CN110567672B - Method for testing output characteristics of stacked piezoelectric ceramics under large-range temperature change - Google Patents

Abstract

The invention discloses a method for testing the output characteristics of stacked piezoelectric ceramics under wide temperature changes, belonging to the field of active control of wind tunnel model vibration based on piezoelectric ceramic actuators, and relates to a Test method for output characteristics of ceramic actuators. The method utilizes a testing mechanism to install an optical fiber displacement sensor, a pressure sensor and a stacked piezoelectric ceramic actuator to form a whole testing device, and then the testing device is connected with a measurement and control system and a computer to form a whole testing system. Use the test device to apply a certain preload force to the stacked piezoelectric ceramic actuator, obtain data through the pressure sensor, and compare the output strain of the piezoelectric ceramic itself with the displacement sensor to obtain information such as pressure and displacement. The test device is put into the high and low temperature environmental test box to complete the test of the output characteristics of the piezoelectric ceramic actuator under the conditions of a wide range of temperature changes. The test method is accurate, convenient and highly feasible.

Description

Test method for output characteristics of stacked piezoelectric ceramics under wide temperature changes

technical field

The invention belongs to the field of active vibration control of a wind tunnel model based on piezoelectric ceramic actuators, and relates to a method for testing the output characteristics of stacked piezoelectric ceramic actuators under conditions of wide temperature changes.

Background technique

The purpose of wind tunnel model test is to simulate the complex flight state to obtain the aerodynamic characteristics of the aircraft, so as to provide data support for its aerodynamic performance evaluation, system manipulation and design. However, in the wind tunnel simulation test, the transonic wind tunnel model is fixed by means of struts and tail supports. When the aircraft model is in the test state of large attack angle, there will be low frequency and large vibration due to airflow separation, which not only affects the quality of test data, but also occurs in severe cases. The strut is broken and the wind tunnel is vulnerable to damage. Therefore, the vibration control of the wind tunnel model must be carried out to ensure the smooth and safe conduct of the wind tunnel test.

At present, the active vibration control of wind tunnel model based on piezoelectric ceramic actuator is the most effective. The stacked piezoelectric ceramic actuator can achieve fast and reliable high-frequency response, but the output characteristics of the stacked piezoelectric ceramic actuator will be affected by a wide range of temperature changes in the wind tunnel, and the impact is more serious in the low temperature wind tunnel. The active vibration control method that does not consider the temperature-affected output characteristics of the stacked piezoelectric ceramic actuator will threaten the stability of the wind tunnel active vibration control system and the safety of the wind tunnel test. Therefore, it is necessary to test the output characteristics of the stacked piezoelectric ceramic actuator under a wide range of temperature changes to provide a basis for the active control method of wind tunnel model vibration based on the stacked piezoelectric ceramic actuator.

At present, for the test of the output characteristics of the stacked piezoelectric ceramic actuator: Liu Yugang, Li Zhanjing and others from the Xi'an Flight Automatic Control Research Institute of China Aviation Industry Corporation of China For CN201820577952.3, the device provides a method that can realize the synchronous measurement of piezoelectric ceramic sheet displacement and force, wherein there are several displacement sensors, which are arranged around the piezoelectric ceramic sheet to be measured, which can improve the measurement accuracy, but does not consider the measured piezoelectric ceramic sheet. There is a displacement difference between the piezoelectric ceramic sheet and the displacement sensor, which affects the accuracy of the micron-level displacement change of the piezoelectric ceramic driver, so it cannot be applied to engineering and testing systems.

