Variable Structure Tracking of DC Motor for High Performance Applications

This paper presents a novel application of the Variable Structure System Control (VSS) for on-line tracking of dc motors. By the proposed technique, the rotor position, speed and current can follow preselected tracks (a track is a time history selected in advance). The theory of the VSS is modified to include the tracking option for the general case of multi-input/multi-output system. The robustness of the proposed tracking controller is ensured at all time. By selecting the tracks as proposed in this paper, the electrical and mechanical stresses on the motor are substantially reduced, and the "soft starting" of the motor is achieved. The entire drive system is built and tested in the laboratory by using off-the-shelf components and software. The test results show the effectiveness of the proposed tracking controller in the high performance drive applications such as robotic, manipulation and actuation.