Robust decoupled adaptive fuzzy sliding mode control for a class of underactuated mechanical systems

Abstract

Nowadays, Underactuated Mechanical Systems (UMS) remain an interesting research field for control laws development. This work deals with the design of an adaptive controller on the basis of Sliding Mode Control (SMC) and the universal approximation property of Fuzzy Systems (FS) for a classe of second order UMS two Degrees of Freedom (DOF). We first design an SMC law to force a coupled sliding urface to be reached in finite time. Second, by considering model uncertainties, fuzzy systems are then introduced to approximate the unknown controller. The adjustable parameters are updated by using gradient descent method. Through the stability analysis for both cases, it is shown that the system converges asymptotically to its equilbrium points in finite time. To demonstrate the validity and the performance of the proposed methods, an appropriate numerical application to an overhead crane systems is presented