Torque-compensated motion control design for a mobile robot moving on ground with ill-conditioned road situations

Proportional-Integral (PI) control is usually employed in motion control design for mobile robots. However, external torque disturbances induced by ill-conditioned road situations still deteriorate the running performance of the driving motors, and thus limit the robots' motion performance. To improve motion accuracy, a torque-compensated PI control is presented that integrates conventional PI control with a disturbance observer. A simplified computed-torque control with disturbance torque compensation is also presented to improve the motion of mobile robots. Simulation and comparative studies show that, in comparison with conventional PI control, the torque-compensated PI control and the simplified computed-torque control with disturbance torque compensation can provide both good position and orientation accuracy of the robot's motion. This paper also concludes that the compensation of external torque disturbances is significantly important for controlling a mobile robot moving on ground with ill-conditioned road situations.