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Research On Terminal Area Energy Management And Autolanding Technology For Reusable Launch Vehicle

Posted on:2009-01-23Degree:DoctorType:Dissertation
Country:ChinaCandidate:C Z SunFull Text:PDF
GTID:1102360272976762Subject:Navigation, guidance and control
Abstract/Summary:PDF Full Text Request
For Terminal Area Energy Management (TAEM) and Autolanding of Reusable Launch Vehicle (RLV), the flight envelope is wide, the flight states are variable, and the range of uncertainties is large. RLV shows distinct characteristics in different flight phases, the guidance and control (G&C) problems must be resolved. The thesis aims to resolving G&C problems of Terminal Area Energy Management (TAEM) and Autolanding.In order to improve the autonomy and the robustness, using the concept of hybrid dynamic system, the modularization, hierarchical architecture is built. The hierarchy architecture basing on functions decomposition can enhance the capability to autonomously perform and make decisions when in the presence of uncertainties, and make entire system robust and easy to maintain.The trajectory design method basing on dynamic pressure profile is formed using the nonlinear equations of motion in space, and the method of energy corridor robust analysis is proposed. In order to improve the trajectory robustness to uncertainties of initial states, the correlative concept about online trajectory design is proposed. The idea and design scheme of online trajectory design is analyzed. The trajectory design method basing on dynamic pressure profile can reduce the step of integral and computational time; improve the robust of trajectory design.To improve the performance and robustness of TAEM control system for RLV, the nonlinear tracking control system architecture basing on trajectory linearization is developed. This architecture includes two parts: feed-forward control system and feedback control system, the feedback control system is used to augment the stability and the feed-forward control system improves the transition performance. The control system by trajectory linearization can improve the transition performance, and improve the ability of nonlinear tracking. The control system not only can meet the need of stability in large fligh envelope, but also adapt to the chariacters of slow transition of high attitude and fast flight state varity of entire flight.According to the flight task of TAEM, the energy management scheme is proposed, which is robust. The guidance law is designed along the nominal trajectory profile and the guidance robustness is assessed. The results show that the guidance scheme is robust and full, which can complete the task of TAEM. The guidance loop also provides an approach of realizing guidance system in engineering.According to the characteristics of autolanding trajectory, the trajectory design method basing on altitude profile is proposed. The velocity profile is planned along altitude profile, which makes the touchdown velocity agree with the desired states. In order to assess the trajectory performance, the concept of autolanding trajectory robustness is proposed, and the trajectory robustness is assessed.Adapt to the task of unpowered dropping autolanding, an adaptive guidance technology with online trajectory shaping is developed. This technology takes full advantage of the vehicle's flight capability; plans trajectory profile between the known initial states and the desired terminal states; combines online trajectory shaping with guidance scheme; creates the adaptive guidance loop.The adaptive guidance system with online trajectory shaping is robust and practical.Last, the hardware-in-loop entire flight simulation and unpowered dropping experimentation simulation are completed. The results show that the mission management is logical, the guidance scheme and control scheme is reasonable, the guidance law and control law is robust.
Keywords/Search Tags:Reusable Launch Vehicle, Terminal Area Energy Management, Autolading, Flight control, Trajectory, Trajectory robustness, Guidance, Control, Robustness, Trajectory linearization
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