Performance bounds for testing a failure accommodation system for a flexible grid

This paper presents performance projections for a redundancy management system that must interact with appreciable structural dynamics. The system is designed to control the rigid body and the first three flexible modes of the grid apparatus at the NASA Langley Research Center. It uses torque wheel actuators and rate gyro sensors in the primary control and deflection sensors and accelerometers as system evaluation sensors. Failures of both sensors and actuators are considered in the control law design which is based on Kalman filter and regulator theory. Combinations of failures taken one and two at the time are considered. The class of failures considered is null output for actuators and sensors. Linear quadratic Gaussian control theory is used to calculate the best achievable performance of the control system subject to the failures considered. Performance bounds are presented which can serve as goals for an on-line advanced redundancy management system.