DESIGN AND DEVELOPMENT OF ROBUST PID AND FUZZY CONTROLLERS FOR UNCERTAIN MACHINING PROCESSES

摘要

Force control is an effective means of improving the quality and productivity of machining operations. However, One of the greatest difficulties in regulating metal cutting processes is that these processes are inherently nonlinear exhibit nonlinear, uncertain and time-varying characteristics. Robust control, or fuzzy logic control is a good control method for such uncertain and nonlinear systems. Robust control is traditional method used to design of uncertainty-tolerant feedback systems. Fuzzy logic control is particularly suited for those systems whose mathematical models are not known, complex, or time-varying, or nonlinear, and where human experience can play an important role. Robust PID and fuzzy controllers were developed to deal with the difficulty in machining processes to obtain constant cutting-force by adjusting the feed rate automatically under time-varying cutting conditions in this paper. Simulation and experimental results on machining processes show that both robust PID control and fuzzy control can deal with uncertainty and nonlinearity in the machining processes.