System and method to predict and avoid musculoskeletal injuries

• US 8,942,662 B2
• Filed: 02/15/2013
• Issued: 01/27/2015
• Est. Priority Date: 02/16/2012
• Status: Active Grant

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: The United States of America As Respresented By The Secretary of The Department of Health and Human Services Centers For Disease Control and Prevention
• Inventors: Pan, Christopher S., Zeng, Shengke, Wimer, Bryan
• Primary Examiner(s): TRAN, CONGVAN
• Application Number:
  US13/768,290
• Publication Number:
  US 20130217352A1
• Time in Patent Office: 711 Days
• Field of Search: 340/539.11, 340/539.12, 340/540, 340/573.1, 455/404.1, 455/403, 455/408
• US Class Current: 455/404.1
• CPC Class Codes: A61B 2503/20 Workers
• CPC Class Codes: A61B 5/0024 for multiple sensor units attached to the patient, e.g. using a body or personal area network
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• CPC Class Codes: A61B 5/1112 Global tracking of patients, e.g. by using GPS
• CPC Class Codes: A61B 5/1117 Fall detection
• CPC Class Codes: A61B 5/1121 Determining geometric values, e.g. centre of rotation or angular range of movement
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61B 5/747 in case of emergency, i.e. alerting emergency services
• CPC Class Codes: G08B 21/02 Alarms for ensuring the safety of persons
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment
• CPC Class Codes: G16H 50/70 for mining of medical data, e.g. analysing previous cases of other patients

Abstract

A miniaturized, ruggedized, field-deployable Portable Exposure Assessment System (PEAS) is used to remotely monitor workers and provide real-time warning of exposure to musculoskeletal injury conditions via alarm and smart-phone transmission. The PEAS unit wirelessly acquires exposure data from sensors; conducts initial data analysis; triggers proximal and remote alarms; sends out text messages with abnormal data, GPS locations, and time stamps to a safety office; and saves data for more extensive assessment. Sensor technology is used in this field-deployable system to simultaneously measure and collect the body loads and awkward postures imposed by package handling as well as driving-related, low-frequency vibration exposures. Wireless technology is used to set up wireless communication links between the sensors and a data logger and between the data logger and a smart phone with GPS, date/time stamp and text messaging capabilities.

Claims

1. A system for assessing whether a user is exposed to conditions which might lead to a musculoskeletal injury, comprising:

a plurality of body-worn sensors, each sensor being operative to measure conditions associated with body loading, posture or vibration and transmit a wireless signal containing data about such conditions;

a portable, body-worn data logger including a wireless receiver for receiving the signals transmitted by the sensors, the data logger including a processor and a memory for storing predefined safety thresholds, the processor being operative to calculate hand (wrist) positions and torso angles, and compare the data received from the sensors or retrieved from its calculation results to the safety thresholds to determine if the user'"'"'s body loading, posture or vibration may lead to a musculoskeletal injury; and

an alarm generated in response to a determination that a risk of musculoskeletal injury is present.

2. The system of claim 1, including a body-worn alarm and a remote alarm in wireless communication with the data logger.

3. The system of claim 1, wherein the data logger is operative to generate a remote alarm to a smart phone with GPS, data/time stamps and text messaging capabilities.

4. The system of claim 1, wherein the sensors include one or more of the following:

angular sensors disposed on the upper and lower arms,

angular sensors disposed on the torso,

a vibration sensor disposed on the torso, and

foot force sensors.

5. The system of claim 4, including right and left wireless gyroscope angular measurement sensors to determine the hand (wrist) positions of a user.

6. The system of claim 5, wherein each wireless gyroscope angular measurement sensor includes a triaxial gyroscope (G1, G2) to measure the angular velocities of the upper arm and lower arm and a microcontroller to calculate the elbow position relative to the shoulder joint and the wrist position relative the elbow joint.

7. The system of claim 6, wherein:

each wireless gyroscope angular measurement sensor further includes a radio frequency (RF) transceiver to transmit the elbow and wrist position data to the data logger; and

the data logger calculates the wrist position relative to the shoulder joint.

