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A Robust Fuzzy Tracking Control Scheme for Robotic Manipulators with Experimental Verification

Research Authors
A. Sharkawy, M. Othman and A. Khalil
Research Member
Research Year
2011
Research Journal
Intelligent Control and Automation
Research Publisher
NULL
Research Vol
Vol 2
Research Rank
1
Research_Pages
PP. 100-111
Research Website
NULL
Research Abstract

The performance of any fuzzy logic controller (FLC) is greatly dependent on its inference rules. In most cases, the closed-loop control performance and stability are enhanced if more rules are added to the rule base of the FLC. However, a large set of rules requires more on-line computational time and more parameters need to be adjusted. In this paper, a robust PD-type FLC is driven for a class of MIMO second order nonlinear systems with application to robotic manipulators. The rule base consists of only four rules per each degree of freedom (DOF). The approach implements fuzzy partition to the state variables based on Lyapunov synthesis. The resulting control law is stable and able to exploit the dynamic variables of the system in a linguistic manner. The presented methodology enables the designer to systematically derive the rule base of the control. Furthermore, the controller is decoupled and the procedure is simplified leading to a computationally efficient FLC. The methodology is model free approach and does not require any information about the system nonlinearities, uncertainties, time varying parameters, etc. Here, we present experimental results for the following controllers: the conventional PD controller, computed torque controller (CTC), sliding mode controller (SMC) and the proposed FLC. The four controllers are tested and compared with respect to ease of design, implementation, and performance of the closed-loop system. Results show that the proposed FLC has outperformed the other controllers.