Method and device for measuring the progress of a moving person

• US 20090018794A1
• Filed: 12/19/2007
• Published: 01/15/2009
• Est. Priority Date: 07/11/2007
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: VTI Technologies Oy (Murata Manufacturing Co Limited)
• Inventors: Meriheina, Ulf
• Granted Patent: US 7,962,309 B2
• Time in Patent Office: Days
• 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 5/112 Gait analysis
• 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 5/6804 Garments; Clothes
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: G01C 21/10 by using measurements of speed or acceleration G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: G01P 15/00 Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
• CPC Class Codes: G01P 3/50 for measuring linear speed G01P3/56 takes precedence

Abstract

The invention relates to measuring devices to be used in physical measuring, and more particularly, to a method and a device for measuring the progress of a moving person. In the solution according to the invention the quantities describing the progress of the moving person can be calculated based on vertical acceleration values of the body measured by means of an acceleration sensor, and on the measured time. The invention aims at providing a solution, better and simpler than prior solutions, for measuring the progress of a moving person, which solution is applicable for use in a multitude of measuring solutions for ways of locomotion of various types.

Claims

1. A method for measuring the progress of a moving person, characterized in that at least one of the following quantities describing the progress of the moving person:

speed, step rate, step count, step length, distance and way of progress, is calculated based on values of the vertical acceleration of the body measured by means of an acceleration sensor, and on the measured time.

2. Method according to claim 1, characterized in that step cycle-specific characteristic maximum accelerations a_max falling within the positive half-cycle, i.e. during the acceleration stage, and correspondingly step cycle-specific characteristic minimum accelerations a_min falling within the negative half-cycle, i.e. during the braking stage, are defined based on the measured values of vertical acceleration of the body.

3. Method according to claim 2, characterized in that the step cycle-specific characteristic maximum accelerations a_max are obtained as the maxima of the step cycle-specific measured acceleration values and characteristic minimum accelerations a_min are obtained as the minima of the step cycle-specific measured acceleration values.

4. Method according to claim 2, characterized in that the step cycle-specific characteristic maximum accelerations a_max are obtained as the maxima for each step cycle of the analogically filtered acceleration sensor signals a_in and characteristic minimum accelerations a_min are obtained as the minima for each step cycle of the analogically filtered acceleration sensor signals a_in.

5. Method according to claim 2, characterized in that the step cycle-specific characteristic maximum accelerations a_max are obtained as the maxima for each step cycle of the digitally filtered acceleration sensor signals a_in and characteristic minimum accelerations a_min are obtained as the minima for each step cycle of the digitally filtered acceleration sensor signals a_in.

6. Method according to claim 2, characterized in that the step cycle-specific characteristic maximum acceleration values a_max are obtained as the mean values for each step cycle of the digitally filtered acceleration sensor signals a_in over times selected during the positive half-cycle and characteristic minimum accelerations a_min are obtained as the mean values for each step cycle of the digitally filtered acceleration sensor signals a_in over times selected during the negative half-cycle.

7. Method according to claim 5, characterized in that the function used in the digital filtering is:

a_out=a_in/√

{square root over ([1+(f/f₀)²)}],

where f is the frequency and f₀ is a suitably selected boundary frequency.

8. Method according to claim 2, characterized in that the step cycle-specific characteristic maximum accelerations a_max are obtained as the maxima for each step cycle of the signals a_in from the acceleration sensor, filtered with digital weighting, and characteristic minimum accelerations a_min are obtained as the minima for each step cycle of the signals a_in from the acceleration sensor, filtered with digital weighting.

9. Method according to claim 2, characterized in that the step cycle-specific characteristic maximum accelerations a_max are obtained as the mean values for each step cycle of the signals a_in from the acceleration sensor filtered with digital weighting over times selected during the positive half-cycle and characteristic minimum accelerations a_min are obtained as the mean values for each step cycle of the signals a_in from the acceleration sensor filtered with digital weighting over times selected during the negative half-cycle.

