Research On The Algorithm Of Iterative Learning Control

Iterative learning control(ILC)is an important branch in the control theory,which is an intelligent control method and mainly suitable for the system which repeatedly operates and is difficult to model.This control method tries to control the system,updates non-ideal control input with error signals between the system output and the desired output,and generates new control signals so as to gradually improve tracking performance of the system and finally realize perfect tracking of the desired output.Plentiful research achievements on the ILC theory have been made,but it is still not perfect,such as arbitrary initial value problem,convergence speed problem and time delay problem,and so on.This paper studies these problems in ILC and further improves the achievements on ILC theory.This paper mainly conducts some research on the following aspects:For the initial value problem of ILC for linear discrete system,this paper proposes an ILC algorithm with initial rectifying action,so the initial state value of the system is optional for each cycle and the desired trajectory can be perfectly tracked on the time interval besides the initial points.For the linear discrete systems,this paper proposes an ILC algorithm with variable forgetting factor and proves convergence and effectiveness of the proposed algorithm.For nonlinear continuous systems,this paper proposes an ILC algorithm with variable forgetting factor based on information fusion and proves algorithm convergence in theory.For the linear continuous system with state time-delay,this paper proposes an ILC algorithm with initial state learning.At the first operation,the initial state of the time-delay system is arbitrary.The desired trajectory can be perfectly tracked via controlled input learning and initial state learning in later operation.The algorithm convergence is proved in theory.The actual output can perfectly track the desired trajectory.Finally the algorithm effectiveness is verified by numerical simulation.For discrete singular systems with control time-delay,this paper proposes a closed-loop D-type ILC algorithm,gives the convergence conditions of this algorithm,and completely analyzes and proves that the iterative output of the system converges at the desired output with the influence of this algorithm in theory.