Transcript Propulsiometer Instrumented Wheelchair Wheel

Propulsiometer
Instrumented
Wheelchair Wheel
Prepared by:
Seri Mustaza (BME)
Siti Nor Wahida Fauzi (BME)
Ahmad Shahir Ismail (EECE)
Hafizul Anwar Raduan (CompE)
Advisor:
Dr. W Mark Richter (PhD, Director of Research and
Development, MAXmobility)
MAXmobility
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Accessible wheelchair treadmill
Basically, working with ergonomic wheelchair:
 Propulsiometer instrumented wheelchair wheel
 Transfer friendly wheelchair
 Variable Compliance Hand-Rim Prototype (VCHP)
 Effective ways to propel the wheel
Propulsiometer
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Located on tubular hoop that can be mounted on
different sizes of wheelchair’s wheel.
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To access the load applied by manual wheelchair user.
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Consist of DAQ, load cell, wireless transmitter, battery,
DC/DC converter, sensor.
Propulsiometer
Battery
Viasat MiniDAT™
Sensor
Load Cell
DC/DC Converter
Propulsiometer
Data Collected
Angle vs. time
 Torque vs. time
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 Tx
 Ty
 Tz
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Force vs. time:
 Fx
 Fy
 Fz
Force, Torque,
Moments & Wheel
Angle
Data collected from propulsiometer to the PC
Load Cell Signals
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Each of the 6 signals ranges from -5 V to +5 V
12-bit A/D converter
Resolution = range/# of states (10/4096)
For each step size, would equals to 2.4412mV.
Problem
MiniDAT is no longer available
 Bulky
 Use too much power
 Cost = $4,625.00
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Specific Goals
Size: 2 x 2 x 0.5 inches (LWH)
 Weight: ~0.25lb
 Cost: less than $1000.00
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Target Specification
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6 analog channels
A/D converter with 12-bit resolution
1 quadrature encoder input
Wireless capability
Sampling rate of at least 10 kHz
Accepts voltage signal of ±5 volts
Low power consumption (15 watts max)
Small and compact (5 x 5 inches max)
1st Approach
Sensoray Model 526
 Pros:
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 Meet
all requirements
 Built-in Linux/Windows OS
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Cons:
 Does
not support LabVIEW
 Expensive ~$1500
Model 526
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Four 24-bit quadrature
encoder inputs
Eight 16-bit analog ±10V
differential inputs
10kHz sampling rate
Approximately 4 x 4 inches
Single supply (5V, 5mA) input
power
2nd Approach
Sheldon SI-MOD68xx
 Pros:
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 Meet
all requirements
 Built-in Linux/Windows and support the
LabVIEW
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Cons:
 Too
expensive ~$2500
SI-MOD68xx
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Up to 64SE/32DE Analog
Inputs
16-bit resolution, ±10V
100khz/250khz sampling
Two 32-bit quadrature
inputs
7 watts in maximum
configuration
Approximately 4 x 4 inches
3rd Approach
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Multi-companies
Connect the quadrature decoder, A/D converter
and wireless transceiver onto one single PCB board
Pros:
 Optimum functionality
 Low cost
Cons:
 Finding the right components
Solution
3rd approach
 Decision base on:
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 Low
cost
 Flexibility in combining the
components
 No unnecessary functions
Current status
Design the circuit
 Finalize & buy the components for the
circuit
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Components
(A/D converter)
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MAX186
8
channel single-ended
 12-bit resolution
 Input range:  5V
 Sampling rate of 133kHz
 Operates at 5V
Components
(Quadrature decoder)
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GEN-2122-5
 22-bit
Up/Down counter
 5V or 3.3V I/O capability
 Max input speed of 10MHz
 Operates at 5V
Components
(2.4 GHz wireless transceiver)
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Nordic Semiconductor nRF2401
 Data
rate up to 1MHz
 Operating voltage: 3V
 Built-in antenna
 Size: 1.44 x 0.79 x 0.9 inches (LWH)
Components
(5V Voltage Regulator)
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National Semiconductor LM2937
 Max
input voltage: 26V
 Output voltage: 5V
 Current output: 10mA (max)
Circuit example
Work Contribution