针对精密柔性机构多自由度高精度运动的需求,以传统Delta并联机构为基础,设计了一种采用压电陶瓷驱动方式的空间柔性并联机构,基于伪刚体模型进行运动学分析。将从动臂质量分布作简化处理并主要考虑结构中柔性铰链的弹性应变能,利用拉格朗日方程建立动力学弹性振动微分方程,得到其固有频率表达式,并结合实际结构参数得到了相应的理论结果。3个主要运动方向的三阶固有频率的试验结果和理论分析结果误差分别为:12.71%、12.14%和14.90%,有限元仿真结果和试验结果误差分别为:6.20%、5.66%和10.28%,表明理论分析时所作的简化处理合理,得到的动力学数学模型有效、可信。
Due to the requirement of multi-dimensional nanometer level positioning of the compliant precision mechanism, a piezo-driven spatial compliant parallel mechanism was presented through the conventional Delta parallel mechanism. The inverse kinematics was developed on the basis of the Pseudo-Rigid-Body (PRB) model. After the simplifying of the mass of passive arm and calculating the strain energy of the flexure hinges, the dynamic equation was established through the Lagrangian approach, and the natural frequencies are evaluated by utilizing the geometric parameters. Three natural frequency errors, which were along with three primary translation directions, between the experiment results and the theoretical analysis were 12. 71% ,12. 14% and 14. 90%. The error between the finite element simulation and the theoretical results were 6.20% ,5.66% and 10.28%. The results also showed that the simplified process during the theoretical analysis was reasonable and the derived mathematics model was creditable.