Sensorless Torque and Thrust Estimation of a Rotational/Linear Two Degrees-of-Freedom Switched Reluctance Motor

A rotational/linear two degrees-of-freedom switched reluctance motor (2DOF-SRM) has been developed for the purpose of independent control of rotational and linear actuations on one actuator. In the previous study, noncontact-type angular and linear position sensing system that used photoelectric sensors was developed. It was successfully applied to the independent rotational speed and linear displacement control of the 2DOF-SRM. In this paper, both the torque and thrust control are developed as the new function of the 2DOF-SRM. This control is achieved by the electric current control for each phase windings. In this system, actual torque and thrust are independently estimated by a simplified matrix expression from the information of the phase winding current. The performance test results for torque and thrust estimation are presented.