Iterative learning control for nonlinear MIMO systems with unknown nonparametric uncertainties and input saturations

In this paper, an iterative learning control (ILC) approach is proposed for a class of nonlinear multi-input-multi-output (MIMO) systems with unknown nonparametric uncertainties and input saturations. The nonlinear system is assumed to be under state alignment condition. The proposed scheme can address the nonparametric uncertainties which satisfy the local Lipschitz condition. Also, the proposed control law can deal with the input saturations which widely exist in the practical fields. By designing the composite energy function (CEF), we prove the convergence of the tracking error along the iteration axis. From the proof, we can see that the proposed control approach can warrant a L²_{[0, T]} convergence of the tracking error. Finally, we give an numerical simulation to demonstrate the effectiveness of the ILC approach.