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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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.
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Located on tubular hoop that can be mounted on
different sizes of wheelchair’s wheel.
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Mainly use as research tool in lab. Ex: Calculating
metabolic rate
Propulsiometer
Propulsiometer
Battery
Viasat MiniDAT™
Sensor
Load Cell
DC/DC Converter
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, &
Wheel Angle
Data collected from propulsiometer to the PC
Load Cell signals
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.
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MiniDAT™
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MiniDAT™
 16-bit resolution
 16 single ended or 8 differential analog inputs
 8 digital I/O lines
 IEEE 802.11 wireless LAN
 Uses 15V DC voltage
 7.9 x 4.2 x 1.42 inches (LWH)
 Weight = 1.5lb
 Cost = $4,625.00
Problem
MiniDAT is no longer available
 Bulky
 Uses too much power
 Cost = $4,625.00
 Have to wait about 20 minutes to reboot
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Main GOAL
 Replacing
MiniDAT™
Specific Goals
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Size: 4 x 4 x 0.5 inches (LWH)
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Weight: ~0.25lb
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Cost: less than $1000.00
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Low power consumption
Target Specification
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7 analog channels and 1 digital channel
A/D with 12 bit resolution
1 quadrature encoder input
Wireless capability
Sampling rate of at least 10 kHz
Accepts voltage signal of -5/+5 volts
Power consumption ~5 watts
Small and compact
Circuit Diagram
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
(Multichannel RS232 Drivers/Receivers)
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MAX220
 Chip
that made it possible to connect RS232
and MAX186
 Data rate =120 kbps
 Operates at 5V
Components
(5V/Programmable Voltage Regulator)
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MAX666
 Dual
mode operation: Fixed +5V or
Adjustable +1.3V to +16V
 Regulates the power supply to provide
specific voltage to components in the circuit
 Operating range +2V to +16.5V
Components
(Quadrature Decoder)
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US Digital EDAC2
 Converts
incremental encoder into analog
position sensor
 12-bit analog resolution
 Output range:  10V
 Operates at 12V
Components
(Wireless Serial Adapter)
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Socket Cordless Serial Adapter (CSA)
 Uses
RS232 (Serial Port)
 Has a class 2 Bluetooth
 Range up to 10m
 Simple plug, install, and play
If all else fails…
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Current solution is the most
optimum (cost, size, etc)
There is slight chance that
it would not work
So, we formed a backup
plan
The backup plan
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Consists of two pre-packaged
components and one
software package:
 Sensoray
Model 526
 Airborne Embedded Wireless
Bridge, Ethernet to Wireless
LAN (Module)
 xPC Target 2.9
Sensoray Model 526
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PC/104 Multifunctional I/O
board
Four 24-bit quadrature
encoder inputs
Eight 16-bits analog inputs
Approximately 4’’x4’’
Airborne Ethernet to Wireless
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Add wireless LAN
connectivity to Model 526
IEEE 802.11b compliant
Very small footprint, less
than 2’’x2’’
xPC Target 2.9 from Mathworks
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Provides high-performance,
host-target prototyping
environment
Makes it easier to program
Model 526
Current Status
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Finalizing the
components needed for
current solution
Buying the components
Building the solution