Post on 20-Dec-2015
transcript
ECE415 SDP DesignECE415 SDP Design
MAPPER: A Perfectly Portable Exploration Robot
Rohan Balakrishnan (CSE)
Conan Jen (EE)
Andrew Lok (EE)
Jonathan Tang (EE)
ECE415 SDP Design
Project Vision• Reconnaissance is always important for the
military• Desired solution is autonomous, small and
cheap implementation• With importance of human lives, robots are
perfect replacement
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ECE415 SDP Design
Decided Implementation• Autonomous robotic platform capturing
information about its surroundings • Wireless communication link will transfer data
back to PDA or Laptop• Transferred data used to construct a 2-D bird's
eye view of the environment
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ECE415 SDP Design
Project Considerations • Multiple platform considerations
– Non-mobile• Leaves very little time for scanning• Must be impact hardened• Scan rotation depends entirely on trajectory of throw
• Multiple sensor considerations– Laser
• Expensive, loses accuracy at range, bulky– Radar
• Power hungry, large, expensive, complicated– Optical
• Needs large bandwidth on wireless link, software based distancing detection
– Ultrasound• Inexpensive, accuracy issues
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ECE415 SDP Design
Project Specs / Scenario • Initial Phase– Room Limitations: 20'x20‘, flat floor– Method: rotating ultrasonic sensors– Scan time: 5-15 mins– Stationary walls and large objects (minimum 1'x1')
only– No manual intervention, straight movement into
room– Wireless communications: 100+ ft
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ECE415 SDP Design
Budget PARTS / BUDGET:
Ultrasound Sensor $28Roomba Create $130Roomba Standard Rechargable Battery $50PCB $150Wireless communication device $27-60Arduino Clone (ATmega168) Free (M5) Total $385-418
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ECE415 SDP Design
Roomba Create • Robotics platform from iRobot• Provides serial input to the base• Has a multitude of sensors built in• Allows for addition of parts through expansion
port
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ECE415 SDP Design
Wireless Link Considerations: Bluetooth, RF, WLanSecurity:• Important because of military applications• Do not want enemy knowing what you know• Do not want false data injectionRange:• Need to be able to go through objects• Link must be robust, cannot fail easily• Must be able to deal with interference• Jamming / interference is an issue, especially with
military applications
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ECE415 SDP Design
Stepper Motor • LA23GCK-213 Stepper
Motor• Provides basic platform for
sensor to turn and sweep• Used to mount the
ultrasound sensor onto• 1.8° per step• Ultrasound sensor beam
width @ 20 ft. ≈ 6°• Oversampling max room by
a factor of 3
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ECE415 SDP Design
Microcontroller • Arduino clone - ATmega168• Based on the larger Wiring development
board• Rapid development with Processing.• Flexibility of AVR C on ATmega
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ECE415 SDP Design
Ultrasound Sensor
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Sensitivity to Ambient Conditions:• Average room temperature
changes will cause sensor to report readings of accuracy ± 5%
ECE415 SDP Design
Power Sources • The Roomba has its own internal battery– 12 AA alkalines or rechargeable equivalent– Expected battery life (1.5 hrs)
• 5V supply from Roomba, 16V supply from Roomba battery– Pin 8 (5V regulated)– Pin 9 (Battery power unregulated)
• Power for all our components can be drawn from Roomba
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ECE415 SDP Design
Project Responsibilities • Rohan: Map application on computer/Arduino
interfacing• Conan: Wireless/Ultrasound• Andrew: ATMega168/Arduino interfacing• Jon: Stepper Motor + Wireless
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ECE415 SDP Design
Challenges• Ultrasonic sensor may have accuracy issues• Roomba movement integration
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