Polygon-Based Random Tree Search Algorithm for a Size-Changing Robot

Abstract

This paper proposes the Polygon-based Random Tree search algorithm with Variable polygon size (PRT-V) for Variable Topology Truss (VTT). This algorithm improves on our previous path planning algorithm by using VTTs ability to change its size drastically. The algorithm assigns stopover points at the key locations in environments between the initial and goal points. Stopover points are used as reference points for both path planning and size adjustment. A Voronoi diagram-based roadmap method is used to automatically find appropriate stopover points. Based on the stopover points, the desired support polygons and the corresponding nominal lengths are generated by PRT-V. Then, the locomotion of VTT is generated by a non-impact locomotion algorithm to prevent tipping over. Simulations verify the performance of PRT-V in three different workspaces with obstacles. With PRT-V, VTT can squeeze through narrow passages or move efficiently in large spaces by increasing size, a unique feature.