The large stroke is usually realized by lowering stiffness along the degrees of freedom, which usually leads to a decrease of stiffness along the degrees of constraint. A high stiffness ratio is crucial for reducing the deflections induced by disturbances such as eccentric force and the gravity of the load. Besides, the fatigue life of these mechanisms will be shortened due to the large stress caused by the large deflection. This paper proposed a new guiding mechanism using orthogonally oriented flexures to improve the stiffness along the degrees of constraint and reduce stress concentration. The energy method is utilized to obtain the kinetostatic model of the guiding mechanism by taking the nonlinear deflection into account, based on which the mechanism is optimized by simultaneously considering the topology and size. As compared to the performance of traditional design obtained through the same optimization objective and constraints, the optimal design effectively improves the stiffness along the degrees of constraint, whose accuracy is also validated by the finite element analysis results. Experimental results show that the proposed mechanism increases the stiffness ratio $K_{az}/K_x$ by 3.54 times compared to the traditional mechanism.

大行程通常是通过沿自由度降低刚度来实现的，这通常会导致沿约束度的刚度降低。高刚度比对于减少由偏心力和负载重力等干扰引起的挠度至关重要。此外，这些机构的疲劳寿命会因大挠度引起的大应力而缩短。本文提出了一种使用正交定向弯曲的新导向机构，以提高沿约束度的刚度并减少应力集中。利用能量法得到考虑非线性偏转的导向机构动静力学模型，在此基础上同时考虑拓扑和尺寸对机构进行优化。与通过相同优化目标和约束获得的传统设计性能相比，优化设计有效地提高了沿约束度的刚度，其精度也得到了有限元分析结果的验证。实验结果表明，所提出的机制增加了刚度比${钾}_{\mathrm{一种}z}/{钾}_X$ 3.54 倍与传统机制相比。