Eccentric Center Analysis And Control For Electromechanical Integrated Electrostatic Harmonic Drive

Electromechanical integrated electrostatic harmonic micro drive system is a sort of micro compound drive system. When the stator is excited by sequential electric field, the sequential deformation of the flexible ring is produced. When the electric field rotates by one cycle, the flexible ring generates a small angle displacement in the direction opposite to the rotating electric field. Eccentric center of flexible ring affects dynamics and working performance of the micro system directly. Studies on it are significant and useful.Based on elastic theory, the expressions of the deformation energy, kinetic energy and electric field energy between the rotor and stator are deduced and effects of eccentric center on system statics are investigated. Effects of eccentric center on output torque of electromechanical integrated electrostatic harmonic micro drive system are investigated. Results show that the eccentric center makes driving torque reduce.The dynamic equations of the flexible ring are established by mechanical dynamic theory. Based on it, effects of eccentric center on vibration modes of the micro ring are investigated. By means of mode superposition method, effects of eccentric center on the dynamic response of the system under harmonic force are studied. Results indicate that the eccentric center makes the natural frequency of system rise and vibration amplitude increase.Mathematic model of the eccentric center regulating system is given. PID control parameters are determined. Control capability of open and closed loop control system is investigated and compared. Simulink simulation model of eccentric center control system of flexible ring is presented. Eccentric center control under step voltage is simulated. Results show that eccentric center control by PID controller can give expectant effect.