Tracking Controller of mobile robot

Abstract

Tracking control of parallel wheeled differential drive mobile robot is considered. The robot has to reach the final goal by following a referenced trajectory. The initial position of the robot may be on or off the path. The dynamic model of the robot is composed of two consecutive parts; kinematic model and equations of linear and angular torques. By transforming dynamic error equations of kinematic model to mobile coordinates, the tracking problem changes to stabilization. Nonlinear state feedback controller using integrator backstepping is used to design the tracking controller. In which, depending upon the initial errors in the position and of the robot two controllers are designed; Local Tracking Controller and Global Tracking Controller. These controllers will control kinematic model of the mobile robot. It has been proved that all type of errors ranging from small to large converged to zero optimally with either of the controllers. In this study the effect of uncertain parameters of dynamic model on system performance is considered. It's shown that the suggested method based on model reference adaptive control can save the closed loop performance vis-à-vis changing parameters of mass and inertia of robot. In addition the distinctive simplicity of the proposed controller leads to the possibility of adjusting the parameters to achieve the desired performance including tracking error and control signals. The tracking controllers designed are implemented in MATLAB®. Various results have been included and verified the robust performance of controllers.