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A digital state observer for the attitude control of a flexible space vehicle

Published online by Cambridge University Press:  04 July 2016

E. H. Smith
Affiliation:
Department of Mechanical Engineering, The University of Leeds
K. F. Gill
Affiliation:
Department of Mechanical Engineering, The University of Leeds

Extract

A space vehicle is usually required to maintain a specific orientation with respect to Earth. If flexible appendages (such as panels of solar cells) are associated with the vehicle, the problem of controlling the attitude of the spacecraft becomes more complex. In this paper, attention will be directed towards the control of this class of vehicle when the control law suggested by Hughes is employed. This approach requires that the attitude and its rate of change with time are available in satisfactorily noise-free forms. The measurement of attitude is physically possible, but the measurement of rate is not. Consequently a Luenberger state observer was employed by the authors to reconstruct the rate information. A similar approach was adopted earlier where an analogue model of the observer was employed. It was found that in some situations the design procedure for the observer stipulated that very large amplifier gains should be incorporated into the model, and great care was needed to avoid this problem.

Type
Technical Notes
Copyright
Copyright © Royal Aeronautical Society 1975 

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References

1. Smart, D. R., Gill, K. F., Gething, J. M. and Holt, J. A. Dynamic analysis of flexible space vehicles having uncoupled control axes. The Aeronautical Journal of the Royal Aeronautical Society, Vol 78, No 768, pp 560569. Dec. 1974.Google Scholar
2. Hughes, W. G. Design for high precision in spacecraft jet attitude control systems. Royal Aircraft Establishment Technical Report 71089. April 1971.Google Scholar
3. Luenberger, D. G. Observing the state of a linear system. IEEE Trans, on Military Electronics, Vol MIL-8, pp 74-80. April 1974.Google Scholar
4. Smart, D. R. and Gill, K. F. Attitude control of a flexible space vehicle by means of a linear state observer. The Aeronautical Journal of the Royal Aeronautical Society, Vol 79, No 770, pp 8695. Feb. 1975.Google Scholar