Mechanical CPR device

1. A mechanical CPR device, comprising:

a mechanism configured to attach to a torso of a patient;

a driving component configured to extend the mechanism toward the torso and retract the mechanism away from the torso; and

a controller configured to control the driving component to:

determine a reference position by extending the mechanism to a first position in contact with the torso, extending the mechanism beyond the first position then retracting the mechanism to the first position, retracting the mechanism away from the first position until a threshold is exceeded, and then extending the mechanism to a point when the threshold is no longer exceeded and set the point as the reference position;

compress the torso by extending the mechanism from the reference position to a first distance and retracting the mechanism from the first distance to the reference position, and

decompress the torso by retracting the mechanism from the reference position to a second distance and extending the mechanism from the second distance to the reference position.

2. The mechanical CPR device of claim 1 , wherein the reference position corresponds to the natural resting position of the torso.

3. The mechanical CPR device of claim 2 , wherein the threshold is a force threshold, the mechanical CPR device further comprising a spring activation sensor configured to output a signal when the mechanism has been retracted to exceed the threshold.

4. The mechanical CPR device of claim 3 , wherein the spring activation sensor is further configured to stop outputting a signal when the mechanism has been extended to the point at which the threshold is no longer exceeded.

5. The mechanical CPR device of claim 1 , wherein the threshold is a second threshold, and the controller is further configured to determine the reference position by controlling the driving component to:

extend the mechanism beyond the first position until a first threshold is reached.

6. The mechanical CPR device of claim 5 , wherein the mechanism comprises a suction cup and the first threshold is a force threshold and the mechanical CPR device further comprising a force sensor configured to sense the force applied by the mechanism to cause air to be forced out from an area between the suction cup and the torso.

7. The mechanical CPR device of claim 5 , wherein at least one of the first and second thresholds is a pressure threshold, the mechanical CPR device further comprising a pressure sensor configured to sense pressure in the area between the mechanism and the torso.

8. The mechanical CPR device of claim 5 , wherein the controller is further configured to determine the reference position a predetermined number of times before controlling the driving component to compress the torso by extending the mechanism from the reference position to a first distance when the first threshold was exceeded and retracting the mechanism from the first distance to the reference position, and decompress the torso by retracting the mechanism from the reference position to a second distance when the second threshold was exceeded above the reference position.

9. The mechanical CPR device of claim 1 , wherein the controller is further configured to determine the reference position in response to the mechanical CPR device receiving a user input.

10. The mechanical CPR device of claim 1 , wherein the mechanism comprises a sticker plate.

11. A method for performing mechanical cardiopulmonary resuscitation (CPR), the method comprising:

attaching a mechanism to a torso of a patient;

determining a reference position by:

extending the mechanism to a first position in contact with the torso,

extending the mechanism beyond the first position then retracting the mechanism to the first position,

retracting the mechanism away from the first position until a threshold is exceeded, and

then extending the mechanism to a point when the threshold is no longer exceeded and set the point as the reference position;

extending the mechanism from the reference position to a first distance below the reference position;

retracting the mechanism from the first distance to a second distance above the reference position; and

extending the mechanism from the second distance to the reference position.

12. The method of claim 11 , wherein the reference position corresponds to the natural resting position of the torso.

13. The method of claim 11 , wherein the threshold is a second threshold, the method further comprising determining the reference position by:

extending the mechanism beyond the first position until a first threshold is reached.

14. The method of claim 13 , wherein the first threshold is a force threshold.

15. The method of claim 13 , wherein at least one of the first and second thresholds is a pressure threshold.

16. The method of claim 13 , wherein at least one of the first and second thresholds is a distance threshold.

17. A mechanical CPR device, comprising:

a mechanism configured to attach a torso of a patient;

a driving component configured to extend the mechanism toward the torso and retract the mechanism away from the torso; and

a controller configured to instruct the driving component to:

determine a reference position by extending the mechanism to a first position in contact with the torso, extending the mechanism beyond the first position then retracting the mechanism to the first position, retracting the mechanism away from the first position until a threshold is exceeded, and then extending the mechanism to a point when the threshold is no longer exceeded and set the point as the reference position,

position the mechanism at the reference position when the mechanism is attached to the torso,

retract the mechanism from the reference position to a second distance above a natural resting position of the torso, and

extend the mechanism from the second distance above the natural resting position to the natural resting position.

18. The mechanical CPR device of claim 17 , wherein the controller is further configured to instruct the driving component to:

extend the mechanism from the natural resting position to a first distance below the natural resting position; and

retract the mechanism from the first distance below the natural resting position to the natural resting position.

19. The mechanical CPR device of claim 17 , wherein the threshold is a second threshold and the controller is further configured to instruct the driving component to:

extend the mechanism beyond the first position to a first threshold point until a first threshold is reached.

20. The mechanical CPR device of claim 19 , wherein the first threshold is a force threshold.

21. The mechanical CPR device of claim 19 , wherein at least one of the first and second thresholds is a pressure threshold.

22. The mechanical CPR device of claim 19 , wherein at least one of the first and second thresholds is a distance threshold.

23. The mechanical CPR device of claim 17 , wherein the mechanism comprises a suction cup.

24. The mechanical CPR device of claim 17 , wherein the mechanism comprises a sticker plate.