10. Method according to claim 8, characterized in that the function used in the digital weighted filtering is:

a_out(n)=(1−

k)*a_out(n−

1)+a_in*k,

where n indicates the n;

th sample and k is the weighting factor.

11. Method according to claim 2, characterized in that the speed v is calculated based on the characteristic maximum acceleration values a_max of the vertical acceleration as follows:

12. Method according to claim 2, characterized in that the speed v is calculated based on the characteristic minimum accelerations a_min of the vertical acceleration as follows:

v≈

k·

√

{square root over (|a_min)}|.

13. Method according to claim 1, characterized in that in calculating the quantities describing the progress of the moving person, the time T_step used up for one step is obtained as the time interval between two equivalent points, such as a maximum, a minimum, or a point of exceeding or falling below a certain value, on the acceleration graph derived from the measured values of the vertical acceleration.

14. Method according to claim 13, characterized in that the step length s_step is calculated using the formula:

s_step=v*T_step.

15. Method according to claim 13, characterized in that the step rate f_step is calculated using the formula:

f_step=1/T_step.

16. Method according to claim 13, characterized in that the step count n is calculated on the basis of the number n of equivalent points, such a maximum, a minimum, or a point of exceeding or falling below a certain value, on the acceleration graph given by the measured values of vertical acceleration.

17. Method according to claim 13, characterized in that the distance covered s is calculated as the sum of the lengths of the steps:

18. Method according to claim 1, characterized in that the method distinguishes between ways of progress, like walking, running, and skiing, based on acceleration maximum and minimum, the characteristic maximum and minimum acceleration values a_max and a_min and/or the step rate.

19. Method according to claim 18, characterized in that the method makes an individual calibration for each way of progress, like running, walking, pole walking, or cross-country skiing.

20. Method according to claim 1, characterized in that the method is adapted for use in step-by-step navigation.

21. A device for measuring the progress of a moving person, characterized in that the device is adapted to measure a minimum acceleration and time such, that at least one of the following quantities describing the progress of the moving person:

speed, step rate, step count, step length, distance and way of locomotion, is calculated based on the values of vertical acceleration of the body measured by means of an acceleration sensor, and on the measured time.

22. Device according to claim 21, characterized in that the device is adapted to determine step cycle-specific characteristic maximum accelerations a_max falling within the positive half-cycle, i.e. during the acceleration stage, and, correspondingly, characteristic minimum accelerations a_min falling within the negative half-cycle, i.e. during the braking stage, based on the measured values of vertical acceleration of the body.

23. Device according to claim 22, characterized in that the device is adapted to determine the step cycle-specific characteristic maximum acceleration values a_max as the maxima of the step cycle-specific measured acceleration values and characteristic minimum acceleration values a_min as the minima of the step cycle-specific measured acceleration.

24. Device according to claim 22, characterized in that the device is adapted to determine the step cycle-specific characteristic maximum accelerations a_max as the maxima for each step cycle of the analogically filtered acceleration sensor signals a_in and characteristic minimum accelerations a_min as the minima for each step cycle of the analogically filtered acceleration sensor signals a_in.

25. Device according to claim 22, characterized in that the device is adapted to determine the step cycle-specific characteristic maximum accelerations a_max as the maxima for each step cycle of the digitally filtered acceleration sensor signals a_in and characteristic minimum accelerations a_min as the minima for each step cycle of the digitally filtered acceleration sensor signals a_in.

26. Device according to claim 22, characterized in that the device is adapted to determine the step cycle-specific characteristic maximum accelerations a_max as the mean values for each step cycle of the digitally filtered acceleration sensor signals a_in over times selected during the positive half-cycle and characteristic minimum accelerations a_min as the mean values for each step cycle of the digitally filtered acceleration sensor signals a_in over times selected during the negative half-cycle.

