Design of the control system for a robotic manipulator for Space-Station On-Orbit Replaceable Unit ground testing

Abstract

In this paper we describe a hierarchid robot controller designed and built at NASA's Johnson Space Center. The mbot used is a six dep-of-freedom hydraulic manipulator equipped with joint position sensors and a wrist forcebrque sensor. The objective of the project is to emulate the performance chcteristics of the Space Station's Special Purpose Dexterous Manipulator (SPDM), which will perform various telerobotic extemal maintenance tasks. Some feaaues implemented in the controller include a resolved position control algorithm, force/moment accommodation, and gravity compensation. This multiple-processor control system is divided, by processor, into a servo controller, a forcehnoment data filter, a Cartesian-space controller, a host/Mic conmller and a network communication controller. This paper describes the functions of each individual processor and the design of their inter-processor communication.