Research On Guidance And Control Technology Of Unpowered Autolanding For Reusable Launch Vehicle

Autolanding of Reusable Launch Vehicle is the last part of RLV demonstration and is the criticalstage to complete the entire flight mission.The research of G&C system for RLV is based on its dynamics model and correspondingcharacteristics. The six-freedom-degree model is built in this paper, and the aerodynamic characteristicand mode characteristic of RLV are analyzed.Trajectory design is key technology of Unpowered Approach and Autolanding Interface, whichwill affect the RLV’s security directly. According to the characteristics of Autolanding trajectory, thetrajectory design method basing on altitude profile is proposed in this paper. The trajectory designmethod basing on altitude profile is proposed in this paper. According to the trajectory design methodbased on altitude profile and the optimization algorithm of a two-point boundary value, the concept ofautolanding trajectory robustness is proposed, and the trajectory robustness is assessed.Adapt to the stability problems of unpowered dropping Autolanding, the control structure isdesigned, and the aircraft’s natural frequency and damping characteristic are improved, and has aclipping response for step command.According to the differential task in differential flight phase, the altitude control structure,horizontal guidance structure and speed control scheme are designed, which could take the RLV returnto runway and landing with right speed and sink rate. The simulation is completed with uncertainty ofaerodynamic and variations in vehicle energy, the results show that the guidance scheme is robust andfull, which can complete the task of ALI.Finally, this paper has set up a simulation platform for RLV carried out a Autolanding flight of thewhole process. Simulation results show that the guidance and control strategy are rational and correct,and a Monte Carlo simulation verifies the guidance and control system robustness for the RLV’suncertainty of aerodynamic, initial conditions and efficiency of horizontal wind.