摘要
分析了一类桥式直接耦合柔性机构的精确的刚度和应力模型.分别采用伪刚体模型和卡氏第二定理推导了该柔性机构理论刚度模型,利用两个理论模型与有限元模型的结果进行对比,并采用正交实验法全面分析了柔性铰链的寄生刚度和旋转刚度的精度对其刚度性能的影响.研究结果表明:该柔性机构的寄生刚度影响较小,误差贡献率小于3%;旋转刚度的精度影响较大,通过选择精确的旋转刚度公式可以得到精确的理论刚度模型,同有限元结果相比其误差在t/r<0.65范围内小于8%;与设计实验及其对应的有限元结果的误差分别为4%和3.96%,验证了刚度模型的正确性.基于刚度模型推导了该柔性机构的应力模型,运用正交实验法与有限元结果进行对比,误差小于4%,验证了应力模型的正确性.
Accurate stiffness and stress models of a class of bridge-type direct coupling compliant mechanism have been studied. First, the analytical stiffness equations for this compliant mechanism were formulated based on pseudo-rigid-body model and Castigliano＇s displacement theorem. Then, the effect of parasitic stiffness equations and the accuracy of rotational stiffness equations of flexure hinges on the overall analytical stiffness equations were comprehensively studied by the orthographic experimental method based on the comparison between the two analytical stiffness equations and the finite element analysis （FEA） results with the design parameters arranged. The results show that parasitic stiffness equations have less than 3% influence with the error, while accuracy of rotation stiffness equations has great effect and thus the accurate stiffness model can be obtained with the choice of the most accurate rotation stiffness equations. Compared with FEA results, the error of the derived stiffness model is less than 8% for t/r 〈 0.65. Finally, an experimental configuration was used to verify the overall stiffness equations and the errors compared with experimental and FEA results are 4% and 3.96% respectively. In addition, the analytical stress equations for this compliant mechanism were formulated based on the overall stiffness equations and the error compared with FEA results is less than 4% , which verifies their accuracy.
出处
《纳米技术与精密工程》
EI
CAS
CSCD
2009年第6期557-562,共6页
Nanotechnology and Precision Engineering
基金
国家教育部归国留学人员基金资助项目
关键词
桥式
柔性机构
刚度
应力
有限元方法
bridge-type
compliant mechanism
stiffness
stress
finite element method
