Transcript ShopBot “Your Mother doesn’t work here, but ShopBot does!”

Mr. Tool
“Because you’re a tool and left the garage dirty, again!”
Max Koessick
IMDL Summer 2003
Mr. Tool
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Autonomous vehicle that will
detect and collect ferrous tools
from a garage floor in a random
pattern
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Based on 1/16th scale R/C tank
chassis (Originally >$300)
Behaviors implemented
include: metal detection,
obstacle avoidance, target
acquisition, target collection
Project Brief
Mr. Tool
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Processor Overview
Originally used ATMega 128 with Atmel
STK500/501 ($79/$79)
ATMega323 (Included)
Uses:
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4 PWM’s (8 Bit)
3 External IRQ’s
I2C (Two Wire Interface)
12V (10 1.2V/1800mAH NiMH AA’s)
Mr. Tool
Mechanical Overview
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Powered by single Marubuchi RS-540S 6V, 1A,
11,000 RPM motor and stout gearbox
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Metal track and 28 wheel independent torsion bar
suspension; 4 fixed wheels
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2 front wheels control track tension
2 rear drive sprockets
Dual clutch for track control (one motor = no turn in
place)
Mr. Tool
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Servos move mechanical arm for clutch and
switch for speed control
Direction control (clutch)
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Mechanical Overview
Slip turn
Pivot turn
3 Forward and 3 Reverse Speeds
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Only use lower two in both F/R
Third speed only effective in O’Dome or for
chasing cars
Mr. Tool
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Carbon fiber/aluminum lifting arm (Free!!)
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Mechanical Overview
Original direct drive ineffective
New winch style much more effective
Tamiya Planetary Gearbox ($11)
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400:1 Reduction at 18,000 RPM
Advertised 15Kg lifting force
Mr. Tool
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Tamiya Planetary Gearbox (Continued)
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Required 3V input is supplied by PWM 7.2V H-Bridge
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Mechanical Overview
.5A Stall Current Draw
1A Texas Instruments SN754410 Quadruple H-Bridge (Free!!)
Electromagnet ($35)
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30 lbs of lifting force
Control by TTL Power FET Fairchild H76107P (Free!!)
Shares main 7.2V Battery
Mechanical Overview
Mr. Tool
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Power Supply
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(24) 1.2V 1800 mAH NiMH
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(2) 7.2V 3000 mAH
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10 required, others for backup
Fabricated 10 cell battery holder
1 required, 1 backup
Provisions for ‘Shore Power’
Mr. Tool
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Sensor Overview
Daventech SRF08 Sonar ($54)
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I2C (TWI) at 100kHz
Pings every 65ms
Read low byte of closest object
No platform interference (parallel
surfaces)
Mounted on servo
Sensor Overview
Mr. Tool
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Bump Switches (¢65)
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Front Collision – Replaced by Sonar
Rear Collision – Replaced by digital IR—now used to start
code (bump to start)
Target Acquisition
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Determines possible target
(2) located on front collector
Selectable negative or positive logic through 10k pullup
In series, normally closed
Port protection through 150Ω series resistor
Mr. Tool
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Sensor Overview
Hall Effect Geartooth Sensor—Cherry Sensors
GS100701 ($32)
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Metal Detection, no external magnet needed
Negative logic
External IRQ
Sensor Overview
Mr. Tool
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Sharp GP2D12 IR Sensor
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Originally used digital GP2D15—toasted with reverse
battery
Devised digital conversion instead of using ‘Next Day Air’
to buy new one (@ $43)
Digital conversion uses LM311 Comparator and a
reference voltage set by a potentiometer
Distance (in)
15
14
Output (V)
.4
1.1
13
5.32 (Vcc)
Mr. Tool
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Sensor Overview
Sharp GP2D12 digital output conversion--Protel
Mr. Tool
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Daughter Board
2 Layer Protel design, intermediate between sensors
and development board (4.9”x2.8”)
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National LM1085 5V, 3A regulator on large copper
heatsink
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Power supplied by 7.2V motor battery
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Noise suppressed by 100uF input capacitor
Mr. Tool
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Daughter Board
Houses Power FET, H-Bridge, pull-ups, and
sensor jumpers
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Large board mounted copper heatsink planes for HBridge and TO-220 Packages
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To prevent unwanted shorts, rubbed out entire
board by hand with Dremel
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60 mil traces—handles large amounts of power,
not susceptible to board flex
Mr. Tool
Daughter Board
Mr. Tool
Daughter Board
Mr. Tool
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Constructed on protoboard
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+5V→Anode
Cathode→330Ω→Port Pin
LED Board
Mr. Tool
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Will it be done by Thursday?
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Concluding Remarks
Will I sleep?
Maybe and maybe
Behavioral code complete-mostly tested
1 day to add winch assembly, front bump switches
(circuitry in place), and basket
1 day left for Murphy
Painted by Media Day (Orange and Blue splinter
camo)