SUMMARY OF THE INVENTION

The problem to be solved by the present invention is based on the defects of the prior art and the leading role of piezoelectric ceramic actuators in the field of active vibration control of wind tunnel struts, the stacked piezoelectric ceramic actuators for micron-level displacement changes and the experimental The influence of temperature changes on its output characteristics is lacking in the exploration and installation of the output characteristics of stacked piezoelectric ceramic actuators under the influence of a wide range of temperature. Test method for output characteristics of stacked piezoelectric ceramic actuators. The method utilizes a testing mechanism, a stacked piezoelectric ceramic actuator, an optical fiber displacement sensor, a pressure sensor and a high and low temperature environment box to form a test system for the output characteristics of the stacked piezoelectric ceramic actuator. The optical fiber displacement sensor adopts a non-contact measurement method, which will not have a contact effect on the surface of the object to be measured, and the measurement accuracy is as high as 3 nanometers. For the output displacement value of the stacked piezoelectric ceramic actuator, as a comparison, the strain gauges installed on the surface of the stacked piezoelectric ceramic actuator are selected to test the strain together to ensure the accuracy and reliability of the experimental data. A certain pre-tightening force is applied to the stacked piezoelectric ceramic actuator by a test and testing institution, and its data is obtained through a pressure sensor. The temperature change environment adopts a high and low temperature environmental box. The equipment selected above is convenient to put into the environmental box. It is safe in the experimental design temperature environment, the high and low temperature environmental box is easy to operate, and the temperature control accuracy is high. This method can accurately test the output displacement characteristics of the stacked piezoelectric ceramic actuator under a wide range of temperature changes. Because the test of the wind tunnel support rod vibration control system is generally under complex environmental conditions, the experimental environment temperature is changeable; And the model test research under high and low temperature wind tunnel conditions is becoming more and more popular, so it is very important to study the output characteristics of the stacked piezoelectric ceramic actuator under the influence of complex environmental temperature. The test method of this experimental test system is simple. It is easy to operate, with high precision and reliable test data.

The technical scheme adopted in the present invention is a method for testing the output characteristics of stacked piezoelectric ceramics under a wide range of temperature changes. In this method, an optical fiber displacement sensor 1, a stacked piezoelectric ceramic actuator 4 and a pressure sensor are installed on the test mechanism. The sensor 6 constitutes the entire test device, and then the test device is connected with the measurement and control system and the computer to form the entire experimental system; the test device is used to apply a certain pre-tightening force to the stacked piezoelectric ceramic actuator 4, and the pressure sensor 6 The data is obtained, and then the optical fiber displacement sensor 1 is connected to the computer to compare the output strain of the stacked piezoelectric ceramic actuator 4 itself to obtain information such as its pressure and displacement. The test of the output characteristics of the stacked piezoelectric ceramic actuator 4 can be completed under the condition of large-scale temperature change; the specific steps of the method are as follows:

The first step: install the optical fiber displacement sensor 1, the stacked piezoelectric ceramic actuator 4 and the pressure sensor 6 on the test mechanism to form the entire test device

The test mechanism is composed of a base 5, a U-shaped plate 2, a gasket 3 and a T-shaped base 10. The base ₅ is composed of a circular chassis ₅₁ and an L-shaped bracket 52, wherein the L _- shaped bracket 52 is composed of The semi-arc structure 5 ₂₁ and the protruding semi-circular ring structure 5 ₂₂ are formed, and the circular chassis 5 ₁ of the base 5 is machined with a number of evenly distributed threaded holes for connecting the pressure sensor 6;

First install the T-shaped base 10 into the center hole of the pressure sensor 6, and then install the base 5 through the T-shaped base 10 to the pressure sensor 6; fit the stacked piezoelectric ceramic actuator 4 to the L-shaped bracket _The semi-arc structure ₅₂₁ of 52 is mounted on the T-shaped base 10, and then the gasket 3 is mounted on the top of the stacked piezoelectric ceramic actuator 4. The lower end of the gasket ₃ has a circular groove 32, which is concave. The size of the slot is the diameter of the stacked piezoelectric ceramic actuator 4, and the upper end of the gasket 3 is a convex spherical surface 3 ₁ ; the U-shaped plate 2 is placed on the gasket 3, and the U-shaped plate 2 is machined with through holes, and the bolts pass through The through hole connects the U-shaped plate 2 and the L-shaped bracket _{5 2} to apply a pre-tightening force to the stacked piezoelectric ceramic actuator 4; In the middle, the U-shaped plate 2 is used for positioning and clamping; finally, the circular chassis 51 of the base ₅ is fixedly installed on the pressure sensor 6 with bolts to form the entire experimental test device;

Then connect the experimental testing mechanism device with the measurement and control system 7, and then connect it with the computer 8, and the entire experimental system is installed;

The second step: according to the design requirements of the experiment, adjust the L-shaped bracket 5 and ₂ bolts installed on the U-shaped plate 2 and the base 5 to make the pressure value reach the expected pre-tightening force;

