Robust Adaptive Control of Uncertain Fully Actuated Systems With Unknown Parameters and Perturbed Input Matrices

Robust adaptive control of fully actuated systems (FASs) with unknown parameters, perturbed input matrices and nonlinear uncertainties is considered. Two novel robust adaptive controllers are developed for the two cases where the unknown parameters are time-varying and constant. For both cases, different from the existing results on FASs with unknown parameters, this article allows the existence of a perturbation matrix that satisfies a certain assumption in the input matrix. Furthermore, for the case of time-varying parameters, under relaxed system assumptions, the global boundedness of the state variables and the estimation error is guaranteed. For the case of constant parameters, under certain assumptions on the nonlinear uncertainty and known nonlinear functions, no pre-estimation of the unknown parameters is required and the state variables globally asymptotically converge to the origin. In addition, a parallel extension of the proposed methods to the generalized multiorder FAS case is also given. The effectiveness of the developed methods is shown by the successful application in the control of electromechanical systems.