Design and analysis of a novel type micro-dispensing mechanism with large displacement

Abstract

To solve the issues of low accuracy and limited speed of a micro liquid-delivery system, a novel micro-dispensing mechanism with a large stroke using a piezoelectric actuator was proposed. To compensate the limited stroke of the piezoelectric actuator, hybrid amplification mechanisms were integrated with the designed flexure-based mechanism. Referring to the operation principle of three typical amplification mechanisms, the magnification ratio was derived. Based on Lagrange’s theorem, the stiffness model of the mechanism was established. In addition, the natural frequency of the mechanism was derived. To validate the correctness of the theoretical analysis, simulations were performed via the ANSYS Workbench, demonstrating that the errors of the stiffness model and magnification ratio were 8.5% and 7.2%, respectively. The proposed mechanism provides insights to the design of the high-performance liquid micro delivery system. 针对传统点胶系统精度低、点胶速度慢等问题，采用柔性机构设计了基于压电陶瓷驱动的一体化微点胶机构。为补偿压电陶瓷驱动器的行程，采用三级混合放大机构，并分析了位移放大倍数的理论值，得到了机构的位移行程。应用拉格朗日定理对机构的刚度建模，求解理论刚度值，得到了机构的固有频率解析表达式。有限元仿真结果表明，机构放大倍数和刚度的理论值与仿真结果的相对误差分别为8.5%和7.2%，验证了理论模型的正确性。该机构为微量液体自动分配系统的设计提供了一定的思路与技术支持。