Attitude Control of Satellites Actuated by Hybrid Actuators

Abstract

This paper proposes combined attitude control algorithm for satellites which are actuated by a combination of magnetic and magneto-Coulombic actuators. Magnetic actuators are the ones which are responsible for providing magnetic control torques and are produced as an interaction between the current flowing through magnetic coils placed along the principal moment of inertia axes and local orbital magnetic field. The torques produced by magnetic actuators are constrained in a plane perpendicular to the local orbital magnetic field thereby resulting in an underactuation problem. The underactuation problem is overcome by using magneto-Coulombic actuators along with magnetic actuators. The magneto-Coulombic actuators provide Lorentz torque which are produced as an interaction between the charges present in the Coulomb shells placed along the principal axes of inertia with that of the local orbital magnetic field. In the case of magneto-Coulombic actuators, the torque is constrained in a plane containing the local orbital magnetic field and angular velocity of the satellite which also results in an underactuation problem. However, the hybrid actuator formulation is capable of providing control torque along any arbitrary direction. Asymptotic stability of the proposed control algorithm is proved and numerical simulations elucidate the efficacy of proposed control.