Claims
- 1. A method for controlling an axial flow rotary blood pump, comprising:
establishing a normal operating range of the blood pump, said normal operating range comprising a normal pump flow range and a normal pressure head range; setting a target rotational speed of said pump in accordance with said normal operating range; determining a current operating condition of the blood pump, said current operating condition comprising a current pump flow, a current pressure head, and a current rotational speed of said pump; comparing the current operating condition with the normal operating range; selecting an appropriate control algorithm from a plurality of available control algorithms based on said comparison; and adjusting the target rotational speed of said pump using said selected control algorithm to maintain or recover said normal operating range.
- 2. A method in accordance with claim 1, wherein:
said rotary blood pump is used as one of a left ventricular assist device or a right ventricular assist device.
- 3. A method in accordance with claim 1, wherein:
measurements of said current pump flow, said current pressure head, and said current rotational speed are used to determine the current operating condition.
- 4. A method in accordance with claim 3, wherein said current pump flow, said current pressure head, and said current rotational speed are measured by one or more sensors.
- 5. A method in accordance with claim 4, wherein said one or more sensors are implantable sensors.
- 6. A method in accordance with claim 1, wherein:
establishing said normal operating range comprises establishing a target operating point for the target rotational speed of the pump which provides a target pump flow and a target pressure head; said normal pump flow range is within a 20% deviation from said target pump flow; and said normal pressure head range is within a 25% deviation from said target pressure head.
- 7. A method in accordance with claim 1, wherein during said normal operating range:
a normal operating condition control algorithm is selected; and said target rotational speed of said pump is maintained by applying proportional and derivative gain control to said pump.
- 8. A method in accordance with claim 7, wherein said proportional and derivative gain control is applied in accordance with the formula:
- 9. A method in accordance with claim 8, wherein:
Kp is set to approximately 0.02; and Kd is set to approximately 0.05.
- 10. A method in accordance with claim 1, wherein in the event that the current operating condition is above said normal operating range:
a first abnormal operating condition control algorithm is selected; and the target rotational speed is decreased until the normal operating range is recovered.
- 11. A method in accordance with claim 10, wherein the target rotational speed is decremented by x rpm every t seconds until said normal operating range is recovered.
- 12. A method in accordance with claim 11, wherein:
x is approximately 600 rpm; and t is approximately 5 seconds.
- 13. A method in accordance with claim 1, wherein in the event that the current operating condition is below said normal operating range:
a second abnormal operating condition control algorithm is selected; and the target rotational speed is increased until the normal operating range is recovered.
- 14. A method in accordance with claim 13, wherein the target rotational speed is incremented by x rpm every t seconds until said normal operating range is recovered.
- 15. A method in accordance with claim 14, wherein:
x is approximately 600 rpm; and t is approximately 5 seconds.
- 16. A method in accordance with claim 13, wherein a suction condition exists in the event that the normal operating range is not recovered by increasing said target rotational speed, and in the event of such a suction condition;
a suction condition control algorithm is selected; the suction condition is released by continuously decreasing the target rotational speed of the pump to obtain a pump flow free from suction and free from overpumping; and once said suction condition is released, the target rotational speed of the pump is gradually increased to recover said normal operating range.
- 17. A method in accordance with claim 16, wherein:
when releasing the suction condition, the target rotational speed is continuously decremented by x1 rpm every t seconds; and once the suction condition is released, the target rotational speed is continuously incremented by x2 rpm every t seconds.
- 18. A method in accordance with claim 17, wherein:
x1 is approximately 600 rpm; x2 is approximately 200 rpm; and t is approximately 5 seconds.
- 19. A method in accordance with claim 1, wherein said blood pump comprises one of an implantable pump or an external pump.
- 20. A method in accordance with claim 1, wherein said axial flow pump has magnets implanted in a pump impeller.
- 21. A method in accordance with claim 20, further comprising:
detecting a position of said pump impeller using one or more Hall sensors.
- 22. A method in accordance with claim 22, wherein said one or more Hall sensors detect at least one of vertical or horizontal movement of the pump impeller.
- 23. A method in accordance with claim 21, further comprising:
adjusting the rpm of said impeller based on said detecting step in order to maintain the impeller position in a dynamic suspension position.
- 24. A method in accordance with claim 23, further comprising maintaining a gap between the impeller and the supporting structure of at least approximately 100 microns.
- 25. A method in accordance with claim 23, wherein said dynamic suspension is achieved either magnetically or mechanically.
