Nonlinear Adaptive Control for Robotic Manipulators

Abstract

In controlling robotic manipulators, dynamic characteristics, such as inertia-moments, centrifugal and Coriolis forces, and gravitational loadings, are to be considered. But those effects are highly nonlinear, and that makes it difficult to achieve the quality dynamic performance by conventional linear control techniques.To overcome those difficulties, many approaches have been examined based on modelreference adaptive control schemes. But most of them are only applications of the usual method to the linearized approximations of nonlinear manipulator models, and then are not useful in controlling over a wide range of motions.In this paper, we propose a new control scheme, in which the quality dynamic performance is achieved without exact knowledge of nonlinear elements and accelerations. It is considered to be a kind of adaptive sliding mode control that adjusts the control gains adaptively. Finally some simulation results show the effectiveness of this method.