Bounded control of a spherical actuator based on orientation measurement feedback

This paper presents a permanent magnetic spherical actuator, which is capable of performing 3-degree-of-freedom (DOF). The orientation measurement of the spherical actuator has been a challenging problem so far. An interesting orientation measurement system for the rotor is proposed in this paper. Based on the position measurements, the trajectory tracking of the rotor with output feedback is addressed. As the current input is usually limited to certain degree in the applications, which leads to the bounded control torque input, the trajectory tracking controller with bounded torque input is designed. Simulation results indicate feasibility of the proposed controller. At last the experimental system is designed to validate the proposed orientation measurement system.