Variable Structure Servomechanisms. Phase 1 Report

摘要

Variable structure control systems are characterized and a continuous real-time demonstration of the speed control of a dc motor using a variable structure design is described. A variable structure design for ac drives is also addressed. Problems with variable structure control systems are considered, including chatter and stochastic disturbances. In the case of single input control systems, the chattering phenomena is explained as a limit cycle in the fast dynamics. An analysis is made based on the use of a symptotic root locus and describing function techniques, and it is shown that chattering can be minimized and often completely eliminated by appropriate design of the variable structure control law. It is determined that the inclusion of noise has a soothing effect which can eliminate, or average out, the chattering behavior.