Tracking control of wheeled mobile robots using iterative learning controller

In this paper, an iterative learning control (ILC) strategy is proposed to resolve the trajectory tracking problem of wheeled mobile robots (WMR) based on dynamic model. In the previous study of WMR trajectory tracking, ILC was usually applied to the WMR kinematical model with the assumption that desired velocity can be tracked immediately. However, this assumption can not be realized in the real world at all. The kinematics model and dynamic model of WMR are deduced in the paper, and the novel combination of D-type ILC algorithm and WMR dynamic model is presented. In order to analysis the convergence of the algorithm, the method of contracting mapping which shows that the designed controller can make the state error converge to zero completely when the iteration times tends to infinite, is adopted. The simulation results also demonstrate the effectiveness of D-type ILC in the WMR trajectory tracking problem.