Abstract
The objective of the study is to design a robust controller to control a system of a linear maglev stage with hybrid magnets for achieving the precision positioning requirement. First, a one-dimensional maglev system model under several assumptions was analyzed, and then the analysis is extended to the three-dimensional system. In the study, a maglev stage system equipped with three air-gap sensors and four supports of hybrid magnets was designed and established. To control the system, three kinds of control laws of PID, switched-PID and sliding mode were employed. The response of the system under these control laws were also analyzed and discussed. In order to verify the performance of the designed controllers, a real maglev stage system was constructed, and experiments regarding the stiffness, the response speed, the settling time and the accuracy of the system were also made. From the simulations and experiment results, it is found that the PID control law is not adequate to the system, and the switched-PID control law may be an alternatively improving choice. The sliding mode control is considered possessing the best characteristics of robustness except the chattering problem influencing its positioning ability.