A DYNAMICS MODEL FOR NONLINEAR ELECTROSTRICTIVE ACTUATORS

This paper examines the nonlinear vibration of an electrostrictive cer amic rod actuator excited by a harmonic voltage source. A frequency-do main model was developed using the nonlinear constitutive law for elec trostriction. The results predict harmonic distortion of the device's displacement due to the ceramic's nonlinear behavior. AC voltage signa l and DC voltage bias were studied to determine the optimum power sour ce parameters for minimizing distortion. The calculations show that th e rod's resonance frequency and amplitude depend on the electromechani cal coupling strength and differ greatly for large AC voltages from th e equivalent linear piezoelectric results. The nonlinear analysis rela tes the device's electromechanical coupling coefficient to the compute d resonance and antiresonance frequencies. This important result could provide the basis for future measurement of the electrostrictive coup ling coefficient using resonance techniques.