Methods and systems for guidance of human locomotion

1. A method for guiding locomotion speed in a human during a locomotion event, the method comprising:

estimating the subject's actual locomotion speed during the locomotion event using one or more sensors to thereby obtain a measured speed as a distance per unit time;

determining an error as a distance per unit time during the locomotion event, the error comprising a difference between a desired speed at a particular instant during the locomotion event as a distance per unit time and the measured speed for the particular instant during the locomotion event; and

outputting, to the subject during the locomotion event, a stimulus frequency signal comprising a tempo wherein the tempo of the stimulus frequency signal is based on the error in such a manner that when the subject ambulates with a gait frequency that matches the tempo of the stimulus frequency signal, the subject's actual speed as a distance per unit time during the locomotion event controllably tracks the desired speed;

wherein outputting the stimulus frequency signal based on the error comprises determining a first control term proportional to the error which is used, at least in part, to determine the stimulus frequency signal; and

wherein outputting the stimulus frequency signal based on the error comprises determining a second control term proportional to a time integral of the error which is used, at least in part, to determine the stimulus frequency signal.

2. A method according to claim 1 wherein outputting the stimulus frequency signal based on the error comprises implementing a proportional-integral-derivative (PID) control scheme.

3. A method according to claim 2 wherein implementing the PID control scheme comprises generating a control signal based on the error and using the control signal as an input to a frequency generator which outputs the stimulus frequency signal in response to the control signal.

4. A method according to claim 1 wherein outputting the stimulus frequency signal based on the error comprises generating a control signal as a combination of available control terms and using the control signal as an input to a frequency generator which outputs the stimulus frequency signal in response to the control signal.

5. A method according to claim 4 comprising updating the control signal with a control period of less than 10 seconds.

6. A method according to claim 4 comprising updating the control signal with a control period of less than 1 second.

7. A method according to claim 4 wherein the stimulus frequency signal is provided to the subject in a form of music and the control signal is updated at a conclusion of each musical piece.

8. A method according to claim 1 wherein the stimulus frequency signal comprises an auditory signal that is output to the subject.

9. A method according to claim 1 wherein the stimulus frequency signal comprises one or more of: a tactile signal that is output to the subject and a visual signal that is output to the subject.

10. A method according to claim 1 wherein the desired speed comprises a user-specified speed profile.

11. A method according to claim 10 wherein the user-specified speed profile comprises an interval profile which comprises a plurality of intervals with each interval comprising at least one of: a desired speed level for a desired period of time; and a desired speed level for a desired distance.

12. A method according to claim 10 wherein the user-specified speed profile comprises a ramping speed profile which includes one or more time periods when the desired speed is increasing constantly with time.

13. A method according to claim 10 wherein the user-specified speed profile comprises a profile downloaded from a communication network.

14. A method according to claim 4 wherein the stimulus frequency signal is provided to the subject in a form of music and the control signal is updated at one or more intervals within a musical piece.

15. A method for guiding locomotion speed in a human during a locomotion event, the method comprising:

estimating the subject's actual locomotion speed during the locomotion event using one or more sensors to thereby obtain a measured speed as a distance per unit time;

determining an error as a distance per unit time during the locomotion event, the error comprising a difference between a desired speed at a particular instant during the locomotion event as a distance per unit time and the measured speed for the particular instant during the locomotion event; and

outputting, to the subject during the locomotion event, a stimulus frequency signal comprising a tempo wherein the tempo of the stimulus frequency signal is based on the error in such a manner that when the subject ambulates with a gait frequency that matches the tempo of the stimulus frequency signal, the subject's actual speed as a distance per unit time during the locomotion event controllably tracks the desired speed;

wherein outputting the stimulus frequency signal based on the error comprises determining a first control term proportional to the error which is used, at least in part, to determine the stimulus frequency signal; and

wherein outputting the stimulus frequency signal based on the error comprises determining a third control term proportional to a time derivative of the error which is used, at least in part, to determine the stimulus frequency signal.

16. A method according to claim 15 wherein outputting the stimulus frequency signal based on the error comprises implementing a proportional-integral-derivative (PID) control scheme.

17. A method according to claim 16 wherein implementing the PID control scheme comprises generating a control signal based on the error and using the control signal as an input to a frequency generator which outputs the stimulus frequency signal in response to the control signal.

18. A method according to claim 15 wherein outputting the stimulus frequency signal based on the error comprises generating a control signal as a combination of available control terms and using the control signal as an input to a frequency generator which outputs the stimulus frequency signal in response to the control signal.

