Effects of eccentricity on dynamic behavior of electromechanical integrated electrostatic harmonic actuator

The authors earlier invented an electromechanical integrated electrostatic harmonic actuator consisting of a flexible ring and segmented stator. As the dimension of the actuator decreases, the effect of ring eccentricity on the dynamic behavior of the actuator becomes significant. In this paper, the equations for the displacements of the flexible ring and the electromechanical coupled dynamic equations under eccentricity are deduced. Using these equations, changes of the natural frequencies and vibrating modes as a function of the eccentric center distance are analyzed. For different eccentric center distances, changes of the forced response along with the system parameters are given. Results show that the ring eccentricity causes significant changes of the natural frequencies and vibrating amplitudes of the flexible ring, which could cause loss of the load-carrying ability for the actuator. The flexible ring radius, thickness, and clearance and voltage between the flexible ring and stator influence the relationship between the eccentricity and the dynamic behavior of the actuator.