| Tensegrity is a new type of deployable structure composed of continuous tension string and discrete compression bars.All string members are tensioned and bar members are compressed,which greatly improves the utilization rate of materials,makes light-weight materials have high bearing capacity,and the structural stiffness can also be controlled by the size of prestress.The overall external degree of freedom of the structure is zero,and any member is neither under constrained nor redundant.External force is applied to any member of the structure,and the structure can disperse the external force to all members.Therefore,the structure has certain bearing and impact resistance and excellent stability.Based on the overall forces characteristics of tensegrity structure and Summarize the existing deployable methods.In order to optimize the internal space,improve the utilization rate,realize large deployable ratio,solve the problems of interference between components and increase the cushioning performance and elasticity,it is proposed that making the traditional tensegrity structure straight bar to bending bar,and the appropriate driving mode is selected to realize the axial deployment of the structure.This paper mainly analyzes the mechanical and deployable properties of the proposed bending bar tensegrity structure.Finally,the model is made and the rationality of the structure is verified by experiments.Firstly,starting from the basic unit,fully understand the basic relationship between components,so as to pave the way for the subsequent bending bar configuration.The necessity of tensegrity deployment is put forward,and the necessary conditions for realizing deployment are:bar shortening or string extend.Compare and analyze the advantages and disadvantages of different deployable schemes,such as deployable ratio,bar compression ratio,etc.On this basis,bending bar tensegrity structure is put forward.Then,the geometric derivation of the bending node configuration is carried out,the node coordinates at any bending angle of the number of bars p are found,and the drawing is solved by programming.The relationship between node coordinates,bending angle,bending bar length and space utilization is established,and the structural characteristics,stability,strength and energy storage are analyzed.Then,the appropriate driving mode is selected to flexible modeling the position and stress state of the bar and string in the deployable process.The time response curves of rotation angle,force and position of single-layer and multi-layer elements are obtained,and the effects of basic factors such as bending bar angle,height diameter ratio and element configuration are analyzed.Finally,the experimental prototype is built,and the stepper motor is used to add uniform displacement drive to verify the feasibility of axial deployment,which corresponds to the simulation part.Two bending and deployment schemes of string member contraction are provided to analyze the feasibility of structural deployment and unfolding.The error sources of experiment and simulation are analyzed to make an overall evaluation for the bending bar tensegrity structure.To summary this structure possible application fields in the future and problems to be solved in the research process. |
