Thrust-vector control of a three-axis stabilized spacecraft with fuel slosh dynamics

The thrust vector control problem is studied for an upper-stage rocket with fuel slosh dynamics. The sloshing propellant is modeled as a multi-mass-spring system. The coupled equations of motion of the spacecraft and the fuel are expressed in terms of the three dimensional spacecraft translational velocity vector, the attitude, the angular velocity, and the internal coordinates representing the slosh modes. A Lyapunov-based nonlinear feedback control law is proposed to control the translational velocity vector and the attitude of the spacecraft, while attenuating the sloshing modes. A simulation example is included to illustrate the effectiveness of the control law.