Flexible Piezoelectric Film Sensor Performance Testing Tooling and Its Testing Method

Abstract

Flexible piezoelectric thin film sensor performance testing tooling and its testing method, which relates to the technical field of sensor performance testing, especially belongs to a flexible piezoelectric thin film sensor performance testing tooling and its testing method. It includes a base (1), on which a power supply module (2) and an oscilloscope (3) are movably connected. The power supply module is connected to a reduction motor (7), and the oscilloscope is connected to the flexible piezoelectric thin film sensor to be tested (13). A first support rod (4) and a second support rod (5) are arranged on the base. A motor support platform (6) is installed on the first support rod, and a reduction motor (7) is fixed on the motor support platform. The output end of the reduction motor is connected with a blade (10); a sensor clamping platform is installed on the second support rod. The invention has the positive effects of simple structure, strong practicability, and being able to simultaneously measure the sensitivity, normal temperature service life (fatigue test), and high and low temperature service life performance of the flexible piezoelectric thin film sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of sensor performance testing, and in particular, to a performance testing tooling and testing method for a flexible piezoelectric film sensor. Background Art

[0002] Flexible piezoelectric film is a functional material that can achieve the mutual conversion between electrical signals and force signals, mainly including polyvinylidene fluoride piezoelectric film and polypropylene piezoelectric electret. The piezoelectric strain constant is an important parameter reflecting the performance of piezoelectric materials. The piezoelectric strain constant reflects the change in the charge of the piezoelectric material in a certain direction when it is subjected to stress in a certain direction. When the flexible piezoelectric film material is made into a flexible piezoelectric film sensor, the piezoelectric strain constant will change due to reasons such as encapsulation, and it is no longer valuable to use the piezoelectric strain constant to reflect the sensitivity of the flexible piezoelectric film sensor. Similar sensors on the market generally usually adopt a more intuitive measure, that is, the change value of the output voltage ΔV with the load to reflect the sensitivity of the sensor.

[0003] However, there is currently no testing equipment on the market that can simultaneously measure the sensitivity, high and low temperature performance, and service life of flexible piezoelectric film sensors. Summary of the Invention

[0004] The purpose of the present invention is to provide a performance testing tooling and testing method for a flexible piezoelectric film sensor, so as to achieve the purpose of being able to simultaneously measure the performance of the flexible piezoelectric film sensor, such as sensitivity, high and low temperature performance, and service life.

[0005] A performance testing tooling for a flexible piezoelectric film sensor provided by the present invention is characterized in that it includes a base, on which a power supply module, an oscilloscope are movably connected, the power supply module is connected to a reduction motor, the oscilloscope is connected to the flexible piezoelectric film sensor to be tested, a first support rod and a second support rod are arranged on the base, a motor support platform is installed on the first support rod, a reduction motor is fixed on the motor support platform, and the output end of the reduction motor is connected with a blade; a sensor clamping platform is installed on the second support rod, the sensor clamping platform includes an upper clamping piece and a lower clamping piece, the flexible piezoelectric film sensor to be tested is placed between the upper clamping piece and the lower clamping piece, and among them, the blade is in contact and induction cooperation with the flexible piezoelectric film sensor to be tested within its sensing range.

[0006] Further, the upper end of the first support rod has a threaded section, the threaded section of the first support rod penetrates through the motor support platform and is fitted with a fastening nut for installation and fixation.

[0007] Further, the upper end of the second support rod has a threaded section, the threaded section of the second support rod penetrates through the lower clamping piece and the upper clamping piece, and the bottom end of the lower clamping piece and the top end of the upper clamping piece are respectively fitted with fastening nuts and installed at the upper end of the second support rod.

[0008] Further, the length of the test end of the flexible piezoelectric film sensor is 15-20 mm, and the two poles of the oscilloscope are connected to the two poles of the flexible piezoelectric film sensor to be tested.

