阅读说明：本技术 一种利用压电式传感器反推小球质量的测试方法 (Method for testing quality of small balls by utilizing reverse thrust of piezoelectric sensor ) 是由 黄学坤 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种利用压电式传感器反推小球质量的测试方法,提供一种测试装置,所述测试装置包括用于对下落小球进行夹持的柔性夹持爪、用于固定柔性夹持爪且高度可调的测量支架、用于稳固压电式传感器的稳定支撑结构以及与压电式传感器的非受力面直接连接且用于减少压电式传感器的受力面在被下落小球砸中时发生的待测力分流的连接结构；所述压电式传感器的受力面包括第一测试区域、第二测试区域和第三测试区域,压电式传感器的输出端经过放大倍数确定的共射放大电路后输出瞬时受力图谱。本发明提供了一种操作简单且测量精准度高的压电式传感器的测试方法。(The invention discloses a method for testing the mass of a reversely pushed small ball by using a piezoelectric sensor, which provides a testing device, wherein the testing device comprises a flexible clamping claw for clamping a falling small ball, a measuring support which is used for fixing the flexible clamping claw and has adjustable height, a stable supporting structure for stabilizing the piezoelectric sensor and a connecting structure which is directly connected with a non-stressed surface of the piezoelectric sensor and is used for reducing the shunting of a force to be measured when the stressed surface of the piezoelectric sensor is hit by the falling small ball; the stress surface of the piezoelectric sensor comprises a first test area, a second test area and a third test area, and the output end of the piezoelectric sensor outputs an instantaneous stress map after passing through a common-emission amplifying circuit determined by amplification factors. The invention provides a testing method of a piezoelectric sensor, which is simple to operate and high in measurement accuracy.)

1. The method for testing the mass of the reversely pushed small balls by using the piezoelectric sensor is characterized by providing a testing device, wherein the testing device comprises a flexible clamping claw for clamping a falling small ball, a measuring support which is used for fixing the flexible clamping claw and has adjustable height, a stable supporting structure for stabilizing the piezoelectric sensor and a connecting structure which is directly connected with a non-stressed surface of the piezoelectric sensor and is used for reducing shunting of a force to be measured when the stressed surface of the piezoelectric sensor is hit by the falling small ball;

the stress surface of the piezoelectric sensor comprises a first test area, a second test area and a third test area, and the output end of the piezoelectric sensor outputs an instantaneous stress map after passing through a common-emission amplifying circuit determined by an amplification factor;

the testing method comprises the steps of carrying out a small ball falling experiment according to a testing strategy and calculating experiment data and an instantaneous stress map according to a data processing strategy to obtain the measured mass m of the small ball;

the test strategy comprises a falling matching step for adjusting the falling direction of the small ball, a first test step, a second test step and a third test step for testing, wherein the falling matching step is configured to enable the falling direction of the small ball under the first test step to fall into a first test area, enable the falling direction of the small ball under the second test step to fall into a second test area and enable the falling direction of the small ball under the third test step to fall into a third test area;

the data processing strategy comprises the following steps:

output from piezoelectric transducer according to formula oneThe impulse value I of the first contact process of the falling small ball and the piezoelectric sensor is calculated in the instantaneous stress map, and the first formula is as follows:

the standard mass of the small ball is M, the falling height of the small ball is h, and the initial time t0 of the first contact of the falling small ball and the piezoelectric sensor, the final time t1 of the first contact and the initial time t2 of the second falling contact of the rebounded small ball and the piezoelectric sensor are read from the instantaneous stress map output by the piezoelectric sensor;

calculating the impulse change value according to a second formula, wherein the second formula is as follows: i ═ Δ P ═ mv1-mv0 (note that the v1 direction is the positive direction);

v0 is calculated according to equation three, which is:

v1 is calculated according to formula four, formula three being:

and substituting the impulse value I of the first contact process calculated according to the formula I, the values of v0 calculated according to the formula III and v1 calculated according to the formula IV into the formula II, calculating the measured mass M of the pellet and comparing the measured mass M with the standard mass M of the pellet.

