CN102175892B - Multidimensional acceleration sensor with cored piezoelectric rods and acceleration measurement method - Google Patents

Abstract

The invention discloses a multidimensional acceleration sensor with cored piezoelectric rods and an acceleration measurement method, which relate to a multidimensional piezoelectric acceleration sensor. Four identical cored piezoelectric rods are symmetrically arranged about a base, and are all positioned in the same plane to integrally form a crossed layout. One end of each cored piezoelectric rod is fixed on the base, and the other end of each cored piezoelectric rod is free. Each cored piezoelectric rod is formed by winding an electric material on a core rod, or by adhering a piezoelectric element to the core rod. When subjected to the action of linear acceleration, the sensor can judge the direction and magnitude of the acceleration according to numerical charge values on each electrode of different cored piezoelectric rods.

Description

Contain core piezoelectric rods multi-axis accelerometer and acceleration measurement method

Technical field

The present invention relates to piezoelectric sensor, be specifically related to a kind of multidimensional piezoelectric acceleration sensor and measuring method thereof.

Background technology

The structure of piezoelectric acceleration sensor commonly used mainly contains 3 kinds of compression-type, shearing-type and flexure types.Wherein the sensitive element of flexure type piezoelectric acceleration sensor is the semi-girder that piezoelectric is made, or is pasted with the semi-girder of piezoelectric, and its natural frequency is low, highly sensitive, is applicable to low frequency measurement, and shortcoming is that volume is large, and physical strength is relatively poor.

Piezoelectric accelerometer in the market mostly is single shaft and two axis accelerometers, and three axis accelerometer is generally combined by a twin-axis accelerometer and a single-axis accelerometer, and volume is large.Chinese patent (application number: 200810222531.X) disclose a kind of quadrature ring-type piezoelectric accelerometer, be used for measuring 3-axis acceleration, but complex structure, volume is larger.

Chinese invention patent (application number: 200810124088.2) disclose metal-cored piezoelectric ceramic fibers of containing of a kind of surface portion coating electrode, on the piezoelectric ceramic fiber containing metal core surface, along length bearing of trend coated electrode partly, can realize the flexural vibrations function, also can be used for measuring the acceleration magnitude of special angle, can't measure acceleration direction and the size of 2 peacekeeping multidimensional.

Summary of the invention

The object of the invention is to overcome the linear acceleration that conventional accelerometer generally can only be measured one dimension, and baroque shortcoming, provide a kind of and can measure 3-axis acceleration, highly sensitive piezoelectric acceleration sensor and measuring method thereof.

A kind of piezoelectric acceleration sensor, it is characterized in that: comprise base, be installed on pedestal, symmetry on the base be installed on around the pedestal and be co-located in four of the whole across layout of same plane identical contain the core piezoelectric rods, be respectively first and contain core piezoelectric rods, second and contain core piezoelectric rods, the 3rd and contain core piezoelectric rods, the 4th and contain the core piezoelectric rods; Contain core piezoelectric rods one end and be fixed on the pedestal, the other end freely; Also comprise the shell that is installed on the base; The above-mentioned core piezoelectric rods that contains is comprised of piezoelectric parcel plug, or by the piezoelectric element symmetry stick on around the plug and piezoelectric element between vacant part fill up with epoxy resin and form, on piezoelectric or piezoelectric element surface also vertically by upper and lower, left and right symmetrical four surface electrodes.

Utilize the acceleration measurement method of above-mentioned piezoelectric acceleration sensor, it is characterized in that comprising following process: (1), whole acceleration transducer is placed cartesian coordinate system, contain the residing plane of core piezoelectric rods as XOY plane, the center of four core piezoelectric rods and pedestal installation place is the O point, wherein first contains the core piezoelectric rods and overlaps with the X-axis positive dirction, second contains the core piezoelectric rods overlaps with the Y-axis positive dirction, the 3rd contains the core piezoelectric rods overlaps with the X-axis negative direction, the 4th contains the core piezoelectric rods overlaps with the Y-axis negative direction, crosses the vertical XOY plane of O point and direction and upwards is the Z axis positive dirction; (2), contain successively meter work: Q of the upper surface electrode of core piezoelectric rods, right surface electrode, lower surface electrode, the electrically charged value difference of left surface electrode institute with first ₁₁, Q ₁₂, Q ₁₃, Q ₁₄Contain successively meter work: Q of the upper surface electrode of core piezoelectric rods, right surface electrode, lower surface electrode, the electrically charged value difference of left surface electrode institute with second ₂₁, Q ₂₂, Q ₂₃, Q ₂₄(3), acceleration a acts on when containing core piezoelectric rods multi-axis accelerometer, the angle of establishing the positive dirction of acceleration a and coordinate axis X, Y, Z is respectively and is α, β, γ; (4), according to the size and Orientation of following Formula For Solving acceleration a

