Method of confirming motion parameters apparatus for the same, and motion assisting device

• US 8,725,452 B2
• Filed: 10/07/2011
• Issued: 05/13/2014
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: Beijing Shunyuan Kaihua Technology Limited
• Original Assignee: Zepp Labs, Inc. (Zepp Health Corporation)
• Inventors: Han, Zheng
• Primary Examiner(s): CHERRY, STEPHEN J
• Application Number:
  US13/269,236
• Publication Number:
  US 20120278023A1
• Time in Patent Office: 949 Days
• Field of Search: 702/152
• US Class Current: 702/152
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 2562/028 Microscale sensors, e.g. electromechanical sensors [MEMS]
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/7242 using integration
• CPC Class Codes: A63B 2102/32 Golf
• CPC Class Codes: G01C 21/1654 with electromagnetic compass

Abstract

The invention provides a method of confirming motion parameters, an apparatus for the same, and a motion assisting device. The invention obtains and utilizes the motion data of a recognized object sampled at each of the sampling time, comprising the acceleration of the recognized object sampled by a tri-axial accelerometer, the angular velocity of the recognized object sampled by a tri-axial gyroscope, and the angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system sampled by a tri-axial magnetometer. Feedback calculation is utilized to obtain an actual acceleration at each sampling time from the motion original time to the motion end time, and the actual acceleration is obtained by reducing the acceleration of gravity from the acceleration sampled by a tri-axial accelerometer. The invention reduces the complexity of the system, and the accuracy is less affected by environmental factors, particularly light.

Claims

1. A method of ball game motion recognition, comprising:

obtaining and storing motion data at each sampling time, the motion data comprising;

acceleration of a recognized object, angular velocity of the recognized object, and an angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system;

performing motion static detection utilizing the acceleration stored at each of the sampling time to confirm a motion original time t_o and a motion end time t_e of a motion;

confirming an original stance matrix T_m^bInit corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_o according to the angle stored at the motion original time t_o; and

using each of the sampling time sequentially as a current sampling time to perform the steps of;

confirming and recording a stance change matrix T_bInit^bCur from the current sampling time to the motion original time t_o according to the angular velocity stored at the current sampling time and at a previous sampling time, and a stance change matrix T_bInit^bPre from the previous sampling time to the motion original time t_o;

confirming a stance matrix T_m^bCur at the current sampling time corresponding to the three-dimensional geomagnetic coordinate system as T_m^bCur=T_m^bInitT_bInit^bCur; and

obtaining an actual acceleration a_m^Mcur at the current sampling time by adjusting the acceleration a^Cur at the current sampling time utilizing the stance matrix T_m^bCur to reduces an acceleration of gravity {right arrow over (g)} from the acceleration a^Cur at the current sampling time.

2. The method as claimed in claim 1, further comprising, after obtaining and before storing the motion data at each sampling time, at least one of:

performing interpolation processing to the motion data obtained at each of the sampling time; and

performing filtering processing to the motion data obtained at each of the sampling time.

3. The method as claimed in claim 1, further comprising, after obtaining and before storing the motion data at each sampling time:

performing data calibration to the motion data at each of the sampling time utilizing a zero drift {right arrow over (ω

)}₀ of a tri-axial accelerometer sampling the acceleration.

4. The method as claimed in claim 1, wherein the storing of the motion data further comprises:

storing most recently obtained number N of the motion data to a cache;

wherein N is an integer of 3 or higher, and the motion data in the cache is in an order of the sampling time with the motion data of a latest sampling time at an end of a queue in the cache.

5. The method as claimed in claim 1, wherein performing motion static detection further comprises:

performing judgment according to predetermined motion time confirming tactics to each of the sampling time in sequence of the sampling time, if at the sampling time t_o the predetermined motion time confirming tactics are satisfied and at the sampling time t_o−

1 the predetermined motion time confirming tactics are not satisfied, confirming the sampling time t_o as the motion original time; and

if at the sampling time t_e the predetermined motion time confirming tactics are satisfied and at the sampling time t_e+1 the predetermined motion time confirming tactics are not satisfied, confirming the sampling time t_e as the motion end time.

6. The method as claimed in claim 5, wherein the predetermined motion time confirming tactics comprises:

confirming one of the sampling time t_x as motion time if a modulated variance a_v of the acceleration from a number T of the sampling time before the sampling time t_x is larger than or equal to a predetermined acceleration variance threshold and a modulated acceleration a₀ at the sampling time t_x is larger than or equal to a predetermined motion acceleration threshold, wherein the number T is a predetermined positive integer.

7. The method as claimed in claim 1, further comprising, before confirming an original stance matrix T_m^bInit:

comparing a time interval between the motion original time t_o and a last motion original time t′

to a predetermined time period threshold, and if the time interval is shorter than the predetermined time period threshold, confirming a stance matrix corresponding to the three-dimensional geomagnetic coordinate system at the last motion original time t′

as the original stance matrix T_m^bInit corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_o, and not confirming an original stance matrix.

