Wall-following control of a mobile robot

The wall-following control problem is characterized by moving the robot along a wall in a desired direction while maintaining a constant distance to that wall. From ultrasonic distance measurements the distance and the orientation of the robot with respect to the wall can be calculated. This is solved by the use of an observer: the distance and orientation are estimated using a robot model and corrected by sensor measurements. Since a wall may not be available continuously (e.g., an open door), the robot must be able to navigate on its dead-reckoning as well. The feedback controller has been set up in such a way that it can handle both the observer data and dead-reckoning data. The controller has been verified by means of experiments. The results show a good performance with an absolute error of a few millimeters from the desired distance to the wall