Configurations And Collision Researches Of Tensegrity Landers

Soft landing is an important way for airdropping,spacecraft and aircraft recovery landing.The tensegrity structure,which has the characteristics of light weight,large internal space and good anti-collision and damping capacity,is very suitable to be used as the key component of the buffer device.In this paper,the stable configurations,available internal space and cushioning performance of various of spherical tensegrity structures are discussed.The specific research contents include:(1)A method for assembling a complex tensegrity structure with tensegrity basic units is given,and the condition of judging the equilibrium of the structure is simplified using the symmetry of the structure.That is,the problem of determining the structural stability is transformed into the problem of analyzing the force balance of each node,and simplified into the balance problem of three forces in common point,then transformed into the coplanar problem of four points using mixed product.The parameter expressions of different spherical tensegrity structures are given.The numerical and analytical solutions of the stable configurations of each structure are obtained by exhaustive method and symbolic derivation method respectively.Finally,the stable configurations of each truncated regular polyhedron tensegrity structure can be obtained only by determining two parameters,the circumscribed radius R of the structure and the radius r of each section circle.(2)The sizes of available internal space of different spherical tensegrity structures are evaluated using the payload space proportion.According to the characteristics of the tensegrity structures that each member only bears axial force thus the external loads of the structure,such as tension,compression,bending and torsion,can be applied to each node equivalently,the minimum mass design method is used to calculate the minimum size of the cross-section of each component and the corresponding minimum total structural mass of each truncated regular polyhedron tensegrity structure with equal length of bar and string respectively,while the conditions such as the size of the structure,the types of the component materials and the axial force magnitude of one bar are given.(3)The simulation models of the stable configurations are established,and the maximum static bearing capacity of each structure is tested based on whether the elongation of each string exceeds the maximum elongation without failure.The high-altitude falling simulations of different structures are carried out with and without the payloads,and the corresponding maximum dropping heights are tested.(4)Several methods of making physical models of the tensegrity structures are introduced.The cushioning performance of the structures during landing are enhanced by assembling the soft elastic joint caps suitable for collision cushioning,increasing the number of over constraint strings and improving the manufacturing technology of strings.The static bearing capacity tests and high-altitude falling collision tests with different payloads are carried out for each physical model,and several methods to further enhance the buffer capacity of the structure are put forward,which provide references for the future research.