Mobile robots in complex environments: a three-layered hierarchical path control system

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