1. The Streamliner Artificial Heart
Brad Paden
University of California, Santa Barbara
& LaunchPoint Technologies LLC
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Outline
LVAD’s for artificial heart assist
Background
Next generation devices
Design & Prototypes
Actuators
Sensor
Control
Commercialization
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3. Need for Mechanical Circulatory Assist
15,000,000 heart disease deaths/yr.
5-10% could be saved with circulatory assist
Several options:
Transplant (limited supply)
Ventricular assist device
Total artificial heart (not needed in general)
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4. Heart Transplants in the US
2500/yr
2000/yr
1500/yr
1000/yr
500/yr
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Left Ventricular Assist Devices (LVAD) are the Leading Alternative to Transplants
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7. Lumped-element model of the cardiovascular system
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8. 1st Generation LVADs are in use and are pulsatile
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9. 1st Generation Devices
Increase 2-year survival from 8% to 23% in end-stage heart failure patients*
Issues remain:
Thrombus (clot) formation,
Mechanical reliability.
Energy efficiency.
*Rose et al, “Long-term use of a left ventricular assist device for end-stage
heart failure,” The New England Journal of Medicine, Vol 345(20), 2001
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10. 1st Generation (pulsatile)
2nd Generation (rotary)
3rd Generation (maglev)
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12. Background on 3rd Generation LVADs
Extracorporeal Prototypes (Olsen and Bramm, 1981; Allaire, Maslen, and Olsen, 1995; Chen et al, 1998)
Implantable devices in animal trials (StreamLiner 1998, TCI/Sulzer 1999, Berlin Heart ?)
Human Trials (Berlin Heart AG, June 16th 2002)

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Utah/UVA Mag-Lev LVAD
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14. Cleveland Clinic/Mohawk LVAD
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15. LVAD Design Objectives
Avoid mechanical shearing of the blood
6 Liters/min and 100 mmHg
High reliability and efficiency
… hence magnetic bearings
low power
~10 g loading
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16. Shear-Induced Hemolysis: a design constraint
L.B. Leverett et al, “Red Blood Cell Damage by Shear Stress,”
Biophysical Journal, Vol. 12, pp , 1972.
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17. 1st Streamliner Concept (HemoGlide 1)
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Conical Bearing Prototype a wonderful 8x8, 10-state nonlinear multivariable control problem. Stabilized using static linear decouplers and and 5 SISO lead-lag controllers.
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This is too complicated!
Can we just use permanent magnets?
Earnshaw’s Theorem (1842)
In a divergence-free electric field there are no stable
equilibria for charged particles.
Similarly for ideal permanent magnets in a
static magnetic field.
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more formally…
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Design Corollary:
We can’t use all permanent magnet levitation...
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22. HG3 concept But we can eliminate all but one active axis...
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Final Design
JA Holmes
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24. Section View and Final Device
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25. Jarvik-7, Novacor LVAD, HG3b
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HG3b Animal Trial (July ‘98) first fully maglev pump sufficiently compact and energy efficient for implantation
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34 Day Animal Trial
(August 24, 1999)
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28. Design Approach: Computer Modeling and Optimization
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29. Design Procedure XIV Brazilian Automatic Control Conference
TOPOLOGY SELECTION
LUMPED PARAMETER MODELS
FINITE ELEMENT MODEL
OPTIMIZATION
RAPID PROTOTYPE
OPTIMIZATION
IMPLANTABLE PROTOTYPE
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30. Topology Selection (via design grammar)
(FH,AO) Sp - PRB-DCBM-ATB-PRB-Sp
|| ||
sb ib sb
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31. Lumped-Element Modeling and Finite-Element Analysis
Motor & Thrust Actuator
Lumped reluctance analysis w/FEA-derived Correction Factors
Some FEA optimization
PM Bearings
closed form solution of maxwell’s equations
FEAanalysis
Rotor
rigid body model
linear fluid damping
Controller, Actuator, Sensor
finite-dimensional models
Pump
Meanline Analysis
Empirical Formulae
Computational fluid dynamics (CFD)
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PM Bearing Design
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PM Bearing Model
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Motor Design
STATOR
ROTOR
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38. Motor Parameterization
Ls =14.66
W1 = 3.73
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Motor Optimization 4 6 2 1
h = 90%
V = 20.3
N = RPM
V = 12.4
P = 8W
V = 18.2 5 7 3
N = 5000 RPM
h = 85%
P = 4W
V = 16.1
N = RPM
V = 11.0
h = 95%
V = 40.2
P = 16W
V = 20.8
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40. Motor redesign and re-optimization to reduce radial instability
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41. Pump Design (CFD) (James Antaki & Greg Burgreen)
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Final impeller design
5 impeller blade refinements
4 internal flow path refinements
6 aft stator blade refinements
18 month development effort
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43. Flow visualization of early design
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44. Hydrodynamic performance
Efficiency
0.16
0.15
0.14
0.13
0.12
0.11
0.10
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
PRESSURE mm-Hg
8000 RPM
FLOW RATE (LPM)
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Control system design
Linear actuator with optimized force/watt1/2
Virtual Zero Power (VZP) axial control
(1.5W coil power while pumping)
Ultra low-noise eddy-current sensors
Sensorless Motor Control
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Sensor System
1 MHz
Osc.
(-90 deg) -1
Current
Driver
s-a
s+b
-90º
90º
Voltage
Sense Amp
LPF
V(x) +
offset
adjust
mixer x
L(x)
1/(2(L(x0)C) ½) = 1MHz C
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47. PID Controller Structure
(for reference only)
impeller axial
disturbance force
heat
Eddy-Current
Sensor Ka
(Ms2 -Kb )-1 Ks
force
displacement
Linear Motor
~2 N/ root watt
Rotor Mass &
Bearing Negative Stiffness
Pos. Reference
= 0
noise
~1Å / root Hz -
Kp+Kd s
coil current
PID Controller
Ki/s
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48. Virtual Zero Power (VZP) Controller Structure*
impeller axial
disturbance force
less
heat Ka
(Ms2 -Kb )-1 Ks
force
displacement
Eddy-Current
Sensor
Linear Motor
~2 N/ root watt
Rotor Mass &
Bearing Negative Stiffness
noise
~1Å / root Hz
current
reference = 0
Kp+Kd s
coil current -
s(Kp+Kd s)
Ki/s
Ki Kp +(1-Kd Ki)s
Anti-windup included
VZP Controller
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*J. Lyman, “Virtually zero powered magnetic suspension,” US Pat. 3,860,300, 1975.

