Stability and four-posture control for nonholonomic mobile robots

In this paper, a four-posture control for nonholonomic mobile robots is proposed. Based upon posture velocity error dynamics, the empirical kinematic motion requirements of a mobile robot are proposed, and the four-posture control is designed in order to generate the robustly required moving trajectory with posture error reduction. The controller is designed with four possible moving directions of linear and angular velocities. The robustness of the controller is confirmed using Lyapunov stability theory. The proposed controller is experimentally demonstrated under high velocity and acceleration conditions with different control parameters. It is shown that the four-posture control algorithm is effective and feasible, even if an unsophisticated velocity controller is used as the deriving unit of a mobile robot.