Trajectory Generation of a Multi-Arm Robot Utilizing Kinematic Redundancy
Faculty of Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima, Hiroshima, 724 Japan
This paper proposes a method of generating trajectories of multiple manipulators by using virtual arms. First, it is shown that a closed link structure composed by multiple manipulators can be resolved into closed link structures composed by a pair of manipulators and then each closed link structure is modelled as a connected arm. A connected arm expresses a single manipulator as a pair of manipulators that are connected at the end-points. By defining a connected arm in this way, it becomes possible to make use of redundant degrees of freedom of manipulators by means of virtual arms. A virtual arm is a virtually supposed arm whose end-points are placed on the joints or links of the connected arms. The virtual arms makes it possible to treat the postures of multiple manipulators as a set of virtual end-points. This paper not only carries out the modeling of the kinematics of connected arms and virtual arms in general but also derives inverse kinematic solutions of connected arms by the use of virtual arms. In addition, the paper shows that it is possible to realize a variety of postures of manipulators while controlling the object being grasped.