[0009] The test method of the performance test tooling for the flexible piezoelectric film sensor provided by the present invention is characterized in that it includes sensitivity test, service life test and high and low temperature performance test, wherein,

[0010] In the sensitivity test:

[0011] Turn on the power supply of the oscilloscope; turn on the power supply of the reduction motor, the blade rotates, the oscilloscope displays the voltage signal collected in real time, record the peak value of the voltage signal collected by the oscilloscope each time within a period of time, and obtain the maximum value of the voltage peak value. Then, the sensor sensitivity s can be calculated by the following formula, that is:

[0012] s = Ur / T, where,

[0013] s is the sensitivity, unit: V / g;

[0014] U is the maximum value of the voltage peak value, unit: V;

[0015] r is the distance between the motor axis and the center in the width direction of the sensor to be measured, unit: m;

[0016] T is the torque of the motor, unit: g•m;

[0017] In the service life test:

[0018] Under normal temperature conditions, turn on the power supply of the oscilloscope and the reduction motor, the blade rotates, the oscilloscope starts to display the voltage signal generated by the blade hitting the sensor, record the moment t1 when the power supply is turned on, and record the moment t2 corresponding to when the peak value of the voltage signal displayed by the oscilloscope is the same as the peak value of the noise signal. Then, the normal temperature service life t0 of the sensor can be calculated by the following formula, that is:

[0019] t0 = 2(t2 - t1)n, where,

[0020] t0 is the normal temperature service life of the sensor, unit: times;

[0021] n is the blade rotation speed, unit: RPM;

[0022] t1 is the moment when the power supply is turned on, unit: minute;

[0023] t2 is the moment corresponding to when the peak value of the voltage signal displayed by the oscilloscope is the same as the peak value of the noise signal, unit: minute;

[0024] Three flexible piezoelectric film sensors of the same batch are used. According to the above formula, the service life of the sensor at room temperature is obtained, and the lowest value of the service life at room temperature is selected as the service value;

[0025] In the high and low temperature performance test:

[0026] This tooling (except for the DC power supply and oscilloscope) is placed in an oven or a refrigerator; the power supply of the oscilloscope and the reduction motor is turned on, the blade rotates, and the temperature of the oven is gradually increased to a high temperature (80 - 85 °C, heating rate 1 - 2 °C / min) or the temperature of the refrigerator is gradually decreased to a low temperature (-40 °C, cooling rate 0.5 - 2 °C / min); at the same interval of time in the high or low temperature environment, record the peak value of the voltage signal generated in the oscilloscope, and the electrical performance attenuation information of the sensor in the high or low temperature environment can be obtained; record the moment t1' when the high or low temperature environment reaches the preset temperature, and record the moment t2' corresponding to when the peak value of the voltage signal displayed on the oscilloscope is the same as the peak value of the noise signal. Then, the high and low temperature service life t' of the sensor can be calculated by the following formula, that is:

[0027] t’ = 2(t2’ - t1’)n’

[0028] t’ is the high and low temperature service life of the sensor, unit: times;

[0029] n’ is the blade rotation speed, unit: RPM;

[0030] t1’ is the moment when the preset temperature is reached, unit: minutes;

[0031] t2’ is the moment corresponding to when the peak value of the voltage signal displayed on the oscilloscope is the same as the peak value of the noise signal, unit: minutes;

[0032] Three flexible piezoelectric film sensors of the same batch are used. According to the above formula, the high and low temperature service life of the sensor is obtained, and the lowest value of the high and low temperature service life of the sensor is selected as the service value.

[0033] Furthermore, the high and low temperature service life of the sensor is greater than or equal to 50% of the room temperature service life of the sensor.

[0034] The performance test tooling and its test method for the flexible piezoelectric film sensor provided by the present invention can effectively, quickly and conveniently evaluate various performances of the flexible piezoelectric film sensor. The setting of the reduction motor can make the force received by the flexible piezoelectric film sensor the same each time, thus effectively avoiding the result deviation caused by uneven force. To sum up, the present invention has the positive effects of simple structure, strong practicability, and being able to concurrently measure the sensitivity, room temperature service life (fatigue test) and high and low temperature service life performance of the flexible piezoelectric film sensor. Description of the Drawings

[0035] The accompanying drawings partially disclose specific embodiments of the present invention, wherein,

