Fuzzy-Tuned PD Tracking Control of a 3-RRR Parallel Manipulator: Stability Analysis and Simulations

Abstract

In this work we propose a variable gains PD tracking controller, in which the gains are tuned by a Fuzzy controller, for a parallel robot. The stability analysis of the closed-loop system is performed by using the Lyapunov-based perturbed systems theory. The closed-loop system is formed by the PD with variable gains control law and a so-called reduced model of the robot, which exhibits some properties similar to those found on the model of a serial robot. As a result, we demonstrate that, under a proper selection of the bounds of the variable gains, the tracking errors are uniformly ultimately bounded. Simulation results of the Fuzzy-tuned PD controller, applied to a 3-RRR planar parallel manipulator, are presented. The superior performance of the proposed approach is validated when compared with a classic PD controller.