3-PRS型柔性并联机构运动学分析及驱动行程优化

Kinematics analysis and driving stroke optimization of 3-PRS compliant parallel mechanism

为简化3-PRS型柔性并联机构运动学计算过程和提高计算结果的准确性,提出一种等效刚性替换的计算方法,并通过回归对驱动行程与平台位姿进行拟合,实现柔性并联机构的运动学分析及驱动行程优化。首先,通过3-PRS并联机构的逆运动学分析,得到刚性关节位姿;然后,建立3-PRS型柔性并联机构有限元模型,计算柔性关节的转动情况,并与等效刚性机构结果进行对比分析;最后,通过多元非线性回归的方法拟合驱动行程与运动平台位姿的关系,进而得到适用于柔性机构的驱动行程,通过有限元分析,验证优化后模型的准确性。结果表明,优化后平台位姿仿真结果更加接近预设值,为3-PRS型柔性并联机构的运动学分析及驱动行程优化提供了必要的理论依据。

In order to simplify the kinematics calculation process of the 3-PRS compliant parallel mecha⁃nism and improve the result accuracy,the equivalent rigid replacement method was proposed.The driving stroke fitted with the platform position and orientation by regression.The kinematics analysis and driving stroke optimization of the compliant parallel mechanism were achieved.First,the rigid joint positions and ori⁃entations were obtained by the inverse kinematics of 3-PRS parallel mechanism.Then,the finite element model of the 3-PRS compliant parallel mechanism was established.The rotation of compliant joints was cal⁃culated and the results were compared with the equivalent rigid mechanism.Finally,the relationship between the driving stroke and the moving platform position and orientation was fitted by the multiple nonlinear re⁃gression method and the driving stroke suitable for the compliant mechanism was obtained.The optimized model accuracy was verified by finite element analysis.The results showed that the platform position and ori⁃entation obtained by finite element simulation was closer to the preset values,which provided a necessary theoretical basis for the kinematic analysis and driving stroke optimization of the 3-PRS compliant parallel mechanism.