Application of a hierarchical control structure in the implementation of a manipulator real-time collision avoidance system

Discusses the use of hierarchical control for advanced robotic manipulators, and specifically the three layer hierarchical control system adopted by ARRL. Particular consideration is given to the tactical layer and the desired functionality within a manipulator control system, and it is shown that these functions lead to the requirement for a real-time trajectory planner embedded within the layer. The implementation of a low-level end-effector collision avoidance control system is described in the light of these considerations. The results, based on a PUMA 562 manipulator arm driven by a multiprocessor controller with ultrasonic sensing, are discussed.<>