[0036] Figure 1 is a schematic structural diagram of the present invention. Specific embodiments

[0037] As Figure 1 shown, the performance test tooling for the flexible piezoelectric thin film sensor provided by the present invention includes a base 1, and a power supply module 2 and an oscilloscope 3 are movably connected to the base. In a specific embodiment, the power supply module can adopt a 3W isolated regulated AP12N03-ZeroAC-DC switching power supply module that converts 220V to 12V, or 5th and 7th dry batteries or lithium-ion batteries can also be selected to form the working voltage of 3-12V required for the reduction motor to provide working power for the reduction motor. The oscilloscope can adopt the UPO2102CS dual-channel oscilloscope of UNI-T Electronic Co., Ltd. When the oscilloscope is used, it is externally connected to 220V alternating current, and the positive and negative poles of the oscilloscope are connected to the two poles (regardless of positive and negative) of the flexible piezoelectric thin film sensor to be tested. Specifically, when the reduction motor drives the blade to rotate, the voltage signal information generated by the piezoelectric thin film sensor under the impact of the blade can be measured through the oscilloscope.

[0038] A first support rod 4 and a second support rod 5 are also provided on the base. A motor support platform 6 is installed on the first support rod, and a reduction motor 7 is fixed on the motor support platform. Specifically, the upper end of the first support rod has a threaded section, and the threaded section of the first support rod penetrates through the motor support platform and is installed and fixed with a fastening nut 8. In order to strengthen the stability of the reduction motor, it can also be assisted and fixed by a cable tie 9. Among them, a blade 10 is connected to the output end of the reduction motor. A sensor clip platform is installed on the second support rod. The sensor clip platform includes an upper clip 11 and a lower clip 12. Specifically, the upper end of the second support rod has a threaded section, and the threaded section of the second support rod penetrates through the lower clip and the upper clip. The bottom end of the lower clip and the top end of the upper clip are respectively fitted with fastening nuts and installed at the upper end of the second support rod. The flexible piezoelectric film sensor 13 to be tested is placed between the upper clip and the lower clip. In this way, by adjusting the position of the fastening nut at the top end of the upper clip, the flexible adjustment of the placement process and the installation and fixation process of the flexible piezoelectric film sensor to be tested can be realized. Among them, the blade and the flexible piezoelectric film sensor to be tested are in contact and induction cooperation within its induction range. Preferably, the test end length of the flexible piezoelectric film sensor is 15-20 mm, and when the blade is in the induction state with the flexible piezoelectric film sensor to be tested, it is just in the same plane as the end face where the induction end of the flexible piezoelectric film sensor to be tested is located. In this way, when the blade is in the horizontal position and contacts and senses the end face of the flexible piezoelectric film sensor to be tested, the lower edge of the blade just coincides with the plane of the flexible piezoelectric film sensor. At this moment, the blade will give a vertically downward force to the flexible piezoelectric film sensor, and the flexible piezoelectric film sensor after being stressed will exhibit a certain strength of voltage signal, and this voltage signal can be detected and displayed by an oscilloscope.

[0039] Next, through the specific test process of the present invention in the performance test of the flexible piezoelectric film sensor, the present invention will be further described and explained.

[0040] 1. When using the performance test tooling of the flexible piezoelectric film sensor of the present invention to perform the piezoelectric performance test of the flexible piezoelectric film sensor, it mainly includes the sensor sensitivity test. Among them,

[0041] During the sensor sensitivity test process, turn on the power supply of the oscilloscope; turn on the power supply of the reduction motor, the blade rotates, and the oscilloscope displays the voltage signal collected in real time. Record the peak value of the voltage signal collected by the oscilloscope each time within a period of time, and obtain the maximum value of the voltage peak value. Then the sensor sensitivity s can be calculated by the following formula, that is:

[0042] s = Ur / T, where,

[0043] s is the sensitivity, unit: V / g;

[0044] U is the maximum value of the voltage peak value, unit: V;

[0045] r is the distance between the axis of the motor and the center in the width direction of the sensor under test, unit: m;

[0046] T is the torque of the motor, unit: g•m.