8. The system of claim 7, wherein:

G1 is mounted near the elbow of the upper arm;

G2 is mounted near the wrist of the lower arm;

G1 measures the elbow'"'"'s pitch, yaw and roll angular velocities;

the microcontroller associated with G1 performs the following operations;

calculates the elbow'"'"'s pitch, yaw and roll angles by computing the integral of G1'"'"'s pitch, yaw and roll angular velocities,

consecutively converts the pitch, yaw and roll angles into the spherical elevation and azimuth angles, and

calculates the elbow position relative to the shoulder joint using the following equations;

x1=r1 sin α

1 cos β

1  

 

(1)

y1=r1 sin α

1 sin β

1  

 

(2)

z1=r1 cos α

1  

 

(3)

where x1, y1, and z1 are the position coordinates of the elbow relative to the shoulder joint, r1 is the length of the upper arm, and α

1 and β

1 are elevation and azimuth angles of G1.

9. The system of claim 8, wherein:

in the same way to calculate the position coordinates of the elbow relative to the shoulder joint, the microcontroller associated with G2 is operative to calculate the wrist position relative to the elbow joint using the following equations;

x2=r2 sin α

2 cos β

2  

 

(4)

y2=r2 sin α

2 sin β

2  

 

(5)

z2=r2 cos α

2  

 

(6)

where x2, y2, and z2 are the position coordinates of the wrist relative to the elbow joint, r2 is the length of the lower arm, and α

2 and β

2 are elevation and azimuth angles of G2.

10. The system of claim 9, wherein:

the data logger receives the x1, y1 and z1 position coordinates from G1'"'"'s RF transceiver and receives the x2, y2 and z2 position coordinates from G2'"'"'s RF transceiver; and

the data logger'"'"'s microcontroller calculates the wrist position relative to the shoulder joint using the following equations;

x=x1+x2  

 

(7)

y=y1+y2  

 

(8)

z=z1+z2  

 

(9)

where x, y, and z are the position coordinates of the wrist relative to the shoulder joint.

11. The system of claim 4, including gyroscope torso angle measurement sensors, one mounted proximate to vertebra L1 and another mounted proximate to S1.

12. The system of claim 11, wherein:

each gyroscope torso angle measurement sensor includes a triaxial gyroscope (G3, G4) to measure the angular velocities, with G3 being mounted on vertebra L1 and G4 being mounted on vertebra S1; and

a microcontroller to calculate the angles of L1 and S1.

13. The system of claim 12, wherein each gyroscope torso angle measurement sensor further includes a radio frequency (RF) transceiver to transmit the L1 and S1 angle data to the data logger.

14. The system of claim 13, wherein:

the microcontroller associated with G3 calculates the pitch, yaw and roll angles of L1 by computing the integral of the pitch, yaw and roll angular velocities; and

the microcontroller associated with G4 calculates the pitch, yaw and roll angles of S1 by computing the integral of the pitch, yaw and roll angular velocities.

15. The system of claim 14, wherein:

the data logger receives the L1 and S1 pitch, yaw and roll angles from the L1 and S1 transceivers, and calculates the torso pitch, yaw and roll angles;

torso pitch angle is computed as the difference of the L1 and S1 pitch angles;

torso yaw angle is computed as the difference of the L1 and S1 yaw angles; and

torso roll angle is computed as the difference of the L1 and S1 roll angles.

16. The system of claim 1, including a wireless accelerometer sensor to measure torso acceleration.

17. The system of claim 1, including wireless foot force sensors to measure foot force distribution.

18. The system of claim 1, wherein the data logger performs an initial analysis of the sensor measurement data and wirelessly transfer the processed data to a smart phone.

19. The system of claim 18, wherein the data logger further transfers the processed data to a computer via a computer interface.

20. The system of claim 1, wherein the data logger is operative to wirelessly send commands via a Bluetooth module to a smart phone to dial an emergency number and send out a text message containing a prerecorded safety message, a summary of the data, corresponding GPS locations, and time stamps.

21. The system of claim 1, including a smart phone that can wirelessly receive and store the processed data from the data logger via its Bluetooth interface and transfer the saved data to a computer via a computer interface.

22. The system of claim 16, wherein:

the torso vibration sensor includes an accelerometer that measures the low-frequency acceleration of the lower back in real time;

a microcontroller that periodically calculates the root-mean-square (RMS) values of the acceleration; and

a transceiver that transmits the RMS acceleration data to the data logger at the end of each RMS period.