2. The method for testing the mass of the backward propelling pellet by using the piezoelectric transducer as claimed in claim 1, wherein: the first testing step includes substep a1 of dropping the first mass bead from the first designated height with no initial velocity, substep B1 of dropping the first mass bead from the second designated height with no initial velocity, and substep C1 of dropping the second mass bead from the second designated height with no initial velocity.

3. The method for testing the mass of the small balls by using the piezoelectric transducer in the reverse thrust mode as claimed in claim 1 or 2, wherein the method comprises the following steps: the second testing step includes substep a2 of dropping the first mass bead from the first designated height with no initial velocity, substep B2 of dropping the first mass bead from the second designated height with no initial velocity, and substep C2 of dropping the second mass bead from the second designated height with no initial velocity.

4. The method for testing the mass of the small balls by using the piezoelectric transducer in the reverse thrust mode as claimed in claim 1 or 2, wherein the method comprises the following steps: the third testing step includes substep a3 of dropping the first mass bead from the first designated height with no initial velocity, substep B3 of dropping the first mass bead from the second designated height with no initial velocity, and substep C3 of dropping the second mass bead from the second designated height with no initial velocity.

5. The method for testing the mass of the small balls by using the piezoelectric transducer in the reverse thrust mode as claimed in claim 1 or 2, wherein the method comprises the following steps: the flexible clamping claw is provided with a first soft rubber connecting part which is in direct contact with the first mass ball and used for reducing mechanical vibration generated when the flexible clamping claw is opened.

6. The method for testing the mass of the backward propelling pellet by using the piezoelectric transducer as claimed in claim 5, wherein: the flexible support is configured to further include a second soft rubber connection for reducing mechanical vibration of the piezoelectric transducer caused by environmental interference.

7. The method for testing the mass of the backward-thrusted small ball by using the piezoelectric transducer according to claim 6, wherein the method comprises the following steps: the second soft rubber connecting part is directly connected with the piezoelectric sensor.

8. The method for testing the mass of the backward propelling pellet by using the piezoelectric transducer as claimed in claim 1, wherein: the measuring support is vertically provided with a first sliding groove, a first rodless cylinder is arranged below the measuring support, the upper portion of the measuring support is provided with a horizontal adjusting plate matched with the first sliding groove, and the first rodless cylinder is used for driving the horizontal adjusting plate to move up and down along the first sliding groove.

9. The method for testing the mass of the backward propelling pellet by using the piezoelectric transducer as claimed in claim 8, wherein: a first telescopic cylinder is slidably mounted on the horizontal adjusting plate through a second sliding groove, and a connecting rod is fixedly connected to the free end of the first telescopic cylinder.

10. The method for testing the mass of the backward propelling pellet by using the piezoelectric transducer as claimed in claim 9, wherein: one end of the flexible clamping claw is fixedly provided with a first clamping cylinder, and the first clamping cylinder is used for driving the flexible clamping claw to perform clamping or releasing operation; and one end of the first clamping cylinder, which is far away from the flexible clamping claw, is fixedly connected with the connecting rod.

Technical Field

The invention relates to the technical field of piezoelectric sensor testing, in particular to a method for testing the mass of a small ball by utilizing a piezoelectric sensor in a backstepping mode.

Background

The piezoelectric sensor adopts piezoelectric ceramics or piezoelectric crystals as a sensitive element, when the piezoelectric ceramics is pulled, pressed or sheared, induced charges and induced voltages are formed, and the amplitude of the vibration force is obtained by measuring the magnitude of the induced charges or the induced voltages. The piezoelectric vibration force sensor has the advantages of stable performance, wide measurement frequency band and the like, and is widely applied. However, the conventional piezoelectric sensor test method generally has low measurement accuracy, and has a large limitation in measuring minute vibration. The method mainly shows that the sensitivity is difficult to meet the requirement, and when the micro-vibration of the movable part is measured, the magnitude of the induction voltage is often equal to the magnitude of background noise, so that the disturbance characteristic of the movable part cannot be accurately obtained.

