DE102011101229A1 - Digital track information system for use as transducer to e.g. determine positions, has transmitting unit transmitting electric conductor, which is displaced along tracks, and receiving unit comprising asymmetrical antennas - Google Patents

Abstract

The system has a transmitting unit transmitting an electric conductor, which is displaced along individual tracks. Pulses prepared by the transmitting unit are supplied to the electric conductor. A receiving unit comprises asymmetrical antennas. The individual tracks are combined to a network, and a transceiver is arranged at ends of the tracks. The transceiver is connected with transceivers of successive tracks with respect to communication. A vehicle drives independently over digital tracks or passes data to users.

Description

It is an object of this invention to provide data and information by simple engineering means to describe routes and routes. For this purpose, based on the state of the art, the well-known guidewire technology is used and supplemented with digital methods. The inventive idea is shaped by the very digital technology for the previously analogous concepts. Linked to this is the option to replace electronics with software. Especially this idea shows a great potential of this invention: it requires only a little electronics, the devices are smaller and lighter, are less susceptible to interference and easier to convert. And, the scrap of tomorrow will not be soldered in the first place.

Typical applications for guidewire technology are conveyor technology. But also in metrology the Digital Lane Information System described here can be used. Applications as encoder or button etc. are possible.

The desire to automatically promote or control vehicles on their way becomes possible as early as the first half of the 20th century through technical means. Many patent applications have since been known, only a few of which are mentioned here: US 1 798 641 (1927) DE 639 813 (1933) US 2,331,144 (1940) US 2,317,400 (1940) US 2 424 288 (1944) DE 932 171 (1955) US 3,039,554 (1962) US 3,033,305 (1962) DE 1 125 521 (1962) US 3,147,817 (1964) DE 1 902 037 (1970) US Pat. No. 3,507,349 (1970) DE 2 137 631 (1971) US 3,811,112 (1972) US 3,848,836 (1973) US 3,942,087 (1974) US 4,077,486 (1975) US 4,215,759 (1975) US 3,993,156 (1976) US 4,307,329 (1979) DE 30 37 221 (1980) US4310789 (1980) DE3906962 (1981) GB2104686 (1981) EP 0 138 097 (1983) AT E 98 937 (1986) AT 391 563 (1987) WO 82 00122 (1989) US 5 218 542 (1991) DE 694 03 508 (1993) DE 694 07 024 (1993) EP 0 658 467 (1993)

• – magnetische, aber auch optische Spuren realisiert,
• – die Mittel, mit denen Fahrzeuge der Spur des Leiters folgen,
• – Daten zum und vom Fahrzeug übermittelt,
• – Kurven optimal kalkuliert und gelegt,
• – zusätzliche Markierungen auf Bahnen aufgebracht und ausgewertet,
• – die Systeme mit Kartenmaterial ergänzt
• – und optische und magnetische Information parallel genutzt werden.

These, as well as the many inventions not mentioned, show solutions that help to promote automated. The inventions show how

• - implemented magnetic, but also optical tracks,
• - the means by which vehicles follow the track of the conductor,
• - transmit data to and from the vehicle,
• - Curves optimally calculated and laid,
• - applied and evaluated additional markings on tracks,
• - The systems supplemented with maps
• - And optical and magnetic information to be used in parallel.

This is only one, albeit significant, excerpt of the technical standard defined in the above inventions.

To explain this invention, it is necessary first to analyze the known control systems and to present the features of the hitherto analogous technique.

If the solutions of said inventions directly relate to the control system, they have one thing in common: agents are introduced into the roadway which can be detected by the vehicle and which typically reveal deviations from the lane. Thus, in the patent specification No. 639 813 of the Reich Patent Office:
"The invention may also be embodied such that the conductive strips 2, 3 are formed as electrical or magnetic conductors, for. B. in the form of cables, wires, bands or scrap iron are embedded in the road and act capacitively or inductively on one or more circuits on the car. "

The signals should be detected by coils or capacitor plates. The patent application US 2,317,400 from 1940 then describes in more detail the interpretation of such transducers and how these data are processed. Coils are connected together with capacitor and thus form a resonant circuit, which is excited by the conductor. This circuit has the great advantage that the transmitter and the receiver can be matched. The parallel resonant circuit with the highest resistance at resonance frequency shorts all other frequency fields acting on the coil so that the downstream amplifier sees only the relevant signals from the guide wire.

