ATHLETE SPEED PREDICTION METHOD USING DATA FROM ATTACHED INERTIAL MEASUREMENT UNIT

• US 20140297008A1
• Filed: 03/25/2014
• Published: 10/02/2014
• Est. Priority Date: 03/28/2013
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: PERKINS, Noel C., MCGINNIS, Ryan S.
• Granted Patent: US 9,213,889 B2
• Time in Patent Office: Days
• US Class Current: 700/91
• CPC Class Codes: G06V 40/23 Recognition of whole body movements, e.g. for sport training

Abstract

An apparatus and method for calculating athlete speed non-invasively, on the field/court of play using data from a torso-mounted inertial measurement unit. The method complements existing, GPS-based methods for calculating athlete speed by enabling use in environments where GPS signal is unavailable (i.e. indoors).

Claims

1. A method for non-invasively obtaining velocity information of a subject, said method comprising:

attaching an inertial measurement unit to the subject, said inertial measurement unit providing three-axis sensing of angular velocity and linear acceleration of the subject;

calculating data associated with said angular velocity and linear acceleration at at least a first time, the subject being stationary at said first time;

determining a drift error of a velocity of the subject as a function of time in response to said data at said first time; and

calculating a corrected velocity of the subject at said second time in response to said drift error and outputting said corrected velocity.

2. The method according to claim 1 wherein said determining said drift error of said velocity of the subject comprises determining a vector function in time of said velocity of the subject.

3. The method according to claim 1 wherein said angular velocity is substantially due to noise and said linear acceleration at said first time is substantially due to gravity and noise.

4. The method according to claim 1 where said first time is prior to the start of motion of the subject.

5. The method according to claim 1 wherein said first time is after completion of motion of the subject.

6. The method according to claim 1 wherein said second time is during motion of the subject.

7. The method according to claim 6 wherein said calculating data associated with said angular velocity and linear acceleration at at least said first time and said second time comprises calculating data associated with said angular velocity and linear acceleration at at least said first time, said second time, and a third time, the subject being stationary during said first time and said third time such that said determining said drift error of said velocity of the subject is performed in response to said data at said first time, said second time, and said third time according to a piece-wise linear function in time.

8. The method according to claim 7 wherein said drift error determined in response to said first time and said drift error determined in response to said third time are consecutive and approximately equal to each other.

9. The method according to claim 1 wherein said calculating a corrected velocity of the subject at said second time in response to said drift error comprises calculating a corrected velocity according to the following equation:

{right arrow over (ν

)}_c={right arrow over (ν

)}−

{right arrow over (ƒ

)}(t)

where {right arrow over (ν

)} is an uncorrected subject velocity calculated from said measured angular velocity and linear acceleration, {right arrow over (ν

)}_c is said corrected velocity of the subject, and {right arrow over (ƒ

)}(t) is a vector function in time of said drift error.

10. The method according to claim 1 wherein said attaching said inertial measurement unit to the subject comprises attaching an inertial measurement unit to a torso of the subject.

11. The method according to claim 1 wherein said attaching said inertial measurement unit to the subject comprises attaching an inertial measurement unit to a neck of the subject.

12. The method according to claim 1 wherein said attaching said inertial measurement unit to the subject comprises attaching an inertial measurement unit to a mass center of the subject.

13. The method according to claim 1 wherein said calculating said corrected velocity of the subject at said second time in response to said drift error and outputting said corrected velocity comprises calculating said corrected velocity of the subject at said second time at a first location on the subject in response to said drift error and outputting said corrected velocity of said first location and further calculating a corrected velocity of a second location on the subject in response to said corrected velocity of said first location and predetermined kinematic constraints.