Guidance Law And Control Law Design Of Terminal Area Energy Management For Reusable Launch Vehicle

Terminal area energy management (TAEM) is a critical flight phase of the unpowered returning forreusable launch vehicle (RLV). In order to realize the energy control of initial energy deviation, theTAEM trajectory, guidance and control technologies are studied to solve trajectory design,longitudinal/lateral integration-energy control and multi-constrained control problems.In this paper, the three-freedom-degree model and six-freedom-degree model of RLV are built, andthe object characteristic of RLV is analyzed. For the shortcomings of the trajectory design algorithmbased on iterative optimization, the trajectory design method basing on interpolation is formed using thenonlinear equations of motion. Using the method as mentioned above, TAEM energy corridor isdesigned, and the robustness of energy corridor is analyzed. For the trajectory tracking error problem ofthe initial energy deviation, the number of nominal trajectory design method is used. This method canimprove the self-adaptive of the guidance system.In order to achieve the guidance objectives what RLV can safely return to airport landing in anyinitial energy, the TAEM longitudinal/lateral integration-guidance scheme by changing the lateralguidance scheme and tracking the longitudinal trajectory profile is formed. In order to track thelongitudinal trajectory, the height and speed guidance law are designed. For lateral guidancecharacteristics, the heading and track guidance law are designed. For uncertainties of TAEM, theguidance robustness is assessed. The results show that the guidance scheme is full and the guidance lawis robust.To improve the performance of TAEM control system, the longitudinal control uses pitch ratecontrol and the lateral control uses roll control. The pitch rate control law, attack control law, overloadcontrol law and roll control law are designed to improve the transition performance. Formulti-constrained problem, the control system including dynamic constrain make the system safety byswitching the control command.Finally, the nonlinear simulation environment is built in the Matlab/Simulink environment. Thecontrol robustness is assessed by the application of Monte Carlo method. The results show that thecontrol scheme is reasonable and the control law is robust.