49. Axial Disturbance Force
4 Newtons
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19 August 1999
Streamliner HG3C sn001
pre-implant
What is next?
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Commercialization
Teamed with MedQuest Products Inc, Salt Lake City, Utah.
commercially competitive engineering, clinical, and business team.
a large maglev patent portfolio and has acquired the Streamliner patents
Moved to a centrifugal pump design to maximize efficiency
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52. Optimized Clinical HeartQuest™ VAD
Height : 34.7 mm
Diameter: 76.4 mm
Weight: 550 grams

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Conclusions
Control engineers have much to offer
System optimization is at the center of the design process
The language of mathematics, objectives and constraints is essential
Clever control design makes low-power maglev possible (Lyman Patent 1975)
Physiologic control is next...
Responsive to condition of heart and body
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Streamliner Team
Mechatronics
Brad Paden, Control engineering
Chung-Ming Li, Analog Design
Tom Dragnes, Electrical
Dave Paden, Mechanical
Randy Crowsen, Mechanical
Lina Arbelia, bio-coatings
Nelson Groom, mag-lev
Fluids/Biological
James Antaki, Streamliner Director
Greg Burgreen, CFD
Jon Wu, exp. fluids
Marina Kameneva, blood damage
Phil Litwak, veterinary surgery
Bartley Griffith, surgery
Funding
McGowan Foundation
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55. MedQuest Products Team
Business
Pratap Khanwilkar, CEO
Tim Walker, Marketing
Mechatronics
Brad Paden, & Garrick McNey,control engineering
Jed Ludlow, dynamics
Chung-Ming Li, electronics
Dirk Cooley, electronics
Dave Paden, Mechanical
Randy Crowsen, Mechanical
Fluids/Biological
James Antaki, LVAD design
Jon Wu, exp. fluids
Gordon Jacobs, experimental
Jim Long, surgery
Don Olsen, veterinary surgery
Funding
NIH
Venture Capital
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The End
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