Behavior-based robust fuzzy control

Fuzzy control has achieved great acceptance in the form of fuzzy versions of the PID, sliding mode and gain scheduling controllers. These fuzzy control techniques ignore the original intent of fuzzy logic: implementation of symbolic, linguistic control laws based on qualitative models of the plant, and control behaviors. We have developed a new fuzzy control methodology, one that achieves robust control objectives, even for simple plants, by using qualitative behaviors that first stabilize the plant, and then superimposing additional tracking behaviors that achieve control objectives. Specifically, our fuzzy controller accomplishes superior stability and tracking performance as compared to the best published linear compensators for the 1992 ACC Robust Control Benchmark. Furthermore, the stability behavior of the fuzzy controller allows for fault rejection in the presence of deadzone and backlash actuator faults.