Such filter circuits in particular, and the selection of certain frequencies in general, are used in similar fashion in almost all guidewire technologies. This is the important property E1 of such systems and is needed to hide interference from other transmitter 1 frequencies.

But US 2,317,400 has another important feature: the difference between two oscillating circuits or antennas is considered and evaluated in order to influence the steering system. Also DE 932 171 from 1955 uses the difference left and right of the conductor arranged transducer. At 5.4 it is explained from line 30 how this difference can be used to control a servomotor of the steering system. This is the second important property E2 of such systems and is needed to detect deviations from the track.

From E1, an important property for the transmitter can be derived. This transmitter has to provide periodic and harmonic signals. The amplitude spectrum shows correspondingly only one or only a few spectral lines. DE 639 813 shows in 6 coupled resonant circuits. US 2,317,400 informed on page 4, left column, 2nd line: "The cable is energized from a source 2 'of low frequency alternating current, preferably not exceeding audible frequencies ...". DE 932 171 on page 2, from the penultimate paragraph, names 2 frequencies in the listening area, and that these can be hidden by high and low filters. 4 shows how alternately the two sinusoidal signals are fed into the conductor. Thus, for the first time, a message is provided for the track data, which is processed acoustically there. In particular, the further development of the control systems for telecommunications systems then leads to the third important property E3, according to which the signals of the conductors are sinusoidal. That the above-mentioned control systems must be operated with a particular sinusoidal current is a consequence of the inductive antenna. Power is inductively fed into the coils from the control system. This requires a constantly changing magnetic flux. In contrast, could DE 1 125 521 to be operated from 1962 without an alternating field. There, instead of coils Hall generators are used, which are arranged to optimize the magnetic flux between pole shoes. Nevertheless, an additional control is proposed in such a way to superimpose the magnetic fields by alternating magnetic fields of a certain frequency "whose presence first makes the control effective ...". In claim 4, this is referred to as magnetic modulation.

DE 1 125 521 shows also known from older sources arrangements of guidewire and transducers. There are embodiments with a wire - the return conductor is the earth - and those with a spaced wire as the return conductor shown. For this purpose, advantageous and substantially known arrangements of the sensors are shown. These aim to produce a differential voltage that signals a deviation from the prescribed path. The value of 0 volts shows there in particular that there is no deviation. Values greater or lesser zero indicate the direction and amount of deviation.

There are many interesting inventions that describe advantageous designs and arrangements of the coils and how the signals are processed with electrical circuits. But with US 3,039,554 . US 3,147,817 and US 3,848,836 introduces options for the use of control systems that open up new applications. It shows how complex systems can be mapped with control systems. In addition, means are presented that enable a sponsor to choose a particular route or action. At the same time, these new possibilities are placing new demands on such systems. The need to send messages to mobile systems to influence behavior was soon recognized, and solutions were soon found.

To send messages to the mobile objects via the control system is described in the patent US 3,811,112 presented. There, a secure and digital communication model is described. For this purpose telegrams are defined with a defined pulse sequence. The general communication model is further specialized there for applications in control systems. It is believed that the coils acting as receivers for the steering system are relatively insensitive to frequency changes. The solution is based on mapping digital quantities with different frequencies. The guidewire is operated in normal operation with the "carrier frequency", which is not used for information technology. In contrast, a certain frequency greater than the carrier frequency is recognized as 1, a smaller than 0. That frequencies are chosen to be larger and smaller than the carrier frequency, shows that you do not want to move too far from this. The coils are probably not so insensitive to frequency changes - the safe operation of the steering system must also be ensured during data transmission.

Already US 1 798 641 shows a comparable solution: Information elements are imaged there by dedicated frequencies with the aim of being able to transmit them over longer distances by radio.

This confirms E3 and leads to the property E4 according to which control systems are advantageously equipped with telecommunications equipment.

