Voltage/frequency rate dependent modeling for nano-robotic systems based on piezoelectric stick-slip actuators

In order to define trajectory-tracking strategies for nano-robotic systems using piezoelectric stick-slip actuators, the dynamics of the elementary actuator must be studied and well modeled. The modeling of this class of actuators is complex because several nonlinear parameters are involved. In this paper, we propose a systematic modeling methodology of piezoelectric stick-slip actuators for nano-robotic systems control. The main idea is the proposition of an augmented voltage/frequency rate dependent modeling of the friction force based on a multi-state elasto-plastic formulation. Experimental and simulation results demonstrate the efficiency of the model in the time and the frequency domains. As a case of study, the proposed model is used to define a control strategy in order to detect collisions when the nano-robotic system is operating inside a Scanning Electron Microscope (SEM). This application demonstrates the need of a voltage/frequency rate dependent modeling.