压电陶瓷驱动的精密微操作平台特性与优化

Characteristics and Optimization of Piezo-Driven Precise Micro-Manipulation Stage

设计一种结构紧凑、具有大运动空间和响应快的微操作平台，并对其静态和动态特性进行分析和优化．利用杠杆机构和连杆机构设计一种能实现两级放大的微操作平台，结构对称地设计在同一平面，并采用导向机构实现精确的导向运动．利用功能原理，采用伪刚体方法建立反映平台的静态和动态特性封闭形式的理论模型．由理论模型与有限元分析的结果比较分析可知，两者所得的结果误差范围为6．0％～7．2％，说明所推导模型的正确性．基于理论模型分析构型参数和柔性铰链尺寸参数对放大倍数、输出刚度、应力和固有频率的影响．结果表明，结构参数变化对输出刚度与固有频率的影响是矛盾的，对放大倍数和应力的影响也相互矛盾，需要通过优化结构参数以综合平衡其性能指标．提出一种以综合平衡平台的静态和动态特性为目标，并考虑应力、放大倍数和几何尺寸为约束的优化模型．结果表明优化后的固有频率和放大倍数比优化前均提高，而输出刚度降低，说明优化后的平台性能更好．

A compact micro-manipulation stage with large overall-motion and fast response was presen- ted, and its static and dynamic characteristics were analyzed and optimized. By using a lever mechanism and linkage, the micro-manipulation stage was designed which can achieve two-stage amplification. The structure lies symmetrically in the same plane, and a guide mechanism is adopted to realize accurate ori- entation movement. Using the work-energy principle, the pseudo rigid-body method is applied to build the closed-form theoretical model which can illustrate the static and dynamic performance of the stage. By comparative analysis of the results obtained by theoretical model and finite element method, it is shown that the error range is 6.0% --7.2% , which illustrates the correctness of the derived model. The effect of the configuration parameters and size parameters of the flexure hinge on the amplification ratio, output stiffness, stress and natural frequency were investigated based on the theoretical model, The results show changing the structure parameters has contradictory effect on output stiffness and natural frequency, and the relationship between magnification ratio and stress is also contradictory. Thus, the structural parame- ters require optimization for tradeoff of all performance indexes. An optimization model is presented to balance the static and dynamic characteristics, considering the constrains such as sstress, amplification ratio and geometry size. The optimization results show the natural frequency and magnification ratio are greater, whereas the output stiffness is smaller, whieh illustrates the stage has better performance after optimization.