Modular elements of variable geometry trusses with octahedral truss elements

Abstract

The invention discloses a modular unit of a variable geometry truss of an octahedron truss unit. The modular unit comprises a set of drive mechanism, two sets of driven mechanisms and twelve parallel connection driven rods used for connecting the drive mechanism with the driven mechanisms. Especially, a mutual penetrating and inserting serial connection manner is adopted in three actuators of the drive mechanism, the elongation of drive rods can be greatly improved under the situation that the size of the unit is not increased, and the maneuvering performance of the mechanisms is improved. The modular unit of the variable geometry truss of the octahedron truss unit has the beneficial effects of being small in size, large in motion range, high in precision and rigidity, capable of being folded and stored, capable of being expanded outwards and the like, and the modular unit can be used in an aerospace expandable mechanism, an operation mechanism, a tracking mechanism, an industrial control mechanism and the like.

Description

technical field [0001] The invention relates to a modular unit of an octahedral truss unit variable geometry truss. Background technique [0002] The octahedral unit is a statically determinate unit, each node is properly constrained, and the configuration of the mechanism can be changed by changing the length of any rod. Therefore, a variety of parallel kinematic mechanisms are derived based on the octahedral unit. A variable geometry truss is formed by connecting multiple such octahedral units in series. Compared with the traditional series mechanism, it has the advantages of light weight and high rigidity while maintaining precision, and its movement speed is slightly slower. Therefore, the variable geometry truss mechanism is especially suitable for the aerospace field with strict quality requirements. [0003] Chen Wujun, Guan Fuling, Chen Xiangyang, etc. "Research on the Extended Arm of the Octahedron Unit" (Acta Astronautics, 1999, 20(2): 41-47) studied the geometric...

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Problems solved by technology

[0012] The Chinese patent "Octahedral truss unit variable geometry truss active rod" with application number 201310150753.6 has a large motor size, complex structure, high power, small thrust, large nodes, and large impact

[0013] Application No. 201410223230.4 of the Chinese patent "An octahedral truss unit variable geometry truss active rod", but its overall length is relatively large, making it difficult to miniaturize and increase the elongation of the active rod

[0014] The Chinese patent "Octahedral truss element variable geometry truss active node" with authorized patent number 201310153044.3 discloses an octahedral truss element variable geometry truss active node, but the node is kinematically coupled with the parts connected by the upper and lower passive rods, resulting in passive There are irregularities and singular points in the movement of the rod, and there are many parts

[0015] The application number is 201410217693.X for the Chinese patent "Octahedral truss element variable geometry truss active node", but the eccentric connection of the passive rod leads to inaccurate dynamic model, and there is a rotation redundancy, resulting in low overall stiffness of the system, which has Singularity

[0016] The Chinese patent "Octahedral truss unit variable geometry truss actuator" with application number 201510261004.X proposes a compact active rod and main node integrated mechanism. Compared with other designs, it effectively improves the elongation ratio of the active rod. However, when the elongation is relatively large, the stiffness loss is serious, and the elongation required for the overall folding of the mechanism is still not reached (the required elongation is 200%)

In addition, the active and passive mechanisms of the above variable geometry truss are closely connected, and the truss assembly is cumbersome, which is not conducive to expansion

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