A mobile robot wishing to explore unknown and dynamic environments, has to build up maps of its environment while at the same time ensuring that it does not become lost in the process. However current feature based localisation techniques can become unstable if the robot drives in such a way that its sensors cannot recognise these features. A novel dynamic path planning approach is presented that supports the data acquisition for the localisation process as well as the extraction of new feature while exploring an a priori unknown indoor environment. Real experiments on the authors' mobile robot Roamer have shown that the overall localisation stability and the feature extraction process were improved significantly while exploring an unknown environment.

This paper presents a novel local obstacle avoidance module. The main idea of the steer angle field approach is to discard all steer angles that, given the nonholonomic kinematics of the robot, would lead to collisions within a certain hit distance. The approach has been implemented and tested over a period of one year on our mobile robot. Results have shown that the robot is able to operate robustly in unknown, unprepared and cramped in-door environments for hours.>

Autonomous navigation in unknown cluttered environments is one of the corner-stones of future applications of mobile robots. The complexity even of seemingly simple problems like point-to-point travel, to be solved in real-time, calls for a hierarchical system architecture. The authors present a three-layered path control system with three modules "global planning", "local navigation", and "collision avoidance". Each module is restricted to a subtask of limited competence and responsibility, allowing for on-line implementation within the associated time frame. Suitable module interaction provides the desired behavior of the overall system. This paper summarizes the main idea of each of the three modules. Experimental results with the Siemens mobile platform ROAMER illustrate the methodology and performance of the path control system in unprepared cluttered environments.>