基于7杆闭环机构提出一种新型四棱锥单元,其可作为一种基本可展机构单元,组合成大型可展机构。利用机构学方法研究,分析了单元机构的自由度、运动学和奇异性,给出了单元组合方法并基于四棱锥单元机构设计了一平板式可展开收拢机构,最后计算了机构的伸缩比。分析结果表明,这种单元机构组合方便简单,组合后的机构自由度为1,便于机构的展开收拢控制。当机构完全展开时,由于其奇异特性,机构有较好的力学性能。利用这种单元可以设计出新型大型可展开收拢机构,在航空航天领域有很好的应用前景。
A new four pyramid cell mechanism based on a spatial seven-linkage loop mechanism is proposed in this article which can be employed to assemble large deployable mechanisms.The mobility,kinematics and singularity characteristics of this cell mechanism are analyzed and the assembling method is provided.Based on this kind of cells,a new plane deployable mechanism is designed and its retractable ratio calculated.The results show that these cells are easy to be assembled into a large structure of deployable mechanism.The mobility of the assembled mechanism is only one,and thus its fold deployment is well controllable.When the mechanism is wholly deployed,it has good mechanic performance due to its singularity.Large deployable mechanisms can be designed by these cells and they have a good prospect in aeronautic and astronautic engineering.