Real-time localisation of a low-cost mobile robot with poor ultrasonic data

In order to open the field of autonomous mobile robotics to new application s such as the provision of assistance to disabled people, the research is b eing focused upon low-cost solutions. That implies the use of poor percepti on systems and low computing power. In such a context, the algorithms used have to be simple, if they are to be executed in real time, and proof again st the weaknesses of the sensing systems. The localisation approach present ed here is based on the fact that the higher the localisation algorithm spe ed is, the lower the error in the position and the orientation, due to the odometry. Any systematic errors in the relative localisation using odometry are corrected on-line by using a limited set of ultrasonic data. If a non- systematic error occurs, a more complex procedure is necessary. Both simulation and experimentation show that the systematic odometric erro rs become bounded, thanks to those algorithms. Moreover, they are robust to a high rate of false ultrasonic measures. (C) 1998 Published by Elsevier S cience Ltd. All rights reserved.