CN100489475C - Piezoelectric type hexa-dimensional force sensor - Google Patents

Abstract

The invention claims a piezoelectric six-dimensional force sensor, which includes a sensor base, a cover, and a piezoelectric four-dimensional force gauge with two opposing working planes fixed in the base through a force transmission pretension frame. The right-handed Cartesian coordinate system is established with the installation plane of the sensor, and the installation positions of the Y0° and X0° cut piezoelectric quartz wafers of the dynamometer meet: the wafers are all even-numbered pieces, evenly distributed on two concentric circles, and the X0° The sensitive axes of the sliced piezoelectric quartz wafers are in the same direction and parallel to the Y-axis; two slices with the same sensitive axes in the same direction and parallel to the X-axis and Z-axis are respectively arranged in the horizontal and vertical directions passing through the center of each dynamometer. For the Y0° cut piezoelectric quartz wafer, the sensitive axes of the remaining wafers are arranged along the tangential direction of the circumference, and the sensitive axes are arranged along the same clockwise direction. The sensor has the advantages of simple and compact structure, small size, no inter-electrode interference, and the output result can be obtained without decoupling the output signal of the sensor.

Description

A piezoelectric six-dimensional force sensor

technical field

The invention belongs to the technical field of piezoelectric sensors, in particular to a sensor for measuring six-dimensional force in space.

Background technique

At present, the known six-dimensional force sensor widely adopts the method of sticking strain gauges on the complex elastic body, and the six-dimensional force signal is obtained by decoupling the output signal of the strain gauges. Processing this type of multi-dimensional force sensor requires high-precision processing equipment, which is difficult to process, and it is difficult to realize the miniaturization of the sensor. At the same time, due to the coupling phenomenon in all directions, it is necessary to perform complex decoupling operations on the output signal to obtain the output result. In addition to the method of directly pasting strain gauges on the elastic body, Chinese patent CN00119096.2 discloses a method of using thick film technology to sinter a thick film force sensitive resistor on the diaphragm, and realize the six-dimensional force signal by decoupling. Although this method overcomes most of the shortcomings of the traditional six-dimensional force sensor pasting strain gauges, there are still coupling phenomena in all directions, and further decoupling operations are still required for the output signals of the force sensitive resistors. Get the output result.

There are also piezoelectric three-dimensional force sensors, which use quartz wafers as sensitive elements, and can directly obtain output results without decoupling operations. But this piezoelectric three-dimensional force sensor cannot realize the measurement of six-dimensional force in space.

Contents of the invention

The object of the present invention is to address the above-mentioned shortcomings in the prior art, and provide a direct output piezoelectric six-dimensional force sensor with a simple structure and no need for decoupling calculations.

Technical solution of the present invention is as follows:

The piezoelectric six-dimensional force sensor proposed by the present invention includes a sensor base, a sensor cover, a piezoelectric force gauge fixedly installed in the sensor base and the like.

Among them, the piezoelectric dynamometer adopts a piezoelectric four-dimensional dynamometer, and the piezoelectric four-dimensional dynamometer is composed of Y0 ⁰ and X0 ⁰ cut piezoelectric quartz wafers, an insulating positioning frame, a signal lead-out socket and a dynamometer box. Y0 ⁰ and X0 ⁰ cut piezoelectric quartz wafers are installed in the positioning holes on the same plane as the insulating positioning frame, and the insulating positioning frame is fixed in the dynamometer box. The right-handed Cartesian coordinate system is established with the installation plane of the sensor, in which the Z axis is vertical to the sensor installation plane upwards, the Y axis is to the right, and the installation positions of Y0 ⁰ and X0 ⁰ -cut piezoelectric quartz wafers should meet the following conditions: Y0 ⁰ cut Both the X0 0-cut piezoelectric quartz wafer and the X0 ⁰ -cut piezoelectric quartz wafer adopt an even number of slices, which are evenly distributed on two concentric circles; the sensitive axes of the X0 ⁰ -cut piezoelectric quartz wafer have the same direction and are parallel to the Y axis; Y0 ⁰ The layout of the cut piezoelectric quartz wafer on the circumference should satisfy: in the horizontal direction and vertical direction passing through the center of each dynamometer, two pieces of Y0 ⁰ with the same sensitive axis direction and parallel to the X-axis and Z-axis should be respectively arranged. For the cut piezoelectric quartz wafer, the sensitive axes of the remaining ^Y00 cut piezoelectric quartz wafers are arranged along the tangential direction of the circumference, and the sensitive axes are arranged along the same clockwise direction, that is, clockwise or counterclockwise.

