Robust position tracking control for direct drive motor

Direct drive motors became very popular due to the simple mechanical structure that avoids the use of a speed reducer that can cause position errors and instability. With the use of a direct drive motor, undesired backlash, and flexibility are reduced significantly. However, since load variation is linked to the motor axis directly, an advanced algorithm has to be applied in the motion control scheme. This paper introduces a novel robust position tracking control algorithm, which is derived with the use of sliding mode theory. The control algorithm was tested using the experimental nonlinear direct driven "ball-in-cage" system. Experimental results are presented and discussed