Space Modular Manipulators

FY93 was the SMM project's first year, initiating the effort with a MITRE Corporation review of the existing space manipulator design efforts (RMS and FTS) and interaction with ongoing development teams (RANGER, JEM, SPDM, STAR and SAT). Below this system level, custom component vendors for motors, amplifiers, sensors and cables were investigated to capture the state-of-the-art in space robot design. Four main design drivers were identified as critical to the development process:

1. Extreme Thermal Conditions;
2. High Reliability Requirements;
3. Dynamic Performance; and
4. Modular Design.

The thermal-vacuum conditions of space are the most dramatic difference between typical laboratory robot and space manipulator design requirements. Manufacturing robots operate in climate controlled, \|O(+,-)2K factory environments, where space manipulators must be designed for \|O(+,-)75K temperature variations with 1500 W/m2 of solar flux. Despite these environmental extremes, the technology to model and control robot precision over a wide temperature range can be applied to terrestrial robotic operations where the extreme precision requirements demand total thermal control, such as in semiconductor manufacturing and medical robot applications.

Thermal conditions impact reliability by cycling materials and components, adding to the dynamic loading that causes typical robot fatigue and inaccuracy. MITRE built a customized thermal analysis model, a failure analysis model using FEAT, and applied the fault tolerance research funded by JSC at the University of Texas. The strategy is to layer low level redundancy in the joint modules with a high level, redundant kinematic system design, where minor joint failures can be masked and serious failures result in reconfigured arm operation. In this approach, all four design drivers were addressed in the selection of the appropriate level of modular design as a 2-DOF joint module.

The major technical accomplishments for the FY93 SMM project are:

1. Conceptual and detailed design of first joint prototype;
2. Detailed design and fabrication of thermal-vacuum test facility;
3. Custom design of thermal-vac rated motors, bearings, sensors and cables; and
4. Published two technical papers (R. Ambrose & R. Berka) on robot thermal design.

Telerobotics Program page

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Maintained by: Dave Lavery
Last updated: May 10, 1996