Output feedback control of a three degree-of-freedom linear stepper motor with position measurements only

In this paper, an adaptive current-level controller is designed for two-dimensional linear stepper motors that renders the closed-loop system robust to a variety of uncertainties and disturbances prevalent in the motor dynamics. The controller uses only the motor position and the yaw angle for feedback. The tracking error is shown to be globally uniformly bounded. Simulation studies are presented to validate the controller performance.