Mechanical Design And Analysis Of A Triangular Prism Modular Deployable Mast

With the development of space science and technology, space deployablestructures have appeared. Spacial deployable mast is one of the earliest study fieldsand has been widely used. Spacial deployable mast is mainly used to support thesolar panels, space telescope and other payloads in the space exploration missionsas a one-dimensional linear system. With the diversity of spatial mission demands,the requirements for stiffness, strength and reliability of the deployable mast arecontinuously increasing. Whether the deployable mast can unfold smoothly in spaceand achieve sufficient rigidity become the key factors for normal work of the load.This paper focuses on a triangular prism modular deployable mast, whichattains high stiffness, enough strength, large folding proportion and otheradvantageous characteristics. The unit of the proposed mast is a triangular prism.Each unit can be folded by inward folding of the longerons. A scheme based ontaper pin lock is proposed for locking after the expanding process, which is simpleand reliable and it can unlock smoothly. In addition, the overall structure anddriving structure of the mast are designed in detail.The forces of each node are analyzed. Mechanical models of stiffness are builtand influences of structural parameters on the stiffness of the mast are discussed.Stiffness of the longerons in all directions are analyzed using finite element methodand the properties are imported to the entire mast for static analysis. Besides, affectsof the cable on the stiffness of the mast are comparatively analyzed.The kinematics and dynamics of the mast are discussed in detail. Kinematicsequations of the mast are derived using geometric method, and the characteristics ofthe mast with different movement input are analyzed. Dynamic equations areestablished, and the variation of the driving torque are calculated with differentmovement input. The mast becomes a statically determinate truss after fullyextended. Modal analysis are carried out using finite element method and thenatural frequencies and mode shapes for different orders are analyzed.In order to further verify the correctness of the expanding features andtheoretical analysis, prototype of the mast is processed and the functions are testedthrough experiments. Static load experiment and dynamics experiment for the mastare implemented and analyzed. It is found that the mast has high compressivestiffness, bending stiffness and reliability.