The third step: put the entire test device into the high and low temperature environmental box 9, create a temperature change environment, and then operate the entire measurement and control system 7 to carry out pre-designed experiments to obtain output data, including the displacement value measured by the optical fiber displacement sensor 1; pressure; The pressure value measured by the sensor 6; the strain value and the temperature value measured by the high and low temperature environmental box 9 are obtained through the strain gauge pasted on the surface of the stacked piezoelectric ceramic actuator 4;

Step 4: Data acquisition, signal conditioning, and data processing through the computer 8 can obtain the output displacement value of the stacked piezoelectric ceramic actuator 4 and the pressure value it is subjected to and the stacked piezoelectric ceramic actuator The strain value measured by the strain gauge on the device 4.

To sum up, the experimental data is obtained through the entire test system, and the corresponding records are recorded and saved.

The corresponding data is obtained through experiments and the following formulas. The analog output of the optical fiber displacement sensor 1 is 0-5v voltage, and its output displacement value is obtained according to formula (1):

Among them, ΔL represents the displacement value of the optical fiber displacement sensor 1, S is the sensitivity, the calibration curve provided by the supplier of the optical fiber displacement sensor 1 gives the sensitivity value in the linear range of the near end and the far end, ΔU is obtained by experiment, After data processing, the final voltage change is obtained;

The displacement value of the stacked piezoelectric ceramic actuator 4 is given by the formula (2):

ΔL=ε×L (2)

Among them, ΔL represents the displacement value of the stacked piezoelectric ceramic actuator 4 , ε represents the relative axial deformation of the stacked piezoelectric ceramic actuator 4 , and L is the length of the stacked piezoelectric ceramic actuator 4 ;

The displacement value ΔL obtained according to the above two formulas, and the average value of the two is taken as the final data result of the experiment. For the temperature environment with a wide range of changes, it can be directly obtained from the indication of the high and low temperature environmental box.

The beneficial effect of the invention is that the base is connected with the pressure sensor, and the pre-tightening force can be monitored in real time; the optical fiber displacement sensor has the highest measurement accuracy when the distance between the probe and the measured device is 0-5mm. The length dimension and the probe length of the optical fiber displacement sensor design the L-shaped bracket of the base, the lower end of the gasket 3 has a circular groove 3 ₂ , and the groove size is the diameter of the stacked piezoelectric ceramic actuator, so that the stacked pressure The electric ceramic actuator and the gasket are firmly installed to prevent the gasket from sliding due to the application of pre-tightening force, which affects the accuracy of the experimental data. The upper end of the gasket 3 adopts a spherical surface to ensure that it and the upper U-shaped plate only transmit the axial force and the force is balanced, so as to avoid the damage of the stacked piezoelectric ceramic actuator due to the shear force; The distance between the optical fiber displacement sensor and the stacked piezoelectric ceramic actuator is exactly 3mm to ensure the measurement accuracy. The stacked piezoelectric ceramic actuator is fixed by a semi-enclosed base and large bolts. The semi-enclosed form is convenient for the placement and removal of the stacked piezoelectric actuator. The arc form that fits its diameter can ensure that it has no Hard contact, protects the strain gauges and traces on the surface of the stacked piezoelectric ceramic actuator. By screwing the bolts on the U-shaped plate, the preload force can be adjusted in real time. And through the pressure sensor to observe whether the test data reaches the estimated test value, and to ensure that the equipment will not be damaged due to excessive preload. The temperature change environment adopts a high and low temperature environmental box. The equipment and instruments selected above are easy to put into the high and low temperature environmental box. The equipment is safe under the experimental design temperature environment. The high and low temperature environmental box is easy to operate and has high temperature control accuracy. The experimental test method is accurate, convenient and highly feasible.

Description of drawings

Fig. 1 is the principle diagram of the comprehensive experiment system of the present invention.

Fig. 2 is the overall schematic diagram of the experimental system of the present invention, wherein 1-fiber displacement sensor, 2-U-shaped plate, 3-gasket, 4-stacked piezoelectric ceramic actuator, 5-base, 6-pressure Sensor, 7-measurement and control system, 8-computer, 9-high and low temperature environmental box, 10-T-shaped base.

