CN201081720Y - Capacitance method tester for testing driving force characteristics of electrostriction material - Google Patents

Abstract

The utility model relates to a capacitance method test device for the driving force characteristic of an electrostrictive material, which relates to a micro strain and a micro driving force test device for the electrostrictive material, in particular to a capacitance method test device for the characteristic of the electrostrictive material. The utility model comprises a base and a supporting frame, and the supporting frame is set on the base. Adjustable high-voltage source, the two ends of the adjustable high-voltage source are respectively connected with negative and positive plates, the electrostrictive material to be tested is placed between the two plates, one of the plates is in contact with the three-dimensional micro-displacement stage, A dynamic excitation coil is arranged on the supporting member connected to the other pole plate, and a capacitive dynamic pole plate is arranged on the end face of the dynamic excitation coil. The utility model realizes the purposes of simple structure and convenient operation of the testing process.

Description

Capacitance test device for driving force characteristics of electrostrictive materials

Technical field:

The utility model relates to a testing device for micro-strain and micro-driving force of electrostrictive materials, in particular to a capacitance method testing device for properties of electrostrictive materials.

Background technique

Non-optical methods in line displacement or strain test applications are divided into line resistance method (10 ^-2 -20mm), strain resistance method (10 ^-4 -10 ² mm), capacitance method (10 ^-4 -10mm), induction Synchronous method (10 ^-3 -10 ² mm), differential inductance method (10 ^-4 -10 ^-1 mm), etc., which have different measurement speeds, ranges and accuracy, such as the marking resistance method is only It is suitable for low-speed occasions. The differential inductance method has high measurement accuracy but the measurement range is limited. The strain resistance method requires a large driving ability of the measured object.

Electrostrictive materials need both micro-deformation and a certain driving force, while traditional tests can only test the electrostrictive coefficient of free-state electrostrictive materials. For the electrostrictive coefficient and its driving force under the condition of force load There are few studies, so it is necessary to further study the driving force performance of electrostrictive materials. A very important part of the research on driving force performance is micro-force measurement. Micro-force measurement is usually done with MEMS devices, and also with optical fiber sensors, balances and other methods.

Capacitance method and differential transformer method convert micro-deformation measurement into electric quantity measurement, both of which need to be in contact with the surface to be measured, which is a contact method measurement. The capacitance method has the advantages of fast response speed, high sensitivity, and strong anti-noise ability. It also has a large measurement range and high measurement accuracy. way.

Capacitive sensor is a very important type of sensor, which converts the change of measured non-electricity into capacitance change, and obtains the measured change by detecting the change of capacitance. It has simple structure, high resolution, and non-contact measurement , low cost, fast response, high sensitivity, strong anti-noise ability, etc., and can work under harsh conditions such as high temperature, radiation and strong vibration, widely used in pressure, humidity, solid moisture content, touch, information fusion imaging, Detection of sensing quantities such as micro-displacement, material level, and acceleration. Micro-force measurement can convert the micro-displacement generated by micro-force into micro-capacitance changes, so as to measure micro-force by measuring micro-capacitance.

Utility model content

The purpose of this utility model is to propose a capacitive method test device for the characteristics of electrostrictive materials with simple structure and easy operation in the test process. The device can directly measure the micro-strain characteristics, micro-drive force characteristics.

The utility model adopts the following technical solutions:

Including a base 1 and a support frame 12, the support frame 12 is arranged on the base 1, and is characterized in that a fixed excitation coil 9 is provided on the support frame 12, and a capacitor fixed pole plate 10 is provided on the end face of the fixed magnetic coil 9, An adjustable high-voltage source 3 is provided on the base 1, and the two ends of the adjustable high-voltage source 3 are respectively connected with negative and positive plates 4 and 5, and the space between the two plates 5 and 6 is used to place the electrostrictive material to be tested. One of the pole plates is in contact with the three-dimensional micro-displacement stage 2, and a dynamic excitation coil 8 is provided on a support member 7 connected to the other pole plate, and a capacitive dynamic pole plate 11 is provided on the end face of the dynamic excitation coil 8 , the capacitive fixed plate 10 and the capacitive moving plate 11 face each other.

The utility model proposes a capacitance method electrostrictive material characteristic testing device, which detects the micro displacement caused by the small strain of the electrostrictive material under high electric field strength through the capacitance method, and loads the electromagnetic force through the electromagnetic coil or generates a balanced driving force . Micro-capacitance detection uses a switch-type weak capacitance detection circuit, which is low in cost and can also eliminate the influence of the ground parasitic capacitance, which is much larger than the measured capacitance, on the measurement results.