The invention patent with the patent number of CN201410291350.8 discloses a parallel 3-SPU six-dimensional force measuring sensor, and a space mechanism is formed by connecting a tension and compression sensor, a spherical hinge and a universal hinge to realize six-dimensional force measurement.

Disclosure of Invention

The invention aims to provide a method for testing the mass of a small ball by utilizing a piezoelectric sensor in a backstepping mode, which is simple to operate and high in measurement accuracy.

In order to achieve the purpose, the invention provides the following technical scheme: a test method for reversely pushing the mass of a small ball by using a piezoelectric sensor provides a test device which comprises a flexible clamping claw for clamping a falling small ball, a height-adjustable measurement support for fixing the flexible clamping claw, a stable support structure for stabilizing the piezoelectric sensor and a connecting structure which is directly connected with a non-stressed surface of the piezoelectric sensor and is used for reducing shunting of a force to be measured when the stressed surface of the piezoelectric sensor is hit by the falling small ball;

the stress surface of the piezoelectric sensor comprises a first test area, a second test area and a third test area, and the output end of the piezoelectric sensor outputs an instantaneous stress map after passing through a common-emission amplifying circuit determined by an amplification factor;

the testing method comprises the steps of carrying out a small ball falling experiment according to a testing strategy and calculating experiment data and an instantaneous stress map according to a data processing strategy to obtain the measured mass m of the small ball;

the test strategy comprises a falling matching step for adjusting the falling direction of the small ball, a first test step, a second test step and a third test step for testing, wherein the falling matching step is configured to enable the falling direction of the small ball under the first test step to fall into a first test area, enable the falling direction of the small ball under the second test step to fall into a second test area and enable the falling direction of the small ball under the third test step to fall into a third test area;

the data processing strategy comprises the following steps:

calculating impulse value I of the first contact process of the falling small ball and the piezoelectric sensor from the instantaneous force map output by the piezoelectric sensor according to a first formula:

the standard mass of the small ball is M, the falling height of the small ball is h, and the initial time t0 of the first contact of the falling small ball and the piezoelectric sensor, the final time t1 of the first contact and the initial time t2 of the second falling contact of the rebounded small ball and the piezoelectric sensor are read from the instantaneous stress map output by the piezoelectric sensor;

calculating the impulse change value according to a second formula, wherein the second formula is as follows: i ═ Δ P ═ mv1-mv0 (note that the v1 direction is the positive direction);

v0 is calculated according to equation three, which is:

v1 is calculated according to formula four, formula three being:

and substituting the impulse value I of the first contact process calculated according to the formula I, the values of v0 calculated according to the formula III and v1 calculated according to the formula IV into the formula II, calculating the measured mass M of the pellet and comparing the measured mass M with the standard mass M of the pellet.

Preferably, the first testing step includes substep a1 of dropping the first mass bead from the first designated height with no initial velocity, substep B1 of dropping the first mass bead from the second designated height with no initial velocity, and substep C1 of dropping the second mass bead from the second designated height with no initial velocity.

Preferably, the second testing step includes substep a2 of dropping the first mass bead from the first designated height with no initial velocity, substep B2 of dropping the first mass bead from the second designated height with no initial velocity, and substep C2 of dropping the second mass bead from the second designated height with no initial velocity.

Preferably, the third testing step includes substep a3 of dropping the first mass bead from the first designated height with no initial velocity, substep B3 of dropping the first mass bead from the second designated height with no initial velocity, and substep C3 of dropping the second mass bead from the second designated height with no initial velocity.

Preferably, the flexible clamping claw is provided with a first soft rubber connecting part which is in direct contact with the first mass ball and is used for reducing mechanical vibration generated when the flexible clamping claw is opened.

Preferably, the flexible support is configured to further include a second soft rubber connection portion for reducing mechanical vibration of the piezoelectric sensor caused by environmental interference.

Preferably, the second soft rubber connecting part is directly connected with the piezoelectric sensor.

