Dynamic force/position modeling of a one-DOF smart piezoelectric micro-finger with sensorized end-effector

In this paper, a generic microscale system is studied where a smart microsystem composed of an active based material actuator, sensorized structure and transformation system is studied. This problem is important at the microscale because it offers a force measurement of the applied force by the actuator to a flexible environment which enables to understand the interaction between the complete smart microsystem and the environment and to design and control the interaction between the system and the environment. A special case where a sensorized end-effector is fixed on the tip of a piezoelectric actuator is detailed. Integrating a sensorized end-effector influences the behavior of the smart microfinger and is not studied in recent works. The complete finger, which is called in this paper smart finger, consists of a piezoelectric actuator, an end-effector and a novel piezoresistive force sensor. A complete model is developed for generating both force and displacement at the finger´s tip while interaction with a flexible environment. A nonlinear model of the piezoelectric actuator is considered and a complete model is developed taking into account the frequency dependent hysteresis of the piezoelectric actuator. The model of the hysteresis is based on the Bouc-Wen method which simplifies the parameter estimation. The complete dynamic force/position model of the finger is validated experimentally with small errors (less than 10%).