Consequently, the technical features have been further developed and the performance increased. So describes AT E 98 937 a complex control system consisting of many individual guide wires and a plurality of vehicles. The term control system can also, depending on the context denote complete systems including the mobile objects and the assemblies used or needed for them. It can z. As well as optical signal generators or actuators that act directly or indirectly on the signal formation or objects, assemblies of the control system - even if they are located directly in the vehicle.

AT E 98 937 shows solutions that allow objects to be remotely guided along different paths that are formed with multiple guide wires. This is another property E5: the aggregation of individual control systems into networks. According to AT E 98 937, these networks will enable vehicles to carry out computer-controlled orders on the basis of bi-directional communication.

Also in AT E 98 937 Digital data is transmitted "by means of long-wave radio frequency" with the guide wire. At least two frequencies are intended to map digital information. The values for the long-wave high frequency were 9600 Hz and 19200 Hz. Surprisingly, the invention teaches that the data is sent out as cosine waveforms of substantially equal amplitude. Overall, it is clear that the operation of guidewires is not trivial, especially if information is also transmitted. Legal requirements must be met, FCC approval is listed here. It is assumed that the situation in 1986, the standards of today are probably even narrower. Further, on page 9, it is stated that not all areas of the conductor function as transmitters. On page 36, in the first paragraph, a possible cause is mentioned: "Because the guidewire 80 serves as the antenna for the communication circuit 71 obviously, its properties as an antenna are changed by the pattern chosen ". 1 shows this (relocation) pattern and 6 shows the linker circuit 78 , The guidance systems are more like a loop antenna than a line. In addition, the line is not adapted, but shorted on one side. Such ladder arrangements also show other of the inventions listed above, also there an impedance matching is not mentioned. Such control systems can only be operated with electrically short lines. This is noted as property E6.

Finally, take a look at US Pat. No. 3,507,349 , There solutions are shown, which affect the lane change. For this purpose, the normal "tracking system disabled" and instead a programmed path is followed at intersections. This method is also used for the reason that all guide wires can be operated at the same frequency. There it is regarded as a disadvantage, as otherwise known for distinguishing the track, to make each with its own frequency to recognize. With the solution shown, it is possible to avoid providing different transmitters for the conductors and that the receivers are to be changed to the frequency of each new track. It should be noted here as a property E7: Tracks can be detected or distinguished by the guide wires of the tracks are operated with its own frequency.

The statements made so far make it clear that the operation of control systems with analog technology offers many advantages and can actually only take place with sinusoidal signals. To operate these systems digitally seems at least not trivial when looking at features and implementing similar capabilities. But it works and offers many advantages, as shown below.

Digital technology has the great advantage that the required amount of components is reduced significantly. The solutions described so far contain many analog and digital modules. This is shown by the drawings of said inventions. Digital technology means here in particular that the conductors are now operated with switching. These can be switched almost directly by software in the form of transistors or other active semiconductors. The digital solution already shows advantages here: the software running on a processor can operate the transistor flexibly directly via ports of the processor and generate all possible pulse sequences. Other active components are not needed for signal generation, and a change in signal frequency or duration is possible without changing the hardware.

The possibilities of digital technology are initially not as varied as in analog technology. With signals that are generated by means of switches, in particular many of the known from telecommunications engineering analog modulation and filter technologies are not available. Digital technology typically uses pulses and varies their length, the spacing of the pulses, and more rarely the polarity and signal levels. Many digital bus systems, eg. RS232 and CAN define messages by a train of pulses. All impulses have the same duration, and the occurrence within a defined timeslot forms a digital statement. It will i. d. R. rectangular waveforms used, the edge steepness is often adjustable to limit disturbing effects. Accordingly, digital technology is not limited to rectangular pulses. Trapezoidal with possibly rounded corners, triangular or sinusoidal signals, even without signal-shaping components in front of the switches, can still be assigned to digital technology.

