Experimental demonstration of anti-windup controller for non-linear magnetic levitation system

In this paper, a new way is proposed to show the error windup phenomenon during actuator failure through experiment. The set-point tracking of ball position for Magnetic Levitation System with anti-windup PID controller is experimentally performed. When only PD controller is used for positioning of ball, steady-state error is present in the system. For reducing the steady-state error, integrator is added with PD controller. The integrator present in the system accumulates error during actuator saturation, an undesirable phenomenon known as integral windup occurs. To overcome integral windup, anti-windup technique (conditional integration) with PID controller is used. Experimental result shows that by using anti-windup with PID controller gives better set-point tracking and steady-state error is also minimized.