[0047] 2. When using the performance test tooling of the flexible piezoelectric film sensor of the present invention to conduct the room temperature service life test of the flexible piezoelectric film sensor, the following test process is included:

[0048] Under room temperature conditions, turn on the power supply of the oscilloscope and the reduction motor. The blade rotates, and the oscilloscope starts to display the voltage signal generated by the blade hitting the sensor. Record the moment t1 when the power supply is turned on, and record the moment t2 corresponding to when the peak value of the voltage signal displayed by the oscilloscope is the same as the peak value of the noise signal. Then, the room temperature service life t0 of the sensor can be calculated by the following formula, that is:

[0049] t0 = 2(t2 - t1)n, where,

[0050] t0 is the room temperature service life of the sensor, unit: times;

[0051] n is the blade rotation speed, unit: RPM;

[0052] t1 is the moment when the power supply is turned on, unit: minute;

[0053] t2 is the moment corresponding to when the peak value of the voltage signal displayed by the oscilloscope is the same as the peak value of the noise signal, unit: minute;

[0054] Three flexible piezoelectric film sensors of the same batch are used. According to the above formula, the service life of the sensor under room temperature conditions is obtained, and the lowest value of the service life under room temperature conditions is selected as the service value.

[0055] 3. When using the performance test tooling of the flexible piezoelectric film sensor of the present invention to conduct the high and low temperature performance test of the flexible piezoelectric film sensor, the following test process is included:

[0056] This tooling (except for the DC power supply and oscilloscope) is placed in an oven or a cold storage; turn on the power supply of the oscilloscope and the reduction motor, the blade rotates, gradually raise the temperature of the oven to a high temperature (80 - 85 °C, heating rate 1 - 2 °C / min) or gradually lower the temperature of the cold storage to a low temperature (-40 °C, cooling rate 0.5 - 2 °C / min); at the same interval of time in the high temperature or low temperature environment, record the peak value of the voltage signal generated in the oscilloscope, and the electrical performance attenuation information of the sensor in the high temperature or low temperature environment can be obtained; record the moment t1' when the high temperature environment or low temperature environment reaches the preset temperature, record the moment t2' corresponding to when the peak value of the voltage signal displayed on the oscilloscope is the same as the peak value of the noise signal, then, the high and low temperature service life t' of the sensor can be calculated by the following formula, that is:

[0057] t’ = 2(t2’ - t1’)n’

[0058] t’ is the high and low temperature service life of the sensor, unit: times;

[0059] n’ is the blade rotation speed, unit: RPM;

[0060] t1’ is the moment when the preset temperature is reached, unit: minutes;

[0061] t2’ is the moment corresponding to when the peak value of the voltage signal displayed on the oscilloscope is the same as the peak value of the noise signal, unit: minutes;

[0062] Use 3 flexible piezoelectric film sensors of the same batch. According to the above formula, obtain the high and low temperature service life of the sensor, and select the lowest value of the high and low temperature service life of the sensor as the service value. Among them, the high and low temperature service life of the sensor is greater than or equal to 50% of the normal temperature service life of the sensor.

