外置-串联复合型LET铰链的设计与性能分析

Design and performance analysis of outside-series-shaped LET joint

针对LET铰链存在拉压刚度低、工作精度差的问题,基于外置LET铰链,设计了外置-串联复合型抗拉压LET铰链,推导了铰链弯曲等效刚度与拉压等效刚度的理论计算式。实例计算与有限元分析误差在5%以内,验证了理论分析与等效刚度计算式的正确性。将外置-串联复合型LET铰链与相同尺寸的外置LET铰链、Nested-LET铰链进行性能对比,在保持弯曲变形能力的前提下,外置-串联复合型LET铰链拉压刚度是外置LET铰链的43.3倍,是Nested-LET铰链的1.43倍,充分表明该铰链结构设计的合理性与有效性。

In this article,in order to improve the tension/compression stiffness and rotation accuracy,based on the outside lamina emergent torsional(LET)joint,a new tensile/compressive outside-series-shaped LET Joint is worked out.The formulas of the bending equivalent stiffness and the tensile/compressive equivalent stiffness are derived.The error between the theoretical calculation and the finite element analysis(FEA)is less than 5%,thus indicating that both the theoretical analysis and the formulas of equivalent stiffness are correct.A series of comparison are conducted on the performance of the outside-series-shaped LET joint,the outside LET joint and the Nested-LET joint with the same overall dimensions.The FEA results show that the bending stiffness of the outside-series-shaped LET Joint slightly decreases,but its tensile/compressive stiffness is 43.3 times that of the outside LET joint and 1.43 times that of the Nested-LET joint respectively.Therefore,the joint design is rationale and valid.