Robust tracking control of a permanent magnet stepper motor without current measurements

This paper illustrates a new control design approach which can be utilized for developing a robust tracking controller for a permanent magnet (PM) stepper motor driving a pure inertial load. The significant advantage of this controller is that it does not require current measurements. This is due to the fact that our approach uses the model reference robust control (MRRC) technique for SISO systems. The controller compensates for parametric uncertainty while yielding a global uniform ultimate bounded stability result for the motor position tracking error