Robust controllers for space station momentum management

The design of controllers for space station attitude control and momentum management is described. Fundamental control performance tradeoffs between stabilization, attitude regulation, and momentum magnitudes are explored using H-infinity optimization. The resulting controllers stabilize the unstable gravity gradient torques, keep attitudes and momentums due to aero disturbance torques small, and are robust to uncertainties in the moments of inertia of the space station. Structured singular values of the closed-loop system are computed to verify the robustness of the controllers. Simplified controllers that achieve near-optimal performance with good robustness properties and with significantly reduced complexity are also given.<>