There are two piezoelectric four-dimensional dynamometers as mentioned above, which are symmetrically installed at both ends of the force transmission pretension frame in the sensor base. The working planes of the two piezoelectric four-dimensional dynamometers should be opposite, and each piezoelectric four-dimensional Each dynamometer has four signal lead-out sockets to lead out the signals, Y0 ⁰ with the same sensitive axis direction, Y0 ⁰ cut piezoelectric quartz crystal with the sensitive axis arranged clockwise or counterclockwise, and X0 ⁰ with the same sensitive axis direction The signal output electrodes of the cut-shaped piezoelectric quartz wafer are respectively connected in parallel and then respectively connected to the signal lead-out sockets, and the signal lead-out sockets are exposed from the sensor cover to output measurement signals to the outside. The center of the force transmission pretension frame is provided with a connecting screw hole of the force application device, and the sensor is connected with the force application platform through a screw to obtain an external force.

In the present invention, piezoelectric ceramic wafers can also be used to replace piezoelectric quartz wafers, and their corresponding relationship is: X0 ⁰ -cut piezoelectric quartz wafers can be replaced with Z0 ^0- cut piezoelectric ceramics (that is, the thickness of the wafer is along the Z-axis direction) Wafer, Y0 ⁰ -cut piezoelectric quartz wafer can be replaced by Y0 ⁰ or X0 ⁰ -cut piezoelectric ceramic wafer to achieve the same technical effect.

The piezoelectric six-dimensional force sensor proposed by the present invention has simple and compact structure, small volume, no inter-electrode interference, and the output result can be obtained without decoupling the output signal of the sensor.

Description of drawings

Fig. 1 is the sectional structure schematic diagram of the dynamometer in this piezoelectric six-dimensional force sensor;

Fig. 2 is the plane structure schematic diagram of the insulating spacer that piezoelectric quartz wafer is installed in the dynamometer;

Fig. 3 is a side view of Fig. 2;

Fig. 4 is an expanded view of the layout of the Y0 ⁰ and X0 ⁰ cut piezoelectric quartz wafers in the piezoelectric six-dimensional force sensor;

Fig. 5 is a schematic structural view of the force transmission frame in the piezoelectric six-dimensional force sensor;

Fig. 6 is the front view of the assembly drawing of the piezoelectric six-dimensional force sensor;

Fig. 7 is a top view of the assembly drawing of the piezoelectric six-dimensional force sensor;

Fig. 8 is a signal processing block diagram of the piezoelectric six-dimensional force sensor.

In the figure: 1, 2, 3—Y0 ⁰ -cut piezoelectric quartz wafer, 4—X0 ⁰ -cut piezoelectric quartz wafer, 5—insulation positioning frame, 6—dynamometer box, 71, 72, 73, 74—signal lead socket, 8—pretightening positioning sleeve, 9—pretightening connection pad, 10—pretightening connection pad connecting screw hole, 11—pretightening screw, 12—transmission Force pretension frame, 13—the connection screw hole of the force device, 14—the sensor cover, 15—the sensor installation screw hole, 16—the sensor cover screw, 17—the pretightening connection pad connection screw, 18— Sensor base.

Detailed ways

Referring to Fig. 6 and Fig. 7, the six-dimensional force sensor is mainly composed of a sensor base 18, a sensor cover 14, two piezoelectric four-dimensional force gauges fixedly installed in the sensor base, two pre-tightened connection pads 9 and a Force transmission pretensioner frame 12 etc. parts are formed. Two piezoelectric four-dimensional dynamometers are symmetrically installed at both ends of the force transmission pretension frame 12 in the sensor base, and each piezoelectric four-dimensional dynamometer has four signal lead-out sockets 71, 72, 73, 74. The cover 14 is exposed to output measurement signals to the outside.

Referring to Fig. 5, the center of the force transmission pretension frame 12 is provided with a connecting screw hole 13 of the force application device, which is connected with the force application platform outside the sensor through the screw rod,

