Decentralized Robust Servomechanism Problem for Large Flexible Space Structures Under Sensor and Actuator Failures

The decentralized robust servomechanism problem (DRSP) for colocated large flexible space structures (LFSS) under sensor and actuator failures is considered. A unified treatment of failures is enabled by introducing failure matrices. For colocated LFSS, stabilization, tracking of constant set points, and regulating against constant disturbances such that no “spillover effects” occur, can be simultaneously handled using a fault-accommodating decentralized tuning PID error-feedback controller. Necessary and sufficient conditions for solvability of the DRSP for colocated LFSS under sensor and actuator failures are derived in our analysis. In the case when each control agent is single-input/single-output, the decentralized fault-tolerant controller becomes particularly simple to implement. Steady-state output matrices for failed outputs are computed, and are found to be independent of controller gains.