System-Level Modeling of a Cooperative Microactuator with Free Particle Movement

Over the last years, a considerable effort in enlarging the operational range of microactuators has been made. An important part of this research includes new concepts without mechanical connections limiting the motion of the actuator. Within the project “Kick and Catch” (www.spp-kommma.de/87.php), we therefore investigate concepts for microactuators where small objects can be moved freely within a large working range. In this work, we present an actuator allowing free vertical movements of a magnetic particle, which can be kept levitating at predefined resting positions without energy input. For efficient transitions between these equilibria, a cooperative mechanism between a piezoelectric chip actuator and controlled electromagnets is deployed. In order to design component dimensions and controller architectures, a dynamical model is derived, which allows simulation demonstrating the working principle and the efficiency of the nonlinear feedback controller.