Non-periodic rectangular signals can also be simulated by Fourier components. An evaluable signal requires the fundamental and a number of harmonics, with the highest harmonic being a multiple of the frequency of the fundamental. Therefore, receivers for digital signals require a large bandwidth and thus do not have the property of analog systems E1: Disturbances and signals from other control systems can not be treated with analog filters. Simply use a band limited receiver as a "signal follower", which also works like in US Pat. No. 3,507,349 on p. 2, by means of frequency switching other ways can follow, is not possible with digital systems. At the same time, it is not possible to define routes by means of a specific and unique frequency. In order to display the property E5 digitally, path information is required to be able to design networks consisting of several individual control systems. The simplest way to provide this path information is to digitize path data and send it as a pulse train over the guidewire. As a result, digital control systems are becoming rather telecommunications systems. The provision of track information thus becomes a subordinate functionality.

There are no known means to transmit digital messages of said form without interference. It has been shown that known filters can not be used. However, interference-free communication is an essential prerequisite for the operation of such digital systems. In the search for a suitable solution to this problem, a surprisingly simple method was found: several antennas are used and the signals are subtracted in pairs. In this way, all electromagnetic signals of the environment are suppressed. This receiver system is actually not capable of receiving information from the environment and acting as an antenna. But if this receiver system is guided over the guide wire such that an antenna is closer to the guide wire, information is transmitted.

This surprisingly simple inventive solution will be explained by selected examples. A receiver system is equipped with three antennas, which are arranged side by side. The middle one is above the guidewire, and the sides are equidistant from the guidewire. From the three antennas, three different pairs of signals can be formed: from the two left and the right two arranged antennas, a differential signal not equal to zero can be formed. These differential signals are interference-free and contain only the message from the guidewire. Both difference signals contain the message that should be checked for error-free reception. For this purpose, a procedure is outlined below. Here, however, the signal should first be further evaluated to determine the track information. For this purpose, it is simply assumed that the two differential signals each also have a rectangular waveform. From the voltage values of individual pulses of both signals, the deviation from the track can be calculated. For this purpose, the voltages are preferably digitized and the difference is formed. Multiple pulse levels can be analyzed to detect errors in the track information in addition to message error checking. Alternatively or additionally, the signal of the outer antennas for the track information can be considered. Again, the difference is formed, which is at optimal tracking zero.

The difference, which is a feature of this invention, analog and also formed early. This means in particular that this takes place before a significant reinforcement. This is explained by the fact that the amplifiers, which are designed for the signals of the guidewire, can be overridden by superimposed interference. The signals of the individual antennas are initially only slightly pre-amplified, or the signals are fed directly to a differential amplifier. Alternatively, the difference of the signals can also be made directly by the preservation of the antennas. For example, two antennas may be connected via a resistor at which the differential voltage can be tapped directly. This resistor can be connected in parallel with a capacitance in order to directly suppress high-frequency interfering signals, optimally switching low-resistance resistors in front of and behind this resistor. To protect the downstream electronics additional components may be arranged to dissipate overvoltages or to limit the currents.

The signals of the antenna are processed with the known means so far that they can be further processed by a processor. These typically have the functional groups on the chip, which are necessary for further processing of the signals: timer, external interrupt and ADC. The amplifiers, differential amplifiers, filters, etc. can be realized discretely with transistors or operational amplifiers, or the complete analog circuit is integrated in one component.

It has been described that signals from several antennas are combined and the difference is always formed in pairs. These differential signals are then processed further digital modules available. The aforementioned three-antenna system can be variably transmitted to other systems. Especially with a plurality of juxtaposed antennas, a receiver system can be formed, which changes the lane can describe. Finally, a two-antenna system should be mentioned. This is not suitable in principle because with symmetrical positioning the message is suppressed. Although it is recognized that there is no signal and the track would be followed, but the lack of messages prevents error checking, etc. The information about the pulse for the ADC are not ready. Nevertheless, such a system could be used if it were not symmetrical to the track.

A small step is needed to successfully implement the digital news concept. Short pulses with correspondingly high frequency components must also be transmitted on longer lines. The line is thus electrically long and thus it should be considered: the control systems can not be designed as a loop, in particular, the return and return conductors are in the same medium and at the same distance from each other. This line can thus be regarded as homogeneous, and the characteristic impedance is almost constant. To avoid reflections, the line is also terminated with a resistor equal to the characteristic impedance.

With the means mentioned digital control systems can be operated successfully. It has been shown that digital systems can be more associated with communication technology. It is a software-based system that requires only a few discrete components. This makes this system flexible, which should be demonstrated by network capability.