The capacitive test device for the driving force characteristics of electrostrictive materials generally includes an adjustable high-voltage power supply, a fixed base, a three-dimensional micro-displacement stage, a high-voltage positive and negative plate, a thin film of the measured object, an excitation coil group, a micro-displacement sensing capacitor and its Test the control circuit. When the system is working, the high-voltage power supply loads a strong electric field on the film to be tested, and the film produces strain, and the micro-displacement sensing capacitor measures the corresponding micro-displacement; when the material is subjected to a stress load, the electrostriction coefficient is generated by the driving coil. Force load; when studying the driving force of the material, use the driving coil to offset the micro-displacement generated by the strong electric field or generate an equivalent micro-displacement to indirectly measure the driving force of the material. When the electrostrictive material is used as an elastic body, the micro-displacement sensing capacitor can also be used as a force sensor used.

The entire test device is placed on an anti-vibration platform to eliminate the influence of vibration on the test results. The device includes a three-dimensional micro displacement platform to facilitate the fine adjustment of the sensing capacitance in the test, and the micro displacement platform is also suitable for the calibration and calibration of micro capacitance and micro displacement.

Compared with the prior art, the utility model has the following advantages:

1. The mechanical structure of the utility model is simple and easy;

2. The micro-displacement switch type weak capacitance detection circuit is adopted, which has low cost and can also eliminate the influence of the ground parasitic capacitance, which is much larger than the measured capacitance, on the measurement results;

3. The test principle can be used to measure the electric field-electrostrictive strain curve, equivalent driving force characteristics and equilibrium driving force characteristics of electrostrictive materials under a certain pressure.

Description of drawings:

Fig. 1 is a schematic diagram of the overall structure of the utility model, Fig. 1A is a specific embodiment of the utility model, Fig. 1B is another specific embodiment of the utility model, 1-fixed base, 2-three-dimensional micro displacement platform, 3-adjustable high voltage source, 4-negative plate, 5-positive plate, 6-electrostrictive film, 7-support, 8-moving excitation coil, 9-fixed excitation coil, 10-capacitance moving plate, 11- Capacitor fixed plate, 12-support rod.

Fig. 2 is the test result figure of the present utility model, displacement and microcapacitance method detection voltage output are not linear relationship when measuring range is very big, but for very little microdisplacement (within dozens of microns scope) can think and exist between microcapacitance linear relationship.

Figure 3 shows the results of microcapacitance measurement of electromagnetic force. The capacitance method is used to measure the elastic deformation of polyurethane under the action of electromagnetic force. By measuring the change of microcapacitance, the magnetic force loaded on polyurethane elastomer can be obtained. DC coils are used in the system to generate electromagnetic force. Force, the abscissa in the figure is the voltage loaded on both ends of the fixed coil.

Figure 4 is the electrostrictive strain curves of polyurethane elastomers with different nano barium titanate content with electric field intensity.

Figure 5. The relationship between electrostrictive strain and time of polyurethane elastomer with a certain nanometer barium titanate content under the action of an applied electric field.

Detailed ways

A capacitance test device for driving force characteristics of electrostrictive materials, comprising: a base 1 and a support rod 12, the support rod 12 is arranged on the base 1, and is characterized in that a fixed excitation coil 9 is provided on the support rod 12, On the end face of the fixed excitation coil 9, a capacitor fixed plate 10 is arranged, and an adjustable high-voltage source 3 is arranged on the base 1, and the two ends of the adjustable high-voltage source 3 are respectively connected with negative and positive two-pole plates 4, 5. Negative and positive dipole plates 4 and 5 are used to place the electrostrictive material 6 to be tested, wherein the negative pole plate is in contact with the three-dimensional micro-displacement stage 2, and a dynamic excitation coil 8 is provided on the support member 7 connected to the positive pole plate. The end surface of the dynamic excitation coil 8 is provided with a capacitive dynamic pole plate 10 , and the above-mentioned capacitive fixed pole plate 11 faces the capacitive dynamic pole plate 10 .