19. A method according to claim 18 comprising updating the control signal with a control period of less than 10 seconds.

20. A method according to claim 18 comprising updating the control signal with a control period of less than 1 second.

21. A method according to claim 18 wherein the stimulus frequency signal is provided to the subject in a form of music and the control signal is updated at a conclusion of each musical piece.

22. A method according to claim 15 wherein the stimulus frequency signal comprises an auditory signal that is output to the subject.

23. A method according to claim 15 wherein the stimulus frequency signal comprises one or more of: a tactile signal that is output to the subject and a visual signal that is output to the subject.

24. A method according to claim 15 wherein the desired speed comprises a user-specified speed profile.

25. A method according to claim 24 wherein the user-specified speed profile comprises an interval profile which comprises a plurality of intervals with each interval comprising at least one of: a desired speed level for a desired period of time; and a desired speed level for a desired distance.

26. A method according to claim 24 wherein the user-specified speed profile comprises a ramping speed profile which includes one or more time periods when the desired speed is increasing constantly with time.

27. A method according to claim 24 wherein the user-specified speed profile comprises a profile downloaded from a communication network.

28. A method according to claim 18 wherein the stimulus frequency signal is provided to the subject in a form of music and the control signal is updated at one or more intervals within a musical piece.

29. A method for guiding locomotion intensity in a human during a locomotion event, the method comprising:

estimating the subject's actual locomotion intensity during the locomotion event using one or more sensors to thereby obtain a measured intensity;

determining an intensity error during the locomotion event, the error comprising a difference between a desired intensity at a particular instant during the locomotion event and the measured intensity for the particular instant during the locomotion event; and

if an absolute value of the intensity error is outside of a threshold region around the desired intensity during the locomotion event:

estimating the subject's actual locomotion speed as a distance per unit time at the particular instant during the locomotion event using one or more sensors to thereby obtain a measured speed as a distance per unit time for the particular instant during the locomotion event;

converting the desired intensity to a desired speed as a distance per unit time;

determining a speed error as a distance per unit time during the locomotion event, the error comprising a difference between the desired speed at the particular instant during the locomotion event and the measured speed for the particular instant during the locomotion event; and

outputting, to the subject during the locomotion event, a speed-based stimulus frequency signal comprising a tempo wherein the tempo of the speed-based stimulus frequency signal is based on the speed error in such a manner that when the subject ambulates with a gait frequency that matches the tempo of the speed-based stimulus frequency signal, the subject's actual intensity during the locomotion event approximately controllably tracks the desired intensity; and

if the absolute value of the intensity error is within the threshold region around the desired intensity during the locomotion event:

outputting, to the subject during the locomotion event, an intensity-based stimulus frequency signal comprising a tempo wherein the tempo of the intensity-based stimulus frequency signal is based on the intensity error in such a manner that when the subject ambulates with a gait frequency that matches the tempo of the intensity-based stimulus frequency signal, the subject's actual intensity during the locomotion event controllably tracks the desired intensity.

30. A method according to claim 29 wherein outputting the speed-based stimulus frequency signal based on the speed error comprises implementing a proportional-integral-derivative (PID) control scheme.

31. A method according to claim 30 wherein implementing the PID control scheme comprises generating a speed-based control signal based on the speed error and using the speed-based control signal as an input to a frequency generator which outputs the speed-based stimulus frequency signal in response to the speed-based control signal.

32. A method according to claim 31 wherein the speed-based stimulus frequency signal is provided to the subject in a form of music and the speed-based control signal is updated at one or more intervals within a musical piece.

33. A method according to claim 31 comprising updating the speed-based control signal with a speed-based control period of less than 10 seconds.

34. A method according to claim 31 comprising updating the speed-based control signal with a speed-based control period of less than 1 second.

35. A method according to claim 31 wherein the speed-based stimulus frequency signal is provided to the subject in a form of music and the speed-based control signal is updated at a conclusion of each musical piece.

36. A method according to claim 29 wherein outputting the intensity-based stimulus frequency signal based on the intensity error comprises implementing a proportional-integral-derivative (PID) control scheme.

37. A method according to claim 36 wherein implementing the PID control scheme comprises generating an intensity-based control signal based on the intensity error and using the intensity-based control signal as an input to a frequency generator which outputs the intensity-based stimulus frequency signal in response to the intensity-based control signal.

38. A method according to claim 37 wherein the intensity-based stimulus frequency signal is provided to the subject in a form of music and the intensity-based control signal is updated at one or more intervals within a musical piece.

39. A method according to claim 37 comprising updating the intensity-based control signal with an intensity-based control period of less than 10 seconds.

40. A method according to claim 37 comprising updating the intensity-based control signal with an intensity-based control period of less than 1 second.

