Adaptive Robust Precision Control of Piezoelectric Positioning Stages

Positioning stages using piezoelectric stack actuator (PEA) have very high theoretical bandwidth and resolution. However, as the total length of travel increases, nonlinear dynamics due to inherent hysteresis starts to dominate. In this paper, we separate the fast and slow dynamics of the total displacement and propose a simple first-order model. By approximating the hysteresis mapping with simple functions, it is linearly parameterized for subsequent adaptive robust controller design. Experimental results from tracking control of sinusoidal and point-to-point trajectories show tracking error on the magnitude of the sensor noise level and demonstrate the effectiveness of the approach.