METHOD AND SYSTEM FOR QUANTIFYING AN INTENTION OF MOVEMENT OF A USER

• US 20100292617A1
• Filed: 05/15/2009
• Published: 11/18/2010
• Est. Priority Date: 05/15/2009
• Status: Active Grant

• Current Assignee: Chak Seng Leung
• Original Assignee: Chak Seng Leung
• Inventors: Leung, Wallace Woon-Fong, Lei, Kin Fong
• Granted Patent: US 8,376,968 B2
• Time in Patent Office: Days
• US Class Current: 600/595
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/4519 Muscles A61B5/389, A61B5/224 take precedence
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric

Abstract

A method for quantifying an intention of movement of a user, the method comprising: extracting (61) a mechanomyogram (MMG) signal in response to surface vibration of a muscle of the user; and averaging (62) the MMG signal by calculating the MMG root mean squared (RMS) amplitude (63) or frequency variance (64) in a predetermined time window; where an increasing RMS amplitude of the MMG signal corresponds to increasing muscle voluntary contraction or a decreasing frequency variance of the MMG signal corresponds to increasing muscle voluntary contraction.

Claims

1. A method for quantifying an intention of movement of a user, the method comprising:

extracting a mechanomyogram (MMG) signal in response to surface vibration of a muscle of the user; and

averaging the MMG signal by calculating the MMG root mean squared (RMS) amplitude or frequency variance in a predetermined time window;

where an increasing RMS amplitude of the MMG signal corresponds to an increasing muscle voluntary contraction or a decreasing frequency variance of the MMG signal corresponds to an increasing muscle voluntary contraction.

2. The method according to claim 1, wherein the frequency variance of the MMG signal is the scale or degree of frequency being spread out in a power density spectrum (PDS).

3. The method according to claim 1, wherein both RMS MMG amplitude and the frequency variance of the MMG signal are used to estimate a level of muscle contraction.

4. The method according to claim 1, wherein the muscle contraction level is normalized to a percentage of maximal voluntary contraction (MVC).

5. The method according to claim 4, further comprising instructing a robotic system according to the estimated percentage of MVC.

6. The method according to claim 1, wherein the RMS amplitude is normalized as a percentage of a span between a maximal and a minimum value.

7. The method according to claim 1, wherein the frequency variance of the MMG signal is normalized as a percentage of a span between a maximal and a minimum value.

8. The method according to claim 1, wherein the predetermined time window is 1 second with 100 ms step forward.

9. A system for quantifying an intention of movement of a user, the system comprising:

a measurement unit to extract a mechanomyogram (MMG) signal in response to surface vibration of a muscle of the user;

a signal processing unit to average the MMG signal by calculating the MMG root mean squared (RMS) amplitude or frequency variance in a predetermined time window;

where an increasing RMS amplitude of the MMG signal corresponds to an increasing muscle voluntary contraction or a decreasing frequency variance of the MMG signal corresponds to an increasing muscle voluntary contraction.

10. The system according to claim 9, further comprising another signal processing unit to pre-process a raw signal corresponding to the surface vibration of a muscle of the user.

11. The system according to claim 9, further comprising a modeling unit to translate the RMS amplitude signal and the frequency variance of the MMG signal into a set of instructions for recording or actuating a robot or an actuation unit of the robot.

12. The system according to claim 9, wherein the measurement unit comprises at least one sensor to detect surface vibration of the muscle and generate an output signal.

13. The system according to claim 9, wherein the measurement unit weighs less than or is equal to five grams.

14. The system according to claim 12, wherein the sensor is any one from the group consisting of:

condenser microphones, piezoelectric transducers, dual-axis accelerometers, MEMS-based accelerometers and angle-measurement devices.

15. The system according to claim 12, wherein the output signal is passed through a band pass filter from 2 to 40 Hz to extract the MMG signal from the output signal.

16. The system according to claim 9, wherein the instructions are transmitted to a robotic system to control the robotic system.

17. The system according to claim 11, wherein motion and environmental parameters of the robotic system are recorded by sensors and transmitted back to the modeling unit via a feedback signal.

18. The system according to claim 17, wherein the motion parameters include dynamic parameters such as force and torque, and kinematic parameters such as linear and angular displacement, velocities, and accelerations.