Wherein K is the sensitivity of sensor, size for when acceleration vertical with the axis that contains the core piezoelectric rods, and the central vertical that is positioned at surface electrode is when dividing the plane equally, the charge value of surface electrode generation and the ratio of acceleration magnitude;

$\mathrm{\&alpha;}=\arccos \frac{Q_{24}}{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}};$

$\mathrm{\&beta;}=\arccos \frac{Q_{12}}{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}};$

$\mathrm{\&gamma;}=\arccos \frac{Q_{11}}{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}}.$

In the present invention, when whole device is subject to linear acceleration or rotary acceleration is done the time spent, single by containing on the core piezoelectric rods that piezoelectric parcel plug forms, because the difference of electrode position, the electric charge that produces on the electrode or voltage are different, and its concrete numerical value (comprising positive and negative and big or small) is relevant with the axial angle of acceleration and piezoelectric rods.Like this, the size and Orientation of two-dimensional direct linear acceleration can be judged with a piezoelectric rods, with two piezoelectric rods that distribute at an angle, direction and the size of 3 d-line acceleration can be judged.

Can be found out by solution procedure, contain in 8 electrode electric charges that core piezoelectric rods and second contains the core piezoelectric rods first, only use the numerical value of 3 electrode electric charges, other electrode electric charge is as the reference electric charge.The 3rd contains core piezoelectric rods and the 4th contains core piezoelectric rods role and has 2:

The one, constitutional balance; The 2nd, after corresponding electrode series connection, the electric charge that produces on the electrode is multiplied, and has improved the sensitivity of sensor.

Use by piezoelectric element stick on form on the plug contain the core piezoelectric rods, can receive same effect.

During containing the core piezoelectric rods and is comprised of piezoelectric parcel plug among the present invention, can make fiber shape with containing the core piezoelectric rods, whole acceleration transducer can be made MEMS, for portable terminal.

Description of drawings

Fig. 1 is system architecture schematic diagram front view sectional view of the present invention.

Fig. 2 is system architecture schematic diagram vertical view sectional view of the present invention.

Fig. 3 of the present inventionly contains core piezoelectric rods structural representation by piezoelectric around what plug formed.

Fig. 4 be of the present invention by piezoelectric element stick on form on the plug contain core piezoelectric rods structural representation.

Fig. 5 is piezoelectric element structural representation sectional view of the present invention.

Fig. 6 is acceleration measurement method schematic diagram of the present invention.

Fig. 7 is the distribution of electrodes figure that contains core piezoelectric rods 10 of the present invention.

Fig. 8 is the distribution of electrodes figure that contains core piezoelectric rods 20 of the present invention.

Fig. 9 is acceleration measurement method schematic diagram of the present invention.

Figure 10 is the piezoelectric element distribution plan that contains core piezoelectric rods 50 of the present invention.

Figure 11 is the piezoelectric element distribution plan that contains core piezoelectric rods 60 of the present invention.

Figure 12 is transducer sensitivity K value calculating chart of the present invention.

Number in the figure title: 1, contain the core piezoelectric rods, 101, plug, 102, piezoelectric, 103, surface electrode, 111, plug, 112, piezoelectric element, 113, filling material, 11201, the first electrode, 11202, piezoelectric, 11203, the second electrode, 2, pedestal, 3, shell, 4, base, 10, contain the core piezoelectric rods, 20, contain the core piezoelectric rods, 30, contain the core piezoelectric rods, 40, contain the core piezoelectric rods,, 50, contain the core piezoelectric rods, 60, contain the core piezoelectric rods, 70, contain the core piezoelectric rods, 80, contain the core piezoelectric rods, 11, the upper surface electrode that contains core piezoelectric rods 10,12, the right surface electrode that contains core piezoelectric rods 10,13, the lower surface electrode that contains core piezoelectric rods 10,14, the left surface electrode that contains core piezoelectric rods 10,21, the upper surface electrode that contains core piezoelectric rods 20,22, the right surface electrode that contains core piezoelectric rods 20,23, the lower surface electrode that contains core piezoelectric rods 20,24, the left surface electrode that contains core piezoelectric rods 20,51, the upper surface electrode that contains core piezoelectric rods 50,52, the right surface electrode that contains core piezoelectric rods 50,53, the lower surface electrode that contains core piezoelectric rods 50,54, the left surface electrode that contains core piezoelectric rods 50,61, the upper surface electrode that contains core piezoelectric rods 60,62, the right surface electrode that contains core piezoelectric rods 60,63, the lower surface electrode that contains core piezoelectric rods 60,64, the left surface electrode that contains core piezoelectric rods 60.

