A new interconnection structure is constructed for applying mu -tests to the robust stability problem associated with real parameter variations. Some remarks are made concerning the computability of upper bounds for real- mu , and an application of the theory to analysis of the lateral axis flight control system of the space shuttle is given. The nominal plant mode had 26 states (including actuator and sensor dynamics), and the controller had 27 states. There were three plant inputs considered: aileron, jets, and rudder; and three outputs used by the controller: rollgyro, yawgyro, and side force accelerometer. A real parameter variation set was found which caused system instability at low frequency for this flight condition. The results indicate that for the inner loop design the aileron gain is placed near optimal. A possible instability is predicted at 12 radians/s. This indicates that the high-frequency gain margin is something less than 12 dB.
|Original language||English (US)|
|Number of pages||4|
|Journal||Proceedings of the American Control Conference|
|State||Published - Dec 1 1985|