Dynamic efficient collision checking method of robot arm paths in configuration space

摘要

This article describes a method for reducing the number of collision checks during motion planning. The paper proposes a greedy distance computation that is a combination of Gilbert Johnson Keerthi (GJK) algorithm and Oriented Bounding Box(OBB). Two pre-computing steps are done: the calculation of maximum possible radius for each joint, used later to find the maximum curve length that the robot arm can travel in 3D space, as well as the calculation of the bounding boxes for all links and obstacles. Commonly, incremental planners need an expansion from configuration q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</sub> to q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> . The new collision checking method detects for each sample in configuration space (C-Space), if the maximum length of the curve traveled from the robot in Cartesian space is bigger from the distance of the pair obstacle-robot. The new dynamic collision checking method detects near obstacles and computes only necessary distances, giving high performances. The algorithm is implemented in a 7 Degrees of Freedom(DoF) robot arm with revolute joints mounted in FRIEND rehabilitation system.