Development of Automated Cell Manipulation System

在畜牧业、医学和食品供应等领域，对生物细胞进行克隆和人工授精的需求日益增加。然而，大多数商业化的工具都是手动或半自动的。操作10 ~ 100μm的微小物体需要操作者经过长时间的训练，才能借助显微镜完成握住、穿透、注射和吸入等任务。操作繁琐，耗时长，且产出率低。本研究的目的是开发一种具有高性能和可重复性的生物自动化操作系统。本文提出并实现了一种视觉控制方案来控制刀具臂的运动。利用带CCD（电荷耦合器件）成像装置的光学显微镜在像素坐标处计算目标和工具的位置、运动路径和速度。该视觉控制方案能够消除在机械阶段通常存在的不对准、滞后和漂移等机械误差，而这些误差在精细运动控制中是至关重要的。多个工具臂和目标对象通常共享像素坐标，这对于实现顺利的协同操作至关重要。结果表明，在直径小至3μm的循环跟踪测试中，在2D中获得了很高的刀具轨迹精度和可重复性。在力/触觉传感器的辅助下，该系统还可以进行三维操作。

There are increasing demands of manipulation on bio-cells for cloning and artificial insemination in the fields of animal husbandry, medical science and food supply. However, most commercialized tools are manual or semiautomatic. Manipulation of tiny objects sized at 10〜100μm requires the operators to experience a long time training to implement the tasks, such as holding, penetration, injection and suction, with the aid of a microscope. The operations are tedious and time consuming, yet with very low yield rate. The objective of this research is to develop an automated manipulation system with high performance and repeatability for the biological applications. In this paper, a vision control scheme has been proposed and implemented to steer the movements of the tool arms. The positions of the targets and tools, the paths and speed of the movement are calculated at the pixel coordinate by use of an optical microscope with a CCD (charge-coupled device) image device. This vision control scheme is able to eliminate mechanical inaccuracy including misalignment, hysteresis and drift which normally exist at mechanical stage but are crucial in fine movement control. The pixel coordinate is also commonly shared by multiple tool arms and targeted objects, and essential to achieve smooth cooperative operations. As the result, the great accuracy and repeatability of tool path have been achieved in 2D at a test of following a cycle as small as 3μm in diameter. With an assistance of force/tactile sensor for sensing at third dimension, the system is also able to perform 3D manipulation.