Magnetically suspended balance beam with disturbances: A test rig for nonlinear output regulation

This paper presents an experimental test rig for nonlinear output regulation. This experimental setup consists of a beam free to rotate on a pivot at its center of mass, and stabilized by two active electromagnets located at each end of the beam. The rotation of the beam is measured by a non-contacting displacement sensor. A motor with unbalance weight is mounted on a track on top of the beam. This mounted motor serves as an exosystem in the problem of output regulation. By moving the motor position along the track and adjusting the motor rotational speed, constant and sinusoidal disturbances of different frequencies and magnitudes can be imposed on the system to test controllers. The input output characteristics of the active electromagnets are nonlinear and are difficult to be determined precisely. The air gaps between the beam and the electromagnets are narrow. These properties of the setup make it a good platform for testing nonlinear output regulation controllers, including robust output regulation and output regulation under the actuator and state constraints.