| 摘要 |
Apparatus and a related method for detecting failures of control elements, such as skewed-axis reaction wheels with closed-loop speed control, used in satellite attitude control systems, and for compensating for such failures and thereby maintaining continuity of operation. The apparatus includes a wheel loop model for simulating operation of each of the reaction wheels and speed control loops in the satellite, and for deriving an estimated wheel speed from a command speed for each wheel. By comparing the estimated speed of each wheel with the corresponding actual or observed speed, the apparatus determines whether a failure was occurred in the wheel, or in its control loop. Upon detection of such a failure, the apparatus disconnects driving power from the failed wheel, modifies the corresponding wheel loop model to reflect disconnection of power, and reconfigures a distribution matrix in such a manner that a set of desired momentum commands with respect to the vehicle axes is properly redistributed among the remaining reaction wheels. Compensation is also made for the momentum contributions of failed wheels that continue to spin after being powered down.
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