Bionic Design And Capturing Dynamics Of Space Net

The collision risk of space debris and occupation of Geostationary Earth Orbit(GEO)defunct satellites have become urgent problems for spaceexploring activities,which indicate the urgent needs for the active space debris and defunct satellites capturing and removal methods.Flexible net capturing is regarded as one of the most promising capturing methods due to its multiple advantages e.g.,its structure is simple,it costs efficiently,allows a long capturing distance and lowers capturing precision requirement and collision risk,especially suitable for capturing noncooperative space target.The structure configuration of space net and its deployment and impact dynamics are vital for capturing mission.Inspired by the special structure characteristics of spider net,the structure of space net is designed in a bionic way and then its capturing dynamics are also analyzed to investigate the deployment mechanism,impact mechanism and capturing parameters of bionic space net,and the ground impact experiment of space net is also conducted.(1)Design of bionic space net.The excellent capturing property and impact resistance ofspider net is analyzed,then based on the silk and structure characteristics of spider net and the mission requirements of space net,the net structure is designed to be nonuniform from the respect of structure bionics through setting different axial rigidity of radial and spiral silk.Then based on the bionic space net and engineering application,a self-storage method with hollow radial silk storing solid spiral silk and a installing method with rotation shaft are designed,and a knitting method is also proposed.(2)Deployment mechanism of bionic space net.The applicative tether unit models are analyzed,and the deployment process of bionic space net is simulated.Then the variations of net geometry,state of flying mass,energy and tether force are analyzed to investigate the tractive relation and deployment mechanism of bionic space net.The results show that the flying mass firstly drag the radial silks to deploy and the deployed radial silks then drag the adjacent spiral silks to deploy,which achieves the successive and ordered deployment of bionic space net and a clear transitive load path.(3)Impact dynamic model and impact mechanism of bionic space net.The rigid impact dynamic model is established.In particular,the focus is on the rigid-flexible coupling impact dynamic model forspace net,which are respectively established based on the Hertz impact method and appending constraint method.Then the impact process between bionic space net and rigid target are simulated and compared with both established impact dynamic models.The variations of net geometry,closing up of flying mass,energy,impact force and tether force are analyzed to investigate the impact mechanism of bionic space net.The results show that the flying masses gather together to make the bionic space net well wrap the target for the impact response,the bionic space net experiences drastic response and the radial silks bear main loads during the impact process.(4)Capturing parameters of bionic space net.The deployment process and impact process of bionic space net are simulated.Then the capturing parameters are investigated from the view of net structure,casting index and impact position.Specifically,the effects of net mesh,mass ratio of flying mass and net,weight ratio of radial and spiral silks,casting angle,casting velocity,capturing distance and eccentric distance on net geometry,energy and dynamics of bionic space net are analyzed.And the capturing validity of bionic space net is also discussed.(5)Ground impact experiment.The ground impact experiment of space net is designed and conducted.Then the ground impact dynamic model is established and verified from the comparison of experiment and simulation results.Based on the impact dynamic model,the impact characteristics of space net is discussed,and the differences of impact process under space and ground environment are also investigated.A bionic space net is proposedreferring to the special structure characteristics of spider net in present paper.Then the simulation and experiment are combined to explore its working mechanism.The research works not only provide new ideas for structure design of space net,but also provide some theoretical analysis andsimulation methods for the mission design and engineering application of space net.