8. The method as claimed in claim 1, wherein confirming and recording a stance change matrix T_bInit^bCur further comprises:

confirming the stance change matrix T_bPre^bCur from the previous sampling time to the current sampling time according to the angular velocity data stored at the current sampling time and at the previous sampling time; and

obtaining the stance change matrix T_bInit^bPre from the previous sampling time to the motion original time t_o, and confirming a stance change matrix T_bInit^bCur from the current sampling time to the motion original time t_o as T_bInit^bCur=T_bInit^bPreT_bPre^bCur.

9. The method as claimed in claim 8, wherein the step S411 further comprises:

confirming the angular velocity data w_P stored the previous sampling time is w_P=[ω

_Px,ω

_Py,ω

_Pz]^T and the angular velocity data w_C at the current sampling time is w_C=[ω

_Cx,ω

_Cy,ω

_Cz]^T; and

confirming the stance change matrix T_bPre^bCur from the previous sampling time to the current sampling time as T_bPre^bCur=R_ZR_YR_X, wherein R_Z is a stance change matrix of the angular velocity data w_P rotating (ω

_Pz+ψ

_Cz)t/2 around a Z-axis, R_Y is a stance change matrix of the angular velocity data w_P rotating (ω

_Py+ω

_Cy)t/2, around a Y-axis, R_X is a stance change matrix of the angular velocity data w_P rotating (ω

_Px+ω

_Cx)t/2 around a X-axis, and t is a time interval between adjacent sampling time.

10. The method as claimed in claim 1, wherein obtaining an actual acceleration further comprises:

obtaining the actual acceleration a_m^Mcur at the current sampling time as a_m^Mcur=T_m^bCura^cur−

{right arrow over (g)}, wherein {right arrow over (g)} is the acceleration of gravity under the three-dimensional geomagnetic coordinate system.

11. The method as claimed in claim 10, wherein the acceleration of gravity {right arrow over (g)} can be confirmed by:

obtaining the acceleration and the angle sampled from a nonmoving object with M numbers of consecutive sampling time; and

confirming the acceleration of gravity {right arrow over (g)} under the three-dimensional geomagnetic coordinate system as

12. The method as claimed in claim 1, further comprising, after obtaining an actual acceleration:

performing integral to the actual acceleration a_m^Mcur from the motion original time t_o to the current sampling time to obtain a real-time velocity at the current sampling time, and performing integral to the real-time velocity from the motion original time t_o to the current sampling time to obtain a position at the current sampling time.

29. The method of claim 1, further comprising confirming an original stance matrix T_m^bInit corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_o according to the angle stored at the motion original time t_o.

13. An apparatus for confirming motion parameters, comprising:

a motion data obtaining unit to obtain motion data at each sampling time of a motion, the motion data comprising;

acceleration of a recognized object sampled by a tri-axial accelerometer, angular velocity of the recognized object sampled by a tri-axial gyroscope, and an angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system sampled by a tri-axial magnetometer;

a data storage unit to store the motion data;

a motion static detecting unit to perform motion static detection utilizing the acceleration stored in the data storage unit at each of the sampling time to confirm a motion original time t_o and a motion end time t_o of the motion;

an original stance confirming unit to confirm an original stance matrix T_m^bInit corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_o according to the angle stored in the data storage unit at the motion original time t_o; and

a motion parameter confirming unit to confirm the acceleration at each of the sampling time by using the sampling time after the motion original time t_o and before the motion end time t_o sequentially as a current sampling time;

wherein the motion parameter confirming unit comprises;

a stance change confirming module to confirm and record a stance change matrix T_b^bCur from the current sampling time to the motion original time t_o according to the angular velocity stored in the data storage unit at the current sampling time and at a previous sampling time, and a stance change matrix T_bInit^bPre from the previous sampling time to the motion original time t_o;

a real-time stance confirming module to confirm a stance matrix T_m^bCur at the current sampling time corresponding to the three-dimensional geomagnetic coordinate system as T_m^bCur=T_m^bInitT_bInit^bCur; and

a degravitation module to obtain an actual acceleration a_m^Mcur at the current sampling time by adjusting the acceleration a^Cur at the current sampling time utilizing the stance matrix T_m^bCur to reduces an acceleration of gravity {right arrow over (g)} from the acceleration a^Cur at the current sampling time.

14. The apparatus as claimed in claim 13, further comprising at least one of a preprocessing unit and a filtering processing unit, wherein:

the preprocessing unit is configured to perform interpolation processing to the motion data obtained by the motion data obtaining unit and sent to the data storage unit; and

the filtering processing unit is configured to perform filtering processing to the motion data obtained by the motion data obtaining unit and sent to the data storage unit.

15. The apparatus as claimed in claim 13, further comprising a data calibration unit to perform data calibration to the motion data obtained by the motion data obtaining unit and sent to the data storage unit utilizing a zero drift {right arrow over (ω

)}_o of the tri-axial accelerometer sampling the acceleration.

16. The apparatus as claimed in claim 13, wherein the data storage unit stores most recently obtained number N of the motion data to a cache, wherein N is an integer of 3 or higher, and the motion data in the cache is in an order of the sampling time with the motion data of a latest sampling time at an end of a queue in the cache.

