Study On The Physiological Controller Of The Rotary Blood Pumps Based On The Mock Circulation System

Blood pump has been an alternative therapy for heart failure patients.It is a device which can temporarily or permanently substitute the heart function and derive the circulation of blood.This study focuses on the research of physiological control strategy and vitro test system.The system is used to evaluate the performance of the blood pump while the strategy is used to improve the performance of the blood pump.In this paper,a physiological control of rotary blood pump based on BP neural network is used to control the blood pump speed and is verified in the blood circulation system model and in the vitro test system respectively.Main research work of the thesis is as follows:(1)A lumped parameter model of blood circulation system is built.A blood circulation system mathematical model is built in the MATLAB/Simulink,according the corresponding mathematical formula of the ventricle,atrium,valves and so on.The model provides a numerical platform for the physiological control strategy and the vitro test of the blood pump.(2)A model is built,which the cardiovascular system and the blood pump can be coupled.And a physiological controller of rotary blood pumps based on BP neural networks has been proposed,which realizes the adaptive adjustment of the controller while the states of the recipients are changing.Choosing the mean arterial pressure as the control object,the controller optimizes the PID parameters of the blood pump controller online when the physiological state of the circulatory system changes.Then this method is verified on the mathematical model of blood circulation system.The result shows that in all of the cases the mean arterial pressure is stabilized at 100 mmHg after about 150 s since the controller takes effect.The BP neural network based controller could overcome the disturbances well when physiological states change,exhibiting good effectiveness of the control method.(3)Vitro experiment platform based on blood circulation system for assessment of the left ventricular assist is built to carry out experimental research on the influence of the blood circulation system dynamics.The experiment simulates human different physiological states to achieve the measurement of the aortic pressure under different conditions which include the normal,heart failure and controller assistance,to verify the feasibility of the PID controller based on BP neural network.This result shows that the effects of the left ventricular assist device on hemodynamics are consistent with the numerical results.