure 3A. The step 350 entitled "A" also indicates a branch of the flow chart which continues from Figure 3B to Figure 3C. Several branches of the method 300 flow chart lead to a step 331 entitled "continue" which is intended to signify essentially a looping back to the equivalent step 330 entitled "run continuously".
The TIRE TIIvIEOUT CHECK subroutine (step 310) as illustrated in Figure 3A
performs the (b) process of the method 300 summarized hereinabove, watching for removed tags 202 (and therefore tires 204) and updating the database 267 accordingly.
The subroutine 310 proceeds to step 312 which indicates that the subroutine 310 is nm periodically. The next step 314 indicates that for each periodic running of the subroutine 310, each of the tire position records (records in the TIRE DB database 267) is processed in turn by the steps 316 to 328 (as appropriate) and then looping back to step 314 for the next record. Although not shown by an arrow, the "for each... record" step 314 is generally assumed to be run once for each record after which program control exits the loop (i.e., halts) until the step 314 is re-started after a period of time by the "iun periodically"
step 312. Thus, for an individual "current" tire position record, the next step 316 checks if the tire position is used, i.e., is the TIRE 1?OS USED flag for the current record set (true)?
If not, the record is effectively out of consideration, and program flow loops back to step 314 to point to the next record. If yes, then step 318 checks if the tire is removed, i. e. , is the TIRE REMOVED flag for the current record set? If yes, then step 326 sets the ANY_TIRE REMOVED flag, and then program flow loops back to step 314. If no, then step 322 checks the value in the RECEIVE TI1V1ER field for the current record.
If the RECEIVE TI1VIER value is greater than the TI1VVIEOUT parameter value, then it has been too long since a data stream has been received from the tag having the TAG ID
for the current record. (Note that the RECEIVE TINIER value is reset to zero and restarted (step 336) whenever a data stream is received from the tag having the TAG ID for the current record.) The method 300 software assumes that the associated tag 202 (and tire 204) has been removed, and updates the appropriate fields. The overall ANY TIRE REMOVED
flag is set, and the fields of the current record are changed as follows: the TAG ID field is set to null (zero) to indicate no known tag. The tire data fields are pulled out, the TIRE REMOVED flag is set, and the RECEIVE TINIER is effectively stopped. From step 328 program flow loops back to step 314. If step 322 has determined that the RECEIVE TTI1VVIER value is not greater than the TiMEOUT parameter value, then the current record has been updated recently enough, and step 324 increments the RECEIVE TINIER before looping program flow back to step 314 for processing of the next record.
Processes (a) and (c) of the summarized method 300 are executed concurrently with the TIRE TIMEOUT CHECK subroutine 310, and are illustrated by the flow chart in Figures 3B and 3C. Starting in Figure 3B, the continuous running of step 330 flows through step 390 which presents a tire ID and other associated monitoring data which have been parsed from a new received data stream (most recently received, therefore "current").
It should be understood that the process of step 390 includes means for rejecting data streams which duplicate within a window of time, and that only new received data streams are presented in the step 390, so that program flow will not proceed through step 390 to the next step 332 until and unless such "new" ID-plus-data are presented. In the next step 332, the records of the TIRE DB database 267 are searched to attempt to match a known 3 0 TIRE ID field value with the value of the current ID, i. e. , is the current ID in the database 267? If yes, then the current data stream has been received from a known tag 202 and a matched record has been found which contains the TIRE ID field which matches the current ID, therefore step 334 updates the data fields in the matched record with the current data. Since the matched record's tag has just been heard from, and therefore confirmed as known, the next step 336 restarts the receive timer by zeroing the value of the RECEIVE TIMER for the matched record. Program flow then continues (step 331).
