Torque pulsation compensation for a DC motor using an extended Kalman filter approach

Brushless permanent magnet (PM) servomotors are appealing candidates for many high-performance applications. A persistent problem with PM motors is the non-uniformity in the developed torque which gives rise to a torque pulsation that varies as a function of operating conditions. In this paper a torque pulsation compensation scheme based on an Extended Kalman Filter (EKF) is developed. The compensation scheme is based on a simple lumped parameter model of the motor to-ether with the signals generated from the measured angular position and the closed loop position controller. The compensating signal is added directly to the motor's position control signal, so that compensation is accomplished in closed loop, and no new hardware is necessary. The effectiveness of the proposed torque pulsation compensation is demonstrated by means of experiments.