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XIV Brazilian Automatic Control Conference 1 The Streamliner Artificial Heart Brad Paden University of California, Santa Barbara & LaunchPoint Technologies.

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Presentation on theme: "XIV Brazilian Automatic Control Conference 1 The Streamliner Artificial Heart Brad Paden University of California, Santa Barbara & LaunchPoint Technologies."— Presentation transcript:

1 XIV Brazilian Automatic Control Conference 1 The Streamliner Artificial Heart Brad Paden University of California, Santa Barbara & LaunchPoint Technologies LLC

2 XIV Brazilian Automatic Control Conference 2 Outline n n LVADs for artificial heart assist n n Background n n Next generation devices n n Design & Prototypes – –Actuators – –Sensor – –Control n n Commercialization

3 XIV Brazilian Automatic Control Conference 3 Need for Mechanical Circulatory Assist n n 15,000,000 heart disease deaths/yr. n n 5-10% could be saved with circulatory assist n n Several options: – –Transplant (limited supply) – –Ventricular assist device – –Total artificial heart (not needed in general)

4 XIV Brazilian Automatic Control Conference 4 Heart Transplants in the US 2500/yr 2000/yr 1500/yr 1000/yr 500/yr

5 XIV Brazilian Automatic Control Conference 5 Left Ventricular Assist Devices (LVAD) are the Leading Alternative to Transplants

6 XIV Brazilian Automatic Control Conference 6

7 7 Lumped-element model of the cardiovascular system

8 XIV Brazilian Automatic Control Conference 8 1st Generation LVADs are in use and are pulsatile

9 XIV Brazilian Automatic Control Conference 9 1st Generation Devices n n Increase 2-year survival from 8% to 23% in end-stage heart failure patients* n n 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

10 XIV Brazilian Automatic Control Conference 10 1st Generation (pulsatile) 2nd Generation (rotary) 3rd Generation (maglev)

11 XIV Brazilian Automatic Control Conference 11

12 12 Background on 3rd Generation LVADs n n Extracorporeal Prototypes (Olsen and Bramm, 1981; Allaire, Maslen, and Olsen, 1995; Chen et al, 1998) n n Implantable devices in animal trials (StreamLiner 1998, TCI/Sulzer 1999, Berlin Heart ?) n n Human Trials (Berlin Heart AG, June 16th 2002)

13 XIV Brazilian Automatic Control Conference 13 Utah/UVA Mag-Lev LVAD

14 XIV Brazilian Automatic Control Conference 14 Cleveland Clinic/Mohawk LVAD

15 XIV Brazilian Automatic Control Conference 15 LVAD Design Objectives n n Avoid mechanical shearing of the blood n n 6 Liters/min and 100 mmHg n n High reliability and efficiency – –… hence magnetic bearings n n low power n n ~10 g loading

16 XIV Brazilian Automatic Control Conference 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.

17 XIV Brazilian Automatic Control Conference 17 1st Streamliner Concept (HemoGlide 1)

18 XIV Brazilian Automatic Control Conference 18 Conical Bearing Prototype a wonderful 8x8, 10-state nonlinear multivariable control problem. Stabilized using static linear decouplers and and 5 SISO lead-lag controllers.

19 XIV Brazilian Automatic Control Conference 19 In a divergence-free electric field there are no stable equilibria for charged particles. Similarly for ideal permanent magnets in a static magnetic field. This is too complicated! Can we just use permanent magnets? Earnshaws Theorem (1842)

20 XIV Brazilian Automatic Control Conference 20 more formally…

21 XIV Brazilian Automatic Control Conference 21 Design Corollary: We cant use all permanent magnet levitation...

22 XIV Brazilian Automatic Control Conference 22 HG3 concept But we can eliminate all but one active axis...

23 XIV Brazilian Automatic Control Conference 23 JA Holmes Final Design

24 XIV Brazilian Automatic Control Conference 24 Section View and Final Device

25 XIV Brazilian Automatic Control Conference 25 Jarvik-7, Novacor LVAD, HG3b

26 XIV Brazilian Automatic Control Conference 26 HG3b Animal Trial (July 98) first fully maglev pump sufficiently compact and energy efficient for implantation

27 XIV Brazilian Automatic Control Conference Day Animal Trial (August 24, 1999)

28 XIV Brazilian Automatic Control Conference 28 Design Approach: Computer Modeling and Optimization

29 XIV Brazilian Automatic Control Conference 29 TOPOLOGY SELECTION FINITE ELEMENT MODEL LUMPED PARAMETER MODELS RAPID PROTOTYPE IMPLANTABLE PROTOTYPE OPTIMIZATION Design Procedure

30 XIV Brazilian Automatic Control Conference 30 Topology Selection (via design grammar) ( FH,AO) Sp - PRB-DCBM-ATB-PRB-Sp || || sb - ib - sb