Fig. 3 is a schematic view of the structure of the spherical mesoporous gasket of the present invention, wherein, 3 - gasket, 3 ₁ - spherical surface, 3 ₂ - circular groove surface.

Figure 4 is a schematic diagram of the structure of the base of the present invention, wherein 5-base, ₅₁ -circular chassis, 52 _- L-shaped bracket, ₅₂₁ -semi-arc structure, ₅₂₂ -protruding semi-circular ring structure.

Figure 5 is a front view and a side view of the experimental structure device of the present invention, wherein 1-fiber displacement sensor, 2-U-shaped plate, 3-spacer, 4-stacked piezoelectric ceramic actuator, 5-base , 6-pressure sensor, 10-T-shaped base.

Figure 6 is a flow chart of the testing method of the present invention.

specific implementation

The specific implementation method of the present invention will be described in detail below with reference to the technical solutions and the accompanying drawings.

As shown in Figure 2, a comprehensive test system based on the output performance of the stacked piezoelectric ceramic actuator consists of a base 5, an optical fiber displacement sensor 1, a U-shaped plate 2, a gasket 3, and a stacked piezoelectric ceramic The actuator 4, the pressure sensor 6, the T-shaped base 10, the measurement and control system 7, the computer 8 and the high and low temperature environment box 9 are composed.

FIG. 1 is a schematic diagram of the comprehensive experimental system of the present invention. First, the pre-tightening force preset in the test is given to the stacked piezoelectric ceramic actuator 4, and the real-time pre-tightening force value can be known by the pressure sensor 6, which is pasted on the stacked piezoelectric ceramic actuator 4. The strain gauge on the surface of the piezoelectric ceramic actuator 4 obtains its strain value; at the same time, the displacement value of the stacked piezoelectric ceramic actuator 4 is measured by the optical fiber displacement sensor 1, and the measured strain value and displacement value are transmitted. To the automated test system, the test system transmits all the data to the computer for data acquisition, signal conditioning, and data processing, and finally obtains ideal experimental data.

In the experimental case of the present invention, the range of the pressure sensor 6 is 5000N, and when the preset preload force is 500N, the displacement value of the stacked piezoelectric ceramic actuator 4 is tested, and the experimental mechanism is placed in a high and low temperature environment. Inside the box, the measurement of the output characteristics of the stacked piezoelectric ceramic actuator 4 is carried out under the conditions of a wide range of temperature changes. The working temperature range of the piezoelectric ceramic actuator 4 is -20°C to +85°C, and the experimental temperature range is -15°C to +75°C to ensure that the experimental process is in a safe state for each device. Figure 6 is a flow chart of the experimental method of the present invention.

The specific steps of this method are as follows:

The first step is to install the optical fiber displacement sensor 1, the stacked piezoelectric ceramic actuator 4 and the pressure sensor 6 on the test mechanism to form the entire test device

The whole experimental test system is shown in FIG. 2 . The test mechanism is composed of a base 5 , a U-shaped plate 2 , a gasket 3 and a T-shaped base 10 . Since the optical fiber displacement sensor 1 is used, vertical measurement is required, and the upper part of the base 5 is designed as a protruding semi-circular ring structure 5 ₂₂ , as shown in FIG. 4 , for positioning and clamping the optical fiber displacement sensor 1 . Compared with the general measurement method using rack clamping, the mechanism is more stable. There are threaded holes at the bottom of the base 5, which is convenient for connecting the pressure sensor 6 at the bottom; the middle of the base 5 and the pressure sensor 6 is connected by a T-shaped base 10; the base ₅ is composed of an L-shaped bracket 52 and a circular chassis ₅₁ , The part of the L-shaped bracket that fits the stacked piezoelectric ceramic actuator 4 adopts a semi-arc structure 5 ₂₁ , which is convenient for the placement and removal of the stacked piezoelectric ceramic actuator 4 , and the arc shape that fits its diameter can ensure its There is no hard contact, and the strain gauges on the surface of the stacked piezoelectric ceramic actuator 4 are protected and the wiring is smooth. The stacked piezoelectric ceramic actuator 4 is placed in the middle of the base of the semi-arc structure 5 _21. The middle of the semi-surrounded base is punched with threaded holes on both sides and covered with a gasket 3 with a circular groove in the middle. , in order to ensure that the distance between the optical fiber displacement sensor 1 and the stacked piezoelectric ceramic actuator 4 is exactly 3mm to ensure the measurement accuracy. The specific structure is shown in Figure 4 and Figure 5. The lower end of the gasket 3 has a circular groove 3 ₂ , the size of the groove is the diameter of the stacked piezoelectric ceramic actuator 4 , and the upper end of the gasket is designed as a convex spherical surface 3 ₁ , as shown in FIG. 3 . The U-shaped plate 2 is placed on the gasket, the U-shaped plate 2 is machined with through holes, and the U-shaped plate 2 and the L-shaped bracket 5 ₂ of the base 5 are connected by bolts, and the stacked piezoelectric ceramic actuator 4 is applied preload. The semi-circular ring structure 5 ₂₁ on the upper part of the L-shaped bracket 5 ₂ is used for positioning and clamping the optical fiber displacement sensor 1, so that the installation of the whole testing device is completed. Then, the experimental test device is connected with the measurement and control system 7, and then connected with the computer 8, and the whole experimental system is installed.

