Transcript Tom and Jerry - University of Florida

EEL-5666 – Intelligent Machines Design Lab
Tom and Jerry
By: Nicholas Johnson & Joshua Hartman
Overview
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Overall Function
Tom’s Design
Jerry’s Design
Special Sensor – RF Link
Conclusions
Possible Improvements
Questions
EEL-5666: Intelligent Machines Design Lab
Overall Function
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Jerry and Tom simulate a Predator / Prey
Model.
Jerry is the prey and has prey behaviors
such as wandering and grazing.
Tom is the predator and searches for Jerry.
When Tom detects Jerry he will try to
capture Jerry who tries to run away.
EEL-5666: Intelligent Machines Design Lab
Tom
EEL-5666: Intelligent Machines Design Lab
Platform
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MAVRIC-IIB
Development board
Wood
Cardboard part stands
Black duct tape.
Black duct tape.
More black duct tape.
EEL-5666: Intelligent Machines Design Lab
Locomotion
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GHM-03 Spur Gearhead
Motor
TPIC0107B-based motor
driver
These motors are fast
EEL-5666: Intelligent Machines Design Lab
Obstacle Avoidance
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3 Devantech SRF05
Use fuzzy-logic ideas to define
obstacles as close, far, or in
between
Very rarely hit obstacles
EEL-5666: Intelligent Machines Design Lab
Searching for Jerry
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Futaba S148
Panasonic PNA4611
Infrared Photo IC
Servo rotates from -45o,
-22.5o, 0o, 22.5o, 45o
At each location, reads A/D
and detects if value<200. If
so, Jerry is detected!
EEL-5666: Intelligent Machines Design Lab
Searching for Jerry II
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IR detection not so easy:
Must use ADC to read photo IC output
Vout goes low upon detection
Must have receiver highly shielded to
give directional output
EEL-5666: Intelligent Machines Design Lab
Jerry
EEL-5666: Intelligent Machines Design Lab
Platform
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Material: Wood
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Small, Compact
Design
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Cut using the T-Tech
Had to be smaller than
Tom
Limited Space
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Difficult to fit all the
electronics
Addition of unforeseen
pieces problematic
EEL-5666: Intelligent Machines Design Lab
Actuation
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2 Tamiya 70168 Double Gearboxes
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Driven by TPIC0108B PWM H-Bridge
Wheels on either side function
independently
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114.7:1 Gear Ratio
4 wheels total
Each side driven by 1 Motor Driver
Servo Motor to turn “Tom Detector”
EEL-5666: Intelligent Machines Design Lab
Sensors
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Bump Switches
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Maxbotix Ultrasonic Rangers
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2 Front, 2 Back
2 Front, 1 Back
IR Emitter / Detector (Close Range)
56.8 KHz IR Detector
315 MHz RF Receiver
434 MHz RF Transmitter
EEL-5666: Intelligent Machines Design Lab
Sonar
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Provides analog interface
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The higher the voltage the further away the object.
Start time of each sonar can be controlled.
Readings obtained 50ms after start.
Sequentially check each sonar
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If returned value below threshold then obstacle detected.
EEL-5666: Intelligent Machines Design Lab
Jerry’s Design – Close IR
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Analog output
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Brighter areas give lower voltages.
If returned value above threshold then obstacle
detected.
EEL-5666: Intelligent Machines Design Lab
Jerry’s Design - Behaviors
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Wandering
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Randomly moves around avoiding
obstacles.
If “food” (black spot) is detected it will
switch to grazing behavior.
Frequently looks for Tom.
If Tom is detected it will immediately
switch to running behavior.
EEL-5666: Intelligent Machines Design Lab
Jerry’s Design - Behaviors
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Grazing
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Holds on top of food for a preset time.
Will slowly move across the food until
passes it completely.
Infrequently looks for Tom.
If Tom is detected it will switch to running
behavior.
EEL-5666: Intelligent Machines Design Lab
Jerry’s Design - Behaviors
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Running
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Moves away from Tom as fast as
possible.
Turns frequently in order to escape Tom.
If caught, will stop and wait to be reset.
If preset time has gone without being
caught will return to wandering behavior.
EEL-5666: Intelligent Machines Design Lab
Special Sensor - RF Link
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www.sparkfun.com
Tom:
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Jerry:
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434MHz Receiver
315MHz Transmitter
315MHz Receiver
434MHz Transmitter
Links used to communicate
robot status to determine
exhibited behaviors.
EEL-5666: Intelligent Machines Design Lab
RF Link Difficulties
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Receiver designed to “lock on” to signal. Therefore,
sender must transmit alternating bits for receiver to lock
onto the baud rate.
Receiver will increase gain until it finds a detectable
signal. Therefore, it will output garbage if the transmitter
is not sending.
EEL-5666: Intelligent Machines Design Lab
RF Link difficulties
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Receiver must “synchronize” with transmitter. If a
transmission looks like: 0 0 0 1 0 1 1 0 1 0 1 0…,
the USART has no real way to recognize the start
of a transmission. Over a wired link, the line is
usually high and is pulled low using the start bit.
This is not the case in RF.
Finally, the receiver has a band-pass filter centered
at its tuned frequency. When the robots get far
enough away, this is washed out by the local
transmitter.
EEL-5666: Intelligent Machines Design Lab
RF Link Algorithm
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Use interrupts to continually send
0xAA, the locking code.
When want to transmit, send out 0xFF
to resynchronize the link
Finally, send out data.
EEL-5666: Intelligent Machines Design Lab
Conclusions
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Both robots successfully avoid
obstacles.
Wireless successfully incorporated.
Tom successfully detects Jerry and will
head towards him.
EEL-5666: Intelligent Machines Design Lab
Possible Improvements
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More reliable detection method.
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IR not always reliable and dependent on
environment.
EEL-5666: Intelligent Machines Design Lab
Questions?
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Acknowledgements
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Dr. A. A. Arroyo
Dr. E. M. Schwartz
Julio Suarez
Adam Barnett
Thomas McDonley
Jason Taylor
EEL-5666: Intelligent Machines Design Lab