Transcript ENG H193 - Tips for Motors and Handy Board

Engineering H193 - Team Project
Tips for Motors &
Handy Board Care
Week 3 Day 2
Spring Quarter
Gateway Engineering Education Coalition
P. 1
Engineering H193 - Team Project
Motors Information
Motor
Shaft
adapt?
Noise Volt.
Other
Suppr. Adapt?
Tamiya $9.50
Twin
Motor
Gearbox
2 at
$1.00
Yes
$0.20
2 at
$3.25
2 – 12 v $24.20
Mabuchi at
$3.00
Acroname
2@
$9.50
2 at
$1.00
Yes
$0.20
No
No
$21.20
Hacked
Servo
2@
$9.00 /
$9.50
Depends
– maybe
2 bush
wheels
No
2 at
$3.25
No
$27.00
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Cost
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Total
P. 2
Engineering H193 - Team Project
Motors Information
• Voltage Adaptors are required when the motor
rated voltage is lower than the source voltage.
The Acroname is OK. Hacked Servos run at 5 V.
Tamiya motors run at 2.5 (recommended) or 3.3
volts. The Handy Board runs at ~9-10 volts.
• The carbon brushes from the Mabuchi 12 volt
motors can replace the metal leaf brushes in the
lower voltage motors and make them more
reliable. This is STRONGLY RECOMMENDED if
running at 3.3 volts. It may be needed when
running at 2.5 volts.
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P. 3
Engineering H193 - Team Project
Motors Information
• Noise – This means that the motors have enough
electronic/electrical noise to alter data input from
sensors or, more importantly, cause the Handy
Board to reset. A capacitor provides the
protection so that this does not happen.
• There is heavier gage 2-conductor wire for
motors rather than thinner gage ribbon cable.
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P. 4
Engineering H193 - Team Project
Tips for a More Enjoyable Robotics Experience
1. Handle the robot with some care. (Your wiring is
fragile -- be careful. Reinforce joints with shrink
tubing and/or hot glue. Design wiring so that the
wire takes the strain and not the joint.)
2. Prevent short circuits. (The edge of circuit board
of the Handy Board has battery voltage and 5 volts
present. Protect it with electrical tape.)
3. Don't wedge your processor. (Don't use a printf in
tight program loops. Among other problems, you
could lose encoder counts.)
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P. 5
Engineering H193 - Team Project
Tips for a More Enjoyable Robotics Experience
4. Reduce friction, keep things aligned. (It will
actually improve battery life.)
5. Don’t zap charge for more than 20 minutes at a
time (or less if battery begins to get warm).
6. Don't change or edit any files in the IC "libs"
directory. (It only causes problems for the next
team to use the computer.)
7. Clean up the work area before you leave.
8. Share the resources so they don't have to be
placed on limited access.
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P. 6
Engineering H193 - Team Project
Tips for a More Enjoyable Robotics Experience
9. Write code that allows your team to test a section
of the course rather than the whole course.
10. Write code that allows your robot to continue to
perform even if a sequential step is missed.
11. After turning HB off, wait a moment before turning
it back on again. And only turn on HB with robot
held up in the air.
12. Be prepared to run on either course and any of the
four starting points. You will not have a choice in
the final competition.
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P. 7
Engineering H193 - Team Project
Tips for a More Enjoyable Robotics Experience
13. Attach your sensors, particularly the ‘bump’
sensors (micro switches), so that they can be
removed and replaced easily.
14. Make up a spare for critical sensors.
15. Use the same color wire(s) for the same types of
devices. Avoid the "spaghetti" approach to
wiring of the robot.
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P. 8
Engineering H193 - Team Project
Tips for a More Enjoyable Robotics Experience
16. If a wheel is fastened to a shaft with set screws,
you might want to file a flat spot on the shaft for
each screw.
17. If you are using nuts and bolts, you may want to
buy some cheap, bright colored nail polish to
use as ‘Locktite’ to prevent your robot from
coming apart.
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P. 9
Engineering H193 - Team Project
Head to Head Competition Requirement
• Robots need to have a flag or plaque of their
team’s letter and number – e.g., A1 – mounted on
the robot and readable from both sides for judges.
• It must be high contrast – black on white, white on
dark blue, etc. and 1.5” high (e.g., Arial 140).
• No fancy fonts!!!
• Sample:
A1
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P. 10
Engineering H193 - Team Project
Assignment Notes
•
Due Friday: Sketches of chassis, chassis
requirements, either good mockup or chassis
with wheels
– Sketches must be three views in correct
projection with scale and annotations
– A pictorial sketch to supplement above 3-view
drawing will be looked upon favorably
– Requirements include estimated weight,
identification of critical members
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P. 11
Engineering H193 - Team Project
Lab Safety
• No open-toe shoes in lab
• Must have a TA “buddy” with you in the shop
• The shop will be open from 8:30 am – 4:30 pm on
MW, 10:30 am to 4:30 pm on TR, and 8:30-1:30 on
Friday.
• This is the ME student shop and we are sharing it.
• Keith is responsible for the shop, we will follow
all safety rules in his shop ! Remember your
safety glasses.
• Only two people per team in the shop at a time
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P. 12