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Instrumented Wheel. For Wheelchair Propulsion Assessment. Jacob Connelly Andrew Cramer John Labiak. Problem Statement. Manual wheelchair users (MWU) are at considerable risk of developing upper extremity (UE) overuse injuries. UE are primary means of mobility.
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Instrumented Wheel For Wheelchair Propulsion Assessment. Jacob Connelly Andrew Cramer John Labiak
Problem Statement • Manual wheelchair users (MWU) are at considerable risk of developing upper extremity (UE) overuse injuries. • UE are primary means of mobility. • Extensive UE use in seating transfer. • UE function is injury level dependent.
Instrumented Wheel for Propulsion Assessment • Decrease UE use in propulsion. • Increasing push length: • Decreases overall resultant force need. • Study resultant force application to: • Achieve equal propulsion with less force. • Increased stroke length • Decreased cadence.
Project Goals • Develop an inexpensive instrument capable of measuring applied resultant force in order to analyze propulsion techniques of MWU. • Propulsion assessment. • Properly seat user. • Train user. • Lower instrument cost < $5K • SmartWheel ~ $25K • Load cell propulsiometer > $10K
Solution • Strain gauges used to measure resultant force. • ΔV calculate strain calculate resultant force. • Create ΔV vs. Force standard curve. • 6 push-rim attachments. This is variable.
Solution • Voltage divider circuit. • 1mV change with a 4V offset result in 1.25mV sensitivity. • Contingencies involve instrumentation amplifier design. • 8-Pin DAQ unit. • Bluetooth wireless transceiver (USB compatible) T C
Completed Work • Instrumented wheel design complete – opposing strain gauges per push-rim attachment. • Circuit design complete – voltage divider config. with offset voltage compensation designed. • backup circuit design of differential operational amplifier config. designed • All experimental elements ordered and received. • Gauges attached to instrumented wheel. T C
Current Work • Wire gauges to circuit network and DAQ card. • Set-up Bluetooth wireless transmitter and receiver. • Ensure that proper software (LabVIEW, MatLab) is available to us through Max Mobility LLC. • Attempt to move some product on campus for easier and more frequent access.
Future Work • Begin recording change in voltage data. • Relate change in voltage to obtain strain data. • Analyze trends in the strain data. • Calibrate the strain data to form a resultant force curve. • Gauge success/need to reevaluate system.