Claims

1. Testing method for performance of a flexible piezoelectric thin film sensor testing tooling, characterized in that, the tooling includes a base (1), on which a power supply module (2), an oscilloscope (3), the power supply module and a reduction motor (7), and the oscilloscope and a flexible piezoelectric thin film sensor to be tested (13) are movably connected. A first support rod (4) and a second support rod (5) are arranged on the base. A motor support platform (6) is installed on the first support rod, and a reduction motor (7) is fixed on the motor support platform. The output end of the reduction motor is connected with a blade (10); A sensor clamping platform is installed on the second support rod. The sensor clamping platform includes an upper clamping piece (11) and a lower clamping piece (12). The flexible piezoelectric thin film sensor to be tested is placed between the upper clamping piece and the lower clamping piece. Among them, the blade is in contact and induction cooperation with the flexible piezoelectric thin film sensor to be tested within its sensing range; The testing method includes sensitivity testing, service life testing and high and low temperature performance testing. Among them, in the sensitivity testing: turn on the power supply of the oscilloscope; Turn on the power supply of the reduction motor, the blade rotates, the oscilloscope displays the voltage signal collected in real time, record the peak value of the voltage signal collected by the oscilloscope each time within a period of time, and obtain the maximum value of the voltage peak value. Then, the sensor sensitivity s can be calculated by the following formula, that is: s = Ur / T, where, s is the sensitivity, unit: V / g; U is the maximum value of the voltage peak value, unit: V; r is the distance between the motor axis and the center of the width direction of the sensor under test, unit: m; T is the torque of the motor, unit: g•m; In the service life testing: Under normal temperature conditions, turn on the power supply of the oscilloscope and the reduction motor, the blade rotates, the oscilloscope starts to display the voltage signal generated by the blade hitting the sensor, and record the moment t1 when the power supply is turned on. Record the moment t2 corresponding to when the peak value of the voltage signal displayed by the oscilloscope is the same as the peak value of the noise signal. Then, the normal temperature service life t0 of the sensor can be calculated by the following formula, that is: t0 = 2(t2 - t1)n, where, t0 is the normal temperature service life of the sensor, unit: times; n is the blade rotation speed, unit: RPM; t1 is the moment when the power supply is turned on, unit: minute; t2 is the moment corresponding to when the peak value of the voltage signal displayed by the oscilloscope is the same as the peak value of the noise signal, unit: minute; Three flexible piezoelectric thin film sensors of the same batch are used. According to the above formula, the service life of the sensor under normal temperature conditions is obtained, and the lowest value of the service life under normal temperature conditions is selected as the service value; In the high and low temperature performance testing: The tooling except the DC power supply and the oscilloscope is placed in an oven or a refrigerator; Turn on the power supply of the oscilloscope and the reduction motor, the blade rotates, gradually raise the temperature of the oven to a high temperature of 80 - 85°C at a heating rate of 1 - 2°C / min or gradually lower the temperature of the refrigerator to a low temperature of -40°C at a cooling rate of 0.5 - 2°C / min; At the same interval of time in the high temperature or low temperature environment, record the peak value of the voltage signal generated in the oscilloscope, and the electrical performance attenuation information of the sensor in the high temperature or low temperature environment can be obtained; Record the moment t1' when the high-temperature environment or low-temperature environment reaches the preset temperature, and record the moment t2' when the peak value of the voltage signal displayed on the oscilloscope is the same as the peak value of the noise signal. Then, the high and low temperature service life t' of the sensor can be calculated by the following formula, that is: t' = 2(t2' - t1')n' t' is the high and low temperature service life of the sensor, unit: times; n' is the blade rotation speed, unit: RPM; t1' is the moment when the preset temperature is reached, unit: minutes; t2' is the moment when the peak value of the voltage signal displayed on the oscilloscope is the same as the peak value of the noise signal, unit: minutes; Use 3 flexible piezoelectric film sensors of the same batch. According to the above formula, obtain the high and low temperature service life of the sensor, and select the lowest value of the high and low temperature service life of the sensor as the service value.

2. The test method of the flexible piezoelectric film sensor performance test tooling according to claim 1, It is further characterized in that, The upper end of the first support rod has a threaded section. The threaded section of the first support rod penetrates through the motor support platform and is fitted with a fastening nut for installation and fixation.

3. The test method of the flexible piezoelectric film sensor performance test tooling according to claim 1, It is further characterized in that, The upper end of the second support rod has a threaded section. The threaded section of the second support rod penetrates through the lower clamping piece and the upper clamping piece. The bottom end of the lower clamping piece and the top end of the upper clamping piece are respectively fitted with fastening nuts and installed at the upper end of the second support rod.

4. The test method of the flexible piezoelectric film sensor performance test tooling according to claim 1, It is further characterized in that, The test end length of the flexible piezoelectric film sensor is 15 - 20 mm. The positive and negative poles of the oscilloscope are connected to the two poles of the flexible piezoelectric film sensor to be tested.

5. The test method of the flexible piezoelectric film sensor performance test tooling according to claim 1, It is further characterized in that, The high and low temperature service life of the sensor is greater than or equal to 50% of the normal temperature service life of the sensor.

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