The second step: according to the design requirements of the experiment, adjust the bolts of the L-shaped bracket 52 installed on the U-shaped plate ₂ and the base 5, so that the pressure value reaches the expected pre-tightening force of 500N;

The third step: place the entire experimental device in the high and low temperature environmental box 9, move the high and low temperature environmental box to an appropriate position on the test work surface, and close the box door. The experimental design temperature range is -15°C to +75°C, and data is recorded every 10°C from -15°C until 75°C. Turn on the power switch of the temperature controller, when doing high temperature test, after setting the test temperature, turn the switch key to heating and press the run key. At this time, the blower fan in the environmental box starts to rotate, and the heating wire is energized and heated. When doing low temperature test, after setting the test temperature, turn the switch key to cooling, and then press the run key. After the test, press the stop button first, and then turn off the power switch of the temperature controller. Operate the entire measurement and control system 7 to carry out pre-designed experiments to obtain output data, including the displacement value measured by the optical fiber displacement sensor 1; the pressure value measured by the pressure sensor 6; the self-strain collection value of the stacked piezoelectric ceramic 4, and the high and low temperature environment. The temperature value displayed by the box.

Step 4: Data acquisition, signal conditioning, and data processing through the computer 8 can obtain the output displacement value of the stacked piezoelectric ceramic actuator 4 and the pressure value it is subjected to. The strain value measured by the strain gauge on the actuator.

In summary, the experimental data is obtained through the entire test system, and the corresponding records and storage are carried out.

The pressure value of the stacked piezoelectric ceramic actuator 4 is obtained by the pressure sensor 6 and the entire experimental test control system, and the displacement value of the stacked piezoelectric ceramic actuator 4 is determined by the optical fiber displacement sensor 1 and the entire experimental test. The control system obtains that the same strain information is obtained from the strain gauge on it and the entire experimental test control system. The output displacement value of the optical fiber displacement sensor 1 can be obtained from the formula (1). The stacked piezoelectric ceramic actuator The displacement of 4 is obtained by formula (2). The two sets of data can be compared, and the average value of the two can be taken as the final data result of the experiment.

Claims (1)

