Propulsiometer Instrumented Wheelchair Wheel
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Transcript of Propulsiometer Instrumented Wheelchair Wheel
Propulsiometer Instrumented
Wheelchair WheelPrepared 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 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 To access the load applied by manual wheelchair
user.
Consist of DAQ, load cell, wireless transmitter, battery, DC/DC converter, sensor.
Located on tubular hoop that can be mounted on different sizes of wheelchair’s wheel.
Mainly use as research tool in lab. Ex: Calculating metabolic rate
Propulsiometer
Propulsiometer
Viasat MiniDAT™
Battery
Sensor
Load Cell DC/DC Converter
Data Collected
Angle vs. time Torque vs. time
Tx Ty Tz
Force vs. time: Fx Fy Fz
Data collected from propulsiometer to the PC
Force, Torque, & Wheel Angle
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.
MiniDAT™
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
Main GOAL
Replacing MiniDAT™
Specific Goals
Size: 4 x 4 x 0.5 inches (LWH)
Weight: ~0.25lb
Cost: less than $1000.00
Low power consumption
Target Specification 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)
MAX1868 channel single-ended12-bit resolution Input range: 5VSampling rate of 133kHzOperates at 5V
Components (Multichannel RS232 Drivers/Receivers)
MAX220Chip that made it possible to connect
RS232 and MAX186Data rate =120 kbpsOperates at 5V
Components (5V/Programmable Voltage Regulator)
MAX666Dual mode operation: Fixed +5V or
Adjustable +1.3V to +16VRegulates the power supply to provide
specific voltage to components in the circuit
Operating range +2V to +16.5V
Components (Quadrature Decoder)
US Digital EDAC2Converts incremental encoder into
analog position sensor 12-bit analog resolution Output range: 10V Operates at 12V
Components (Wireless Serial Adapter)
Socket Cordless Serial Adapter (CSA)Uses RS232 (Serial Port)Has a class 2 BluetoothRange up to 10m Simple plug, install, and play
If all else fails…
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
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
PC/104 Multifunctional I/O board
Four 24-bit quadrature encoder inputs
Eight 16-bits analog inputs
Approximately 4’’x4’’
Airborne Ethernet to Wireless
Add wireless LAN connectivity to Model 526
IEEE 802.11b compliant Very small footprint, less
than 2’’x2’’
xPC Target 2.9 from Mathworks
Provides high-performance, host-target prototyping environment
Makes it easier to program Model 526
Current Status
Finalizing the components needed for current solution
Buying the components
Building the solution