US 11,832,931 B2
Methods for calibrating a motion and ground reaction force analysis system
Stanislaw Czaja, Cardiff, CA (US); and Lora O'Leary, Cardiff, CA (US)
Assigned to Motion Metrics Limited, London (GB)
Filed by Motion Metrics Limited, London (GB)
Filed on Mar. 17, 2021, as Appl. No. 17/204,817.
Application 17/204,817 is a continuation in part of application No. 15/953,439, filed on Apr. 14, 2018, abandoned.
Application 15/953,439 is a continuation in part of application No. 14/747,179, filed on Jun. 23, 2015, granted, now 9,968,840, issued on May 15, 2018.
Prior Publication US 2021/0196150 A1, Jul. 1, 2021
Int. Cl. A61B 5/103 (2006.01); A61B 5/00 (2006.01); A61B 5/11 (2006.01); A43B 3/34 (2022.01)
CPC A61B 5/1038 (2013.01) [A43B 3/34 (2022.01); A61B 5/112 (2013.01); A61B 5/6807 (2013.01); A61B 2562/0219 (2013.01); A61B 2562/0247 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method of calibration of a system designed for analysis of motion of a user's feet in relation to ground reaction forces, wherein the system comprises at least two motion processing elements, each motion processing element including a three-axis accelerometer, a three-axis gyroscope, a three-axis magnetometer and a plurality of force sensors, and wherein the system further comprises a left and a right footwear, and wherein the left footwear has a corresponding and associated motion processing element, and wherein the right footwear has another corresponding and associated motion processing element, wherein the method compensates for inaccuracies arising in some instances from fabrication and assembly of the motion processing elements and the footwear, the method comprising:
a. instructing the user to step into the left and the right footwear, wherein the user's weight is equally distributed between the left footwear and the right footwear and wherein the footwear each have a longitudinal axis and wherein the longitudinal axis of the footwear are approximately parallel to each other, for each of the footwear performing the following:
b. for the x-axis and the y-axis of the accelerometer of the footwear:
i. obtaining a plurality of independent data measurements from the x-axis and the y-axis of the accelerometer;
ii. calculating an average of the x-axis and y-axis data measurements obtained from the x-axis and y-axis of the accelerometer;
iii. recording an average of the data measurements as the calibration offset of the respective x and y axis of the accelerometer; and
c. for the z-axis of the accelerometer:
i. obtaining a plurality of independent data measurements from the z-axis of the accelerometer;
ii. obtaining a plurality of independent data measurements from the z-axis of the magnetometer of the footwear;
iii. subtracting the value obtained from the magnetometer z-axis from the value obtained from the accelerometer z-axis and storing the result as a calibration offset of the z-axis of the accelerometer; or subtracting the value of 0.98066 from the value of the accelerometer z-axis and storing the result as a calibration offset of the z-axis of the accelerometer; and
d. for the data measurements obtained from the x, y, and z-axis of the gyroscope of the footwear:
i. computing Euler angles of each respective x, y, and z-axis of the gyroscope; and
ii. recording the computed Euler angles of each respective x, y, and z-axis as the calibration offsets of each respective x, y, and z-axis of the gyroscope; and
e. for the data measurements obtained from the plurality of force sensors of the footwear, subtracting a value of 0.00 and recording the difference as a calibration offset of the respective force sensors.