Time optimal path following with bounded velocities and accelerations for mobile robots with independently steerable wheels

摘要

Mobile robots with independently steerable wheels provide better robustness and efficiency compared to the other types of omnidirectional mobile robots. However, the non-holonomic constraints and singular configurations give rise to several challenging issues in exploiting the high maneuverability features of the robot. Many proposed motion controllers for such robots force the robot to stay outside of bulky regions around its singular points, which in turn limits the robot's dexterity. In this paper, which extends our previous works, we present an online trajectory generation along with a globally stable path following controller that enables the robot to follow any given smooth path and heading function. We show that the control signals extensively simplify the kinematic constraints and are utilized to develop an efficient online “Phase Plane” switching algorithm that bounds the velocities and accelerations of the actuators. Moreover, we show that the algorithm efficiently regulates the velocity of the robot around the singular configurations which allows the robot to realize wide ranges of complex maneuvers. The proposed control algorithm has been tested on iMoro(our four-wheeled independently steerable mobile manipulator), and the presented results show the efficacy of our method.