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Casey Dill – Team Lead Arthur Connors Andrew Torkelson
- Fourth project in artificial limb track
Casey Dill Team Lead Arthur Connors Andrew Torkelson - - PowerPoint PPT Presentation
Casey Dill Team Lead Arthur Connors Andrew Torkelson - - PowerPoint PPT Presentation
Casey Dill Team Lead Arthur Connors Andrew Torkelson Fourth project in artificial limb track First three projects focused on hand DOF To create a
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- To create a computer simulation of the kinematics
- f an air muscle-controlled human joint (the elbow)
Build a prototype joint to compare to and improve
the computer model
Make end product adaptable and useful for future Make end product adaptable and useful for future
iterations
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- Casey
Math Theory Pneumatics Arm Design Arm
Arthur
Controls
System
Electronics Simulation
Andrew
- Test Stand
Design
- Test Stand
Fabrication
Arm
Fabrication
EDGE Simulation Integration
Fabrication
- Testing
- Data Analysis
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- Air Muscle
Artificial Limb Test Stand Relays
Elbow joint moved by pneumatic actuators Holds arm and sensors in place Provide power to
Pressure Gauge w/ Flow Restrictor
Measures and/or slows airflow
Solenoid Vacuum Pump Air Tank Strain Gauge
in place Controls airflow Sucks air out of muscles Provide power to and control solenoid 2 count: one holds pressurized air, one is vacuumed Produces voltage change with displacement
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- (
) ( )t
t e σ
muscle Tank Tank muscle
28 . P P : Hold P P P P : Fill − = + − =
Calculating Air Pressure 1) LabView first calculates what air pressure should be in the air muscle given the amount of time that has passed. 2) LabView calculates the force the air muscles should be exerting based on the
( )t
e σ
muscle muscle
P P : Drain =
( )
− − + − =
2 muscle 2 muscle 2
sin 1 sin 2 P 1 cos 3 4 P
k k
t Dt D F θ θ π θ π
Apply Calculation of Force Out of McKibben Air Muscles*
*”Measurement and Modeling of McKibben Pneumatic Artificial Muscles” by Ching-Ping Chou and Blake Hannaford
exerting based on the pressure in the air muscle given a few characteristics of the air muscle.
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- Components
Pressure Tests Elastic Cord/Strain Gauge
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- Air muscles – contract the way they
should
Relays and Solenoid – Power works Vacuum Pump – Failed to power up; Vacuum Pump – Failed to power up;
worked after rewiring
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- Muscles filled with air at different
increments (0.05, 0.125, 0.25 seconds)
Data fitted to function
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- 60
70 80 90
Test Results
- 10
10 20 30 40 50 0.5 1 1.5 2 2.5 3 3.5 Pressure Time
Test 1 Test 2 Test 3 Test 1
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!
60.0 70.0 80.0 90.0
Case Fill
Fitted Theory 0.0 10.0 20.0 30.0 40.0 50.0 60.0 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Pressure (psi) Time (sec)
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"
6 strings, different sizes Weights 50g-2kg added Displacement measured Linear Regression to find k Cord tied onto gauge Cord displaced set amounts,
voltage measured
LRA to find Constant
- Elastic Cord
k≈0.212 lbs/in Strain Gauge Constant≈2347 lbs/Volt
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#$$$
Mechatronics Toolkit is a linking tool
between LabVIEW and COSMOS Motion
Each program receives, translates, and Each program receives, translates, and
passes data to the next program
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%%
- Using a single 3-position, 5-way solenoid is cheaper than
four 2-way, 2-position solenoids, and takes half of the relays.
- Find local suppliers:
- Find local suppliers:
- Roessel has many pneumatic parts on hand.
- Cross Bros has sprockets and chain on hand.
- Don’t rely on non-team members for mission critical parts.
- Start programming earlier.
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