System and method for measuring the linear and rotational acceleration of a body part

• US 20020060633A1
• Filed: 10/10/2001
• Published: 05/23/2002
• Est. Priority Date: 10/11/2000
• Status: Active Grant

• Current Assignee: Riddell Incorporated (BRG Sports, Inc.)
• Original Assignee: Riddell Incorporated (BRG Sports, Inc.)
• Inventors: Greenwald, Richard M., Crisco, Joseph J. III
• Granted Patent: US 6,826,509 B2
• Time in Patent Office: Days
• US Class Current: 340/669
• CPC Class Codes: A42B 3/046 Means for detecting hazards or accidents
• CPC Class Codes: A42B 3/125 with a padded structure, e.g. foam
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/4076 Diagnosing or monitoring particular conditions of the nervous system A61B5/4821, A61B5/4824 take precedence
• CPC Class Codes: A61B 5/6803 Head-worn items, e.g. helmets, masks, headphones or goggles
• CPC Class Codes: A61B 5/6814 Head
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: A63B 2208/12 specially adapted for children
• CPC Class Codes: A63B 2220/40 Acceleration
• CPC Class Codes: A63B 2230/60 muscle strain, i.e. measured on the user
• CPC Class Codes: A63B 2243/007 American football
• CPC Class Codes: A63B 71/06 Indicating or scoring devices for games or players , or for other sports activities
• CPC Class Codes: A63B 71/10 for the head A63B71/081 takes precedence ; in the form of caps or hats A42B1/08; helmets A42B3/00

Abstract

A system and method for determining the magnitude of linear and rotational acceleration of and direction of impact to a body part, such as a head includes positioning a number of single-axis accelerometers proximate to the outer surface of the body part. A number of accelerometers are oriented to sense respective linear acceleration orthogonal to the outer surface of the body part. The acceleration data sensed is collected and recorded. A hit profile function is determined from the configuration of the body part and the positioning of the plurality of accelerometers thereabout. A number of potential hit results are generated from the hit profile function and then compared to the acceleration data sensed by the accelerometers. One of the potential hit results is best fit matched to the acceleration data to determine a best fit hit result, which yields the magnitude of linear acceleration to and direction of an impact to the body part. The rotational acceleration of the body part can also be estimated from the magnitude of linear acceleration of and direction of the impact to the body part.

Claims

1. A device for monitoring the acceleration of a body part having an outer surface, comprising:

a plurality of sensing devices constructed and arranged orthogonal to the outer surface of the body part to detect acceleration;

the plurality of sensing devices being constructed and arranged to generate a signal in response to a sensed acceleration;

a processing device connected to the plurality of sensing devices and being constructed and arranged to receive signals from the plurality of sensing devices and determine the magnitude and direction of an impact to the body part.

2. The device of claim 1, wherein said plurality of sensing devices are single-axis linear accelerometers.

3. The device of claim 1, wherein said plurality of sensing devices are multi-axis linear accelerometers with at least one axis thereof being orthogonal to the outer surface of the body part.

4. The device of claim 1, further comprising:

a protective layer of material positioned about the body part;

a plurality of portions of cushioning material disposed between the body part and the protective layer of material;

8. The device of claim 1, wherein the plurality of sensing devices are three devices positioned 120 degrees apart from one another about the circumference of the body part.

9. The device of claim 1, further comprising:

a recording station connected to the plurality of sensing devices;

10. The device of claim 9, wherein the recording station is connected to the plurality of sensing devices by wire.

11. The device of claim 9, wherein the recording station is connected to the plurality of sensing devices by radio transmission.

12. The device of claim 1, wherein the body part is a head.

13. The device of claim 1, wherein said plurality of sensing devices are mounted in a helmet.

14. The device of claim 1, wherein said plurality of sensing devices are mounted in a head band.

16. The method of claim 15, wherein the surface of the body part is defined by the circumference of the body part, along which the plurality of accelerometers is approximately a circle.

17. The method of claim 16, wherein the hit profile function is equal to a * cos (s−

b)+c where a is the impact magnitude, s is the arc defining the accelerometer position, b is the impact direction and c is the radial acceleration due to pure rotation about the superior-inferior Z-axis and known data ranges are employed to generate potential hit results.

18. The method of claim 15, wherein the configuration of the body part is a geometric shape.

19. The method of claim 18, wherein the configuration of the profile generating function corresponds to the geometric shape.

20. The method of claim 15, wherein matching one of the potential hit profiles to the acceleration data employs least-squares regression model to determine the best fit profile.

21. The method of claim 15, further comprising:

estimating the rotational acceleration of the body part from the magnitude of linear acceleration and the location of the impact to the body part from the best fit hit result by multiplying the distance from the location of the impact to an axis of rotation of the body part by the magnitude of the linear acceleration of the body part.

5. The device of claim 5, further comprising:

a carrier web being closely fitted around the body part;

the plurality of sensing devices being attached to the carrier web and positioned orthogonal and proximal to the outer surface of the body part.

6. The device of claim 5, further comprising:

a plurality of carrier clips positioned between the plurality of portions of cushioning material;

the carrier clips respectively carrying the plurality of sensing devices and being positioned orthogonal and proximal to the outer surface of the body part.

7. The device of claim 5, wherein the plurality of sensing devices are embedded within the plurality of portions of cushioning material and are positioned orthogonal and proximal to the outer surface of the body part.

15. A method for determining the magnitude and direction of impact to a body part having a geometric shape, comprising the steps of:

positioning a plurality of accelerometers proximate to the outer surface of a body part;

orienting the plurality of accelerometers to sense respective linear acceleration orthogonal to the surface of the body part;

positioning the plurality of accelerometers in a defined arrangement about the surface of the body part;

recording acceleration data sensed by the plurality of accelerometers;

providing a hit profile function from the geometric shape of the body part and the positioning of the plurality of accelerometers thereabout;

generating a plurality of potential hit results from the hit profile function;

comparing the plurality of potential hit results to the acceleration data sensed by the plurality of accelerometers;

best fit matching one of the potential hit results to the acceleration data to determine a best fit hit result; and

determining the magnitude of linear acceleration and the direction of an impact to the body part from the best fit hit result.

22. A method of acceleration monitoring, comprising the steps of:

attaching an acceleration-monitoring technology device, having acceleration sensors, to an individual such that the acceleration sensors remain fixed relative to a body part of the individual during physical activity where the body part has an outer surface;

measuring accelerations of the body part of the individual during physical activity along at least a first, a second and a third acceleration measurement direction, wherein the first acceleration measurement direction is orthogonal to the outer surface of the body part, and the second acceleration measurement direction is orthogonal to the outer surface of the body part, and the third acceleration measurement direction is orthogonal to the outer surface of the body part;

storing the accelerations of the body part of the individual during the physical activity as acceleration data in a mass storage device;

retrieving the acceleration data of the body part of the individual during physical activity;

determining a direction and magnitude of the impact to the body part of the individual during the physical activity and the rotational acceleration of the body part of the individual during the physical activity from the acceleration data.