Flexible link robot arm control by a hierarchical fuzzy logic approach

Abstract

This paper concentrates on hierarchical fuzzy logic using the singular perturbation approach for flexible-link robot arm control. A two-time-scale fuzzy logic controller is applied to such a system. A large-scale system is decomposed into a finite number of reduced-order subsystems, thereby eliminating the need for a large-sized inference engine. In this paper, a fast-subsystem controller damps out the vibration of the flexible structure by means of two hierarchical fuzzy logic controllers. Another, slow-subsystem fuzzy controller dominates the trajectory tracking. It appears that the fuzzy control method is quite useful as regards reliability and robustness.