AN APPROACH TO MODEL ERROR COMPENSATION IN THE CONTROL OF NONRIGID SPACECRAFT Academic Article uri icon

abstract

  • Improvement is sought in the convergence properties of state estimators as used in spacecraft controller designs, when the linearized model upon which the estimator is based is subject to parameter errors, truncated modes, and neglected disturbances. Instead of choosing orthogonal mode shapes multiplied by varying coefficients (a conventional approach for modeling elastic modes) to represent the truncated modes, the model error vector discussed herein is approximated, over short observation windows tau units long, by functions which are orthogonal over the interval tau , where the coefficients of the orthogonal functions are automatically updated via the use of real time measurements from the system. The device which updates the coefficients of the orthogonal functions is called an orthogonal filter and takes on the form of a state estimator for the synthetic modes of a model error system which generates the orthogonal functions. The method is illustrated for a 15th order model of a flexible spacecraft.

published proceedings

  • IFAC-PapersOnLine

author list (cited authors)

  • Skelton, R. E., & Likins, P. W.

citation count

  • 6

complete list of authors

  • Skelton, Robert E||Likins, Peter W

publication date

  • July 1977