The Cardiovascular System Modeling And Control Strategy Based On Left Ventricular Assist

In today’s society,heart failure has become one of the main threats to human health.transplantation as the only solution at the end of disease,but the donor heart has been in short supply in the most of time.Therefore,design a ventricular assist device which plays a transitional role in the recovery or waiting for donor is particularly important.Ventricular assist devices is a machinery equipment used to maintain the normal needs of the human body which rely on replace some or all of the heart to complete organ perfusion.In the course of research need to do lots of experiments,while direct use the ani-mal experiment and human body experiment,which is not only time-consuming,but also has many limitations and differences.Through modeling building and simulation,we can study the value and change trend of cardiovascular hemodynamic parameters in an intuitive and detailed way.Provide the basis for diagnosis and research for medical research.The main contents of this paper are as follows:(1)A lumped parameter model of the equivalent electric network is proposed based on the analogy between the fluid network theory and the electric network theo-ry.Then build the mathematical model in MATLAB/Simulink and do the correspond-ing simulation,given the hemodynamic results of normal cardiovascular system and diastolic heart failure、systolic heart failure、mixed failure 、peripheral heart failure.From the numerical analysis can obtain the changing tendency of hemodynamic para-meters such as cardiac output,blood pressure and blood flow etc.which is effects by the physiological parameters such as peripheral resistance and compliance etc.To validity the results by compared with the actual results.(2)Give the parallel model of cardiovascular system and blood pump,simulate the arterial blood is provide by both the left ventricular and ventricular assist devece.Build simulation model to study the influence of dynamic characteristics of bloodpump to the parameters of cardiovascular system value.and to control the pump spee-d increases linearly to discuss the influences of pump speed to the blood output of blood pump,to find the critical point of aspiration,and limited to a certain range of speed.The maximum and minimum values of the rotational speed are the critical valu-es for the occurrence of suction and reflux.(3)In order to study the effect of pump speed on the output of the pressure and blood flow of the Ventricular assist device,then used to study the effects of cardiovas-cular system from the aspects such as blood flow,mean arterial pressure,pulse press-ure difference and ventricular unloading degree.Chose the mean pressure difference between the aorta and the left ventricle as the reference,the fuzzy PID controller and dynamic adaptive sliding mode controller are designed to control the speed of the blood pump.Given the model to verify the effect of the controller,achieved that the average pressure difference between the aorta and left ventricle is about 75 mm Hg,the average aortic pressure is about 100 mm Hg,the pulse pressure difference is not less than 20 mm Hg,the blood flow is about 5L / min,and the ventricle is partial un-loading which in the absence of suction and reflux,and get the desired results.