Inverse Dynamics Based Tuning of a Fuzzy Logic Controller for a Single-Link Flexible Manipulator

Abstract

Since its introduction to engineering applications, fuzzy logic has attracted many researchers because of its simplicity and robustness. Experience with a system is translated into heuristic rules which can be used to control that system. This article proposes a novel method for a generalized inverse dynamics based fuzzy logic controller (FLC) of a single-link flexible manipulator. The deflection of the flexible link was modeled using the assumed modes method. The control action is distributed between two FLCs: A joint angle controller and a tip controller. Each controller produces a torque value. The torque values are summed, and the resulting control action is used to drive the manipulator. A novel method for varying the ranges of the variables of the two controllers as a function of the motion parameters and the inverse dynamics of the system is presented. The relative shapes and distribution of the fuzzy membership sets (with respect to each other) are kept fixed. Simulation results show that joint trajectory tracking is accomplished, and that the residual vibration of the flexible link is suppressed.