基因测序仪运动平台的高精度定位控制

High-precision position control of a gene sequencer motion stage

为了实现对基因测序仪运动平台的高精度定位控制,建立了基因测序仪运动平台控制系统。对该系统所采用的数学建模、模型辨识、控制器设计、输入整形等方法进行研究。根据运动平台动力学方程和永磁同步直线电机电压-推力关系构建了运动平台数学模型,利用频域扫描法在实物实验的基础上辨识出运动平台的模型参数。最后,基于运动平台模型设计了双闭环控制器和前馈控制器组成的复合控制器来保证运动平台的稳定性和高精度,同时根据整个系统的主导极点设计了输入整形器以抑制运动平台的残余振荡。实验结果表明:加入了输入整形的复合控制器将运动平台的稳态重复定位精度从±1.47μm提高到±0.354μm。较传统复合控制器,本文提出的方法能使基因测序仪运动平台更快进入可用重复定位精度范围,并基本满足基因测序仪采集图像时所需的稳定性强、精度高等要求。

To realize high precision position control of a gene sequencer motion stage,a gene sequencer motion stage control system was developed,and its applied methods such as mathematical modeling,model identification,controller design,and input shaping were investigated.First,based on the dynamic equation of the motion stage and the voltage-force relationship of a permanent magnet linear synchronous motor,a model of the motion stage was established.Then the method of frequency domain scan was adopted to determine the model parameters.Finally,a compound controller,combined with a double closed loop controller and forward feedback controller,was designed based on the model of motion stage to ensure stability and high precision of the motion stage,and an input shaper was designed based on the dominant pole of the compound control system to eliminate oscillation in the motion stage.Experimental results indicate that the compound controller with the input shaping improves the repeated positioning accuracy of the motion stage from±1.47μm to±0.354μm.The proposed design allows the motion stage to achieve the ultimate repeated positioning accuracy faster than the conventional compound controller,and satisfies the requirements of high stability and precision when the gene sequencer generates an image.