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ECE 640: Intro to Biomedical Engineering. -Guruprasad A. Giridharan. Human Circulatory System. The Heart Natural Control Nervous Humoral Local Failing Heart Why it happens? Effects. Why Model?. Learning tool Inexpensive research tool First step of device design
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ECE 640: Intro to Biomedical Engineering -Guruprasad A. Giridharan
Human Circulatory System • The Heart • Natural Control • Nervous • Humoral • Local • Failing Heart • Why it happens? • Effects
Why Model? • Learning tool • Inexpensive research tool • First step of device design • Predict effects and deepen understanding • Play GOD !! (idealizations, assumption, know true values)
Modeling:Human Circulatory System Utah Circulation Model (UCM)
Modeling Assumptions • Physical parameters are linear and lumpable • Blood flow is influenced only by pressure, resistance and compliance • Blood is a Newtonian fluid • Ideal valves • Resistance and compliance remains constant for any block (except heart)
Modeling:Valves P P 1 2
Ventricular Assist Device • What is a VAD • Axial & Centrifugal Flow VADs • How does it help? • VAD Control • Objectives • Adequate perfusion • Avoiding Suction • Low rpm oscillations • Sensor Issues • Previous strategies
Modeling:Ventricular Assist Device • VAD Model • Equations & Assumptions • RPM • Torque • Flow
Control • Control Objective • RPM constraint • Why P setpoint ? • Equations • PI VAD controller • Simulation Results
Sensor Issues • Required 3 sensors (2 pressure, 1 rpm) • Pressure sensors unreliable • Data Noise • Estimate pressure using rpm and current • Extended Kalman filter for estimation
Artificial Vasculature Device (AVD) • Conceptual recovery directed device. • No damage to the left ventricle. • Ability to alter the impedence seen by the LV. • Increase coronary perfusion by counter-pulsation.