Embodiment

The present invention is described in further detail below in conjunction with example example and accompanying drawing, but embodiments of the present invention are not limited to this.

Embodiment 1

Fig. 1～2 show the system architecture of the present embodiment, originally contain core piezoelectric rods acceleration sensing, comprise that several contain core piezoelectric rods 1, pedestal 2, base 4 and shell 3; Contain core piezoelectric rods 1 and be distributed in symmetrically around the pedestal 2, and in the same plane; An end that contains core piezoelectric rods 1 is fixed on the pedestal 2, and the other end freely; Pedestal 2 is installed on the base 4; Whole device is included in the shell 3; Shell 3 also is installed on the base 4.

Fig. 3 has described by piezoelectric and has contained core piezoelectric rods structure around what plug formed, contains the xsect of core piezoelectric rods and plug for circular, and piezoelectric 102 is looped around around the plug 101, is piezoelectric ceramics; The surface of piezoelectric 102 is covered with metal electrode 103 symmetrically; Plug 101 is made by metal material, works on the one hand to support piezoelectric, on the other hand, also is used as an electrode.

Fig. 6 has described the measuring method of 3 dimension linear accelerations, whole acceleration transducer is placed cartesian coordinate system, contain the residing plane of core piezoelectric rods as XOY plane, be arranged symmetrically with 10,20,30,40 4 along true origin and contain the core piezoelectric rods, the axial line and coordinate axis X, the Y that contain the core piezoelectric rods overlap, the suffered acceleration of sensor is a, with the angle of the positive dirction of coordinate axis X, Y, Z be α, β, γ.

Fig. 7 has described the distribution of electrodes that contains core piezoelectric rods 10, and surface electrode 11,12,13,14 distributes symmetrically along the axle center, and electrode 11 and 13 center line are positioned on the XOZ plane, and electrode 12 and 14 center line are positioned on the XOY plane.

Fig. 8 has described the distribution of electrodes that contains core piezoelectric rods 20, and surface electrode 21,22,23,24 distributes symmetrically along the axle center, and electrode 21 and 23 center line are positioned on the YOZ plane, and electrode 22 and 24 center line are positioned on the XOY plane.

Figure 12 has described definite method of transducer sensitivity K value, contains the both sides that core piezoelectric rods surface electrode 103 is distributed in plane B symmetrically, and plane B is by containing the axis 0-0 of core piezoelectric rods, and acceleration a is positioned on the B of plane, and vertical with axis.When being subject to acceleration a, sensor does the time spent, the charge value Q that produces on the electrode 103 ₁₀₃, the size of acceleration is a ₀, then the K value is: K=Q ₁₀₃/ a ₀

Concrete measuring method is: establishing the suffered acceleration of device is a, then contains the total formula of charge Q that produces on the core piezoelectric rods to be:

Q＝Ka

Wherein K is the sensitivity of sensor, and is relevant with the material that contains the core piezoelectric rods, structure and size.If the angle of acceleration a and X, Y, Z axis positive dirction is respectively α, β, γ.Then containing on the core piezoelectric rods 10, the electric charge that produces on the electrode 11,12,13,14 is respectively:

Q ₁₁＝Kacosγ(1)

Q ₁₃＝-Kacosγ(2)

Q ₁₂＝Ka cosβ(3)

Q ₁₄＝-Ka cosβ(4)

Then containing on the core piezoelectric rods 20, the electric charge that produces on the electrode 21,22,23,24 is respectively:

Q ₂₁＝Kacosγ(5)

Q ₂₂＝-Kacosα(6)

Q ₂₃＝-Kacosγ(7)

Q ₂₄＝Kacosα(8)

cos ²α+cos ²β+cos ²γ＝1 (9)

In formula (1), (3), (8) substitution formula (9), obtain

$a_0=\frac{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}}{K}---\left(10\right)$

