Whole arm proximity control system for articulated robots working near space vehicles and flight hardware

Abstract

This paper discusses the implementation of a collision avoidance technique using whole-ami proximity scnsing. In contrast to model-based approaches, sensor based control techniques require no a priori knowledgc of thc operational environment. We have developed 11 rull coverage proximity sensing device, the sensorCel1, tliat can be integrated into new or existing robot manipulators. The sensorcells support multiple sensing media to dclcct a wide variety of materials, and process the data iit thc sensor so that only results of interest are transmincd back to the controller. The controller can use the rcal-time sensor data in a number of ways including: emergency stop, reflexive control, and autonomous motion plamiing around obstacles. We developed a testbed incorporating a PUMA 600 robot, 15 sensorCells (14 infrared and 1 acoustical) about the periphery of the robot, a PC bascd cell controller and a motion control algorithm that combines user commands with the sensor data to produce collision free motion. This system demonstratcs the practical capability of using real-time proximity sensor data to protect the entire robot from colliding with both static and dynamic objects in the environment. 'This technology has applications in a wide variety of Irighvalue robotic tasks including ground-based and on-orbit processing tasks.