If, in step 332, it is determined that the current ID is not in the database 267, then the data stream is from a presently-unknown tag, and a set of steps beginning with step 338 is performed to deal appropriately with this fact. In step 338, the ANY TIRE
REMOVED
flag is checked. If the ANY TIRE REMOVED flag is not true, then the unknown tag must be truly foreign because all of the "used" tire positions 205 have tires 204 with known tags 202 in those positions 205. Therefore, the foreign tag is not relevant to the monitoring system 250 and can be ignored (step 346) while the program flow loops back to continue at step 330. If, on the other hand, the ANY_TIRE REMOVED flag is true, then the unknown tag may either be foreign, or it may have been installed in whichever tire position 205 has had its tire 204 and/or tag 202 removed. The next step 348, checks to see if the current ID has been received before, by comparing it with the most recently received foreign tag ID (MRR FOREIGN TAG ID). If they do not match, then the current tag and ID are new, and step 342 replaces the value in the MRR FOREIGN TAG m field with the current tag ID to make it the new most recently received foreign tag ID. Then, in step 344 the MRR TIMER is restarted at zero before the program flow continues (step 331). As can be seen in subsequent steps described hereinbelow, the MRR TI1VIFR tracks the amount of time elapsed from the first detection of a repeatedly received unlrnown (and therefore potentially foreign) tag ° s data stream .
If in step 348 the current ID does match the value in the MRR FOREIGN TAG ID
field, then that means that this is at least the second consecutive receipt of a data stream from the same unknown tag. In this case, program flow proceeds via continuation step "A"
(350) to step 352 in Figure 3C. Step 352 checks to see if the consecutive repeating of the current ID has proceeded long enough (as defined by the value of the TI1VIEOUT
parameter) to justify an assumption that the tag with the current ID (which matches the MRR FOREIGN TAG ID) has been installed on the vehicle 252. Note that this is a possibility because at least one tire is removed as determined by the preceding step 338. If the foreign tag timer has a value in the MRR TI1VIER field which does not exceed the TllVIEOUT value, then the current ID has not been repeating long enough to justify the assumption of installation, and the MRR TIMER value is incremented in step 362 before the program flow continues (step 331). On the other hand, if the answer to decision step 352 is "yes", then program flow proceeds to step 354 where the possibility of the current tag being installed is given an extra check, by searching the TIRE DB database 267 for the first occurrence (in case there are more than one) of a tire position record which has both of its TIRE POS USED and TIRE REMOVED flags set (true). If no such record is found, then no further action is taken (step 364) before continuing (step 331).
However, if such a record is found, then step 356 modifies several fields of the found record:
The TAG ID
field is changed to the value of the current ID (which matches the MRR FOREIGN TAG ID), thereby making the current m known to the monitoring system 250; the RECEIVE TIMER value is set to zero to start timing the interval until the next receipt of a data stream from the TAG 1D tag 202; and the TIRE REMOVED
flag is cleared (to false). In addition, step 356 changes the ANY-TIRE REMOVED flag to false (cleared). Note that if there happens to be a second tire position 205 which is used but has its tire 204 and/or tag 202 removed, the concurrently rumiing TIRE TllVIEOUT
CHECK
subroutine 310 will soon detect this fact and will set the ANY TIRE REMOVED
flag back to its correct value of true (steps 316, 318, and 326). Finally, step 358 resets the MRR
fields to prepare them for tracking other unlmown tags: the MRR FOREIGN TAG ID
is cleared to a null value; and the MRR TI1V1ER value is reset to zero and effectively stopped (until program flow returns to step 362 to increment it again). After step 358, program flow continues in step 331, effectively looping back to the run continuously step 330.
Thus is disclosed a preferred embodiment of a method 300 for automatically associating tags (transponders) 202 with appropriate tire positions 205 on a vehicle 252 which has a tire monitoring system 250 for implementing the inventive method 300. The inventive system 250 and method 300 have the advantage of automating the tag/position association process in the case where tags are removed and/or replaced one at a time as typically happens frequently during the life of a vehicular tire monitoring system 250. In the prior art systems, the tag/position association generally had to be manually performed whenever a tire or tag change occurred on the vehicle 252.