17. The apparatus as claimed in claim 13, wherein the motion static detecting unit performs judgment according to predetermined motion time confirming tactics to each of the sampling time in sequence of the sampling time, and if at the sampling time t_o the predetermined motion time confirming tactics are satisfied and at the sampling time t_o−

1 the predetermined motion time confirming tactics are not satisfied, the sampling time t_o is confirmed as the motion original time; and

if at the sampling time t_e the predetermined motion time confirming tactics are satisfied and at the sampling time t_e+1 the predetermined motion time confirming tactics are not satisfied, the sampling time t_e is confirmed as the motion end time.

18. The apparatus as claimed in claim 17, wherein the predetermined motion time confirming tactics comprises:

confirming one of the sampling time t_x as motion time if a modulated variance a_v of the acceleration from a number T of the sampling time before the sampling time t_x is larger than or equal to a predetermined acceleration variance threshold and a modulated acceleration a₀ at the sampling time t_x is larger than or equal to a predetermined motion acceleration threshold, wherein the number T is a predetermined positive integer.

19. The apparatus as claimed in claim 13, wherein the original stance confirming unit comprises:

a motion interval comparing module to compare a time interval between the motion original time t_o and a last motion original time t′

to a predetermined time period threshold; and

an original stance confirming module to confirm the original stance matrix T_m^bInit corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_o according to the angle stored in the data storage unit at the motion original time t_o if the time interval is not shorter than the predetermined time period threshold, and to confirm a stance matrix corresponding to the three-dimensional geomagnetic coordinate system at the last motion original time t′

as the original stance matrix T_m^bInit corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_o if the time interval is shorter than the predetermined time period threshold.

20. The apparatus as claimed in claim 13, wherein the stance change confirming module comprises:

a first stance change confirming submodule to confirm the stance change matrix T_bPre^bCur from the previous sampling time to the current sampling time according to the angular velocity data stored at the current sampling time and at the previous sampling time; and

a second stance change confirming submodule to obtain the stance change matrix T_bInit^bPre from the previous sampling time to the motion original time t_o, and confirming a stance change matrix T_bInit^bCur from the current sampling time to the motion original time t_o as T_bInit^bCur=T_bInit^bPreT_bPre^bCur.

21. The apparatus as claimed in claim 20, wherein the first stance change confirming submodule confirms the angular velocity data w_P stored the previous sampling time is w_P=[ω

_Px,ω

_Py,ω

_Pz]^T and the angular velocity data w_C at the current sampling time is w_C=[ω

_Cx,ω

_Cy,ω

_Cz]^T, and confirms the stance change matrix T_bPre^bCur from the previous sampling time to the current sampling time as T_bPre^bCur=R_ZR_YR_X, wherein R_Z is a stance change matrix of the angular velocity data w_P rotating (ω

_Pz+ω

_Cz)t/2 around a Z-axis, R_Y is a stance change matrix of the angular velocity data w_P rotating (ω

_Py+ω

_Cy)t/2, around a Y-axis, R_X is a stance change matrix of the angular velocity data w_P rotating (ω

_Px+ω

_Cx)t/2 around a X-axis, and t is a time interval between adjacent sampling time.

22. The apparatus as claimed in claim 13, wherein the degravitation module obtains the actual acceleration a_m^Mcur at the current sampling time as a_m^Mcur=T_m^bCura^cur−

{right arrow over (g)}, wherein {right arrow over (g)} is the acceleration of gravity under the three-dimensional geomagnetic coordinate system.

23. The apparatus as claimed in claim 22, further comprising a gravitational motion parameter confirming unit, wherein the gravitational motion parameter confirming unit comprises:

a data obtaining module to obtain the acceleration and the angle sampled from a nonmoving object with M numbers of consecutive sampling time; and

a gravity acceleration confirming module to confirm the acceleration of gravity {right arrow over (g)} under the three-dimensional geomagnetic coordinate system as

24. The apparatus as claimed in claim 13, wherein the motion parameter confirming unit further comprises:

a velocity confirming unit to obtain a real-time velocity at the current sampling time by performing integral to the actual acceleration a_m^Mcur from the motion original time t_o to the current sampling time, and

a position confirming unit to obtain a position at the current sampling time by performing integral to the real-time velocity from the motion original time t_o to the current sampling time.

25. A motion assisting device, comprising:

an apparatus for confirming motion parameters as claimed in claim 13; and

a sensor device to sample the motion data of the recognized object at each of the sampling time, the motion data comprising;

the acceleration of the recognized object, the angular velocity of the recognized object, and the angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system.

26. The motion assisting device as claimed in claim 25, wherein the sensor device comprises:

a tri-axial accelerometer to sample the acceleration of the recognized object;

a tri-axial gyroscope to sample the angular velocity of the recognized object; and

a tri-axial magnetometer to sample the angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system.

27. The motion assisting device as claimed in claim 25, further comprising:

a processor to retrieve and transmit the motion data from the sensor device to the motion parameter confirming device according to predetermined transfer protocol.

28. The motion assisting device as claimed in claim 25, further comprising:

data transmit interface to send motion parameters of the predetermined ball game type recognized by the apparatus for ball game motion recognition to a peripheral device.