Known control systems use a conductor, which originates from a control unit and is looped back. There is no interruption on the conductor route to connect another controller to this conductor. It is therefore not possible to pass on messages via the ladder to other control systems. By contrast, digital technology makes it particularly easy to design networked control systems. Namely, the wired transmitter can be upgraded with a little software and a few transistors with receiver functionality. Here it is first provided that transmitter and receiver are connected to the same line. The module, consisting of transmitter and receiver, is called transceiver. If a control system is equipped with transceivers at both ends, further control systems with transceivers can simply be arranged in front of and behind it. The neighboring transceivers are optimally housed in a housing and on a circuit board and are connected via an interface (eg I2C). Now it is possible to define messages that are defined for the network - global messages for all vehicles - or a specific module of the network can send to or receive from a control center.

Such transceivers could simply be used as amplifiers in networks. But it would be better to shorten the stage length and to provide a new stage instead of the amplifier. This allows more detailed position information.

The messages are placed as a pulse train on the guidewire. For example: a pulse duration of 4 μs corresponds to a 1, 7 μs of a 0. The time between two pulses can also be evaluated: pause duration of 5 μs corresponds to 1, 9 μs of 0. The following explains a possible structure of the messages: Messages are divided into individual pieces of information: each message has a preamble that follows an identifier. This is followed by the data. The meaning of the message is determined by the ID and the following data is defined in terms of length and content. This organization should increase data security and reduce the amount of data. The messages are compressed in this way so that a maximum of 28 bits of data are needed for a message. If longer package lengths are required, this must be indicated by means of an ID.

The average duration of a message is: 28 data bits + 5 bits ID + 4 bits preamble = 37 bits. At ~ 160 Kbit / s ~ 231 μs is needed. This sets the message rate as 4000 msg / s and at the same time a unique time interval for the messages.

Every 250 μs a message is to be sent or expected. If these remain active for a little longer than 3 intervals (if the transmitter A fails, then A transceiver B would become active), there is a fault and appropriate measures should be taken.

Messages for the track information are so typically every 7 mm (v = 100 km / h) ready. These are optimally provided in short form with the ID NC. This message, "no comment", is used very often because others, such as For example, explicit information about the stage or system time may need to be provided less frequently (intervals of> 30 s are sufficient). This reduces the power consumption of the modules.

At intersections, triangles and possibly also at exits several guidance systems are provided per lane. These are, so to speak, points. The ladders run side by side there to follow each new or old direction. The switches are used to unload or thread vehicles or columns. There is only a reduced amount of messages provided, which has only the goal of the maneuver to organize. So that the adjacent in the first part of the switch Leitsyteme not interfere with each other, here a time-division multiplex method is introduced: there are defined time ranges or time slots with a length of 100 microseconds available for each conductor. Thus, a separate time window is provided for each conductor of the switch. Turnouts messages have their own preamble and no identifier. The amount of data trailing the preamble shows the way. Weeds do not use bit times for the preamble: this is formed by a quartet of 4 μs long edge distances. The following data phase consists of 9 bits according to the bit definition. The first 8 bits describe the logical path number, the last the direction.

The preamble maps all bit types into each combination and consists of a sequence of 3 pulses and correspondingly two pauses. The 3rd impulse already belongs to the ID field. Through the three pulses, the third signals only the end of the break, the signals are again explicitly described: there are short and long pulses and pauses in the preamble. The bit sequences 1100, 1001, 0110 and 0011 are permitted, others can not be used due to lack of uniqueness. The receivers can thus check the bit time for each bit type. Only if this preamble is valid, the track data is valid. Exceptions may be provided to prompt the transceiver AB to send an ACK. This then gives only 111 - the second pulse has the same length as the first. The receiver can determine the way (in the direction of travel) from the two messages. There are two more embedded information in the preamble. The combination of bit sequences allows to embed 2 bits. These are used as follows: bit 0 is the last bit of the stage number, and bit 1 indicates the use of the message. If bit 1 = 0, the message remains in the stage, otherwise it will be passed on to the following stage (if the stage is not the target of the message). Since stages are consecutively numbered, bit 0 immediately returns the info "change of stage". The mileage counter can be set to zero etc. 32 messages can be distinguished via the 5-bit identifier. In addition to the control system, the mobile systems can also use maps that provide further information, eg. B. data on the curve and slope runs.

