A Parallel Leaf Spring Structure Driven by Piezoelectric Bimorph Actuators

A parallel leaf spring structure driven by a piezoelectric bimorph actuator is mod elled using a Rayleigh-Ritz formulation; model truncation is performed for feedback controller design. Using a strain gauge sensor, a precise positioning of the end point mass is realized. The posi tion of the strain gauge sensor is found to be an important factor in achieving a stable response with an estimator based feedback control system. Excitation of higher structural modes, which becomes an obstacle to a wide servo bandwidth actuator, is discussed. Using multi electrodes arranged on the bimorph actuator, and appropriately tuning the voltage ratio applied to them, pole-zero cancellation of the higher modes is experimentally demonstrated.