Although the preferred embodiment of the invention is described in conjunction with monitoring systems 250 which are mounted on vehicles 252 for the purpose of monitoring conditions in pneumatic tires 204 which are mounted on the vehicle 252, it should be noted that the scope of the inventive method 300 is broad enough to encompass other systems which monitor a plurality of transponder/tags wherein the location of each tag must be associated with a self reported m for each tag.
Although the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character - it being understood that only preferred embodiments have been shown and described, and that all changes and modifications that come within the spirit of the invention are desired to be protected. Undoubtedly, many other "variations" on the "themes" set forth hereinabove will occur to one having ordinary skill in the art to which the present invention most nearly pertains, and such variations are intended to be within the scope of the invention, as disclosed herein.
Claims (16)
1. A method for associating transponders with tire positions for a vehicular tire monitoring system which comprises a transponder receiver mounted on a vehicle, the receiver having an antenna for receiving signals from the transponders which are mounted in each of the vehicle's multiple tires which are to be monitored, and each transponder having a unique ID which is included as part of a data stream which is periodically transmitted from the transponder to the receiver, the method characterized by the steps of:
maintaining a database including ID's known to the tire monitoring system for the vehicle, wherein each specific known ID is associated with a specific tire position on the vehicle, and labeling as "NOT REMOVED" each tire position which has an associated known ID;
whenever the specific ID associated with the specific tire position is not detected by the receiver, labeling the specific tire position as "REMOVED"; and whenever an unknown specific ID is detected while any tire position is labeled as "REMOVED", automatically associating the unknown specific ID with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED ".
maintaining a database including ID's known to the tire monitoring system for the vehicle, wherein each specific known ID is associated with a specific tire position on the vehicle, and labeling as "NOT REMOVED" each tire position which has an associated known ID;
whenever the specific ID associated with the specific tire position is not detected by the receiver, labeling the specific tire position as "REMOVED"; and whenever an unknown specific ID is detected while any tire position is labeled as "REMOVED", automatically associating the unknown specific ID with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED ".
2. The method of claim 1 further comprising the step of:
enabling an operator to manually make a specific ID known and associated with a specific tire position on the vehicle;
enabling an operator to manually make a specific ID known and associated with a specific tire position on the vehicle;
3. The method of claim 1 further comprising the step of:
including flags in the database wherein a specific flag is associated with each specific tire position in the database, and using a value of each specific flag to indicate each specific tire position which is expected to have a transponder with a known specific ID
associated with the specific tire position.
including flags in the database wherein a specific flag is associated with each specific tire position in the database, and using a value of each specific flag to indicate each specific tire position which is expected to have a transponder with a known specific ID
associated with the specific tire position.
4. The method of claim 1, wherein the step of labeling the specific tire position as "REMOVED" further comprises:
nulling the specific ID associated with the specific tire position, thereby removing it from the list of known ID's.
nulling the specific ID associated with the specific tire position, thereby removing it from the list of known ID's.
5. The method of claim 1, wherein the step of labeling the specific tire position as "REMOVED" further comprises:
utilizing a time period for attempting detection of the specific ID associated with the specific tire position; and waiting until after the time period ends before labeling the specific tire position as "REMOVED" if the specific ID was not detected during the time period.
utilizing a time period for attempting detection of the specific ID associated with the specific tire position; and waiting until after the time period ends before labeling the specific tire position as "REMOVED" if the specific ID was not detected during the time period.
6. The method of claim 1, wherein the step of automatically associating further comprises:
utilizing a memory field to store only a single most recently received unknown specific ID;
recording the length of time for which the memory field maintains the same foreign tag ID; and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED
".
utilizing a memory field to store only a single most recently received unknown specific ID;
recording the length of time for which the memory field maintains the same foreign tag ID; and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific tire position labeled as "REMOVED", and changing the specific tire position label from "REMOVED" to "NOT REMOVED
".
