论文总字数：13247字

摘 要

本篇文章致力于设计和研发一种可以自动对肉类进行检测并且可以准确定量吸取相关试剂的组合移液器。这套设计出的组合移液器需要在每个动作顺序中完成安装吸头、吸取试剂、挤出试剂、卸下吸头这一系列循环动作。组合移液器的加液臂是由四个单通道的移液器组成的，这四个单通道移液器之间的距离可调，可以同时动作，也可以分别控制，每个移液器都可以进行单独的控制。这套四通道移液器是固定在运动平台的机器臂上，该机械臂可在XYZ三个方向上进行自由移动。单通道移液器要求吸取溶液容量为20ml，每次挤出液体量为5ml,精度为20ul，这套组合移液器对单通道移液器的精度有着较高的要求。单通道移液器吸取溶液时液面检测功能的实现，要求在针管接触到液面时，能自动反馈信息，从而不出现空吸现象，也能控制深入液面的高度。这套组合移液器总体尺寸为400mm150mm350mm,四组单通道移液器尺寸为40mm65mm340mm。每组单通道移液器是由步进电机的驱动滚珠丝杠螺母副来实现吸取和挤出试剂的动作，它的理论精度小于5ul。四通道组合移液器的理论精度小于20ul。由步进电机驱动的T形丝杠螺母副和用来导向的滑块导轨共同作用可以实现对四个单通道移液器的间距进行调节，本文设计的调节范围为40-45mm。组合移液器的液面检测装置是由由吸头座、气管、气管接头和微差压传感器组成的，它能检测出的压差变化范围为-100Pa100Pa。不仅如此，组合移液器在每个循环的动作周期中，需要自动更换吸头，因此移液器与针头的自动装卸功能也是设计任务之一。本次设计要求完成以上功能的机械结构设计、运动控制部分的硬件设计和液面检测技术。其难点在于对具体实现所需功能装置的设计和液面检测方案的选用，并且在实现整体功能和满足一定精度要求的前提下，来控制整个组合移液器的总体尺寸大小以及来尽量减小四个单通道移液器之间的最短距离。

关键词：四通道移液器；装置结构设计；液面检测方案；运动控制硬件设计

DESIGN OF COMBINATORIAL PIPETTORS

Abstract

This article is devoted to the design and development of a kind of can automatically detect for meat and can draw relevant reagent combination of accurate quantitative liquid move. The combination of the designed pipetting device suction head need in each action in order to complete installation, absorbing reagent, extrusion reagents, unload suction this a series of circulation. Combination of moving fluid liquid arm is composed of four pipetting device consisting of a single channel, the four single channel liquid moving distance is adjustable, can move at the same time, also can control respectively, and each pipetting device can be controlled individually. The four-channel pipetting device is fixed on the motion platform of the machine arm, the mechanical arm can move freely in XYZ three directions. Single channel moves to the accumulator absorbing solution capacity of 20 ml, every time out liquid volume of 5 ml, accuracy of 20 ul, the combination pipetting device on the precision of the single channel pipetting device have higher requirements. Single channel to move when the liquid level detection function of accumulator absorbing solution implementation, in the needle when in contact with the liquid surface. The liquid combination move overall size is 400 mm150mm350mm, four groups of single channel is 40 mm65mm340mm pipetting device size.Each group of single channel pipetting device consists of stepper motor to drive the ball screw nut pair to drain and squeeze out reagent, its theoretical precision is less than 5 ul.Theory of four-channel combination pipetting accuracy is less than 20 ul.Driven by stepping motor T screw nut pair and used to guide slide block guide work together to achieve the four single channel pipetting device adjusted spacing, this paper design the adjusting range of 40-45 mm.Combination moving liquid level detection device is made by the suction head block, trachea, joints and micro differential pressure sensor, it can detect the pa100pa differential pressure changes in the range of - 100.Not only that, liquid combination move in the action of each loop cycle, need to change automatic suction head, automatic loading and unloading liquid so move with needles function is one of the design task.The design requirements to complete the above function of mechanical structure design, motion control part of the hardware design and the liquid level detection technology.The difficulty lies in the design of concrete realization function devices required and the selection of liquid level detection scheme, and in achieving the overall function and satisfy the premise of a certain accuracy requirement, to minimize the four single channel the shortest distance between the moving liquid receiver.

Keywords: four channel pipetting; Device structure design; Liquid level detection scheme; Motion control hardware design

目录

摘要 I

Abstract II

第一章 引言 1

1.1 选题背景及意义 1

1.2 目前研究现状 1

1.2.1 液面检测技术 1

1.2.2 微量移液机械结构 2

1.3 本课题设计任务和目标 3

第二章 组合移液器的机械结构设计 4

2.1 组合移液器整体结构设计 4

2.2.1 单通道移液器需要满足的功能和技术指标 5

2.2.2 微量移液机械结构 5

2.2.3 步进电机的型号选择 6

2.2.4 联轴器的型号选择 7

2.2.5单通道移液机构导杆设计校核 7

第三章 液面检测功能 9

3.1 气压法检测 9

3.2 压力变化 10

第四章 吸头自动安装与卸取的设计 12

4.1 吸头自动安装 12

4.2 吸头自动卸取 13

致 谢 17

参考文献 18

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