Again a is updated in formula (1), (3), (8), obtains angle α, β, γ between a and X, Y, the Z coordinate axis forward,

$\mathrm{\&alpha;}=\arccos \frac{Q_{24}}{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}}---\left(11\right)$

$\mathrm{\&beta;}=\arccos \frac{Q_{12}}{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}}---\left(12\right)$

$\mathrm{\&gamma;}=\arccos \frac{Q_{11}}{\sqrt{{\mathrm{<figure-callout\; id="24"\; label="Q"\; filenames="110125143802.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{24}^2+Q_{12}^2+Q_{11}^2}}---\left(13\right)$

Can be found out by solution procedure, in containing 8 electrode electric charges of core piezoelectric rods 10 and 20, only use the numerical value of 3 electrode electric charges, other electrode electric charge is as the reference electric charge.Contain core piezoelectric rods 30 and 40 roles and have 2:

The one, constitutional balance; The 2nd, after corresponding electrode series connection, the electric charge that produces on the electrode is multiplied, and has improved the sensitivity of sensor.

Embodiment 2

Contain the core piezoelectric rods among the embodiment 2 and sticked on the plug by piezoelectric element and form, other part-structures are identical with embodiment 1.

Fig. 4 described by piezoelectric element stick on form on the plug contain core piezoelectric rods structure, several piezoelectric elements 112 stick on around the plug 111 symmetrically; Fill up with epoxy resin 113 between the piezoelectric element 112, make whole the surperficial complete of core piezoelectric rods that contain; The material of plug is that metal or compound substance are made.

Fig. 5 has described the structure of piezoelectric element, and piezoelectric element comprises piezoelectric 11202, the first electrode 11201 and the second electrode 11203.The first electrode 11201 wherein and the second electrode 11203 are coated in the two sides of piezoelectric 11202, and piezoelectric 11202 is positioned at the centre of 2 electrodes, similar sandwich structure; The xsect of piezoelectric element presents circular shape; The polarised direction of piezoelectric is parallel to the arc diameter direction.Because direct piezo electric effect when piezoelectric element is subject to ess-strain, will produce electric charge and voltage at electrode.

Fig. 9 has described the measuring method of 3 dimension linear accelerations, whole acceleration transducer is placed cartesian coordinate system, contain the residing plane of core piezoelectric rods as XOY plane, be arranged symmetrically with 50,60,70,80 4 along true origin and contain the core piezoelectric rods, the axial line and coordinate axis X, the Y that contain the core piezoelectric rods overlap, the suffered acceleration of sensor is a, with the angle of the positive dirction of coordinate axis X, Y, Z be α, β, γ.

Figure 10 has described the piezoelectric element that contains core piezoelectric rods 50 and has distributed, and piezoelectric element 51,52,53,54 distributes symmetrically along the axle center, and piezoelectric element 51 and 53 center line are positioned on the XOZ plane, and piezoelectric element 52 and 54 center line are positioned on the XOY plane.

Figure 11 has described the piezoelectric element that contains core piezoelectric rods 60 and has distributed, and piezoelectric element 61,62,63,64 distributes symmetrically along the axle center, and piezoelectric element 61 and 63 center line are positioned on the YOZ plane, and piezoelectric element 62 and 64 center line are positioned on the XOY plane.

Concrete measuring method is: establishing the suffered acceleration of device is a, is respectively α, β, γ with the angle of X, Y, Z axis positive dirction.Then containing on the core piezoelectric rods 50, the electric charge that produces on the piezoelectric element 51,52,53,54 is respectively Q ₅₁, Q ₅₂, Q ₅₃, Q ₅₄, containing on the core piezoelectric rods 60, the electric charge that produces on the piezoelectric element 61,62,63,64 is respectively Q ₆₁, Q ₆₂, Q ₆₃, Q ₆₄, then the size of acceleration is

$a_0=\frac{\sqrt{Q_{64}^2+{\mathrm{<figure-callout\; id="52"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{52}^2+{\mathrm{<figure-callout\; id="51"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{51}^2}}{K}---\left(14\right)$

Angle α, β, γ between a and X, Y, the Z coordinate axis forward,

$\mathrm{\&alpha;}=\arccos \frac{Q_{64}}{\sqrt{Q_{64}^2+{\mathrm{<figure-callout\; id="52"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{52}^2+{\mathrm{<figure-callout\; id="51"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{51}^2}}---\left(15\right)$