Preferably, a first sliding groove is vertically formed in the measuring support, a first rodless cylinder is arranged below the measuring support, a horizontal adjusting plate matched with the first sliding groove is arranged on the upper portion of the measuring support, and the first rodless cylinder is used for driving the horizontal adjusting plate to move up and down along the first sliding groove.

Preferably, a first telescopic cylinder is slidably mounted on the horizontal adjusting plate through a second chute, and a connecting rod is fixedly connected to the free end of the first telescopic cylinder.

Preferably, one end of the flexible clamping claw is fixedly provided with a first clamping cylinder, and the first clamping cylinder is used for driving the flexible clamping claw to perform clamping or releasing operation; and one end of the first clamping cylinder, which is far away from the flexible clamping claw, is fixedly connected with the connecting rod.

Compared with the prior art, the invention has the beneficial effects that:

according to the method for testing the mass of the small ball reversely pushed by the piezoelectric sensor, the sensor stabilizing step is arranged, the flexible support is used for stably clamping the piezoelectric sensor to reduce shunting of the force to be measured, and the first soft rubber connecting part which is directly contacted with the first mass small ball is arranged on the flexible clamping claw and is used for reducing mechanical vibration generated when the flexible clamping claw is opened. The flexible support is arranged to include a stable support structure that reduces positional deviation of the piezoelectric sensor when hit by a falling pellet, thereby reducing mechanical vibration and shunting of force to be measured during measurement and improving accuracy of measured data.

According to the method for testing the mass of the small balls by utilizing the reverse thrust of the piezoelectric sensor, the output end of the piezoelectric sensor passes through the common-emission amplifying circuit determined by the amplification factor and then outputs the instantaneous stress map, so that the magnitude of the induced voltage of the micro-vibration to be measured can be amplified, and the testing accuracy of the piezoelectric sensor is improved.

Drawings

FIG. 1 is a sub-step B1 of the method for testing the quality of a small ball by using a piezoelectric transducer to reversely push, according to the present invention, wherein an instantaneous stress map is output after an output terminal of the piezoelectric transducer passes through a common-emitter amplifier circuit with a magnification factor;

FIG. 2 is a schematic structural diagram of the connection between the flexible support and the measuring support in the method for testing the mass of the small balls by using the piezoelectric transducer;

FIG. 3 is a schematic structural diagram of a measuring stand in a method for testing the mass of a small ball by using a piezoelectric transducer;

FIG. 4 is a schematic structural diagram of a flexible clamping claw in the method for testing the mass of the small balls by using the piezoelectric transducer;

FIG. 5 is a schematic structural diagram of a stable support structure in a method for testing the mass of a small ball by using a piezoelectric transducer.

In the figure: 1. a measuring support; 101. a first chute; 102. a horizontal adjustment plate; 103. a second chute; 104. a first telescopic cylinder; 105. a connecting rod; 106. a first clamping cylinder; 2. a flexible gripper jaw; 201. a first soft rubber connecting portion; 3. a connecting structure; 301. a second soft rubber connecting portion; 4. A piezoelectric sensor; 5. stabilizing the support structure.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 2, the present invention provides an embodiment: a test method for reversely pushing the mass of a small ball by using a piezoelectric sensor 4 is provided, and the test device comprises a flexible clamping claw 2 for clamping the falling small ball, a measuring support 1 which is used for fixing the flexible clamping claw 2 and has adjustable height, a stable supporting structure 5 for stabilizing the piezoelectric sensor 4, and a connecting structure 3 which is directly connected with a non-stressed surface of the piezoelectric sensor 4 and is used for reducing shunting of a force to be measured when the stressed surface of the piezoelectric sensor 4 is hit by the falling small ball;

the stress surface of the piezoelectric sensor 4 comprises a first test area, a second test area and a third test area, and the output end of the piezoelectric sensor 4 outputs an instantaneous stress map after passing through a common-emission amplifying circuit determined by an amplification factor;

