Simulating a robotic arm in a box: Redundant kinematics, path planning, and rapid prototyping for enclosed spaces

Joseph T. Wunderlich, Elizabethtown College


Robotic arms often perform industrial tasks requiring complex dextrous manipulation within constrained spaces. For example, automobile unibody assembly can require more than 5000 welds, with many performed within the vehicle's interior. An arm can be designed specifically for this type of task by permuting link lengths and degrees of freedom (DOF) to find a set of feasible designs. Each design can be evaluated for joint-angle displacement, dexterity, simulated speed, and consumption of available redundancy. A heuristic search increases the probability of having the needed kinematic structure. Hyperredundant designs of up to 10 DOF can be created, and searches often yield minimized-DOF designs. The path-planning technique combines pseudo-inverse velocity control with the concept of attractive poles to allow maneuvering through complex enclosures while avoiding many obstacles. This research provides a means of rapid-prototyping robotic arms for enclosed spaces and can yield many designs locally optimized for given tasks and environments. © 2004 The Society for Modeling and Simulation International.