A specific implementation structure of a piezoelectric four-dimensional dynamometer is shown in Figure 1. Taking a piezoelectric quartz wafer as an example, the dynamometer consists of eight Y0 ⁰ -cut piezoelectric crystals 1, 2, 3 and eight X0 ^0- cut piezoelectric crystals. An electric quartz wafer 4, an insulating positioning frame 5, a signal lead-out socket and a dynamometer box 6 form. Referring to Fig. 2 and Fig. 3, process sixteen positioning holes equivalent to the size of the piezoelectric quartz wafer on the two concentric circles of the polytetrafluoroethylene insulating positioning frame 5, and then Y0 ⁰ , X0 ⁰ cut piezoelectric quartz The wafers 1-4 are arranged in the insulating spacer 5 according to the requirements of FIG. 2 and loaded into the load cell 6 . Fig. 4 is an expanded view of the layout of the Y0 ⁰ and X0 ⁰ -cut piezoelectric quartz wafers in the piezoelectric six-dimensional force sensor, where the direction of the arrow indicates the direction of the sensitive axis of the piezoelectric quartz wafer, and the right-handed Cartesian is established with the installation plane of the sensor Coordinate system, in which the Z axis is vertical to the sensor installation plane and upwards, the Y axis is to the right, Y0 ⁰ and X0 ⁰ -cut piezoelectric quartz wafers 1, 2, 3 and 4 are respectively distributed on two concentric circles, X0 ⁰ -cut There are eight piezoelectric quartz wafers 4, which are evenly arranged on the circumference, and their sensitive axes have the same direction and are parallel to the Y axis. There are also eight pieces of Y0 ^0- cut piezoelectric quartz wafers, which are evenly distributed on another circumference, and two pieces of sensitive axes are arranged in the horizontal direction and vertical direction passing through the center of each dynamometer respectively. The Y0 ⁰ -cut piezoelectric quartz wafer 1 and 2 of the X-axis and the Z-axis, the sensitive axes of the other four Y0 ⁰ -cut piezoelectric quartz wafers 3 are arranged along the tangential direction of the circle where they are located, and their sensitive axis directions are along the same hour hand ( The illustration is arranged in a counterclockwise) direction.

The assembly method of the six-dimensional force sensor is: first assemble the piezoelectric four-dimensional force gauge according to the above requirements, and then under the positioning action of the pre-tightening positioning sleeve 8, sequentially connect the pre-tightening connection pad 9, the piezoelectric four-dimensional force measuring One end of the meter and the force transmission pretension frame 12 is connected together with a certain pretension force through the pretension screw 11, and the other end of the force transmission pretension frame 12 is connected according to the same structure, and then two pretension connection pads are connected. The force transmission pretension frame 12 of the block 9 and the piezoelectric four-dimensional dynamometer is packed in the sensor base 18, and the two pretension connection pads 9 are fixedly connected to the sensor base 18 with the pretension connection pad connection screws 17, Then the sensor cover screw 16 is fixedly connected with the sensor cover 14, and finally the processed force applying platform is connected with the force transmission pretensioning frame 12 through the screw rod and the connecting screw hole 13 of the force applying device.

Referring to Figure 8, when an external force acts on the six-dimensional force sensor, connect the eight signal outlets to the corresponding charge amplifiers I ₁ -I ₄ , II ₁ -II ₄ respectively, and connect the eight-way charge amplifier to the eight-way signal acquisition card. The output signal is transmitted to the microprocessor (or computer), and the six-dimensional force information can be intuitively obtained through the six-dimensional force display module after performing simple calculations in the microprocessor (or computer).

The following is a description of the working principle of the six-dimensional force sensor:

When F _X acts on the sensor, the piezoelectric quartz wafers I ₁ and II ₁ (I, II represent the number of the dynamometer respectively, and the subscript indicates the number of the piezoelectric quartz wafer in the dynamometer) will produce size and direction have the same charge, that is, $Q_{I_1}-Q_{{\mathrm{II}}_1}=0;$ When M _Z acts on the sensor, the piezoelectric quartz wafers I ₁ and II ₁ will generate charges of equal size and opposite directions, namely $Q_{I_1}+Q_{{\mathrm{II}}_1}=0;$ When M _X acts on the sensor, the piezoelectric quartz wafers I ₂ and II ₂ will generate charges with the same size and direction, namely $Q_{I_2}-Q_{{\mathrm{II}}_2}=0;$ When F _Z acts on the sensor, the piezoelectric quartz wafers I ₂ and II ₂ will have equal and opposite charges, namely $Q_{I_2}+Q_{{\mathrm{II}}_2}=0;$ When M _Y acts on the sensor, the piezoelectric quartz wafers I ₃ and II ₃ will generate charges of equal size and opposite directions, namely $Q_{I_3}+Q_{{\mathrm{II}}_3}=0;$ When F _Y acts on the sensor, the piezoelectric quartz wafers I ₄ and II ₄ will generate charges of equal magnitude and opposite directions, namely $Q_{I_4}+Q_{{\mathrm{II}}_4}=0.$

Therefore, when the external force acts on the center of the force application platform, the output of the six-dimensional force sensor is:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; II</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>\\ {\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; II</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}\\ {\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; Z</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; II</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}\\ {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; II</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}\\ {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; II</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}\\ {\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; Z</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; II</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}\end{array}\right.$

According to the above analysis, it can be seen that there is no interpolar interference in this sensor, and the output result can be obtained without complex decoupling operations on the output signal of the sensor.

