<h2>AAS  96-132</h2><h2>IDENTIFICATION OF SHUTTLE/MIR STRUCTURAL DYNAMICS FOR FLIGHT CONTROL NOTCH FILTERING TUNING</h2><h4>M. Jackson, Charles Stark Draper Laboratory</h4><h2> Abstract </h2>The Space Shuttle Flight Control System includes notch filters in the feedback path to attenuate flexible dynamics and maintain control system stability.  An in-flight experiment was conducted on the first Shuttle/Mir docking mission to gauge the accuracy of structural models so that redesigned notch filters could be up-linked if required. Filter design techniques are discussed to highlight tradeoffs between stability robustness and fuel performance.  The structural frequency identification process used on STS-71 is covered to show how notch filters can be redesigned in near real-time to reduce conservatism or to correct potential stability problems.<br><br>