41. A method according to claim 37 wherein the intensity-based stimulus frequency signal is provided to the subject in a form of music and the intensity-based control signal is updated at a conclusion of each musical piece.

42. A method according to claim 29 wherein the speed-based stimulus frequency signal and the intensity-based stimulus frequency signal comprise an auditory signal that is output to the subject.

43. A method according to claim 29 wherein the speed-based stimulus frequency signal and the intensity-based stimulus frequency signal comprise one or more of: a tactile signal that is output to the subject and a visual signal that is output to the subject.

44. A method according to claim 29 wherein the desired intensity comprises a user-specified intensity profile.

45. A method according to claim 44 wherein the user-specified intensity profile comprises an interval profile which comprises a plurality of intervals with each interval comprising at least one of: a desired intensity level for a desired period of time; and a desired intensity level for a desired distance.

46. A method according to claim 44 wherein the user-specified intensity profile comprises a ramping intensity profile which includes one or more time periods when the desired intensity is increasing constantly with time.

47. A method according to claim 44 wherein the user-specified intensity profile comprises a profile downloaded from a communication network.

48. A method according to claim 29 wherein the threshold region around the desired intensity is defined to comprise an absolute intensity range around the desired intensity.

49. A method according to claim 48 wherein the locomotion intensity is reflected by one or more intensity indicators which comprise a heart rate of the subject and the absolute intensity range comprise a desired heart rate±x, where x is a beat rate parameter.

50. A method according to claim 49 wherein the beat rate parameter x is user-configurable.

51. A method according to claim 29 wherein the threshold region around the desired intensity is defined to comprise a percentage intensity range around the desired intensity.

52. A method according to claim 51 wherein the locomotion intensity is reflected by one or more intensity indicators which comprise a heart rate of the subject and the absolute intensity range comprise a desired heart rate±x, where x is a percentage parameter.

53. A method according to claim 52 wherein the percentage parameter x is user-configurable.

54. A method according to claim 29 wherein converting the desired intensity to a desired speed comprises using a combination of a model which maps locomotion intensity to locomotion speed and subject specific calibration data.

55. A method according to claim 54 wherein the subject specific calibration data is used to reduce an experimentally determined error between predictions of the model and measured calibration data.

56. A method according to claim 55 wherein the experimentally determined error comprises a combination of experimentally determined errors associated with the model at different intensity levels.

57. A method according to claim 29 wherein converting the desired intensity to a desired speed comprises using experimentally determined subject specific calibration data that maps locomotion intensity to locomotion speed for the subject and for a plurality of discrete intensity levels.

58. A system for guiding a locomotion intensity of a human during a locomotion event, the system comprising:

one or more first sensors for sensing one or more corresponding parameters of the locomotion movement of the subject during the locomotion event and for generating therefrom a measured speed as a function of distance per unit time which represents an estimate of the subject's actual locomotion speed at a particular instant during the locomotion event as a function of distance per unit time;

one or more second sensors for sensing one or more corresponding parameters correlated with an intensity indicator of the subject during the locomotion event and for generating therefrom a measured intensity which represents an estimate of the subject's actual locomotion intensity at the particular instant during the locomotion event;

a controller configured to:

determine an intensity error during the locomotion event, the error comprising a difference between a desired intensity at the particular instant during the locomotion event and the measured intensity for the particular instant during the locomotion event; and

if an absolute value of the intensity error is outside of a threshold region around the desired intensity during the locomotion event:

convert the desired intensity to a desired speed as a distance per unit time;

determine a speed error as a distance per unit time during the locomotion event, the error comprising a difference between the desired speed at a particular instant during the locomotion event and the measured speed for the particular instant during the locomotion event; and

output, to the subject during the locomotion event, a speed-based stimulus frequency signal comprising a tempo wherein the tempo of the speed-based stimulus frequency signal is based on the speed error in such a manner that when the subject ambulates with a gait frequency that matches the tempo of the speed-based stimulus frequency signal, the subject's actual intensity during the locomotion event approximately controllably tracks the desired intensity; and

if the absolute value of the intensity error is within the threshold region around the desired intensity during the locomotion event:

output, to the subject, an intensity-based stimulus frequency signal comprising a tempo wherein the tempo of the intensity-based stimulus frequency signal is based on the intensity error in such a manner that when the subject ambulates with a gait frequency that matches the tempo of the intensity-based stimulus frequency signal, the subject's actual intensity during the locomotion event controllably tracks the desired intensity.

59. A system according to claim 58 wherein, as part of outputting the stimulus frequency signal based on the error, the controller is configured to implement a proportional-integral-derivative (PID) control scheme.