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The Space Station Remote Manipulator System (SSRMS) is an element of the Mobile Servicing System (MSS) which is Canada's contribution to the Space Station Freedom. The SSRMS is a large, flexible, mechanical arm with seven degrees-of-freedom, measuring approximately 17.6 meters when fully extended and is intended to manipulate a wide range of payload masses up to and including the Shuttle orbiter. A project is proposed to address the robotics evaluation and characterization (REACH) of the SSRMS in-orbit. The objectives of this project are to establish the characteristics of the robotics parameters, including structural dynamics parameters, over the SSRMS work-volume. In the collection and analysis of data, extensive use is to be made of the MSS baseline instrumentation, namely, joint resolvers, force/moment sensors, motors currents, and especially the video system. A measurement systems testbed (MST) is planed to define, test, and validate the REACH system concept, the SSRMS measurement systems capabilities, calibration methods for the measurement systems, data processing algorithms, the in-orbit experiments/tests and the in-orbit operational scenarios and configurations. This paper describes the development of the MST and discusses its current status. The MST will be a full-scale mock-up of the SSRMS and will have joint-resolvers and a similar complement of video cameras. It will also have independent measurement systems in order to validate the measurements and parameter identification processes. Though the MST arm will not possess powered joints for manipulation, it will be geometrically similar. Like many large space structures the SSRMS is unable to support itself on the ground; consequently, it is proposed to suspend the MST arm from a soft spring suspension mechanism. A unique feature of the MST will be its ability to emulate the three-dimensional kinematics of the SSRMS. In addition, some important dynamics properties will be simulated, such as the first one or two modal frequencies. To facilitate manual reconfiguration of the MST the supporting mechanism for the arm will be equipped with seven mechanical degrees- of-freedom.
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