Tracking Guidance Strategy for Low-thrust Transfer Trajectory Based on NMPC Theory

A tracking guidance scheme based on nonlinear model predictive control is proposed for low-thrust transfer trajectory. According to the optimal nominal transfer trajectory, the NMPC is used to design the predictive model of perturbed orbit. Performance index of receding optimization is established, which can indicate the difference between the nominal trajectory and prediction trajectory. Taking the orbit state of nominal transfer trajectory as the initial value, the optimal control sequence is solved by the sequential quadratic programming algorithm. Meanwhile, in order to eliminate the predictive model error, the accuracy of the next control sequence is improved by the introduction of feedback compensation. Taking earth-mars low-thrust transfer as an example, numerical simulation is used to verify the efficiency of the proposed method.