Design And Fabrication Of Space Foldable-bar Boom

Deployable boom is one of the most important mechanism of spacecraft.They have two stable state.One is stowed state,the other is deployed state.In stowed condition,Deployable boom has a small volume,which is convenient for resettlement and transportation.In deployed condition,deployable boom could work as expected.Firstly,based on the abundant understanding of developable mechanism,analyzing the advantages and disadvantages of different kinds of support mechanism,folding-bar deployable boom is deisgned in details.It consists of bars and hinges.The folding principle of bars and the locking principle of hinges are analyzed.The locking manner of hinge is simple and effective.Constant torque spring is regard as driver which has less surplus energy when the deployment process is finish.Then,hold-down and release mechanism is design to carry and release deployable boom.Besides,In order to avoid collision and interference of members,the plan of deploying synchronously and deploying sequentially is introduced to solve the problem.Secondly,Lagrange equation is established to analyze the deployment process of deploying synchronously and sequentially.By means of MATLAB,Motion curve is obtained easily.Then,ADAMS is used to analyze the deployment process again,which would verify the reliability of output of Lagrange equation.Besides,the impacts of model of deployable boom are analyzed with different material of hinges,different wall thickness and diameter of bars after locked.What's more,the relationship between radical frequency and the ratio of the stiffness of hinge and the stiffness of bar is deduced and analyzed in finite element method.Thirdly,stiffness analysis is carried out by ANSYS Workbench.A comparative analysis of different parameters of deployable boom is given.Considering the substantially temperature change of space may result in the deformation of deployable boom,Thermoelasticity theory is carried out to check thermal deformation under constant temperature field.And,the output is verified by ANSYS.Finally,based on the structural design and analysis above,the prototype is manufactured.The test-bed is built for the purpose of testing the function and performance of prototype.Experimental projects include: impact force test,stiffness test,repeatability test and fundamental frequency test.What the paper design and analyze would provide the referencewith other deployable mechanism.