ece 640: intro to biomedical engineering
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
ECE 640: Intro to Biomedical Engineering
-Guruprasad A. Giridharan
Human Circulatory SystemThe HeartNatural Control
NervousHumoralLocal
Failing HeartWhy it happens?Effects
Why Model?Learning toolInexpensive research toolFirst step of device designPredict effects and deepen
understandingPlay GOD !! (idealizations,
assumption, know true values)
Modeling:Human Circulatory System
Utah Circulation Model (UCM)
Modeling AssumptionsPhysical parameters are linear and
lumpableBlood flow is influenced only by
pressure, resistance and complianceBlood is a Newtonian fluidIdeal valvesResistance and compliance remains
constant for any block (except heart)
Modeling: Active and Passive blocks
P= Pressure, V= Volume, C= Compliance, F= Flow rate,R=Resistance
Modeling:Human Circulatory System
Modeling:Valves
Modeling:Failing LH, during rest
Modeling:Failing LH, during exercise
Ventricular Assist DeviceWhat is a VAD
Axial & Centrifugal Flow VADsHow does it help?
VAD ControlObjectives
Adequate perfusionAvoiding SuctionLow rpm oscillationsSensor Issues
Previous strategies
©2000 MicroMed Technology, Inc
©2000 MicroMed Technology, Inc
The DeBakey/NASA VAD
VAD Model Equations & Assumptions
RPMTorqueFlow
Modeling:Ventricular Assist Device
Modeling:Ventricular Assist Device
J= Inertia of the rotor, Te= Motor Torque, Tp= Load Torque,= rpm, I= Amplitude of phase current, Fp= Pump Flow rate
Modeling:Model Integration
Modeling: Axial Flow VADModel Integration
Modeling:Model Integration
Modeling:Model Integration
ControlControl Objective
RPM constraint Why P setpoint ? Equations
PI VAD controllerSimulation Results
Control:Constraints and Objective function
Control:Control Schematic with 3 sensors
VAD Control:Weak LH, Centrifugal VAD, at rest
No VAD:Weak LH, during rest
Performance of the PI VAD Controller
Sensor IssuesRequired 3 sensors (2 pressure, 1
rpm)Pressure sensors unreliableData NoiseEstimate pressure using rpm and
currentExtended Kalman filter for estimation
1 Sensor (rpm sensor only)Weak LH with VAD, during rest
1 Sensor (rpm sensor only)Weak LH with VAD, during rest
Performance of the PI VAD Controller with P Estimator
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.
Design and In-vivo setup
Artificial VasculatureConcept Device
Outflow Cannula
Inflow Cannula
Transonic Inflow Probe
LV Pressure/VolumeCatheter
Transonic Outflow Probe
Transonic Coronary ArteryFlow Probe
IntramyocardialPressure Transducer
EmptyingInletValve
Outlet Valve Return
to Aorta
Linear Actuator
Artificial VasculatureConcept Device
To Power Supplyand Controller
FillingInletValve
Outlet Valve
From Aorta
Artificial Vasculature Device (AVD)
S.V
ArtificialValve
AorticValve
e
Left Heart
AVD
Aorta
FS
PS
Rref
FilterRact
FlowSensor
PressureSensorP
S
FS
Controller
Modeling of the AVD
Reduce resistance and increase cardiac output
Reducing Resistance
Controller action