桥式直接耦合柔性机构的优化设计方法

Optimum Design of Bridge-Type Compliant Mechanism with Direct Coupling

研究设计了用于压电尺蠖驱动器中间驱动机构的桥式直接耦合柔性机构,建立了该柔性机构的简化模型.利用卡氏定理推导了刚度方程,将柔性机构简化为单自由度弹簧质点系统,得到固有频率.通过实验测试了该柔性机构的刚度和固有频率,并分别与有限元法和解析法的结果进行对比分析.结果表明:刚度和固有频率的解析解误差分别为5.5%和14.1%,有限元解的误差分别为7.7%和10.1%,验证了解析解和有限元解的正确性.为了方便初始设计阶段的参数优化设计,利用有限元方法研究了该柔性机构各几何参数对机构静动态特性的影响.给出了一种简单有效的优化设计方法,通过改变该柔性机构的几何参数对其静动态特性进行优化.

A bridge-type compliant mechanism with direct coupling for the intermediate drive mechanism of inchworm actuator is developed and its simplified model is also established. The stiffness equations are deduced according to Castigliano＇s theorem and the natural frequency is derived with the compliant mechanism simplified as one DOF spring-mass system. The experimental tests of stiffness and natural frequency are carded out and the results are compared with the results of finite element analysis （FEA） and analytical method. The results show that the errors of the analytical model of stiffness and natural frequency are 5.5% and 14.1%, and the corresponding errors of FEA are 7.7% and 10.1% respectively. The experimental results show the validity of the analytical model FEA. In order to facilitate parameter optimum design in the initial design stage, FEA is used to study the influence of geometrical dimensions of the compliant mechanism on its static and dynamic performance. Then a simple optimum design procedure by changing geometrical dimensions to optimize static and dynamic performance of the compliant mechanism is presented.