Modelling and H∞ force control of a nonlinear piezoelectric cantilever

During a micromanipulation, it is important to have the same performances whatever the manipulated object is. We present in this paper the control of the force applied to flexible and rigid micro-objects by a piezoelectric cantilever. First, the voltage-force transfer function is modeled. The hysteresis and creep phenomena are taken into account. The reliance of the model on the characteristics of the micro-objects is clearly detailed. Then, in order to reject disturbances and maintain tracking performances required in micromanipulation, a H_infin controller is designed. Finally, the experimental results end the paper.