Tracking Control of a Flexible String System Based on Iterative Learning Control
Tingting Meng, Wei He, Xiuyu He
Abstract
This brief addresses a flexible string with disturbances and a tip payload which is described by a coupled partial differential equation (PDE)-ordinary differential equation (ODE) system. An exosystem under unknown initial condition is utilized to generate the disturbances and prescribed trajectory, both of which can be periodic or aperiodic with respect to iteration. An observer and adaption laws are designed to estimate the distributed and boundary disturbances. The reference system under the estimated distributed disturbance is defined and proved to be uniformly bounded, where the endpoint displacement is set as the known prescribed trajectory in order to address the tracking control problem. Iterative learning controller is then designed to guarantee the convergence of the tracking error and the uniform boundedness of the closed-loop system. A set of simulation examples are presented to describe the performance of a closed-loop system.