31 XIV Brazilian Automatic Control Conference 31 Lumped-Element Modeling and Finite-Element Analysis n n Motor & Thrust Actuator – –Lumped reluctance analysis w/FEA-derived Correction Factors – –Some FEA optimization n n PM Bearings – –closed form solution of maxwells equations – –FEAanalysis n n Rotor – –rigid body model – –linear fluid damping n Controller, Actuator, Sensor –finite-dimensional models n Pump –Meanline Analysis –Empirical Formulae –Computational fluid dynamics (CFD)

32 XIV Brazilian Automatic Control Conference 32 PM Bearing Design

33 XIV Brazilian Automatic Control Conference 33 z

34 XIV Brazilian Automatic Control Conference 34 z

35 XIV Brazilian Automatic Control Conference 35

36 XIV Brazilian Automatic Control Conference 36 PM Bearing Model

37 XIV Brazilian Automatic Control Conference 37 Motor Design ROTOR STATOR

38 XIV Brazilian Automatic Control Conference 38 Motor Parameterization R5 = R3 = R4 = 9.58 Ls =14.66 W1 = 3.73

39 XIV Brazilian Automatic Control Conference 39 Motor Optimization N = 5000 RPM = 85% P = 4W V = N = RPM V = 11.0 N = RPM V = 12.4 = 95% V = 40.2 = 90% V = 20.3 P = 16W V = 20.8 P = 8W V = 18.2

40 XIV Brazilian Automatic Control Conference 40 Motor redesign and re-optimization to reduce radial instability

41 XIV Brazilian Automatic Control Conference 41 Pump Design (CFD) (James Antaki & Greg Burgreen)

42 XIV Brazilian Automatic Control Conference 42 Final impeller design 5 impeller blade refinements 4 internal flow path refinements 6 aft stator blade refinements 18 month development effort

43 XIV Brazilian Automatic Control Conference 43 Flow visualization of early design

44 XIV Brazilian Automatic Control Conference RPM Hydrodynamic performance Efficiency PRESSURE mm-Hg FLOW RATE (LPM)

45 XIV Brazilian Automatic Control Conference 45 Control system design Linear actuator with optimized force/watt 1/2 Virtual Zero Power (VZP) axial control (1.5W coil power while pumping) Ultra low-noise eddy-current sensors Sensorless Motor Control

46 XIV Brazilian Automatic Control Conference 46 LPF + Voltage Sense Amp 1 MHz Osc. Current Driver s-a s+b (-90 deg) V(x) L(x) x C 1/(2 (L(x 0 )C) ½ ) = 1MHz -90º90º offset adjust mixer Sensor System

47 XIV Brazilian Automatic Control Conference 47 KaKa (Ms 2 -K b ) -1 KsKs K p +K d s K i /s impeller axial disturbance force - PID Controller Linear Motor ~2 N/ root watt Rotor Mass & Bearing Negative Stiffness Eddy-Current Sensor Pos. Reference = 0 PID Controller Structure (for reference only) coil current force displacement noise ~1Å / root Hz heat

48 XIV Brazilian Automatic Control Conference 48 KaKa (Ms 2 -K b ) -1 KsKs K p +K d s K i /s impeller axial disturbance force - VZP Controller Linear Motor ~2 N/ root watt Rotor Mass & Bearing Negative Stiffness Eddy-Current Sensor current reference = 0 Virtual Zero Power (VZP) Controller Structure* coil current force displacement noise ~1Å / root Hz less heat s(K p +K d s) K i K p +(1-K d K i )s Anti-windup included * J. Lyman, Virtually zero powered magnetic suspension, US Pat. 3,860,300, 1975.

49 XIV Brazilian Automatic Control Conference 49 Axial Disturbance Force 4 Newtons

50 XIV Brazilian Automatic Control Conference August 1999 Streamliner HG3C sn001 pre-implant What is next?

51 XIV Brazilian Automatic Control Conference 51 Commercialization n n 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 n n Moved to a centrifugal pump design to maximize efficiency

52 52 Optimized Clinical HeartQuest VAD Height : 34.7 mm Diameter: 76.4 mm Weight: 550 grams

53 XIV Brazilian Automatic Control Conference 53 Conclusions n n 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) n n Physiologic control is next... – –Responsive to condition of heart and body

54 XIV Brazilian Automatic Control Conference 54 Streamliner Team n 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 n n Fluids/Biological – –James Antaki, Streamliner Director – –Greg Burgreen, CFD – –Jon Wu, exp. fluids – –Marina Kameneva, blood damage – –Phil Litwak, veterinary surgery – –Bartley Griffith, surgery n Funding –McGowan Foundation

55 XIV Brazilian Automatic Control Conference 55 MedQuest Products Team n Mechatronics –Brad Paden, & Garrick McNey,control engineering –Jed Ludlow, dynamics –Chung-Ming Li, electronics –Dirk Cooley, electronics –Dave Paden, Mechanical –Randy Crowsen, Mechanical n n Fluids/Biological – –James Antaki, LVAD design – –Jon Wu, exp. fluids – –Gordon Jacobs, experimental – –Jim Long, surgery – –Don Olsen, veterinary surgery n Business –Pratap Khanwilkar, CEO –Tim Walker, Marketing n Funding –NIH –Venture Capital

56 XIV Brazilian Automatic Control Conference 56 The End


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