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本文提出一种基于左心辅助的血液循环系统控制模型,该模型由左心血液循环系统和旋转式心脏泵模型耦合而成。考虑心脏泵的水力特性,根据泵相似性原理提出了新型旋转式心脏泵的数学模型。泵模型耦合心血管系统后采用七阶集总参数非线性空间状态方程表示,控制变量为电机转速。本文采用泵心脏舒张期最小流量变化斜率作为反馈机制,确保最大灌注量的同时避免抽吸。通过Matlab对模型进行仿真,结果显示在开环控制下,心衰患者的血液循环系统各项血液动力特性均有改善。当转速为9 000r/min时,经左心辅助的患者每搏心输出量由最初34mL/s提高至正常水平82mL/s,左心室压力-容积环向左偏移并且面积减小,说明辅助装置能够明显改善泵血不足并帮助心室卸载。若持续提高泵转速,当转速达到12 800r/min时,会发生抽吸异常状况,这是因为转速过高导致静脉回流量不足而形成的。经采用反馈控制后,系统可有效避免抽吸现象。本文研究结果表明,基于左心辅助的血液循环系统的控制模型能在确保足量灌注量的同时避免抽吸异常状态。该模型反映了左心辅助装置与心血管系统的交互作用,为左心辅助心衰治疗和生理控制策略设计提供理论依据。
This paper presents a control model of left ventricular-based circulatory system that is coupled by a left ventricular circulation system and a rotary heart pump model. Considering the hydraulic characteristics of the heart pump, a mathematical model of the new rotary heart pump is proposed according to the principle of pump similarity. The pump model is coupled to the cardiovascular system using a seven-order lumped parameter nonlinear state of the equation of state, with the control variable being the motor speed. In this paper, the pump diastolic minimum flow rate of change slope as a feedback mechanism to ensure maximum perfusion while avoiding suction. The model was simulated by Matlab and the results showed that the hemodynamic parameters of the circulatory system in patients with heart failure were improved under open-loop control. When the rotational speed of 9 000r / min, left cardiac support patients stroke volume output from the first 34mL / s to the normal level of 82mL / s, left ventricular pressure - volume ring to the left offset and the area decreases, indicating that auxiliary Device can significantly improve the lack of pumping blood and help unload the ventricle. If you continue to increase the pump speed, when the speed reaches 12 800r / min, suction abnormalities may occur, this is because the speed is too high resulting in insufficient venous return flow formed. After feedback control, the system can effectively avoid the phenomenon of suction. The results of this study show that the left heart-based control model of the blood circulatory system can ensure sufficient perfusion while avoiding aspiration abnormalities. The model reflects the interaction between the left cardiac accessory device and the cardiovascular system and provides a theoretical basis for the left heart-assisted heart failure treatment and physiological control strategy design.