Nonlinear regulation and path tracking of a wheeled mobile robot in polar coordinates

Abstract
This paper presents regulation and path tracking control methods for wheeled mobile robots (WMRs) associated with kinematic models in two‐dimensional polar coordinates. The proposed two regulation control laws are designed via the Lyapunov indirect and direct stability theorems in order to asymptotically achieve nonlinear regulation. With the Lyapunov‐based stabilization law, a novel path tracking control method is proposed to achieve reference path following missions on a global scale except for an arbitrary small region around the origin; in particular, two special path tracking examples are analyzed with large initial tracking errors. Computer simulations and experimental results are described to confirm the efficacy of these proposed control approaches.