Path Planning for a Reconfigurable Robot in Extreme Environments

Abstract

In recent years, the inspection of extreme environments using mobile robots has gained traction, as robots are able to mitigate the risk placed on humans and at times achieve what humans are unable to. In some scenarios, the robot is required to operate in cluttered environments with highly restricted access through 150 mm diameter ports. The MIRRAX robot has been designed to meet these challenges with the capability of reconfiguring itself to both access environments and navigate through tightly spaced obstacles. The joints used for reconfiguration of the robot introduce additional challenges for path planning due to the significant changes that can occur between adjacent poses. This paper presents a global path planner for MIRRAX. A Voronoi diagram is first used to generate a sparse graph to represent the topology of the environment, which allows for fast, coarse path planning. The coarse path is then refined via a heuristic pose fitting routine to ensure that the path is both collision-free and reduce unnecessary joint angle changes. The planner has been evaluated in simulation, demonstrating the feasibility of generating collision-free paths through narrow pathways for a reconfigurable robot.