基于四杆机构单元的柔性铰链设计与尺寸优化

针对柔性铰链存在的转动角度小和径向漂移大等问题,进行了大转角和高精度柔性铰链设计。利用四杆机构中曲柄摇杆机构的转角放大特性,以固化的四杆机构为变形模块,通过摇杆的小变形实现铰链的大转角运动。柔性铰链中固化的四杆机构为超静定结构,基于超静定结构理论进行了柔性单元的受力分析,并建立了柔性铰链的刚度模型,实现柔性铰链的分析和设计。根据设计方案选取设计变量,基于理论推导得到刚度建立目标函数,根据性能和几何边界建立约束条件,利用遗传算法对柔性铰链尺寸进行优化,并通过ANSYS进行了特定尺寸下柔性铰链变形和应力分析,验证了优化结果的正确性。

Design and size optimization of flexible hinge based on unit of four-link linkage

Small rotation angle and big center-shift are the main problems of flexure hinges .To solve these problems ,the flexible hinge with big angle and high precision is designed .Using the characteristics of angle amplification of the crank rock-er mechanism of the four-link linkage ,the articulated points of the linkage are fixed .The fixed four-bar linkage is taken as the deformation module .By using the small deformation of the rocker in the four-link linkage ,motion of large rotational angle of the flexible hinge is realized .The fixed four-bar linkage in the flexible hinge is a statically indeterminate structure .Based on the theory of statically indeterminate structure ,deformation and stress analysis of the flexible unit is conducted .The stiff-ness model for the flexure hinge is given .The objective function is derived based on the stiffness model ,and the design vari-ables and constraints are defined .The size of the flexure hinge is optimized by using the genetic algorithm .Analysis of the deformation and stress of a specific size of the flexible hinge using ANSYS software validates correctness of the optimization results .