Design, construction and control of single axis electromagnetic levitation system using fpga

One of the most attractive topics in the control engineering area is magnetic levitation (maglev) system which produces electromagnetic force to counteract the gravitational force as their levitation method. One of the well-known applications of maglev systems is magnetic levitation train which is valid alternative of the conventional trains. Electromagnetic suspension (EMS) system is one of the most known types of maglev trains that uses magnetic attraction force between iron guide way and electromagnet. In this work, a single-axis EMS system is studied and controlled. The system is unstable and inherently nonlinear. To apply linear controller techniques, the non-linear system is linearized around equilibrium points using Taylor series expansion method. Both of the linear and nonlinear mathematical modeling are presented. Three state space controllers namely complete state feedback controller based on pole-placement technique, feedback linearization and sliding mode controller (SMC) are designed and applied to the system. Simulation results are presented using Matlab Simulink. In the experimental setup, a single-coil maglev ball system is considered. FPGA-based PID controller is designed and implemented with the system as digital controller. Altera DE2-115 FPGA board is used with the real physical plant and the system is controlled. Different weights of magnet ball are successfully tested and levitated in certain set positions. Consequently, the steady state error is minimized.