the testing method comprises the steps of carrying out a small ball falling experiment according to a testing strategy and calculating experiment data and an instantaneous stress map according to a data processing strategy to obtain the measured mass m of the small ball;

the test strategy comprises a falling matching step for adjusting the falling direction of the small ball, a first test step, a second test step and a third test step for testing, wherein the falling matching step is configured to enable the falling direction of the small ball under the first test step to fall into a first test area, enable the falling direction of the small ball under the second test step to fall into a second test area and enable the falling direction of the small ball under the third test step to fall into a third test area;

the data processing strategy comprises the following steps:

calculating impulse value I of the first contact process of the falling small ball and the piezoelectric sensor 4 from the instantaneous force map output by the piezoelectric sensor 4 according to a first formula:

the standard mass of the small ball is M, the falling height of the small ball is h, and the initial time t0 of the first contact of the falling small ball and the piezoelectric sensor 4, the final time t1 of the first contact and the initial time t2 of the second falling contact of the piezoelectric sensor 4 after rebounding are read from the instantaneous stress map output by the piezoelectric sensor 4;

calculating the impulse change value according to a second formula, wherein the second formula is as follows: i ═ Δ P ═ mv1-mv0 (note that the v1 direction is the positive direction);

v0 is calculated according to equation three, which is:

v1 is calculated according to formula four, formula three being:

and substituting the impulse value I of the first contact process calculated according to the formula I, the values of v0 calculated according to the formula III and v1 calculated according to the formula IV into the formula II, calculating the measured mass M of the pellet and comparing the measured mass M with the standard mass M of the pellet.

Preferably, the first testing step includes substep a1 of dropping the first mass bead from the first designated height with no initial velocity, substep B1 of dropping the first mass bead from the second designated height with no initial velocity, and substep C1 of dropping the second mass bead from the second designated height with no initial velocity.

Preferably, the second testing step includes substep a2 of dropping the first mass bead from the first designated height with no initial velocity, substep B2 of dropping the first mass bead from the second designated height with no initial velocity, and substep C2 of dropping the second mass bead from the second designated height with no initial velocity.

Preferably, the third testing step includes substep a3 of dropping the first mass bead from the first designated height with no initial velocity, substep B3 of dropping the first mass bead from the second designated height with no initial velocity, and substep C3 of dropping the second mass bead from the second designated height with no initial velocity.

Preferably, the flexible clamping claw 2 is provided with a first soft rubber connecting part 201 which is in direct contact with the first mass ball and is used for reducing mechanical vibration generated when the flexible clamping claw 2 is opened.

Preferably, the flexible support is configured to further include a second soft rubber connection 301 for reducing mechanical vibration of the piezoelectric sensor 4 caused by environmental interference.

Preferably, the second soft rubber connecting portion 301 is directly connected to the piezoelectric sensor 4.

According to the embodiment provided by the invention, the height-adjustable measuring support 1 is vertically provided with the first sliding groove 101, the first rodless cylinder is arranged below the measuring support 1, the upper part of the measuring support 1 is provided with the horizontal adjusting plate 102 matched with the first sliding groove 101, and the first rodless cylinder is used for driving the horizontal adjusting plate 102 to move up and down along the first sliding groove 101. Correspondingly, a first sliding block matched with the first sliding groove 101 is arranged on the horizontal adjusting plate 102.

In an embodiment provided by the present invention, a first telescopic cylinder 104 is slidably mounted on the horizontal adjustment plate 102 through a second sliding chute 103, and in this embodiment, two sides of the horizontal adjustment plate 102 parallel to the opening direction of the second sliding chute 103 are provided with a square sliding chute, and the first telescopic cylinder 104 is fixedly connected to the horizontal adjustment plate 102 through two first fixing bolts penetrating through the square sliding chute; the free end of the first telescopic cylinder 104 is fixedly connected with a connecting rod 105, and the connecting rod 105 is driven by the first telescopic cylinder 104 to horizontally and telescopically move along the direction vertical to the opening direction of the first sliding chute 101 so as to adjust the horizontal position of the flexible clamping claw 2.

