Modelling of a piezohydraulic actuator for control of a parallel micromanipulator

Piezoelectric actuators have such disadvantageous properties as hysteresis nonlinearity and drift. This paper discusses a hybrid model to describe those properties. The model consists of a dynamic linear part and a static nonlinear part. The dynamic part uses two poles to describe the dynamic response and the drift property. The static nonlinear part modifies the parameters of the linear dynamic model to adapt the model to hysteresis nonlinearity and gain nonlinearity. The model is generated for a piezohydraulic actuator based on a multi-stage step signal. Simulation and experimental results show that the model is able to predict the drift and the nonlinear properties of the actuator