NASA Instep

Microgravity Experiments With Long Reach Manipulator Systems

Sponsor

Martin Marietta Astronautics, Denver, CO and NASA

Investigators

Dubowsky, S., Pisoni, A.C. and Mavroidis, C.

Introduction

Long reach manipulator systems (LRMS) are being considered as a promising solution to the problem of performing remotely operated servicing tasks in space. The proposed Special Purpose Dexterous Manipulator (SPDM) mounted on the Space Station Remote Manipulator System (SSRMS) is an example of long reach manipulator space systems now being developed. While having significant potential, the use LRMS requires the solution of some fundamental control problems that can seriously limit their performance. A key problem is that external disturbances and the motion of the manipulator itself can excite low frequency, lightly damped vibrations of the systems deployable structure. These vibrations would make the system difficult to control. Control methods have been developed to solve this problem, but they have yet to be tested in space. In this NASA INSTEP (In-Space Technology Experimental Program) project an experimental system that, would test in micro-gravity, in a future space shuttle mission, is being designed. It is expected that this system will fly sometime in the next 3 to 4 years.