大间隙磁力驱动血泵调速控制及在线检测系统研究

【作者】 刘恒拓；

【导师】 谭建平；

【作者基本信息】 中南大学 ， 机械电子工程， 2011， 硕士

【摘要】 随着计算机通信技术的高速发展,上位机监控技术在国内外已经得到了深入研究和广泛应用。本文以国内外步进电机调速控制研究为背景,针对在目前外磁血泵调速控制领域内机理性研究尚少的现象,分析探讨了多种适用于轴流式血泵升速过程的调速模型,并以VB6.0作为软件控制平台对调速模型分别进行求解和离散,获得相应地调速控制参数,再通过上位机串行通信技术实时将参数传递给单片机,最终实现了对血泵升速过程的曲线规划控制。此外,针对目前外磁驱动实验系统存在人为工作量大、智能化控制程度不高和在线检测技术不完善等问题,利用上位机与智能仪表或单片机的串行通信技术,建立基于VB6.0的上位机在线检测系统,并根据温度和流量等采集信号的特点采取了相应的数字滤波方法进行滤波分析处理,能够满足系统检测要求。本文主要研究内容如下：1.根据PC机与单片机AT89S52、PC机与智能涡轮流量计之间串口通信数据对象本身的特点,规定了不同的通信协议,设计了不同的数据帧结构,在通信过程中采用按序轮询的方法保证数据结构的紧凑性和完整性。2.以VB6.0为控制分析平台,提出了轴流式血泵调速控制参数求解公式,并建立了由三种初始条件参数控制的基本曲线法模型和血泵三段S曲线升速模型,通过上位机离散获得相应的调速控制参数,可满足系统各种实验研究需求。3.基于血泵动力学模型,利用标准四阶龙格库塔算法求解和分析模型,得到相应的时域曲线和转速稳定点的分布情况,并提出了基于埃尔米特插值算法原理的等分时间法和等分转速法等两种离散方法,最后给出了血泵调速控制具体实现方法,达到了可控性强和精确性高等目的。4.基于数字传感器DS18B20与单片机AT89S52组成的测温电路,建立上位机温度采集系统；建立以LWGY-15C智能涡轮流量计为核心的上位机流量检测采集系统,利用ADO对象访问ACCESS数据库,实现对数据的操作与处理。整个系统在线检测设计研究达到了采集可靠、功能完善和可控性强等目的。5.搭建了大间隙磁力驱动系统检测实验装置,进行了基本曲线法和血泵三段S曲线法等调速模型驱动性能比较实验,结果表明了在相同条件下S曲线调速模型在快速性和平稳性方面更优；对电磁体内的硅钢片进行了温度测量实验和血泵出口流量检测采集实验,得到相应的采集数据与曲线,并对采集信号做了相应滤波分析,利用累积示值法整体上分析流量检测精度为5%以内,验证了上位机系统的可行性,提供了可借鉴的在线检测手段和方法。更多还原

【Abstract】 With the rapid development of computer communication technology, the host computer monitoring technology at home and abroad has been thoroughly studied and widely used. In this paper, it takes the speed control research of step motor at home and abroad as a research background, for the problem that the mechanistc study in the field of speed control of the blood pump is still little, analyzes and discusses a varity of speed control models which suitable to the speed increaing of the axial flow blood pump, and takes VB6.0 as a softwore control platform to solve the speed models,and discrete these models to acquire speed control parameters,then through the PC serial communication to pass parameters to the microcontroller in real time,and utilmately realizes the speed curves’planning.In addition, for the current experimental system exists outside the human workload, low level of intelligent control and on-line detection imperfect, using the serial communication between PC and intelligent instrument or SCM, establishes the host computer line detection system based on VB6.0. And in accordance with the features of temperature and flow, it takes the appropriate digital filter to do the signals filter analysis and processing,which can meet the system’s requirements. The main research contents are introduced as following:1. According to the characteristics of the data object of serial communication between PC and MCU AT89S52, PC and the Turbine Flow Meter, provides different communication protocols, designed a different data frame structure.In the communication process, sequential polling method is used to ensure the data structure integrity and compact.2. In the VB6.0 platform for control analysis, it proposes a general formula for solving speed control parameters of axial flow blood pump. It establishes basic curve model and a three sections S-curve speed-rising-control model controlled by three initial conditions parameters. Speed control parameters are obtained by discrete solution through host computer for more research.3. Based on the dynamics model of blood pump, Runge-Kutta algorithm is used to solve and analysis the model and the result that time-domain curves are obtained and the distribution of the stable point of speed has gotten. Based on the principle of Hermite interpolation, two discrete methods are proposed such as equal time law and equal speed law. Finally, the specific method of blood pump speed control is realized to achieve the purposes in strong controllable and higher accuracy.4. Based on the temperature measurement circuit making up of digital sensor DS18B20 and AT89S52, a temperature acquisition system is established. And it establishes flow acquisition system in the host computer which takes LWGY-15C Turbine Flow Meter as the core. Using ADO object accesses to ACCESS database to implement the operation and treatment of the data. The entire detection system has achieved acquisition reliable, functional and strong controllable.5. It built detection experimental device of a large gap magnetic drive system. Drive performance of the speed control models such as the Baisc Curve law and Blood Pump Three-sections S-Curve law are compared by test,and proves that the S-curve is better.Measurement temperature of the silicon steel sheet inside electromagnet and outlet flow of blood pump acquisition experiments have been done to get the warming curves, instantaneous and cumulative flow curve in the different speed. Acquired signals have been through filter analysis, and accuracy of flow measurement has been analyzed. Using the cumulative method of indication of the overall flow measuring accuracy of less than 5%.It demonstrates the feasibility of the host computer system, and provides valuable tools and methods in detection.更多还原