Analysis and comparison of flexible mechanisms for parasitic motion principle piezoelectric actuator

This paper compares three flexible mechanisms in parasitic motion principle piezoelectric actuator through analytic calculation and experiment investigation. The flexible mechanism used in piezoelectric actuator can be classified into functional shape type and asymmetrical stiffness type. For comparing the benefits of these two types of flexible mechanisms and their hybrid structure, the relation between the force and displacement of three flexible mechanisms are deduced using matrix-based compliance modeling method. Also, the dynamic model of parasitic motion principle piezoelectric actuator is used to explore the influence of dimension of flexible mechanism. After that, a prototype and above-mentioned three flexible mechanisms are manufactured and tested, and the motion characteristics of prototype with different flexible mechanisms are investigated, including the step length, velocity and load capacity under different driving voltage and driving frequency. Based on experiment results, the advantages of three flexible mechanisms are analyzed, the hybrid flexible mechanism can achieve fast velocity at medium driving frequency, but asymmetrical stiffness flexible mechanism shows greater motion efficiency and better performance under high driving frequency.