Overall motion determination

• US 8,880,377 B2
• Filed: 12/22/2008
• Issued: 11/04/2014
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Polar Electro Oy
• Original Assignee: Polar Electro Oy
• Inventors: Niemimki, Mika
• Primary Examiner(s): Teixeira Moffat, Jonathan C
• Assistant Examiner(s): YAMAMOTO, JOSEPH
• Application Number:
  US13/139,541
• Publication Number:
  US 20110264401A1
• Time in Patent Office: 2,143 Days
• Field of Search: 702/141
• US Class Current: 702/141
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6825 Hand
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A63B 2220/12 Absolute positions, e.g. by using GPS
• CPC Class Codes: A63B 2220/22 Stride length
• CPC Class Codes: A63B 2220/30 Speed
• CPC Class Codes: A63B 2220/40 Acceleration
• CPC Class Codes: A63B 2225/50 Wireless data transmission, e.g. by radio transmitters or telemetry
• CPC Class Codes: A63B 2230/06 heartbeat rate only
• CPC Class Codes: A63B 2230/75 calorie expenditure
• CPC Class Codes: A63B 24/0062 Monitoring athletic performances, e.g. for determining the work of a user on an exercise apparatus, the completed jogging or cycling distance
• CPC Class Codes: A63B 69/0028 for running, jogging or speed-walking movable endless bands A63B22/02
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

An apparatus, a method, and a computer program are disclosed. The apparatus comprises a processor. The processor is configured to obtain instantaneous acceleration values representing lower limb motion of a user, to form an effective acceleration value from the instantaneous acceleration values over a plurality of steps of the user, and to determine a motion parameter representing overall motion of the user by means of the effective acceleration value.

Claims

1. An apparatus comprising:

an accelerometer configured to measure instantaneous acceleration values representing lower limb motion of a user, a processor configured to process said instantaneous acceleration values, wherein the instantaneous acceleration values comprise at least two orthogonal acceleration vector components, the processor being configured to form a scalar representation of the at least two orthogonal acceleration vector components and to form an effective acceleration value using only the scalar representation over a plurality of steps of the user without using direction information associated with the orthogonal acceleration vector components, the processor being further configured to determine a motion parameter representing overall motion of the user by using the effective acceleration value, thereby reducing sensitivity to orientation of the apparatus and reducing a need for calibration of the apparatus.

2. The apparatus of claim 1, wherein the scalar representation of an acceleration a is formed with the at least two orthogonal acceleration vector components a_x, a_y, a_z using formula a=√

{square root over (a_x²+a_y²+a_x²)}; and

the processor being configured to form the effective acceleration value from the scalar representation over the plurality of the steps of the user.

3. The apparatus of claim 1, wherein the instantaneous acceleration values represent tangential lower limb motion of the user.

4. The apparatus of claim 1, wherein the instantaneous acceleration values comprise instantaneous foot-flight acceleration values, the processor being further configured to form the effective acceleration value from the instantaneous foot-flight acceleration values over the plurality of the steps of the user.

5. The apparatus of claim 1, wherein the processor is further configured to determine the motion parameter representing the overall motion of the user by means of the effective acceleration value in such a manner that a first functional dependence value of the motion parameter is applied to the effective acceleration value if walking motion is identified, a second functional dependence value of the motion parameter being applied to the effective acceleration value if running motion is identified.

6. The apparatus of claim 1, wherein the apparatus is a mobile apparatus, a sports computer, a running computer, a multi-sports computer, an activity monitor, a pedometer, a foot-pod, a shoe-mounted stride sensor, a measurement unit attachable to a lower limb of the user, and/or a subscriber terminal of a radio system.

7. A method to determine overall motion of a user, the method comprising:

measuring with an accelerometer instantaneous acceleration values representing lower limb motion of a user, wherein the instantaneous acceleration values comprise at least two orthogonal acceleration vector components;

forming using a processing device a scalar representation of the at least two orthogonal acceleration vector components;

forming using said processing device an effective acceleration value using only the scalar representation over a plurality of steps of the user without using direction information associated with the orthogonal acceleration vector components; and

determining a motion parameter representing overall motion of the user by using the effective acceleration value, thereby reducing sensitivity to orientation of the apparatus and reducing a need for calibration of the apparatus.

8. The method of claim 7, the method further comprising:

forming the scalar representation of an acceleration a with at least two acceleration vector components a_x, a_y, a_z using formula a=√

{square root over (a_x²+a_y²+a_z²)}; and

forming the effective acceleration value from the scalar representation over the plurality of the steps of the user.

9. The method of claim 7, wherein the instantaneous acceleration values represent tangential lower limb motion of the user.

10. The method of claim 7, wherein the instantaneous acceleration values comprise instantaneous foot-flight acceleration values, the method further comprising forming the effective acceleration value from the instantaneous foot-flight acceleration values over the plurality of the steps of the user.

11. The method of claim 7, wherein the motion parameter representing the overall motion of the user is determined by means of the effective acceleration value in such a manner that a first functional dependence value of the motion parameter is applied to the effective acceleration value if walking motion is identified, a second functional dependence value of the motion parameter being applied to the effective acceleration value if running motion is identified.

12. An apparatus to determine overall motion of a user, the apparatus comprising:

an accelerometer to measure instantaneous acceleration values representing lower limb motion of a user, wherein the instantaneous acceleration values comprise at least two orthogonal acceleration vector components;

a processing device that performs operations comprising;

forming a scalar representation of the at least two orthogonal acceleration vector components;

forming an effective acceleration value using only the scalar representation over a plurality of steps of the user without using direction information associated with the orthogonal acceleration vector components;

and determining a motion parameter representing overall motion of the user by using the effective acceleration value, thereby reducing sensitivity to orientation of the apparatus and reducing a need for calibration of the apparatus.

13. A non-transitory computer-readable medium, comprising instructions which, when executed by a mobile apparatus, cause the mobile apparatus to:

measure instantaneous acceleration values representing lower limb motion of a user using an accelerometer, wherein the instantaneous acceleration values comprise at least two orthogonal acceleration vector components;

form a scalar representation of the at least two orthogonal acceleration vector components using a processing device;

form an effective acceleration value from using only the scalar representation over a plurality of steps of the user without using direction information associated with the orthogonal acceleration vector components using said processing device; and

determine using said processing device a motion parameter representing overall motion of the user by using the effective acceleration value, thereby reducing sensitivity to orientation of the apparatus and reducing a need for calibration of the apparatus.

14. The non-transitory computer-readable medium of claim 13, the computer-readable medium comprising instructions which when executed by the mobile apparatus, cause the mobile apparatus to:

form the scalar representation of an acceleration a with at least two acceleration vector components a_x, a_y, a_z using formula a=√

{square root over (a_x²+a_y²+a_z²)}; and

form the effective acceleration value from the scalar representation over the plurality of the steps of the user.

15. The non-transitory computer-readable medium of claim 13, wherein the instantaneous acceleration values represent tangential lower limb motion of the user.

16. The non-transitory computer-readable medium of claim 13, wherein the instantaneous acceleration values comprise instantaneous foot-flight acceleration values, the instructions which when executed by the mobile apparatus, cause the mobile apparatus to form the effective acceleration value from the instantaneous foot-flight acceleration values over the plurality of the steps of the user.

17. The non-transitory computer-readable medium of claim 13, wherein the motion parameter representing the overall motion of the user is determined by means of the effective acceleration value in such a manner that a first functional dependence value of the motion parameter is applied to the effective acceleration value if walking motion is identified, a second functional dependence value of the motion parameter being applied to the effective acceleration value if running motion is identified.