This paper investigates the predictive iterative learning control(PILC)problem for a class of nonlinear and nonaffine multiple-input multiple-output(MIMO)discrete-time systems with unknown system mechanism model and under both unknown time delay and iteratively varying trial lengths.First,a new dynamic linearization(DL)model is developed by virtue of the upper and lower bound information of the unknown time delay,and the theoretical analysis shows that the constructed model can equivalently describe the unknown nonlinear system with unknown time delay considered in this paper.At the same time,a new data compensation mechanism is introduced to deal with the problem of data loss caused by the varying trial lengths at each iteration of the system.Based on the developed DL model and data compensation mechanism,a predictive iterative learning control method is designed that can handle both the unknown time delay and the iteratively varying trial lengths.The convergence properties of both the modeling error and the tracking control error are given through rigorous theoretical analysis.Simulation results further verify the effectiveness of the proposed method.
维普
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