Multi-objective Control Strategy And System Design Of Blood Pumps

As an important method for the treatment of severe heart failure,rotary blood pumps can effectively improve the hemodynamics of patients with heart failure.The assist function of blood pumps on patients with heart failure is limited by its control strategy and system design.Although the constant speed assist mode can achieve reliability,it may lead to pulsatility reduction which may complications and abnormal conditions such as suction and regurgitation during long-term use,and it never considers the influence of physiological state.In order to solve this problem,a rotary blood pump control system using multi-objective control strategy is established to meet the requirements of cardiac output,blood flow pulsatility,inhibition of suction and regurgitation through the study of coupled system including a blood pump and cardiovascular system.Numerical method,in vitro experiment and acute in vivo experiment are used to carry out the feasibility study of this system.The main contents are as follows.Based on the characteristics of the interaction between organs and tissues of cardiovascular system,the coupled model of rotary heart pump and blood circulation system is developed.The model is validated through the hemodynamic simulation of the coupled system in different physiological states.At the same time,taking the flow deviation as the control variable,the control strategy of real-time detection and suppression of suction regurgitation is put forward and a multi-objective variable speed physiological control system based on an adaptive fuzzy PI physiological controller is established.The system can monitor the hemodynamic parameters of heart failure with different levels and of different physiological states and meet the requirements of cardiac output,and detect and inhibit the suction regurgitation through the regulation of rotating speed.Firstly,the numerical data show that the cardiac output of the blood pump in the coupled system with multi-objective control strategy can reach 5.51L/min and the deviations of both aortic systolic pressure and aortic diastolic pressure from the healthy state are less than 3.3%,which can meet the perfusion need of patients with heart failure.In the resting and exercise state,the the aortic pulsatility in the coupled system using multi-objective control strategy is increased greatly,with a deviation of3% from healthy state and the cardiac output is increased by 30% and 22.96%differently,much higher than the constant speed control mode.Secondly,in vitro experimental results show that the control system can achieve multiple objectives including cardiac output,blood flow pulsatility,inhibition of suction and regurgitation.The control system can significantly increase the aortic flow and facilitate the unloading of left ventricle.When the speed is too higher and too lower,the control system can effectively detect and control the speed in real-time and inhibit the occurrence of suction and regurgitation.Finally,the animal model of heart failure is established by coronary artery ligation.Then the clinical reliability of the multi-objective control strategy is verified through in vivo experiments.The control system can realize the real-time monitoring of hemodynamic parameters through in vivo experiments of the blood pump in normal state and in heart failure state.In the experiment,the control system can detect suction and regurgitation and eliminate them by changing the speed.In addition,the test results of free hemoglobin and blood biochemical data show that the blood pump with multi-objective control strategy has good hemocompatibility and the functions of the liver and kidney animals are normal,which proves the reliability of the control system in vivo experiments.