Chattering Alleviation Method for Variable Structure Controllers that uses Linear Feedback with Switched Gains

摘要

This pajxr presents a method for chattering alleviation in variable structure control (VSC) signals that are generated by one of the most popular form of control law adopted by VSC for linear systems, namely the use of linear feedback with switched gains. The principle involved in the proposed method is to have sufficiently high controller gains when the representative point (RP) of the system is far away from the switching surface so that it is attracted to it with sufficient driving force; once, in the vicinity of the switching surface, the gains are reduced gradually so that tht RP slows down to reduce the momentum of the. Motion when it hits the switching surface. However, the novelty lies in the fact that the process of gain changing in the vicinity of the switching surface is not a discrete process, but a continuous one where the distance of the RP from the switching surface is automatically being considered by the gain changing law. The gain changing law also does not violate the existence condition of sliding mode, thus maintaining the switching surface as an attractive domain for the RP. The system thus retains its robustness property. The proposed method is applied to the variable structure model following control law for tip position control of a single link flexible manipulator and simulation results are presented to demonstrate the effectiveness of the method.