Preferably, a first clamping cylinder 106 is fixedly installed at one end of the flexible clamping claw 2, and the first clamping cylinder 106 is used for driving the flexible clamping claw 2 to perform clamping or releasing operation; one end of the first clamping cylinder 106 far away from the flexible clamping claw 2 is fixedly connected with the connecting rod 105.

As shown in fig. 2 and 3, fig. 2 is a schematic structural diagram of a flexible support and a measuring support 1 in a testing method for reversely pushing the quality of a small ball by using a piezoelectric sensor 4 according to the present invention, fig. 3 is a schematic structural diagram of a measuring support 1 in a testing method for reversely pushing the quality of a small ball by using a piezoelectric sensor 4 according to the present invention, a first chute 101 is vertically formed on the measuring support 1 for adjusting a vertical distance between a flexible clamping claw 2 and the piezoelectric sensor 4, a horizontal adjusting plate 102 matched with the first chute 101 is arranged at an upper portion of the measuring support 1, the horizontal adjusting plate 102 is driven by a first rodless cylinder to move up and down along the first chute 101 to adjust the vertical distance between the flexible clamping claw 2 and the piezoelectric sensor 4, a first telescopic cylinder 104 is slidably mounted on the horizontal adjusting plate 102 by a second chute 103, the first telescopic cylinder 104 is used for driving a connecting rod 105 to move telescopically in a horizontal direction, one end of the connecting rod 105 is fixedly connected with a first clamping cylinder 106, and the first clamping cylinder 106 is used for driving the flexible clamping claw 2 to perform clamping and releasing operations. Thereby, the operation of moving the flexible holding claws 2 in the horizontal direction and the vertical direction and the operation of releasing the holding of the flexible holding claws 2 are completed.

As shown in fig. 4-5, which are schematic structural diagrams of the flexible clamping claw 2 in the method for testing the mass of the reverse thrust small ball by using the piezoelectric sensor 4 according to the present invention, the flexible clamping claw 2 is provided with a first soft rubber connecting portion 201 directly contacting with the first mass small ball, so as to reduce mechanical vibration generated when the flexible clamping claw 2 is opened, and improve measurement accuracy.

The experiment of the second embodiment provided by the present invention was carried out as follows:

regarding the selection of the pressure sensor: most force sensors contain an elastic element which deforms under the action of force, and the magnitude of the acting force can be determined through the deformation of a spring. In order to obtain a high measurement resolution, the elastic element is required to have sufficient elasticity. However, the frequency range of the sensor is limited by the large elasticity, and the geometry and the arm relationship of the elastic element are changed due to the force, so that the piezoelectric sensor 4 is adopted for experiments in the embodiment to overcome the limitation. Quartz is used as a piezoelectric material, and can generate electric charge proportional to the force applied under the action of force, and the larger the acting force is, the more the electric charge is. And because the rigidity of quartz is very high, displacement is very small under the action of force, and for the measurement of the rapid process of ball falling, the superiority of the quartz is incomparable with any other principle due to the high rigidity of quartz and the high natural frequency associated with the quartz. The quartz piezoelectric sensor 4 directly converts the pressure into a linear output signal without lag, and the output signal outputs an instantaneous stress map after passing through a common-emission amplifying circuit determined by amplification factors.

Selecting two small balls with standard mass of 10g and 30g for carrying out a test experiment of the piezoelectric sensor 4, firstly, stably clamping the piezoelectric sensor 4 by using a flexible support, specifically, the flexible support comprises a connecting structure 3 for reducing the shunt of a force to be measured when a stress surface of the piezoelectric sensor 4 is hit by a falling small ball and a stable supporting structure 5 for reducing the position deviation of the piezoelectric sensor 4 when the stress surface is hit by the falling small ball, and the stable supporting structure 5 is fixedly connected on a measuring plane through bolts; the connecting structure 3 is connected with the stable supporting structure 5 through bolts, the connecting structure 3 further comprises a clamping continuous adjusting mechanism connected with the non-stressed surface of the piezoelectric sensor 4, and the piezoelectric sensor 4 can be stably clamped and the tightness degree of clamping can be continuously adjusted through the clamping continuous adjusting mechanism;

specifically, the clamping continuous adjusting mechanism is set to be a thread clamping structure, and the second soft rubber connecting part 301 is fixedly installed on one side of a screw rod of the thread clamping mechanism, which is in direct contact with a non-stressed surface of the piezoelectric sensor 4, so that mechanical vibration generated by the piezoelectric sensor 4 due to environmental interference can be reduced.

