三自由度精密定位工作台工作空间分析及优化

Workspace Analysis and Optimization of a 3-DOF Precision Positioning Table

针对纳米压印光刻技术(NIL)过程中的纳米级空间定位要求,设计了一种采用柔性并联构型和压电陶瓷驱动的三自由度精密定位工作台。基于伪刚体(PRB)模型理论将柔性铰链等效为理想转动副和线性扭簧,建立了精密定位平台的PRB模型,并以此分析了该类工作台的逆运动学特性;根据弹性铰链转角范围所限定的约束条件分析了定位工作台的工作空间。另外,为了达到以预定的全局条件数为约束条件的最大工作空间体积,对工作台结构参数进行优化,并通过数值仿真验证其有效性。

In order to realize 3-dimensional positioning with nanometer level in nanoimprint lithograph （NIL） , a piezo-driven table with 3 DOF flexible parallel configuration was designed. Based on pseudorigid-body（PRB） modeling theory, both the inverse kinematics and velocity models were established by simplifying the single-axis flexible hinges as ideal revolute joints and torsion springs. In view of the physical constraints imposed by flexible hinges, the workspace of the table was investigated. And for the purpose to achieve a maximum workspace subjected to the given dexterity indices, its kinematic optimization was carried out. The numerical simulation was undertaken to validate the work.