Study On Multi-Piezoelectric Effect And Its Application In Self-sensing Actuators

With the development of micro-testing and micro-measurement technology, piezoelectric sensors and actuators are demanded to be high precision, miniaturization and integration. If primary piezoelectric effect is only considered during the course of electromechanical conversion, a considerable error would be met in the results. So the further research on theory and application of multi-piezoelectric effect is needed urgently.The research is supported by project of "Study on Multi-Piezoelectric Effect and its Application in Micro Sensoriactuators", which is funded by National Natural Science Foundation of China (No.50675026). Contents of this paper include theoretical analysis and experimental proof of multi-piezoelectric effect, and the application in self-sensing actuators.On the basis of classical piezoelectric theory, the relationship between the generation of multi-piezoelectric effect under applied electric field and boundary conditions is analyzed. The generating process of multi-piezoelectric effect is elaborated and the formulas of secondary direct and tertiary converse piezoelectric effect are deduced. The influences of multi-piezoelectric effect on dielectric constant, equivalent capacitance, piezoelectric constant and energy conversion are analyzed.To supply the reference on research for experiment, the output generated by primary converse, secondary direct and tertiary converse piezoelectric effect of piezoelectric ceramics is calculated by using ANSYS. Experiments of secondary direct and tertiary converse piezoelectric effect under applied electric field are performed through PZT-5 stack. The experimental result verifies the existence of multi-piezoelectric effect. And its generation correlates with boundary conditions of piezoelectric crystals.According to the characteristic of bidirectional and reversible effect of multi-piezoelectric effect in single piezoelectrics, theoretical analysis is carried on multi-piezoelectric effect realizing displacement self-sensing of piezoelectric actuators. The design proposal and realization structure of self-sensing actuators are proposed by using driving and sensing function which can be implemented through primary converse and secondary direct piezoelectric effect respectively. The validity of design proposal is verified experimentally.