A multi-model design for robust hybrid control of non-linear piezoelectric actuators at the micro/nano scales

Bumpless switching is a major issue when dealing with hybrid systems. It refers to the fact that in order to prevent instabilities, continuity of the control signals must be satisfied. In this paper, a new approach for robust hybrid control of nonlinear and / or uncertain systems is presented. The strategy is based on an eigenstructure assignment and a multi-model design with a specific structure for the switching compensators. Compared with standard hybrid control methods, the main advantage of the proposed structure is that it allows the designer to synthesize a low order controller that guarantee performance robustness of the uncertain closed loop system and also the robustness of the switching dynamics. Thanks to the low order of the controllers, this method is particularly suitable for an easy real time implementation on chip. As a proof of concept, the control method is applied on a piezoelectric inertial actuator for position control with various closed loop dynamics. This application shows the ability to do, in an automated and robust way, precise micro and nano-robotic tasks involving different control levels and different motion dynamics.