Torque Control Using High Performance Fuzzy Based Controllers for Large Scale Systems

Performance and robustness of fuzzy controllers (FC) and their similarity to sliding mode controllers and PIDs, propels system toward sliding mode conveniently in a short time and independent of parametric uncertainties and disturbances. Comparison between operations of SMC, FC and PID, stimulated us to design FC for SMC controller (FSMC) and PID for FC (Fuzzy PID) to enhance quality of Fuzzy controllers, based on simplicity of PID structure and robustness and performance of SMC against transient phenomena such as noise. In this paper both systematic methods of Fuzzy controller design which are used in nonlinear large scale systems, are analyzed and applied on a two-degrees of freedom robot which are coupled with two DC motors. To eliminate chattering in sliding mode, an adaptive algorithm is applied. Simulation results of this approach on a multi-variable nonlinear system, proves high robustness of Fuzzy sliding mode method against parametric uncertainty and noise mode treatment of system while fuzzy PID has less steady state error.