Precision IPACS in the Presence of Dynamic Uncertainty

An adaptive robust integrated power and attitude control system (IPACS) is presented for a variable speed control moment gyroscope (VSCMG)-actuated satellite. The developed IPACS method is capable of achieving precision attitude control while simultaneously achieving asymptotic power tracking for a rigid-body satellite in the presence of dynamic uncertainty in the VSCMG gimbals and wheels. In addition, the developed controller compensates for the effects of uncertain, time-varying satellite inertia properties. Some challenges encountered in the control design are that the control input is premultiplied by a non-square, time-varying, nonlinear, and uncertain matrix and is embedded in a discontinuous nonlinearity. Globally uniformly ultimately bounded attitude tracking and asymptotic power tracking results are proven via Lyapunov stability analysis.