Path Planning with Collision Avoidance for Free-Floating Manipulators: A RRT-Based Approach

Abstract

The difficulty of creating a path planner with collision avoidance for Space Manipulators (SMs) is well known due to the presence of dynamic singularities and because of its non-holonomic behaviour. Furthermore, the main contributions in the field of motion planning of SMs are often concentrated in the point-to-point strategy, with special interest in the complex dynamics of such systems. In fact, planners for space manipulators generally count on a previously computed path in order to modify it to avoid collisions. Nonetheless, the computing of the previous path still lacks robust formulations, specially in the case of free-floating manipulators. Our goal consists in creating a path planner with collision avoidance for a free-floating planar manipulator. The dynamic model is based on the Dynamically Equivalent Manipulator and the concept of Rapidly-Exploring Random Trees serves as a framework for the developed algorithm. A combination of a method that reduces the metric sensitivity with a bidirectional approach is proposed in order to achieve a solution convergence. Details of the collision checking algorithm are provided. The system is validated by simulating the path planning task for a three-link planar free-floating manipulator, while considering the presence of an obstacle. The results are then discussed and promising directions for future works are presented.