Fully actuated spacecraft attitude control via the hybridmagnetocoulombic and magnetic torques

摘要

A novel fully actuated spacecraft attitude control scheme actuated by the Lorentz and magnetic torques is designed, including the optimal distribution law, sliding mode control law, and parameter adaptation law. Numerical simulations verify the validity of the control scheme, and some concluding remarks are listed as follows: 1) Despite the fact that the attitude dynamics is instantaneously underactuated with single Lorentz or magnetic torque, a combination of these two kinds of electromagnetic torques renders the attitude system fully actuated, which in turn makes it easier to implement a controller design. 2) By using the optimal distribution law of the magnetic dipole moments and charges derived via the geometric approach, an arbitrary desired control torque can be composed, provided that l≠0. Notably, in an ideal two-body environment, this distribution law is invalid in the geostationary orbit because the relative velocity between the c.m. of the spacecraft and the local magnetic field is exactly zero, that is, V_r = 0 and l = 0. 3) By an antisymmetric charging strategy for each pair of coulomb shells, the residual Lorentz force almost vanishes, indicating that a pure couple is nearly formed and the orbit and attitude control of the spacecraft is basically decoupled. 4) With a parameter adaptation law, no prior information on the upper bound of the approximation errors and external disturbances is required and the asymptotic stability of the closed-loop system is ensured.