Claims (3)

1, a kind of piezoelectric type hexa-dimensional force sensor comprises sensor base (18), sensor cover (14) and is fixedly installed in the interior piezoelectricity dynamometer of sensor base (18), it is characterized in that:

Described piezoelectricity dynamometer adopts the four-dimensional dynamometer of piezoelectricity, and the four-dimensional dynamometer of described piezoelectricity is by Y0 ⁰And X0 ⁰Cut type piezoelectric quartz wafer (1,2,3 and 4), insulation locating rack (5), signal are drawn socket and dynamometer box (6) formation; Y0 ⁰And X0 ⁰Cut type piezoelectric quartz wafer is installed in the pilot hole on insulation locating rack (5) the same plane, and insulation locating rack (5) is fixed in the dynamometer box (6); Set up right hand Cartesian coordinates with the mounting plane of sensor, wherein the Z axle perpendicular to the sensor mounting plane upwards, Y-axis to the right, Y0 ⁰And X0 ⁰The installation site of cut type piezoelectric quartz wafer (1,2,3 and 4) meets the following conditions: Y0 ⁰Cut type piezoelectric quartz wafer (1,2,3) and X0 ⁰Cut type piezoelectric quartz wafer (4) all adopts the even number sheet, is evenly distributed on respectively on two concentric circless; X0 ⁰The sensitive axes direction of cut type piezoelectric quartz wafer (4) is identical and be parallel to Y-axis; Y0 ⁰Cut type piezoelectric quartz wafer should satisfy in the layout on the circumference: will arrange respectively on the horizontal direction of crossing each dynamometer center and vertical direction that two sensitive axes directions are identical and be parallel to the Y0 of X-axis and Z axle respectively ⁰Cut type piezoelectric quartz wafer (1 and 2), remaining Y0 ⁰The sensitive axes of cut type piezoelectric quartz wafer (3) is arranged along the tangential direction of place circumference, and its sensitive axes direction is arranged clockwise or counterclockwise;

The four-dimensional dynamometer of described piezoelectricity is drawn socket (71,72,73,74) by four signals signal is drawn, described two Y0 that the sensitive axes direction is identical that cross the horizontal direction at dynamometer center and be parallel to X-axis ⁰Be connected to first signal after the signal output electrode parallel connection of cut type piezoelectric quartz wafer (1) and draw socket (71), described two Y0 that the sensitive axes direction is identical that cross the vertical direction at dynamometer center and be parallel to the Z axle ⁰Be connected to secondary signal after the signal output electrode parallel connection of cut type piezoelectric quartz wafer (2) and draw socket (72), the sensitive axes direction is along Y0 clockwise or that arrange counterclockwise ⁰Be connected to the 3rd signal after the signal output electrode parallel connection of cut type piezoelectric quartz wafer (3) and draw socket (73), X0 ⁰Be connected to the 4th signal after the signal output electrode parallel connection of cut type piezoelectric quartz wafer (4) and draw socket (74);

Totally two of the four-dimensional dynamometers of described piezoelectricity, be installed in power transmission pretension frame (12) two ends in the sensor base symmetrically in the relative mode of working face, signal is drawn socket (71,72,73,74) and is exposed from sensor cover (14), power transmission pretension frame (12) center has application of force platform to connect screw (13), by screw rod sensor is connected with application of force platform.

2, piezoelectric type hexa-dimensional force sensor according to claim 1 is characterized in that: described X0 ⁰Cut type piezoelectric quartz wafer (4) is by Z0 ⁰The cut type piezoelectric ceramic wafer substitutes, and promptly wafer thickness substitutes Y0 along the piezoelectric ceramic wafer of Z-direction ⁰Cut type piezoelectric quartz wafer (1,2,3) is by Y0 ⁰Or X0 ⁰The cut type piezoelectric ceramic wafer substitutes.

3, piezoelectric type hexa-dimensional force sensor according to claim 1 and 2, it is characterized in that: on the four-dimensional dynamometer of the piezoelectricity at power transmission pretension frame (12) two ends, also be separately installed with pretension and connect cushion block (9), the end that pretension connects cushion block (9) and four-dimensional dynamometer of piezoelectricity and power transmission pretension frame (12) links together by pretension screw rod (11) respectively, and it is fixing by attachment screw (17) and sensor base (18) respectively again that pretension connects cushion block (9).

Images