Flexible lander,composed of multiple nodes connected by flexible material,can reducethe bouncing and overturning during the asteroid landing.To satisfy the complex constraints inthe node cooperation of the flexible la...Flexible lander,composed of multiple nodes connected by flexible material,can reducethe bouncing and overturning during the asteroid landing.To satisfy the complex constraints inthe node cooperation of the flexible landing,an intelligent cooperative guidance method is pro-posed.The method consists of a double-layer cooperative guidance structure,a guidance parameterdetermination approach,and an action priority strategy.The double-layer contains a basic guid-ance used to satisfy the terminal state constraints,and a compensatory guidance used to satisfythe lander's attitude constraint.For the compensatory guidance,the parameters are determinedby multi-agent system,which are trained according to the performance index of flexible landing tra-jectories.The action priority strategy is used to reduce the detrimental effect of parameter inconsis-tency on the node cooperation.The simulation of flexible landing shows that the cooperativeguidance method is effective in improving the landing accuracy while satisfying the constraints.Meanwhile,the method is robust to the disturbance in the navigation and control.展开更多
Along with the progress of sciences and technologies, a lot of explorations are taken in many countries or organizations in succession. Lunar, the natural satellite of the earth, become a focus of the space discovery ...Along with the progress of sciences and technologies, a lot of explorations are taken in many countries or organizations in succession. Lunar, the natural satellite of the earth, become a focus of the space discovery again recently because of its abundant resource and high value in use. Lunar exploration is also one of the most important projects in China. A primary objective of the probe in lunar is to soft-land a manned spacecraft on the lunar surface. The soft-landing system is the key composition of the lunar lander. In the overall design of lunar lander, the analysis of touchdown dynamics during landing stage is an important work. The rigid-flexible coupling dynamics of a system with flexible cantilevers attached to the main lander is analyzed. The equations are derived from the subsystem method. Results show that the deformations of cantilevers have considerable effect on the overloading of the lunar lander system.展开更多
Small bodies have the characteristics of noncooperative,irregular gravity,and complex terrain on the surface,which cause difficulties in successful landing for conventional landers.In this paper,a multinode flexible l...Small bodies have the characteristics of noncooperative,irregular gravity,and complex terrain on the surface,which cause difficulties in successful landing for conventional landers.In this paper,a multinode flexible lander is put forward to address the problem.The dynamics of this new lander are constructed based on the port-Hamilton framework.The trajectory-tracking formation controller for the lander is designed in a passive way.The proposed dynamics and controller are further validated through numerical simulations.This research presents a fresh concept that holds inspiration for future design involving small-body landers.展开更多
Traditional landers typically encounter difficulties achieving stable landings because of the weak gravity and complex terrain of small celestial bodies.A multi-node lander with flexible connections can improve the st...Traditional landers typically encounter difficulties achieving stable landings because of the weak gravity and complex terrain of small celestial bodies.A multi-node lander with flexible connections can improve the stability of a small celestial body landing.However,this also poses new challenges,particularly for landing guidance in hazardous terrain.To address this problem,an equivalent simplified dynamic model of a multi-node flexible lander is first constructed,and its flat output is determined.Subsequently,a trajectoryplanning method combining the flow and vector fields is designed to avoid collision,and the parameters of the vector field are optimized online according to the dynamic and obstacle constraints during the descent process to obtain a more suitable trajectory.Finally,the effectiveness of the proposed trajectory-planning method is verified through comparative simulations of landing and obstacle avoidance from the hover point to the landing area.This study offers new prospects for upcoming small celestial body landing missions in complex terrains.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFA0706500)。
文摘Flexible lander,composed of multiple nodes connected by flexible material,can reducethe bouncing and overturning during the asteroid landing.To satisfy the complex constraints inthe node cooperation of the flexible landing,an intelligent cooperative guidance method is pro-posed.The method consists of a double-layer cooperative guidance structure,a guidance parameterdetermination approach,and an action priority strategy.The double-layer contains a basic guid-ance used to satisfy the terminal state constraints,and a compensatory guidance used to satisfythe lander's attitude constraint.For the compensatory guidance,the parameters are determinedby multi-agent system,which are trained according to the performance index of flexible landing tra-jectories.The action priority strategy is used to reduce the detrimental effect of parameter inconsis-tency on the node cooperation.The simulation of flexible landing shows that the cooperativeguidance method is effective in improving the landing accuracy while satisfying the constraints.Meanwhile,the method is robust to the disturbance in the navigation and control.
基金HI-tech Research and Development Program of China
文摘Along with the progress of sciences and technologies, a lot of explorations are taken in many countries or organizations in succession. Lunar, the natural satellite of the earth, become a focus of the space discovery again recently because of its abundant resource and high value in use. Lunar exploration is also one of the most important projects in China. A primary objective of the probe in lunar is to soft-land a manned spacecraft on the lunar surface. The soft-landing system is the key composition of the lunar lander. In the overall design of lunar lander, the analysis of touchdown dynamics during landing stage is an important work. The rigid-flexible coupling dynamics of a system with flexible cantilevers attached to the main lander is analyzed. The equations are derived from the subsystem method. Results show that the deformations of cantilevers have considerable effect on the overloading of the lunar lander system.
基金supported by the National Key R&D Program(grant number 2019YFA0706500)the National Natural Science Foundation of China(grant number 62273118)National defense basic research projects(grant numbers JCKY2021603B030,JCKY2020903B002).
文摘Small bodies have the characteristics of noncooperative,irregular gravity,and complex terrain on the surface,which cause difficulties in successful landing for conventional landers.In this paper,a multinode flexible lander is put forward to address the problem.The dynamics of this new lander are constructed based on the port-Hamilton framework.The trajectory-tracking formation controller for the lander is designed in a passive way.The proposed dynamics and controller are further validated through numerical simulations.This research presents a fresh concept that holds inspiration for future design involving small-body landers.
基金the National Key R&D Program(grant number 2019YFA0706500)the National Defense Basic Research Projects(grant number JCKY2021603B030).
文摘Traditional landers typically encounter difficulties achieving stable landings because of the weak gravity and complex terrain of small celestial bodies.A multi-node lander with flexible connections can improve the stability of a small celestial body landing.However,this also poses new challenges,particularly for landing guidance in hazardous terrain.To address this problem,an equivalent simplified dynamic model of a multi-node flexible lander is first constructed,and its flat output is determined.Subsequently,a trajectoryplanning method combining the flow and vector fields is designed to avoid collision,and the parameters of the vector field are optimized online according to the dynamic and obstacle constraints during the descent process to obtain a more suitable trajectory.Finally,the effectiveness of the proposed trajectory-planning method is verified through comparative simulations of landing and obstacle avoidance from the hover point to the landing area.This study offers new prospects for upcoming small celestial body landing missions in complex terrains.
