左心室辅助装置磁悬浮技术研究

发布时间：2018-12-08 14:34

【摘要】：心力衰竭是人类面临的最具挑战性的心血管疾病，每年夺走全球数十万人的生命。对于终末期心衰，心脏移植是现今最有效的治疗手段，但是自然心脏供体的数量难以满足日益增长的临床需要。人工心脏是以机械装置的方式将血液输送到人体的循环系统中，来辅助或代替自然心脏的泵血功能。心衰患者大多数表现为左心室功能的衰竭，很多患者只需要进行左心室的辅助治疗，就能够有效度过心脏移植手术的等待期，甚至心肌功能逐渐恢复正常。因此，左心室辅助装置是人工心脏研究领域的一个重要分支，被视为未来人工心脏的主要研究对象。磁悬浮技术以其非接触、无摩擦、寿命长等优点，很好地减少早期左心室辅助装置中因机械磨损引起的血栓、溶血以及发热等一系列问题，将磁悬浮技术应用到左心室辅助装置是当前一个新兴的研究方向。国际上针对磁悬浮左心室辅助装的研究取得了长远的发展，已经有少量的产品应用到临床试验中，但都是以主动加被动的方式或是被动的方式实现悬浮，并非在五个自由度上实现主动全磁悬浮。本文提出了以DSP为核心控制器的主动全磁悬浮左心室辅助装置的设计，整个系统由位移传感器、数字控制器、功率放大器、电磁铁、转子五个部分组成。数字控制器DSP采集位移传感器输出的转子位移信号，通过改进型PID控制算法输出控制信号，经由功率放大器放大后输出到电磁铁中控制转子稳定悬浮。本文在论述了左心室辅助装置的发展背景和研究现状的基础上，阐明了课题研究的意义。在此基础上，论文主要完成了一下工作： (1)对磁悬浮左心室辅助装置进行了基础理论和工作原理的分析介绍，根据左心室辅助装置的结构，设计加工了实验用的部分机械零件。建立了磁悬浮转子单自由度数学模型，通过对模型的分析得到了系统的等效传递函数。 (2)针对磁悬浮左心室辅助装置的结构及性能要求，设计选型了DSP数字控制器及其外围硬件电路，TMS320F2812以其高速的数据处理能力、快速的中断响应以及丰富的外设资源能够很好的满足控制系统的处理要求。 (3)本文重点分析研究了几种改进型的PID控制算法，并使用MATLAB仿真对比分析，凸显该种改进PID的优点；结合磁悬浮转子的动态特性，提出了将积分分离和带死区的数字PID控制算法相结合的控制策略。 (4)在实验平台上，测量了转子在不同转速下振动位移，并使用MATLAB分析了转子的动态特性，为后续研究提供了数据支持。
[Abstract]:Heart failure is the most challenging cardiovascular disease that kills hundreds of thousands of people every year. Heart transplantation is the most effective treatment for end-stage heart failure, but the number of natural heart donors is difficult to meet the increasing clinical needs. Artificial heart is a mechanical way to transport blood to the circulatory system of the human body to assist or replace the pump function of the natural heart. The majority of patients with heart failure are left ventricular failure, many patients only need to carry out the left ventricular adjuvant therapy, can effectively survive the waiting period of heart transplantation, and even gradually return to normal myocardial function. Therefore, left ventricular assistive device is an important branch of artificial heart research field, and is regarded as the main research object of artificial heart in the future. Magnetic levitation technology, with its advantages of non-contact, non-friction, long life, and so on, can reduce a series of problems such as thrombosis, hemolysis and fever caused by mechanical wear in early left ventricular assistive devices. The application of magnetic levitation technology to left ventricular assistive devices is a new research direction. The research on magnetic levitation left ventricular accessory device has made long-term development in the world. A small number of products have been used in clinical trials, but they are realized in active and passive way or passive way. Active magnetic levitation is not realized at five degrees of freedom. This paper presents the design of an active magnetic levitation left ventricular auxiliary device with DSP as the core controller. The whole system consists of five parts: displacement sensor, digital controller, power amplifier, electromagnet and rotor. The digital controller DSP collects the rotor displacement signal from the displacement sensor, outputs the control signal through the improved PID control algorithm, and outputs the control signal to the electromagnet to control the rotor stable suspension after amplification by the power amplifier. In this paper, the development background and research status of left ventricular assistive devices are discussed, and the significance of the research is clarified. On this basis, the thesis mainly completes the following work: (1) the basic theory and working principle of the magnetic levitation left ventricular assist device are analyzed and introduced, according to the structure of the left ventricular assist device, Some mechanical parts used in experiment are designed and processed. The single degree of freedom mathematical model of maglev rotor is established, and the equivalent transfer function of the system is obtained by analyzing the model. (2) according to the structure and performance requirements of the magnetic levitation left ventricular auxiliary device, the DSP digital controller and its peripheral hardware circuit are designed and selected. The TMS320F2812 has the high speed data processing ability. Fast interrupt response and abundant peripheral resources can meet the requirements of the control system. (3) several improved PID control algorithms are analyzed and studied in this paper, and the advantages of the improved PID are highlighted by MATLAB simulation. Combined with the dynamic characteristics of maglev rotor, a control strategy combining integral separation with digital PID control algorithm with dead time is proposed. (4) on the experimental platform, the vibration displacement of the rotor at different rotational speeds is measured, and the dynamic characteristics of the rotor are analyzed by using MATLAB, which provides data support for further research.
【学位授予单位】：中南民族大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R318.6;TP273

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