Research Of Stacking Piezoelectric Sensing Actuator Based On Structural Integration

Actuators and sensors are both needed in measure-control technology field of electromechanical system, the device integrated with piezoelectric sensors and actuators is known as piezoelectric sensing actuator. When piezoelectric sensing actuator is working, actuator will generate electric field disturbance on the sensor, precision of the sensor signal will be affected, which will limit the research and application of piezoelectric sensing actuator. Therefore, based on theoretical analysis, simulation research and experimental verification, this paper developed piezoelectric sensing actuator based on structural integration, a nd proposed two filtering scheme to reduce the influence of electric field disturbance, thus to improve precision of sensor signal.Used piezoelectric ceramic as materials, this paper built two piezoelectric sensing actuator models based on structural integration and design the scheme of encapsulation. Taking basic theory of piezoelectric materials as a start point to analyze the basic characteristics of piezoelectric stack, and built corresponding mathematical models which considered the effects of electric field disturbance for two piezoelectric sensing actuator in this paper.This paper proposed two solutions to eliminate error caused by electric field disturbance, one is through theoretical research to analyze the source of electric field disturbance, determining relationship between electric field disturbance and driving voltage amplitude and frequency, thus to put forward filtering scheme based on Fourier transform, according to Fourier expansion of driving voltage can infer the error generated by electric field disturbance in theory, and eliminate the influence of error in circuit. Another solution is from perspective of structural improvement, based on a symmetric structure with electric field disturbance cancelled out at the central position where the sensor was installed, meanwhile, using metal cavity and conductive films to wrap sensor to further reduce the influence of electric field disturbance due to electrostatic shielding effects produced by closed metal space.Building a finite element analysis model to conduct simulation analysis on two piezoelectric sensing actuators developed in this paper and get dynamic characteristics of models, and then learned the relationships between the accuracy of models' output displacement and the frequency of driving voltage, the shape size of piezoelectric ceramic. This paper also analyzed influence of electric field disturbance on piezoelectric sensing actuator, acquired the relationships between filtering charge and the shape size of piezoelectric ceramic. This paper verified the accuracy of theoretical analysis and effectiveness of filtering scheme through finite element analysis, and provide a reference for optimization of model.Building an experimental system, using Lab VIEW software to analyze processing signal of system, through experiment to verify the relationship between electric field disturbance and the amplitude and frequency of driving voltage, analyzed the effects of two filtering scheme in eliminating coupling electric field, and obtained force and displacement sensing characteristics of piezoelectric sensing actuator developed in this paper. This paper designed a hardware circuit to implement filtering scheme, which will make it easier for productization and marketization of piezoelectric sensing actuator developed in this paper.For the two piezoelectric sensing actuator based on structural integration developed in this paper, by using a device can have function s of piezoelectric actuator, force sensor and displacement sensor, and solved the defects of traditional piezoelectric sensing actuator fundamentally. It is economical to use and can save installation space, and no need of complex circuit for signal processing, it has a broad application in fields such as active control of vibration, establishment of micro displacement platform, biomedical and space satellite communications, etc.