Research On Space Net Capture

As a typical representative of flexible capture technology,the space net has the characteristics of good portability,high fault tolerance,strong adaptability,and small impact on the chaser satellite.It has a good application prospect in the capture mission of asteroids and space debris.In this paper,the flexible space net is approximated by the lumped mass method and a dynamics model of net capture is established by using the mass spring-damper model and Hertz contact theory.In addition,according to the position relationship between the space line segments,the judgment method of the self-contact process between the rope segments on the space net is deduced,and the existing dynamics model of the space net is improved.Based on the analysis of the force characteristics in the process of space net capturing the target,this paper divides the process into three capture phases according to the time sequence: free deployment,wrapping target and capturing target.Based on the three capture phases,the analysis framework of this paper is proposed,that is,the process of free deployment of the space net,the process of the space net wrapping the target,and the process of the space net capturing the target.In the analysis of the process of free deployment of the space net,through the analysis of the net mouth trajectory,the potential relationship between the space net movement and the target to be captured is obtained.And based on the net mouth trajectory,a method is proposed to analyze the process of the space net capturing the target.According to the trajectory graph formed in the space by the net mouth trajectory,an index to evaluate the process of the space net capturing the target is proposed,which provides an evaluation basis for the selection of capture parameters.In addition,the effects of shooting parameters,such as shooting speed and shooting angle,on the net mouth trajectory are analyzed,and the basis for their selection is given.In the analysis of the process of the space net wrapping the target,the influence of the contact process between the space net and the target on the net mouth trajectory is analyzed,and the advantages and disadvantages of the net mouth trajectory diagram and the space net model diagram are compared.In addition,the evaluation index is used to analyze the effects of the target radius and the capture distance on the process of the space net wrapping the target.In the analysis of the process of the space net capturing the target,by choosing the effective timing of opening the closing device,a simulation of the process of the space net capturing the target is established completely.For a more general situation,a simulation of the space net capturing target process under the eccentric capture situation is established,and the effect of the eccentric distance on the process of the space net capturing the target is evaluated.The simulation results show that the analysis method based on the net mouth trajectory can more intuitively and comprehensively analyze the process of capturing the target by the space net.It can not only evaluate the relevant capture parameters involved in the capture process,but also provide an intuitive reference basis for the selection of capture parameters.Effective selection of capture parameters can improve the ability of the space net to wrap the target and can also improve the success rate of the space net to capture the target.