Backstepping based position control of active magnetic bearing under bounded disturbance

In this paper we study the position control of the rotor of single-axis active magnetic bearing in presence of bounded disturbance. We apply the approach of integrator backstepping and design a nonlinear position controller for the rotor. With the voltages as the control inputs, which are used to generate the magnetic field, the proposed controller can make the rotor practically track a smooth reference trajectory with an as small as desired tracking error by selecting appropriate design parameters. Simulation results are included to verify the proposed controller.