非合作目标交会的双层MPC全局轨迹规划控制

For the global optimal problem of trajectory planning and tracking control in ultra-close Line-of-Sight (LOS) rendezvous of non-cooperative targets, a double-layer Model Predictive Control (MPC) algorithm is proposed based on the Gaussian Pseudo-spectral Method (GPM) and Linear Time-Varying Model Predictive Control (LTVMPC). In the layer of trajectory planning, an optimization model is established with minimum fuel and optimal control accuracy as performance indicators. The global optimal nominal trajectory is obtained by the GPM method in the MPC framework, which overcomes the disadvantage that traditional MPC is not suitable for global large-scale nonlinear programming. In the layer of trajectory tracking control, considering the time-varying characteristics of the state transition matrix in the prediction horizon, LTVMPC is used to track the nominal trajectory, so as to avoid re-planning of the trajectory in the presence of uncertainty and thus reduce online calculation and ensure online autonomous implementation of the algorithm. Due to the same constraints considered by the planning layer and the control layer, the planning trajectory is controllable and reachable. The simulation results show that the proposed method is significantly better than the traditional MPC method in terms of fuel consumption and rendezvous time. Compared with those of the traditional method, the rendezvous time and fuel consumption based on the proposed method are reduced by about 50% and 30%, respectively.