Dynamic modeling of an innovative piezoelectric actuator for minimally invasive surgery

A small piezoelectric inchworm actuator has been designed for use with a monolithic compliant end-effector in minimally invasive surgery procedures. A dynamic model of the inchworm actuator has been developed using SIMULINK. Utilizing the equations of motion for the inchworm actuator, the dynamic characteristics of the piezoelectric stack material, and the known compliance of the gripper, a force measurement model has been developed which extracts resisting force information from the piezoelectric signal. The focus of this paper is on the development of the dynamic model and the results of a simulation study that will be used to develop optimal driving signals for the inchworm actuator. Simulation results include the predicted displacement capabilities and settling time of the inchworm actuator over a range of driving frequencies.