- 26. Apparatus for controlling an axial flow rotary blood pump, comprising:
a rotary blood pump having an established normal operating range, said normal operating range comprising a normal pump flow range and a normal pressure head range; a motor driver to enable driving of said pump at a target rotational speed in accordance with said normal operating range; a condition estimator to enable determination of a current operating condition of the blood pump, said current operating condition comprising a current pump flow, a current pressure head, and a current rotational speed of said pump; a processor to: (1) enable a comparison between the current operating condition and the normal operating range; and (2) enable the selection of an appropriate control algorithm from a plurality of available control algorithms based on said comparison; and a controller to enable adjustment of the target rotational speed of said pump using said selected control algorithm to maintain or recover said normal operating range.
- 27. Apparatus in accordance with claim 26, wherein:
said rotary blood pump is used as one of a left ventricular assist device or a right ventricular assist device.
- 28. Apparatus in accordance with claim 26, wherein:
measurements of said current pump flow and said current pressure head are provided to the condition estimator to determine the current operating condition; and a measurement of said current rotational speed is provided to said controller.
- 29. Apparatus in accordance with claim 28, wherein said current pump flow, said current pressure head, and said current rotational speed are measured by one or more sensors.
- 30. Apparatus in accordance with claim 29, wherein said one or more sensors are implantable sensors.
- 31. Apparatus in accordance with claim 26, wherein:
said normal operating range is established by determining a target operating point for the target rotational speed of the pump which provides a target pump flow and a target pressure head; said normal pump flow range is within a 20% deviation from said target pump flow; and said normal pressure head range is within a 25% deviation from said target pressure head.
- 32. Apparatus in accordance with claim 26, wherein during said normal operating range:
said processor selects a normal operating condition control algorithm; and said controller maintains said target rotational speed of said pump by applying proportional and derivative gain control to said pump.
- 33. Apparatus in accordance with claim 32, wherein said proportional and derivative gain control is applied in accordance with the formula:
- 34. Apparatus in accordance with claim 33, wherein:
Kp is set to approximately 0.02; and Kd is set to approximately 0.05.
- 35. Apparatus in accordance with claim 26, wherein in the event that the current operating condition is above said normal operating range:
said processor selects a first abnormal operating condition control algorithm; and said controller decreases the target rotational speed until the normal operating range is recovered.
- 36. Apparatus in accordance with claim 35, wherein the target rotational speed is decremented by x rpm every t seconds until said normal operating range is recovered.
- 37. Apparatus in accordance with claim 36, wherein:
x is approximately 600 rpm; and t is approximately 5 seconds.
- 38. Apparatus in accordance with claim 26, wherein in the event that the current operating condition is below said normal operating range:
said processor selects a second abnormal operating condition control algorithm; and said controller increases the target rotational speed until the normal operating range is recovered.
- 39. Apparatus in accordance with claim 38, wherein the target rotational speed is incremented by x rpm every t seconds until said normal operating range is recovered.
- 40. Apparatus in accordance with claim 39, wherein:
x is approximately 600 rpm; and t is approximately 5 seconds.
- 41. Apparatus in accordance with claim 38, wherein a suction condition exists in the event that the normal operating range is not recovered by increasing said target rotational speed, and in the event of such a suction condition;
said processor selects a suction condition control algorithm; said controller releases the suction condition by continuously decreasing the target rotational speed of the pump to obtain a pump flow free from suction and free from overpumping; and once said suction condition is released, said controller gradually increases the target rotational speed of the pump to recover said normal operating range.
- 42. A method in accordance with claim 41, wherein:
when releasing the suction condition, the target rotational speed is continuously decremented by x1 rpm every t seconds; and once the suction condition is released, the target rotational speed is continuously incremented by x2 rpm every t seconds.
- 43. Apparatus in accordance with claim 42, wherein:
x1 is approximately 600 rpm; x2 is approximately 200 rpm; and t is approximately 5 seconds.
- 44. Apparatus in accordance with claim 26, wherein said blood pump comprises one of an implantable pump or an external pump.
- 45. Apparatus in accordance with claim 26, wherein said axial flow pump has magnets implanted in a pump impeller.
- 46. Apparatus in accordance with claim 45, further comprising:
one or more Hall sensors for detecting a position of said pump impeller.
- 47. Apparatus in accordance with claim 46, wherein said one or more Hall sensors detect at least one of vertical or horizontal movement of the pump impeller.
- 48. Apparatus in accordance with claim 46, wherein:
the rpm of the impeller is adjusted based on the impeller position as detected by the one or more Hall sensors in order to maintain the impeller position in a dynamic suspension position.
- 49. Apparatus in accordance with claim 48, wherein a gap is maintained between the impeller and the supporting structure of at least approximately 100 microns.
- 50. Apparatus in accordance with claim 48, wherein said dynamic suspension is achieved either magnetically or mechanically.
Parent Case Info
[0001] The present application is a continuation-in-part of U.S. patent application Ser. No. 10/241,825 filed on Sep. 10, 2002.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
10241825 |
Sep 2002 |
US |
Child |
10291191 |
Nov 2002 |
US |