7. The method of claim 1, wherein the step of automatically associating is characterized by:
using the specific tire position labeled as "REMOVED" which is first in the database.
using the specific tire position labeled as "REMOVED" which is first in the database.
8. The method of claim 1, wherein the steps are all further characterized by:
ignoring each specific tire position which is not expected to have a transponder with a known specific ID associated with the specific tire position.
ignoring each specific tire position which is not expected to have a transponder with a known specific ID associated with the specific tire position.
9. A transponder monitoring system which comprises a transponder receiver having an antenna for receiving signals from a plurality of transponders which are mounted in a plurality of positions which are to be monitored, each transponder having a unique ID
which is included as part of a data stream which is periodically transmitted from the transponder to the receiver, the monitoring system characterized by:
a database including ID's known to the monitoring system, wherein each specific known ID is associated with a specific position, and each position which has an associated known ID is labeled as "NOT REMOVED";
means for labeling the specific position as "REMOVED" whenever the specific ID
associated with the specific position is not detected by the receiver; and means for automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED" to "NOT REMOVED ", whenever an unknown specific ID is detected while any position is labeled as "REMOVED".
which is included as part of a data stream which is periodically transmitted from the transponder to the receiver, the monitoring system characterized by:
a database including ID's known to the monitoring system, wherein each specific known ID is associated with a specific position, and each position which has an associated known ID is labeled as "NOT REMOVED";
means for labeling the specific position as "REMOVED" whenever the specific ID
associated with the specific position is not detected by the receiver; and means for automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED" to "NOT REMOVED ", whenever an unknown specific ID is detected while any position is labeled as "REMOVED".
10. The transponder monitoring system of claim 9 further characterized by:
means for enabling an operator to manually make a specific ID known and associated with a specific position on the vehicle;
means for enabling an operator to manually make a specific ID known and associated with a specific position on the vehicle;
11. The transponder monitoring system of claim 9 is further characterized by:
flags included in the database wherein a specific flag is associated with each specific position in the database, so that a value of each specific flag is used to indicate each specific position which is expected to have a transponder with a known specific ID
associated with the specific position.
flags included in the database wherein a specific flag is associated with each specific position in the database, so that a value of each specific flag is used to indicate each specific position which is expected to have a transponder with a known specific ID
associated with the specific position.
12. The transponder monitoring system of claim 9, wherein the means for labeling the specific position as "REMOVED" is further characterized by:
nulling the specific ID associated with the specific position, thereby removing it from the list of known ID's.
nulling the specific ID associated with the specific position, thereby removing it from the list of known ID's.
13. The transponder monitoring system of claim 9, wherein the means for labeling the specific position as "REMOVED" is further characterized by:
a time period for attempting detection of the specific ID associated with the specific position; and waiting until after the time period ends before labeling the specific position as "REMOVED" if the specific ID was not detected during the time period.
a time period for attempting detection of the specific ID associated with the specific position; and waiting until after the time period ends before labeling the specific position as "REMOVED" if the specific ID was not detected during the time period.
14. The transponder monitoring system of claim 9, wherein the means for automatically associating is further characterized by:
a memory field used to store only a single most recently received unknown specific ID;
recording the length of time for which the memory field maintains the same foreign tag ID; and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED" to "NOT REMOVED "
a memory field used to store only a single most recently received unknown specific ID;
recording the length of time for which the memory field maintains the same foreign tag ID; and waiting until the length of time exceeds a time period before automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED" to "NOT REMOVED "
15. The transponder monitoring system of claim 9, wherein the means for automatically associating is characterized by:
using the specific position labeled as "REMOVED" which is first in the database.
using the specific position labeled as "REMOVED" which is first in the database.
16. The transponder monitoring system of claim 9, further characterized by:
means for ignoring each specific position which is not expected to have a transponder with a known specific ID associated with the specific position.