27. Device according to claim 25, characterized in that the device is adapted to use, in the digital filtering, the function:

a_out=a_in/√

{square root over ([1+(f/f₀)²)}],

where f is the frequency and f₀ is a suitably selected boundary frequency.

28. Device according to claim 22, characterized in that the device is adapted to determine the step cycle-specific characteristic maximum accelerations a_max as the maxima for each step cycle of the signals a_in from the acceleration sensor, filtered with digital weighting, and characteristic minimum accelerations a_min as the minima for each step cycle of the signals a_in from the acceleration sensor, filtered with digital weighting.

29. Device according to claim 22, characterized in that the device is adapted to determine the step cycle-specific characteristic maximum accelerations a_max as the mean values for each step cycle of the signals a_in from the acceleration sensor filtered with digital weighting over times selected during the positive half-cycle and characteristic minimum accelerations a_min as the mean values for each step cycle of the signals a_in from the acceleration sensor filtered with digital weighting over times selected during the negative half-cycle.

30. Device according to claim 28, characterized in that the device is adapted to use, in the digital weighted filtering, the function:

a_out(n)=(1−

k)*a_out(n−

1)+a_in*k,

where n indicates the n;

th sample and k is the weighting factor.

31. Device according to claim 22, characterized in that the device is adapted to calculate the speed v based on the characteristic maximum accelerations a_max of the vertical acceleration as follows:

32. Device according to claim 22, characterized in that the device is adapted to calculate the speed v based on the characteristic minimum accelerations a_min of the vertical acceleration as follows:

v≈

k·

√

{square root over (|a_min|)}.

33. Device according to claim 21, characterized in that the device is adapted, in calculating the quantities describing the progress of the moving person, to determine the time T_step used up for one step as the time interval between two equivalent points, such as a maximum, a minimum, or a point of exceeding or falling below a certain value, on the acceleration graph derived from the measured values of the vertical acceleration.

34. Device according to claim 33, characterized in that the device is adapted to calculate the step length s_step using the formula:

s_step=v*T_step.

35. Device according to claim 33, characterized in that the device is adapted to calculate the step rate f_step using the formula:

f_step=1/T_step

36. Device according to claim 33, characterized in that the device is adapted to calculate the step count n on the basis of the number n of equivalent points, such a maximum, a minimum, or a point of exceeding or falling below a certain value, on the acceleration graph given by the measured values of vertical acceleration.

37. Device according to claim 33, characterized in that the device is adapted to calculate the distance covered s as the sum of the step lengths:

38. Device according to claim 21, characterized in that the device is adapted to distinguish between ways of progress, like walking, running, and skiing, based on acceleration maximum and minimum, the characteristic maximum and minimum acceleration values a_max and a_min and/or the step rate.

39. Device according to claim 38, characterized in that the device is adapted to make an individual calibration for each way of progress, like running, walking, pole walking, or cross-country skiing.

40. Device according to claim 21, characterized in that the device is adapted for use in step-by-step navigation.

41. Device according to claim 40, characterized in that the device is adapted to cooperate with an altimeter, satellite navigation devices, and/or a magnetometer.

42. Device according to claim 40, characterized in that the device is adapted to receive and/or utilize map database data and/or terrain inclination data.

43. A device to be positioned at the middle of the body of a moving person, characterized in that the device comprises a device according to claim 21 for measuring the progress of the moving person.

44. Device according to claim 43, characterized in that the device to be positioned at the middle of the body the moving person is positioned at a piece of clothing, a piece of headwear, the neck, a pocket, or the belt of the moving person.

45. A display unit for a moving person, characterized in that the display unit for the moving person is adapted to cooperate with a device according to claim 21 measuring the progress of a moving person.

46. A system for measuring the progress of a moving person, characterized in that the system comprises a device according to claim 21 for measuring the progress of a moving person, and, adapted to cooperate with this device, a display unit for the moving person.

47. System according to claim 46, characterized in that said device for measuring the progress of the moving person and said display unit for the moving person are integrated in one device.