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[[image of graph]]
[[image of graph]]
[[image of graph]]
Figure 17 Rotational Motion of the "Point of Resolution" In Response to -Z Command in Automatic Mode

Concluding Remarks
The structure of the SRMS mechanical arm has been described and the structural flexibility of the arm has been discussed in terms of finite-element analysis, math modelling and simulation results. Simulation results and flight data from the STS-2 and STS-3 missions have indicated that despite the arm structural flexibility, the SRMS control system remains stable.

The accuracy of ASAD is established by comparing its simulation results with flight data. Preliminary analysis has shown excellent agreements in the frequencies of oscillations and peak amplitudes for joint angles and angular rates, motor rates, End Effector motion and strcutural [[structural]] loads at the shoulder and the wrist. Structural damping is, however, established from flight data and the result is used to update the modal damping factor in the math model for ASAD to improve its simulation accuracy. The structural flexibility representation in ASAD is therefore concluded to be adequate.

References
[1] J.D. Graham, R. Ravindran, K. Knapp, "Space Manipulators - Present Capability and Future Potential", AIAA/NASA Conference on Advanced Technology for Future Space Systems, NASA Langley, Hampton, Va. May 8-10, 1979.

[2] K.H. Doetsch, "The Remote Manipulator System for the Space Shuttle Orbiter", Jahrestagung 1977 of the Deutsche Gasellschaft fur luft-und Raumfartev Berlin, W. Germany, September, 1977.

[3] "Shuttle Remote Manipulator System Design Definition Report", SPAR-R.776E, Spar Aerospace Limited, March, 1980.

[4] R. Ravindran, K.H. Doetsch, "Design Aspects of the Shuttle Remote Manipulator Control System", to be presented at the AIAA Guidance Navigation and Control Symposium, August 9-11, 1982, San Diego, Ca.

[5] D.M. Gossain, E. Quittner, S.S. Sachdev, "Analysis and Design of the Shuttle Remote Manipulator System Mechanical Arm for Launch Dynamics Environment", The Shock and Vibration Bulletin, No. 50, published by the Shock and Vibration Information Center, Naval Research Laboratory, Washington, D.C., September, 1980.

[6] P. Nguyen, "Variations of SRMS "Static" Frequencies with Arm Configurations", SPAR-TM. 1224A, Spar Aerospace Limited, April, 1977.

[7] "Space Shuttle Remote Manipulator System - Control System Design Reprot [[report]]", SPAR-RMS-R.073B, Spar Aerospace Limited, February, 1978.

[8] P.C. Hughes, "Motion Equations for a Flexible Articulated Controlled Manipulator Arm", Dynacon Report 75-05-10, September, 1975.

Acknowledgements
The authors wish to thank National Research Council of Canada and Spar Aerospace Limited for the permission to publish this paper.