18. A method for associating transponders with positions for a monitoring system which comprises a transponder receiver having an antenna for receiving signals from the transponders which are mounted in positions which are to be monitored, each transponder having a unique ID which is included as part of a data stream which is periodically transmitted from the transponder to the receiver, the method characterized by the steps of:
maintaining a database including ID's known to the monitoring system, wherein each specific known ID is associated with a specific position, and labeling as "NOT
REMOVED" each position which has an associated known ID;
whenever the specific ID associated with the specific position is not detected by the receiver, labeling the specific position as "REMOVED"; and whenever an unknown specific m is detected while any position is labeled as "REMOVED", automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED"
to "NOT REMOVED ".
means for ignoring each specific position which is not expected to have a transponder with a known specific ID associated with the specific position.
18. A method for associating transponders with positions for a monitoring system which comprises a transponder receiver having an antenna for receiving signals from the transponders which are mounted in positions which are to be monitored, each transponder having a unique ID which is included as part of a data stream which is periodically transmitted from the transponder to the receiver, the method characterized by the steps of:
maintaining a database including ID's known to the monitoring system, wherein each specific known ID is associated with a specific position, and labeling as "NOT
REMOVED" each position which has an associated known ID;
whenever the specific ID associated with the specific position is not detected by the receiver, labeling the specific position as "REMOVED"; and whenever an unknown specific m is detected while any position is labeled as "REMOVED", automatically associating the unknown specific ID with the specific position labeled as "REMOVED", and changing the specific position label from "REMOVED"
to "NOT REMOVED ".
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US68078300A | 2000-10-06 | 2000-10-06 | |
| US09/680,783 | 2000-10-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2356617A1 true CA2356617A1 (en) | 2002-04-06 |
Family
ID=24732499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2356617 Abandoned CA2356617A1 (en) | 2000-10-06 | 2001-09-04 | Transponder receiver |
Country Status (4)
| Country | Link |
|---|---|
| BR (1) | BR0104332A (en) |
| CA (1) | CA2356617A1 (en) |
| MX (1) | MXPA01009583A (en) |
| ZA (1) | ZA200107874B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8151127B2 (en) | 2000-07-26 | 2012-04-03 | Bridgestone Americas Tire Operations, Llc | System for conserving battery life in a battery operated device |
| US8266465B2 (en) | 2000-07-26 | 2012-09-11 | Bridgestone Americas Tire Operation, LLC | System for conserving battery life in a battery operated device |
| CN105882328A (en) * | 2015-02-18 | 2016-08-24 | 丰田自动车株式会社 | Tire-pressure monitor system |
-
2001
- 2001-09-04 CA CA 2356617 patent/CA2356617A1/en not_active Abandoned
- 2001-09-24 MX MXPA01009583 patent/MXPA01009583A/en unknown
- 2001-09-25 ZA ZA200107874A patent/ZA200107874B/en unknown
- 2001-09-27 BR BR0104332-3A patent/BR0104332A/en not_active IP Right Cessation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8151127B2 (en) | 2000-07-26 | 2012-04-03 | Bridgestone Americas Tire Operations, Llc | System for conserving battery life in a battery operated device |
| US8266465B2 (en) | 2000-07-26 | 2012-09-11 | Bridgestone Americas Tire Operation, LLC | System for conserving battery life in a battery operated device |
| CN105882328A (en) * | 2015-02-18 | 2016-08-24 | 丰田自动车株式会社 | Tire-pressure monitor system |
| CN105882328B (en) * | 2015-02-18 | 2017-09-22 | 丰田自动车株式会社 | Tire pressure monitoring system |
Also Published As
| Publication number | Publication date |
|---|---|
| MXPA01009583A (en) | 2002-04-16 |
| BR0104332A (en) | 2002-05-21 |
| ZA200107874B (en) | 2002-05-21 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Dead |