The structure of the news shows at the same time the performance of this digital control system. It also makes sense to use this solution for other control or information systems. The use in sensor technology or robotics also seems sensible. With a matrix of individual ladders or with meandering laid the position can be determined exactly.

Finally, a comment on the antennas: since the pulses do not provide a constantly changing field, magnetic antennas are not always well suited. Hall sensors or antennas for the electric field are more suitable. A piece of stainless spring wire, possibly provided with a plastic sheath and slightly curved over the conductor, is a robust alternative.

Digital linkage information systems require non-symmetrical antennas to receive messages and track data. Non-symmetric refers to the antennas used for signal formation. It is therefore possible that antennas are positioned so that they are arranged symmetrically to the conductor: the antennas lie in a plane and individual antennas are equidistant to the right and left of the conductor. Such symmetrical at first sight arrangements are connected but unbalanced. For example, two antenna signals arranged to the left of the conductor are evaluated or treated mathematically as described above.

The term "asymmetrical antennas" thus means either an arrangement of symmetrical or asymmetrical antennas meant. If antennas are evidently arranged symmetrically, "unbalanced antennas" implies that the imbalance refers to the signals of these antennas. "Unbalanced antennas" further implies that the signals are processed properly and the difference is formed from at least two unbalanced signals. For the sake of form, it is mentioned that asymmetry is also achieved when antennas are arranged at different levels. With such arrangements, the vertical distance to the conductor or vibrations can be determined. If a signal is inverted by the arrangement of the antennas or sensors, the difference can also be formed by means of an addition, or an inverter is connected upstream.

There are known from the known inventions a variety of applications. Here only one application is described in more detail for the control system. An operator controls a self-powered fire truck via video images provided by radio. On the way, the camera could fail because of smoke and track data would not be available. Now it is possible to switch over to the control system, such that the deletion train runs autonomously or the operator continues the control on the basis of the radio-transmitted data from the control system.

An example of a non-mobile application is the monitoring of objects. For this purpose, the ladder is mounted on the object and the antenna at a fixed point. If the object moves relative to the antenna, this can trigger an alarm.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 1798641 [0003, 0015]
• DE 639813 [0003, 0011]
• US 2331144 [0003]
• US 2317400 [0003, 0008, 0010, 0011]
• US 2424288 [0003]
• DE 932171 [0003, 0010, 0011]
• US 3039554 [0003, 0013]
• US 3,033,305 [0003]
• DE 1125521 [0003, 0011, 0012]
• US 3,147,817 [0003, 0013]
• DE 1902037 [0003]
• US 3507349 [0003, 0020, 0024]
• DE 2137631 [0003]
• US 3811112 [0003, 0014]
• US 3848836 [0003, 0013]
• US 3942087 [0003]
• US 4077486 [0003]
• US 4215759 [0003]
• US 3993156 [0003]
• US 4307329 [0003]
• DE 3037221 [0003]
• US 4310789 [0003]
• DE 3906962 [0003]
• GB 2104686 [0003]
• EP 0138097 [0003]
• AT 98937 E [0003, 0017, 0018, 0019]
• AT 391563 [0003]
• WO 8200122 [0003]
• US 5218542 [0003]
• DE 69403508 [0003]
• DE 69407024 [0003]
• EP 0658467 [0003]

Claims (4)

A digital link information system providing means for transmitting and means for receiving, characterized in that the means for transmitting comprise at least one electrical conductor laid down along a route into which a transmitter feeds telecommunications pulses, and in that the means for receiving comprise unbalanced antennas , Arrangement according to claim 1, characterized in that the individual routes are combined to form a network, in particular transceivers being arranged at the ends of the routes which are communicatively connected to the transceivers of the following route. An application according to any one of the preceding claims, characterized in that a vehicle is enabled to drive autonomously over digital links or to pass this data on to enabled users by detecting the messages and lane data provided by the transmitter by means of unbalanced antennas. Using the digital link information systems as transducers to determine positions or detect deviations.