Feedback-linearization control of a piezo-actuated positioning mechanism

The piezoelectric actuator is a common device for realizing extremely small displacements. For an existing piezo-actuated positioning mechanism a state-space model is available. This model contains a differential equation description of the nonlinear hysteresis effect. The model can be transformed to normal form, which makes it amenable to feedback-linearization control. The controller has been implemented real-time on a Digital Signal Processor system. The nonlinear controller is compared to a linear one. It turns out that the nonlinear controller performs significantly better.