Magnetic Control of Dual-Spin and Bias-Momentum Spacecraft

Abstract

This paper examines simultaneous attitude control and momentum-wheel management of dual-spin and biasmomentum spacecraft using magnetic actuation. Transformations of variables are presented, leading to the derivation of control laws that yield proven stability and asymptotic convergence under appropriate assumptions on theEarth’smagneticfield. The results remain valid in the presence ofmagnetic torquer saturation. Furthermore, it is shown that for a spacecraft equipped with three orthogonal magnetic torquers, the control laws are tolerant to the failure of a single magnetic torquer in the case of a dual-spin spacecraft and tolerant to the failure of two magnetic torquers in the case of a bias-momentum spacecraft, provided that the remainingmagnetic torquer does not generate its dipolemoment parallel to themomentum-wheel spin axis.Additionally, the stability analyses show that the control laws remain stabilizing under the effects of control quantization. The theoretical results rely on the assumption that the spacecraft principal and body axes coincide. Robustness to uncertainties in the spacecraft inertia matrix and to disturbance torques are demonstrated with a numerical example.