$\mathrm{\&beta;}=\arccos \frac{Q_{52}}{\sqrt{Q_{64}^2+{\mathrm{<figure-callout\; id="52"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{52}^2+{\mathrm{<figure-callout\; id="51"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{51}^2}}---\left(16\right)$

$\mathrm{\&gamma;}=\arccos \frac{Q_{51}}{\sqrt{Q_{64}^2+{\mathrm{<figure-callout\; id="52"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{52}^2+{\mathrm{<figure-callout\; id="51"\; label="Q"\; filenames="110125143807.png"\; state="\{\{state\}\}">Q</figure-callout>}}_{51}^2}}---\left(17\right)$

During containing the core piezoelectric rods and is comprised of piezoelectric parcel plug among the present invention, can make fiber shape with containing the core piezoelectric rods, whole acceleration transducer can be made MEMS, for portable terminal.

Although above literal has been described the present invention with reference to specific embodiment and example of the present invention, the invention is not restricted to embodiment described above.According to know-why of the present invention, those of ordinary skills make amendment and are out of shape with reference to above-mentioned know-why embodiment and all belong to protection scope of the present invention.

Claims (3)

1. piezoelectric acceleration sensor, it is characterized in that: comprise base (4), be installed on pedestal (2), symmetry on the base (4) be installed on pedestal (2) all around and be co-located in four of the whole across layout of same plane identical contain the core piezoelectric rods, be respectively first and contain core piezoelectric rods (10), second and contain core piezoelectric rods (20), the 3rd and contain core piezoelectric rods (30), the 4th and contain core piezoelectric rods (40); Contain core piezoelectric rods one end and be fixed on the pedestal, the other end freely; Also comprise the shell (3) that is installed on the base (4);

The above-mentioned core piezoelectric rods that contains is comprised of piezoelectric parcel plug, piezoelectric material surface also vertically by upper and lower, left and right symmetrical four surface electrodes.

2. piezoelectric acceleration sensor according to claim 1 is characterized in that: above-mentionedly contain in the core piezoelectric rods that piezoelectric is that one of piezoelectric monocrystal, piezoelectric ceramics, Kynoar or several combinations of its kind are made in piezoelectric or the piezoelectric element.

3. utilize the acceleration measurement method of the described piezoelectric acceleration sensor of claim 1, it is characterized in that comprising following process:

(1), whole acceleration transducer is placed cartesian coordinate system, contain the residing plane of core piezoelectric rods as XOY plane, the center of four core piezoelectric rods and pedestal installation place is the O point, wherein first contains core piezoelectric rods (10) and overlaps with the X-axis positive dirction, second contains core piezoelectric rods (20) overlaps with the Y-axis positive dirction, the 3rd contains core piezoelectric rods (30) and overlap with the X-axis negative direction, the 4th contain core piezoelectric rods (40) and overlap with the Y-axis negative direction, crosses the vertical XOY plane of O point and direction and upwards is the Z axis positive dirction;

(2), contain successively meter work: Q of the upper surface electrode of core piezoelectric rods (10), right surface electrode, lower surface electrode, the electrically charged value difference of left surface electrode institute with first ₁₁, Q ₁₂, Q ₁₃, Q ₁₄Contain successively meter work: Q of the upper surface electrode of core piezoelectric rods (20), right surface electrode, lower surface electrode, the electrically charged value difference of left surface electrode institute with second ₂₁, Q ₂₂, Q ₂₃, Q ₂₄

(3), acceleration a acts on when containing core piezoelectric rods multi-axis accelerometer, the angle of establishing the positive dirction of acceleration a and coordinate axis X, Y, Z is respectively and is α, β, γ;

(4), according to the size and Orientation of following Formula For Solving acceleration a

Wherein K is the sensitivity of sensor, size for when acceleration vertical with the axis that contains the core piezoelectric rods, and the central vertical that is positioned at surface electrode is when dividing the plane equally, the charge value of surface electrode generation and the ratio of acceleration magnitude;

$\mathrm{\&alpha;}=\arccos \frac{Q_{24}}{\sqrt{Q_{24}^2+Q_{12}^2+Q_{11}^2}};$

$\mathrm{\&beta;}=\arccos \frac{Q_{12}}{\sqrt{Q_{24}^2+Q_{12}^2+Q_{11}^2}};$

$\mathrm{\&gamma;}=\arccos \frac{Q_{11}}{\sqrt{Q_{24}^2+Q_{12}^2+Q_{11}^2}}.$

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