Synthesis of Stable Fuzzy PD/PID Control Laws for Robotic Manipulators from a Variable Structure System Standpoint

In this paper we present a systematic procedure for the synthesis of stable and robust fuzzy PD/PID controllers for robot manipulators from a variable structure systems standpoint. For linear systems and certain classes of non-linear systems variable structure systems theory has been used as a basis for synthesizing so-called fuzzy sliding mode controllers (FSMC)[1]. Variable structure systems theory has also been shown to be useful for understanding the effectiveness and stability of direct fuzzy PD controllers [2]. In this paper we will present a systematic method to exploit these two complementary roles of variable structure systems theory in order to guide the design and analysis of fuzzy PD/PID controllers for the class of non-linear systems characterized by robot dynamics.