Angular velocity-free control for rigid spacecraft attitude stabilization under input constraint

A novel attitude stabilization control scheme is presented for rigid spacecraft. As a stepping stone, a first-order passivity filter is proposed to generate a velocity-related signal from attitude measurements. Then, a velocity-free attitude stabilization controller is synthesized by using a hyperbolic tangent function. It is shown that the controller render the equilibrium points in the closed-loop system globally asymptotically stable. Moreover, the proposed control scheme is independent on the unknown spacecraft inertia and can explicitly account for input constraint with angular velocity measurements eliminated. Numerical simulation results are presented to verify the effectiveness of the control law derived in this paper in comparison with the conventional velocity-free attitude control approaches.