Backstepping-based Robust Control for WMR with A Boundary in Prior for the Uncertain Rolling Resistance

摘要

In this study, we focus on the trajectory tracking control problem ofa wheeled mobile robot (WMR) in an uncertain dynamic environment. Concerningthe fact that the upper boundary may be usually achieved in prior according to thephysical properties of the terrain, this crucial message is utilized to construct thecontrollers. Firstly, a dynamic model for WMR including the rolling resistance ispresented, whose state variables are longitudinal and rotational velocities, as well asthe rotational angle of the mobile platform. Secondly, with the aid of backsteppingtechnique, the robust controllers based on the upper boundary are proposed and theglobally asymptotic stability of the closed-loop system is proven by the Lyapunovtheory in the following. Lastly, a saturation function is applied to replace the signumfunction, by which the inherent chattering can be suppressed greatly. Numericalsimulation results demonstrate that the proposed controllers with upper bound inprior possess robustness characteristics which yields potentially valuable applicationsfor the mobile robot, especially in the unstructured environment.