The output range of the above-mentioned high-voltage power supply is 0-10kV, the test accuracy of the capacitance formed by the above-mentioned capacitor fixed plate 10 and the capacitor moving plate 11 is 300mV/pF, the capacitance test range is 0-10pF, and the capacitance method detects micro-displacement/micro-strain, displacement test Accuracy 1.9mV/μm,

Figure 1A and Figure 1B respectively reflect the two forms of the above technical solution.

When the system is working, the high-voltage power supply loads a strong electric field on the film to be tested, and the film produces strain, and the micro-displacement sensing capacitor measures the corresponding micro-displacement; when the material is subjected to a stress load, the electrostriction coefficient is generated by the driving coil. Force load; when studying the driving force of the material, use the driving coil to offset the micro-displacement generated by the strong electric field or generate an equivalent micro-displacement to indirectly measure the driving force of the material. When the electrostrictive material is used as an elastic body, the micro-displacement sensing capacitor can also be used as a force sensor used.

The entire test device is placed on an anti-vibration platform to eliminate the influence of vibration on the test results. The device includes a three-dimensional micro displacement platform to facilitate the fine adjustment of the sensing capacitance in the test, and the micro displacement platform is also suitable for the calibration and calibration of micro capacitance and micro displacement.

The utility model can carry out the electric field-electrostrictive strain curve of the electrostrictive material, the electric field-electrostrictive strain curve under different pressures, the balance driving force under the action of different electric fields and the equivalent under the action of different electric fields Performance tests such as driving force.

1) Apply a series of high voltages to the tested electrostrictive film through the high-voltage plate, the voltage range is 0 ~ 10kV, the film produces a series of corresponding strain displacements, and the microcapacitance test circuit detects the series of corresponding micro displacements to obtain the electrostrictive material. Electric field-electrostrictive strain curve.

2) Apply pressure to the film through the electromagnetic coil, and apply a series of high voltages to the electrostrictive film under test through the high-voltage plate. The voltage range is 0-10kV. Therefore, the electric field-electrostrictive strain curves of the electrostrictive material under different pressures are obtained.

3) A series of high voltages are applied to the tested electrostrictive film through the high-voltage plate, and the voltage range is 0-10kV. The balance force is applied to the film through the electromagnetic coil to keep the strain of the film at zero, so as to obtain the effect of the electrostrictive material under different electric fields. Under the balance driving force.

4) A series of high voltages are applied to the tested electrostrictive film through the high-voltage plate, and the voltage range is 0-10kV. Equivalent driving force of a stretchable material under different electric fields.

The steps of using the device to detect the characteristics of electrostrictive materials are as follows:

(1) Cut the measured electrostrictive film into a size of 30mm×30mm and clamp it in the positive and negative high-voltage plates, and adjust the initial position of the capacitance sensor by adjusting the three-dimensional micro-displacement stage, so that the output value of the capacitance measurement is zero.

(2) Adjust the voltage on the high-voltage plate to cause corresponding strain on the measured electrostrictive film, and measure the electric field-electrostrictive strain curve through the capacitance measurement circuit.

(3) Adjust the voltage on the high-voltage plate so that the measured electrostrictive film undergoes a corresponding strain, and apply pressure (loading or equivalent strain) or tension (counteracting strain) to the measured electrostrictive film through the driving coil, thereby measuring The electric field-electrostrictive strain curve, equivalent driving force characteristic and equilibrium driving force characteristic of the material under a certain pressure are measured by the circuit.

Claims (2)

1. a capacitive method testing device of electrostrictive material driving force characteristic, comprises base (1) and support frame (12), and support frame (12) is located on the base (1), is characterized in that support frame (12) is provided with fixed field coil (9), is provided with capacitance fixed pole plate (10) on the end face of fixed field coil (9), is provided with adjustable high voltage source (3) on base (1), The two ends of the adjustable high-voltage source (3) are connected with negative and positive plates (4, 5) respectively, and the electrostrictive material to be tested is placed between the two plates (5, 6), and one of the plates is connected to the three-dimensional The micro displacement stage (2) is in contact with each other, and a dynamic excitation coil (8) is provided on the support (7) connected to the other pole plate, and a capacitive dynamic pole plate is provided on the end face of the dynamic excitation coil (8). (11), the above-mentioned capacitance fixed pole plate (10) is opposite to the capacitance dynamic pole plate (11). 2. the capacitive method testing device of driving force characteristic of electrostrictive material according to claim 1, is characterized in that being provided with three-dimensional micro-displacement between described base (1) and described wherein a polar plate Taiwan (2).

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