Four path following controllers for rhombic like vehicles

This paper addresses the path following problem of a wheeled mobile robot with rhombic like kinematics (two drivable and steerable wheels) operating in cluttered environments. Four path following controllers are developed to steer the kinematic model of a rhombic like vehicle (RLV) along a desired path: three are based on feedback laws derived at a kinematic level with geometrical inspiration; the fourth is a nonlinear controller built upon a kinematic model of the vehicle using Lyapunov functions. By fully exploiting the kinematic capabilities of this type of vehicles, all the developed controllers are capable of performing under two situations: when both wheels follow the same path, or when each wheel follows a different path. Simulated and experimental results are presented in the paper to illustrate the performance of the controllers. The main conclusions of these controllers are summarized, leading to a possible application in the vehicles that will operate in the remote handling missions of the International Thermonuclear Experimental Reactor (ITER).