Guidance law of spacecraft for continuous low-thrusts orbital rendezvous problem

The hypothesis of pulse thrust cannot be always satisfied for the short-range stage of space rendezvous. In this article, High isp low-thrust is applied as actuators to solve the fuel optimal control problem of spacecraft rendezvous condition. First, we gave the mathematical models of the orbital rendezvous problem, the performance index function and constraints equations are also presented. Then, we used the direct method to discrete the control variables, though parameter optimization algorithm to get the optimal control variable and rendezvous time constants. Finally, aimed at the fire time deviation, we analyzed the error between the actual trajectory and the nominal trajectory, and obtained the correction value of control variables. Using this correction values, the spacecraft can satisfy the final position constraints and avoid the complex optimization computing process.