Implementation of high precision positioning systems using contactless magnetic levitation

This thesis presents the implementation and control of two high precision positioning systems based on contactless magnetic levitation, actuated by means of permanent magnet linear synchronous motors. Such positioning technology has applications in the manufacturing of semiconductors and other industrial processes. The first system presented in this thesis employs one permanent magnet linear synchronous motor to actuate two translational degrees-of-freedom and serves as a proof of concept testbed. The second system employs four motors to actuate three translational degrees-of-freedom. For each implementation, a procedure is outlined through which a theoretical state-space model is enhanced using system identification. The resulting mathematical model is then validated using experimental data generated from each apparatus. It is shown that the models of both systems accurately describe the real dynamics over a wide operating range. The models are then used to design nonlinear and linear controllers for set point stabilization and sinusoidal tracking. Comprehensive experimental results demonstrate the superior performance of the nonlinear controllers as compared to their linear counterparts.