Modeling of micro object dynamics based on energy transfer for micro manipulation

为了推动工业上零件小型化的发展趋势，必须建立一种能够实现微型零件精确定位而不发生意外变形、断裂或翻转的操作技术。本研究的目的是建立以能量而非力描述的微动力学模型，以建立微物体动力学控制技术。1997年，我们构建了“原位”力测量系统，在扫描电镜观察下测量微物体操纵过程中的力和位移。通过系统实验数据的积累，澄清了静电力的大影响、表面粗糙度不可避免的不确定性以及表面轻微变形存在的大时间效应。1998年，在这些发现的基础上，我们考虑了如何建立微观物体动力学模型。所得数据支持微观物体动力学不一定用简单的表面能来描述。经过一定时间后，物体已经相互连接，物体的拾取应视为裂纹在界面处的扩展和断裂。基于这些考虑，我们认为在处理微观物体时，应该在宏观物体动力学模型中加入附着项和阻力矩项。在扫描电镜下对微球进行了系统的取放实验，验证了该简单模型的正确性。在此基础上，推导出了可靠拾取和精确定位的最佳机械手轨迹，并通过实验验证了其有效性。

To advance the trend of miniaturization of parts in industry, it is indispensable to establish manipulation technique which can realize accurate positioning of micro parts without accidental deformation, fracture, or flipping away. The purpose of this research is to construct the model of micro dynamics described with energy rather than force to establish control techniques of micro object dynamics.In 1997, we have constructed "in situ" force measurement system to measure force and displacement during micro object manipulation under SEM observation. As a result of accumulation of systematic experimental data, the large effect of electrostatic force, the unavoidable uncertainty due to surface roughness, and the existence of large time effect due to slight deformation of surfaces have been clarified.In 1998, based on these findings, we have considered how the micro object dynamics can be modeled. Obtained data support that the micro object dynamics is not necessarily described with a simple surface energy. After a certain period, the objects are already interconnected, and picking up of such object should be considered as the growth of a crack and fracture at the interface. Based on these considerations, we concluded that adhesion term and resistance moment term should be added to macro object dynamics model when we deal with a micro object.Systematic experiment to pick and place micro spheres under SEM observation justified this simple model. Furthermore, we have derived optimum manipulator trajectory for reliable pick and that for accurate positioning, and confirmed their effectiveness by experiment.