Biofeedback Systemfor Propulsion Training

February 22, 2007

Group Members:Noah Reding

Nick Chadwick

Tom Soike

Project Sponsor: Dr. Mark Richter, MAX Mobility

Faculty Advisor: Dr. Paul King, Vanderbilt University

MAX Mobility Lab

• Operating Treadmill with possible incline

• Multiple PCs for data collection

• Radio transmitters for communication

Lab Safety Precautions

• Rising elevator for patients’ use

• Safety harness attached to chair on treadmill

• Discomfort scale for patients

• Emergency stop button for treadmill

Problem of Interest

Currently, there are over 2.5 million1 Americans who are confined to wheelchairs. Some users propel themselves improperly, leading to damage of their upper extremities later in life.

Project Goal

Develop software that works with an established propulsiometer to effectively “teach” new and existing wheelchair users proper propulsion methods, in hopes of reducing their chances of developing injuries of the upper extremities later on.

People Affected

• Approx. 65% wheelchair users experience upper extremity pain or injury2

• Research has linked a relationship between impact stresses placed upon the wrist, elbow, and shoulder during propulsion to upper extremity injury2

Market Analysis

• Currently, the personal mobility device industry is a $2-3 Billion operation3

• Constructive surgeries for extremities start at $10,000 and can greatly increase

• US demand for mobility devices and wheelchairs is projected to increase 6.9% annually and is expected to reach $7.4 Billion by 20124

• Our primary targets are physical therapist treating handicapped individuals, In the US alone there are more than 77,000 practicing physical therapists5

Population Change

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1970 1980 1990 2000 2010 2020

Year

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Wheelchair Users

US population

Performance Criteria

• To improve a pre-existing device for the capturing of real-time propulsion data

• Relay this data to a user-friendly interface, allowing for instantaneous alterations of one’s push tendencies.

• Data to be collected and analyzed:– Push frequency– Push angle– Peak force– Tangential force– Peak loading rate

Existing Solutions

Smart Wheel from 3RiversMeasures:1. Average force of push2. Length of push 3. Smoothness of push4. Push frequency

Disadvantages:1. Only fits one size of wheel2. No real-time data relay3. Costs $22,500

Our Primary Objective

• Collect and analyze data in real-time

• Fits any size wheel

• Develop a program in LabVIEW that can collect and analyze real-time data from the device.

• The data will be compared to the proper propulsion technique determined from research companies in the future.

Hardware Work

• Mini-Dat Computer collects all data with load cells

• Radio transmitter sends data to PC

• Frame with hardware fits on all-size wheels

• Connected new angle sensor to existing hardware for data collection

Solution Description 7 Different Channels of Data

Separate Into Each Channel

Gather Offset Data for Each

Subtract Offset From Each

Perform Calculations

Obtain 5 Variables of Choice

Further Breakdown of Solution

• Offset Removal– Apply to each channel– Coincide with each angle

• Filtering of Data– If needed

• Calibration Matrix– Comes from manufacturer– Scales data

Factors Involved

1. New angle sensor• More sensitive measurements ($40)

2. Simplify software so that only one

application is needed• Enables faster data collection and calculation• Matlab and LabVIEW combined into one ($0)

3. Providing data to the user in an interface• Currently in developed stages

Performance Metrics

• Perform all calculations in < 1 sec.

• Sampling rate of 200 Hz

• Relay information through user-friendly interface

• Improving Cost/Benefit – New device will be cheaper than existing

technology ($22,500 vs. $12,000) and provide real time measurement

System and Environment

Wheelchair User Propels

Data collectedSent to computer

Programs analyze and Interpret data

LabVIEW program(s)

Data read by user;Improves method

Data sent to user interface

Project Flow Chart

Learn to use Programs

Collect Sample Data

Interpret Sample Data

Assess Problems / Concerns

Redesign Programs

Interpret Real Time Data

Assess Progress / Direction For Interface

Meet with Advisor / Discuss Direction and Programs

Divide Programs Among Members

Collect Real Time Data

Completed WorkCurrent Work Future Work

References

1. http://www.wsana.org/id115.html2. http://www.thewheelchairsite.com3. http://www.beneficialdesigns.com/BD/4. http://www.pages.drexel.edu/~garfinkm/

Scale.Mkt.html5. http://www.wheelchairfoundation.org/6. http://www.3rivers.com/swhome.php7. http://www.marketresearch.com/product/

display.asp?productid=1352736&xs=r&SID=55812406-375239627-353243901&curr=USD

Questions?

http://www.bme.vanderbilt.edu/srdesign/2006/group16