Study On Configuration Of Tensegrity Mechanical Arm

People have been using new composite materials and new structures to design structures suitable for continuous robots.In ordinary structures,stiffness and flexibility are a pair of contradictions.As a new structure,tensegrity has the characteristics of light weight,adjustable stiffness and variable shape.In this paper,the deformation process of the basic element,the splicing between the basic elements and the kinematics of the whole structure of the tensegrity mechanical arm are analyzed and studied.Based on the regular 3-bar tensegrity structure,the node matrix,the connection matrix,the vector matrix,the force density matrix and the equilibrium matrix are constructed.The deformation of tensegrity foundation element is obtained by changing the corresponding coordinates in the node.The stability conditions and force density relations of each component in the tensegrity foundation element under different deformation states are obtained by force density method.The configuration of tensegrity element is enriched,which provides the basis for the construction of multi-layer tensegrity bending structure.In order to obtain more abundant multi-layer tensegrity structure,this paper uses node-node splicing mode and node-saddle cable splicing mode to construct multi-layer tensegrity structure.In the process of splicing,not only the differences and relations between the two splicing methods are discussed,but also the mapping relationship between torsion angle and overlap ratio between multi-layer elements is deduced again by force density method,so as to ensure the overall stability of multi-layer tension.According to cylinder envelope method and arc curve method,the structure suitable for tensegrity mechanical arm is selected from various configuration schemes,and the driving scheme is designed for the structure.When analyzing the kinematics of tensegrity mechanical arm,firstly,according to the deformation process and splicing method of the basic element,the parameters of driving rope length,joint element deformation parameters and end pose of the basic element are defined,and then the mapping relationship between these parameters is obtained according to the geometric structure relationship.According to the mapping relation,the trajectory of the end movement is deduced,so that the tensegrity mechanical arm can complete the desired bending action.According to the configuration of the tensegrity mechanical arm,the experimental prototype is built.It is found that different components have different effects on the axial and radial stiffness of the prototype,and the deformation of the joint of the basic units has an impact on the overall bending of the prototype.The scheme of strengthening the stiffness of the joints between the basic elements is determined.According to the bending test of the prototype,the driving scheme is selected,and the spatial coordinates of the end points of the prototype are collected to analyze the bending status of the prototype.