Team Spot A Cooperative Robotics Problem

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Team SpotA Cooperative Robotics Problem

• A Robotics Academy ProjectLaurel Hesch
• Emily Mower
• Addie Sutphen

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Project Goal

• Develop a team of autonomous robots that will,
  within a fixed boundary
• Communicate with each other
• Locate a spot of light on the Robotable
• Follow the spot of light as it moves across table

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Last Semester Lego Prototype

• 1 mobile Lego RCX robot
• 2 stationary Lego RCX robot

Stationary Robot
Mobile Robot
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Last SemesterFirst Prototype

• Team of 1 mobile and 2 stationary robots.
• PVC Body
• PIC chip microprocessor
• IR communication

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This Semester

• Development Process
• Prototype
• Evaluated first semester prototype
• Prototyped new robots
• Programming and EE Design
• Added complexity to the problem
• Developed new and more accurate algorithms
• Developed more accurate communication system
• Production
• Modified prototype
• Final build

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Meet the RobotsLucy, Ray and Zoolander
Lucy
Zoolander
Ray
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Completed Robot Team

• Old Elements
• PIC chip microprocessor
• Reliable and easy to use.
• Robot Motors and wheels

• New Elements
• Body
• New, robot friendly, body design
• Sleek Lexan Material
• Communication
• Long range bluetooth
• More reliable communication
• Programming
• New computation algorithm

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Product Research

• Mobile robots, autonomous robots, robot teams
• Robot Body Design
• Communication between robots
• Microprocessors

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ElectricalOOPic Chip

• Programming Language Object Oriented Basic
• 31 I/O pins and additional voltage sources for
  device interface.
• Voltage source used for Bluetooth communication,
  the servo motors, and the photo-resistor circuits.

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ElectricalMotor Control

• Microprocessors control all servo motors
• Due to highly variable torque- constant motion
  across motors has not been established
• Robot Motion
• Controlled pulses sent to servo motors
• Mobile Robot Calculated using a set of trig
  functions (will be discussed later)
• Stationary Robot Determined through trial and
  error

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ElecticalLight Sensing

• Simple photo-resistor placed in series with a
  resistor
• Output voltage measured at the junction of the
  two resistors
• Voltage level inputted to microprocessor using
  the analog to digital converter
• Accuracy hampered by ambient light spots brighter
  than the spot being sought.

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AlgorithmsFlowchart of Functionality
The position of the greatest spot is transmitted
via Bluetooth to the mobile robot.
Stationary robots scan for position of brightest
light.
Mobile robot reads in light value
Interprets value using trig functions
Mobile Robot moves to correct position
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AlgorithmsStationary Robot Algorithm 1

• Goal
• Determine location of spot of greatest light
  intensity
• Convert location into angle measure
• Transmit angle measure to mobile robot via
  Bluetooth (to be discussed later)

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AlgorithmsStationary Robot Algorithm 2

• Method
• Sweep through 90 degrees
• Number of stops depends on strength of battery
• Store location of greatest light and covert to
  the range accepted by the OOPic sine function

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AlgorithmsMobile Robot Algorithm 1

• Goal
• Given angle measurements from stationary robots
  compute location of spot of light
• Advance to spot of light
• Find new spot of greatest light intensity
• Follow new spot

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AlgorithmsMobile Robot Algorithm 2

• Method
• Using sine functions on OOPic chip calculate
  location of spot of light
• Advance to spot of light using pulses of motor
• Once at spot of light, rotate 360 degrees to find
  the new spot of greatest light intensity
• Follow the new spot by keeping the light between
  the three light sensors on front

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AlgorithmsMobile Robot Algorithm 3
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CommunicationsThe need for wireless

• Goal
• Send angle measurements serially between
  stationary and mobile robots.
• First Semester Infrared communications
• Second Semester Bluetooth communications

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CommunicationsInfrared

• Serial infrared communication was attempted in
  the first semester.
• Problems
• The range was too small.
• Significant accuracy problems.
• True serial communications was not established,
  meaning that pulses representing angle
  measurements had to be sent.
• This adaptation added an additional level of
  inaccuracy.

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CommunicationsBluetooth

• Bluetooth is a open platform communications
  protocol for short distance, high throughput, low
  power communications. 
• Advantages
• Range up to 30 feet.
• A master device can potentially connect with up
  to 8 slave devices at a time.
• Each device has a unique 48 bit address, which
  results in highly accurate identification.
• Bluetooth is also very low power (1mW)

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CommunicationsBluetooth Operation
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MechanicalMotors and Gearing

• Hitech HS-422 Motors
• Purchased from Lynx Motion
• Modified for continuous rotation

• Gearing
• Removed internal gear
• Geared down stationary robot motors

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MechanicalBody Design

• Last semesters design large and bulky
• Square shape interfered with light sensing
• Developed round design
• In scale with Robotable
• Concurrent with light sensors
• Better mobility

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MechanicalSecond Prototype Mobile Robot
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Mechanical Stationary Robot Drawings
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MechanicalMobile Robot Drawings
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MechanicalSecond Prototype
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MechanicalSecond Prototype
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Mechanical Final Design
Ray
Zoolander
Lucy
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Opportunity for Future Research

• Continuing Bluetooth robotic applications
• Implementation of full Bluetooth functionality
• Algorithms to find multiple spots
• Integration of chemical nose
• Expansion of robot team
• Integration of multiple robot teams

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Special Thanks

• James the Bluetooth Man
• Warren Gagosian
• Chris Rogers
• Matt Dombach
• Jim Hoffman
• Robotics Academy Professors
• TUFTL lab

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DemoCross your fingers