1. A method for testing the output characteristics of stacked piezoelectric ceramics under a wide range of temperature changes, the method is to install an optical fiber displacement sensor (1), a stacked piezoelectric ceramic actuator (4) and a pressure sensor on a test and test mechanism (6) Constitute the entire test device, and then connect the test device with the measurement and control system and the computer (8) to form the entire experimental system; use the test device to apply a certain pre-tightening force to the stacked piezoelectric ceramic actuator (4). , obtain data through the pressure sensor (6), and then connect it to the computer (8) through the optical fiber displacement sensor (1) and compare the output strain of the stacked piezoelectric ceramic actuator (4) itself to obtain its pressure and displacement information Put the test device into the high and low temperature environmental box (9), and can complete the test of the output characteristics of the stacked piezoelectric ceramic actuator (4) under the condition of large-scale temperature change, and the concrete steps of the method are as follows: Step 1: Install the optical fiber displacement sensor (1), the stacked piezoelectric ceramic actuator (4) and the pressure sensor (6) on the test mechanism to form the entire test device The test mechanism is composed of a base (5), a U-shaped plate (2), a gasket (3) and a T-shaped base (10), the base (5) is composed of a circular chassis (5 ₁ ) and an L-shaped bracket (52), wherein the L _- shaped bracket (52) is composed of a semi-arc structure ( ₅₂₁ ) and a protruding semicircular ring structure ( ₅₂₂ ), and the base ( ₅ ) is placed on the circular chassis (51) of the base ( ₅ ). Several evenly distributed threaded holes are processed for connecting the pressure sensor (6); First install the T-shaped base (10) into the center hole of the pressure sensor (6), and then install the base (5) through the T-shaped base (10) to the pressure sensor (6); put the stacked piezoelectric The ceramic actuator ( ₄ ) fits the semi-arc structure ( ₅₂₁ ) of the L-shaped bracket (52) and is mounted on the T-shaped base (10); and then the gasket (3) is mounted on the stacked piezoelectric ceramics On the top of the actuator (4), the lower end of the gasket (3) has a circular groove (3 ₂ ), the size of the groove is the diameter of the stacked piezoelectric ceramic actuator (4), and the upper end of the gasket (3) It is a convex spherical surface (3 ₁ ); the U-shaped plate (2) is placed on the gasket (3), the U-shaped plate (2) is machined with a through hole, and the bolt connects the U-shaped plate (2) and the L-shaped plate through the through hole. _The brackets (52) are connected to apply a pre-tightening force to the stacked piezoelectric ceramic actuator (4); and then the optical fiber displacement sensor (1) is installed into the circular hole protruding from the semicircular ring structure ( ₅₂₂ ), Position and clamp with the U-shaped plate (2); finally, use bolts to fix the circular chassis (51) of the base ( ₅ ) to the pressure sensor (6) to form the entire experimental test device; Then the experimental test device is connected with the measurement and control system (7), and then with the computer (8), and the entire experimental test system is installed; The second step: according to the design requirements of the experiment, adjust the L-shaped bracket (5 ₂ ) bolts installed on the U-shaped plate (2) and the base (5) so that the pressure value reaches the expected pre-tightening force; The third step: put the entire test device into the high and low temperature environment box (9) to create a temperature change environment; then operate the entire measurement and control system (7) to carry out pre-designed experiments to obtain output data, including the optical fiber displacement sensor (1) The measured displacement value; the pressure value measured by the pressure sensor (6); the strain value and the temperature value measured by the high and low temperature environmental box (9) are obtained through the strain gauge pasted on the surface of the stacked piezoelectric ceramic actuator (4) ; The fourth step: data acquisition, signal conditioning, and data processing are performed by the computer (8) to obtain the output displacement value of the stacked piezoelectric ceramic actuator (4), the pressure value and the stacked piezoelectric actuator. The strain value measured by the strain gauge on the ceramic actuator (4); To sum up, the experimental data is obtained through the entire test system (7), and the corresponding records and storage are carried out; The corresponding data is obtained through experiments and the following formulas. The analog output of the optical fiber displacement sensor (1) is a voltage of 0-5v, and its output displacement value is obtained according to the formula (1):

Among them, ΔL represents the displacement value of the optical fiber displacement sensor (1), S is the sensitivity, and the calibration curve provided by the supplier of the optical fiber displacement sensor (1) gives the sensitivity value in the near-end and far-end linear ranges, and ΔU is calculated by It is obtained from the experiment that the final voltage change is obtained after data processing; The displacement value of the stacked piezoelectric ceramic actuator (4) is given by the formula (2): ΔL=ε×L (2) Among them, ΔL represents the displacement value of the stacked piezoelectric ceramic actuator (4), ε represents the relative axial deformation of the stacked piezoelectric ceramic actuator (4), and L is the actuation of the stacked piezoelectric ceramics the length of the device (4); The displacement value ΔL obtained according to the above two formulas, and the average value of the two is taken as the final data result of the experiment. For the temperature environment with a wide range of changes, it can be directly obtained from the indication of the high and low temperature environmental box (9).

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