Trajectory Planning and Control for an Underactuated CubeSat

This paper proposes an integrated guidance and control method for an underactuated CubeSat to transfer near the Space Station (SS) to the target position for subsequent operations. Considering the dynamics coupling of the position and attitude of the underactuated CubeSat, the integrated method consists of two layers: the model predictive controller (MPC) based guidance layer and the sliding mode control (SMC) based coordinated controller layer. The MPC calculates the ideal driving force vectors that can transfer the CubeSat to the target position while saving onboard fuel and satisfying obstacle avoidance and thrust limited constraints. The obtained force vectors serve as the guidance for CubeSat attitude control. The coordinated controller is designed based on the attitude dynamic equations of the CubeSat, which regulates the CubeSat attitude to align the direction of the nozzle with the ideal driving force vectors. As a result, the nozzle can provide sufficient thrust to transfer the CubeSat to the target position. A physical simulation system is built for the CubeSat transfer system. Numerical simulations are carried out to verify the applicability and effectiveness of the proposed integrated guidance and control method.