VLSI implementation of a self-tuning fuzzy controller based on variable universe of discourse

A novel self-tuning fuzzy controller and its VLSI implementation are developed based on variable universe of discourse. This fuzzy controller is constructed by applying a contraction factor before each input of a conventional fuzzy controller, and a self-tuning gain factor after its output, while all the factors are adjusted with the input variables according to a simplified adaptive law. This fuzzy controller has some features: the contraction factors and output gain factor that improve the performance of the controller are based on variable universe of discourse; these factors are simplified for VLSI implementation; only the active rules are processed and the division in the operation of COA defuzzification is omitted by setting the denominator equal to 1. Results of Matlab - ActiveHDL co-simulation indicate that this self-tuning fuzzy controller works successfully in controlling a nonlinear system to track a reference trajectory.