Liquid-filled spacecraft finite-time attitude maneuver control with attitude and angular velocity constraints

With development of aerospace industry, the mass of liquid fuel carried by spacecraft is also increasing in order to complete more complex space exploration missions, such as on-orbit refueling and space debris removal. And there is large liquid fuel consumption when spacecraft completes attitude and orbit maneuver, which greatly increases the nonlinearity and uncertainty of spacecraft dynamics and brings great challenges to spacecraft attitude maneuver control. Considering that during attitude maneuver, the control torque is easy to stimulate the liquid slosh, which will affect the attitude control performance and even lead to instability of the system. So it is necessary to constrain the angular velocity during attitude maneuver. In this paper, we consider the large angle attitude maneuver control of liquid-filled spacecraft system. Because of the consumption of liquid fuel, then the mass property of system is unknown and slowly time varying. So a novel finite-time attitude maneuver control law based on barrier Lyapunov function (BLF) and backstepping method in the presence of unknown, time varying system dynamics and angular velocity constraint, which aims at avoidance of violent liquid slosh, is proposed in this paper. Firstly, the sloshing liquid in a partially filled tank carried by the spacecraft is equivalent to a sloshing slug - a sphere of uniform density with a variable radius, and the rigid-liquid coupling dynamic equations with unknown parameters of the spacecraft are deduced by using the law of conservation of moment of momentum. Secondly, a finite-time prescribed performance function (FTPPF) is proposed to guarantee the convergence of spacecraft attitude error to zero within the setting time, with the help of FTPPF and the angular velocity constraint, a time-varying BLF and a logarithmic BLF are proposed correspondingly. Furthermore, a backstepping control law is designed for the spacecraft attitude maneuver based on augmented Lyapunov functions, meanwhile, several adaptive laws are designed to estimate the unknown and slowly time-varying parameters in the spacecraft system. Finally, simulation results are provided to show the effectiveness of the proposed control algorithms and estimation algorithms.