ABSTRACT
This chapter develops a load position tracking controller for the electromechanical model of a brushless direct current (BLDC) motor driving a position-dependent load under the assumptions that only load position measurements are available and that an exact model for the electromechanical system dynamics can be determined. An observed-integrator backstepping procedure is utilized to design an BLDC output feedback controller. Specifically, by utilizing the structure of the BLDC electromechanical system, nonlinear observers are designed to estimate the load velocity and the transformed stator current. The chapter uses a Lyapunov-like argument to motivate the construction of the observers and to prove that all of the signals in the actual electromechanical systems and the observer remain bounded during closed-loop operation. Furthermore, the controller ensures that the load position tracks the desired trajectory exponentially fast. Finally, simulation results are utilized to illustrate the performance of the proposed controller.
