Abstract : iterative learning control is an effective approach to the control of processes that are repetitive in nature . in this paper , an open - closed - loop pi - type iterative learning control scheme for the precise tracking control of a class of discrete nonlinear time - varying systems over a finite time interval is presented . the scheme updates control input with tracking errors of both current and last iterations simultaneously . sufficient and necessary conditions which guarantee the convergence of the scheme are given and then proved with inductive method . finally , the conditions are verified with simulation results 文摘:對于具有重復運動性質(zhì)的對象,迭代學習控制是一種有效的控制方法.針對一類離散非線性時變系統(tǒng)在有限時域上的精確軌跡跟蹤問題,提出了一種開閉環(huán)pi型迭代學習控制律.這種迭代律同時利用系統(tǒng)當前的跟蹤誤差和前次迭代控制的跟蹤誤差修正控制作用.給出了所提出的學習控制律收斂的充分必要條件,并采用歸納法進行了證明.最后用仿真結(jié)果對收斂條件進行了驗證