光学元件狭缝柔性调节机构的设计与分析

设计了一种狭缝柔性结构的光学元件调节机构,使光学元件在具备较高调节精度的同时,保持较高的导向精度。采用弹性力学应力函数法分析了狭缝柔性结构的刚度,以径向刚度与轴向刚度的比值为目标函数,对狭缝柔性结构尺寸参数进行了优化,在不超过柔性结构材料屈服应力等约束条件下,刚度比最优值达到1 573.6,较大的刚度比值可以减小调节机构的耦合位移,从而提高机构的导向精度。该结构加工装配方便,可实现三自由度(θx-θy-Z)调节。对优化后的柔性结构进行仿真分析,结果表明:径向刚度与轴向刚度比值的仿真值为1 660.4,解析值与仿真值误差为5.23%,证明了刚度分析方法的有效性。优化后的结构,轴向调节行程为2.09 mm,绕x轴偏转角度调节行程为±16.6 mrad,绕y轴偏转角度调节行程可达到±14.4 mrad,满足光学元件调节的大行程要求。

Design and analysis of adjustment mechanism with slit diaphragm flexures for optical elements

An adjustment mechanism with slit diaphragm flexures is designed to keep the optical elements with higher guide precision while maintaining higher accuracy of adjustment. The stiffness of the slit diaphragm flexures structure is analyzed using the elastic mechanics stress function method. The ratio of the radial stiffness to the axial rigidity is taken as the objective function to optimize the dimension parameters of the slit diaphragm flexures structure. Under the condition of not exceeding the yield stress of the flexible structure material, the optimal value of the stiffness ratio reaches 1 573.6. A larger stiffness ratio can reduce the coupling displacement of the adjustment mechanism, so as to improve the guide accuracy of the mechanism. This mechanism is easily fabricated and assembled, and allows adjustment of three degree of freedom (θ_x-θ_y-Z). The stiffness of the slit diaphragm flexure is simulated and analyzed. The results show that the ratio of radial stiffness to axial stiffness is 1 660.4, and the error between analytical value and simulation value is 5.23%, which proves the validity of the stiffness analysis method. The optimized structure has an axial adjustment stroke of 2.09 mm, an adjustment stroke of ±16.6 mrad about the x-axis deflection angle and a ±14.4 mrad deflection angle about the y-axis, which satisfies the large stroke adjustment requirement of the optical element.