A new fuzzy logic learning control approach for repetitive trajectory tracking problems

Abstract

In this paper, we consider repeatable tracking control tasks using a new control approach - PD type Fuzzy Logic Learning Control (FLLC). FLLC integrates two main control strategies: Fuzzy Logic Control as the basic control part and Learning Control as the refinement part. The new FLLC is constructed by simply adding an iterative learning mechanism to a fuzzy PD controller. The incorporation of the learning function into fuzzy PD controllers ensures exact tracking because it completely nullifies the effects of reference signal and periodic disturbances on the tracking error. Through rigorous proof based on energy function and functional analysis, we show that the proposed FLLC system achieves the following novel properties: (1) the tracking error sequence converges uniformly to zero; (2) learning control sequence converges to the desired control profile almost everywhere.