Specifically, the flexible clamping claw 2 arranged along the horizontal direction is installed on the measuring support 1, and a first soft rubber connecting portion 201 in direct contact with the first small mass ball is arranged on the inner side of the flexible clamping claw 2 and used for reducing mechanical vibration generated when the flexible clamping claw 2 is opened.

Firstly, the height of the height-adjustable measuring support 1 is fixed at the position which is 10cm away from the stress surface of the piezoelectric transducer 4, the stress surface of the piezoelectric sensor 4 is divided into a first test area, a second test area and a third test area according to the area, then, according to the falling matching step, the falling direction of the small balls under the first testing step falls into the first testing area, the falling direction of the small balls under the second testing step falls into the second testing area, the falling direction of the small balls under the third testing step falls into the third testing area, then, the experimental operations of sub-step a1, sub-step B1, sub-step a2, sub-step B2, sub-step A3 and sub-step B3 were respectively performed at a position 10cm away from the force-bearing surface of the piezoelectric transducer 4 using two small balls having a standard mass of 10g and 30g, and the obtained corresponding data were recorded in corresponding tables. Then, the experimental operation of substep C1, substep C2, and substep C3 was performed on a ball having a standard mass of 30g at a distance of 50cm from the force-bearing surface of the piezoelectric transducer 4, respectively, and the obtained data was recorded in the corresponding tables. Wherein the measurement data in the substep A1 and the substep B1 are experimental data made in the case where the standard mass of the pellet was 10g and 30g, respectively, while keeping the falling height constant at 10 cm. The measurement data in the substep C1 and the substep B1 are experimental data made in the case where the standard mass of the pellet was kept constant at 30g and the falling heights of the pellet were 10cm and 50cm, respectively.

The calculation process of the bead mass through the instantaneous force map output by piezoelectric transducer 4 is described in detail below, taking sub-step B1 as an example:

in this embodiment, the output end of the piezoelectric sensor 4 outputs an instantaneous stress map after passing through a common-emitter amplifier circuit with the amplification factor of fig. 1.

According to the formula one

Calculating the impulse value I of the first contact process of the falling small ball and the piezoelectric sensor 4 from the instantaneous force-bearing map output by the piezoelectric sensor 4 to be 0.072 kg.m/s;

the standard mass of the small ball is 30g, the falling height is 10cm, and the initial time t0 of the first contact of the falling small ball and the piezoelectric sensor 4, the final time t1 of the first contact and the initial time t2 of the second falling contact of the piezoelectric sensor 4 after rebounding are read from the instantaneous force map output by the piezoelectric sensor 4, as shown in fig. 1;

according to the formula three

Calculating v0 ═ 1.4 m/s;

according to the formula fourCalculate v 1-1.0 m/s: (ii) a

Calculating the impulse change value according to a second formula, wherein the second formula is as follows: i ═ Δ P ═ mv1-mv0 (note that the v1 direction is the positive direction);

and substituting the impulse value I of the first contact process calculated according to the formula I, the values of v0 calculated according to the formula III and v1 calculated according to the formula IV into the formula II to obtain the measured ball mass m which is 30 g.

Calculating the calculation processes of the substep A1 and the substeps C1 to C3 according to the calculation process of the substep B1, finally obtaining an experimental data analysis table as shown in Table 1, and performing a comparative test on the obtained measured quality data and the standard quality data according to the table 1.

TABLE 1 analysis of experimental data

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.