WITHDRAWN: Trajectory Tracking of A Mobile Robot Using Adaptive Sliding Mode Control

Abstract

In this paper, a control system for a mobile four-wheeled robot is designed, whose task is to create stability and achieve proper performance in the execution of commands. Due to the nonlinear and time-varying dynamics, structural and parametric uncertainties of this robot, various control approaches are used in order to achieve stability, proper performance and minimize the effect of uncertainties and modeling errors, etc. The purpose of the control here is to follow a predetermined trajectory by adjusting linear and angular velocities in the presence of external disturbances and parametric uncertainty.In previous articles, the upper band of uncertainties has been assumed known. In this paper, and given that in practice, in many cases it is not possible to know the extent of uncertainties and disturbances in robotic systems, we have assumed that this upper band is unknown. Therefore, the sliding mode control law designed in the paper has been generalized and proved its stability so that by adding an adaptive part to the controller and converting it into a robust-adaptive sliding mode control, the upper band uncertainties are estimated online using these adaptive laws. The results of this typology are expressed in a separate theorem and proved to be stable. The results of simulation with MATLAB software show that the proposed controller ensures optimal performance under external disturbances and parametric uncertainty with less fluctuations.