Wheeled Mobile Robot Trajectory Tracking using Sliding Mode Control

Azza El-Sayed Bayoumi Ibrahim

doi:10.3844/jcssp.2016.48.55

Abstract

This paper introduces and discusses a control strategy for nonholonomic wheeled mobile robots. The models of the robots include the kinematic and dynamic equations of motion. Trajectory tracking control problem of parallel wheeled differential drive mobile robot is considered, where the robot should reach the final position by following a referenced trajectory for different initial conditions. A motion control strategy for a mobile robot by only assuming the kinematic model was developed by many researchers. In the case of high-speed robot motion, the dynamical model is important. In this study, two stages of the proposed control strategy are presented. The first one is dealing with the kinematics of the system and denoted as ‘steering’ controller. The second one, a velocity controller is developed based on the robust sliding mode control technique. A new design of the sliding surface is proposed. The switching feedback gain is determined based on a novel mathematical simple rule, considering the initial state of the system. Robustness to parameters uncertainties and stability of the controlled system are achieved. A simulation model of the controlled system is developed in MATLAB-SIMULINK software. Simulation results show the performances of the developed controller. In the case of presence of uncertainties, the results show the superiority of the proposed controller compared with the computed torque method.

Highlights

Mobile robots have been used in many applications and areas such as industrial, medical, etc
The feed forward kinematic controller and the feedback dynamic sliding mode controller are integrated ensuring the exponential convergence of the robot to the desired trajectory in a condition of the system uncertainties is bounded
Where, a, b, γ are positive gains constants. ‫ݒ‬c, ߱c are the required linear and angular velocities for kinematic stabilization which are taken as reference inputs for the dynamic controller stage

Summary

Introduction

Mobile robots have been used in many applications and areas such as industrial, medical, etc. The control inputs of the mobile robot are often considered its linear and angular velocities as described in (Niţulescu, 2007; Saidonr et al, 2011). The feed forward kinematic controller and the feedback dynamic sliding mode controller are integrated ensuring the exponential convergence of the robot to the desired trajectory in a condition of the system uncertainties is bounded.

Results

Conclusion