Dead Reckoning System for Mobile Robots

1
Dead Reckoning System for Mobile Robots

• Lee Fithian Steven Parkinson
• Ajay Joseph Saba Rizvi

2
Dead Reckoning

• Navigation Method used for Centuries
• Based on Measurements of Distance Traveled from a
  Known Point
• Used by Columbus to Discover the New World
• Robots used Dead Reckoning Based on Odometers,
  Accelerometers

3
Problem Statement

• Use a mobile robot to compare accuracy of dead
  reckoning using odometers and accelerometers
• The goal is not for us to build a robot
• The robot is the means by which we will reach our
  goal.

4
Objective 1 Construct

• Assemble a robot capable of
• Following a specified path using odometers
• Odometers based on a shaft encoder and a
  microcontroller
• Following a specified path using accelerometers
  and microcontroller
• Interfacing with a PC for programming and path
  data entry

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Objective 2 Experiment

• Specify a path for the robot to follow
• Record the path the robot actually follows
• Path specified will be drawn on butcher paper
• Robot will drag a marker indicating its actual
  path

6
Objective 3 Analyze

• A grid will be drawn on the butcher paper used
  for trials
• Create a numerical comparison of accuracy between
  two navigation methods
• Area between actual path and specified path can
  be calculated

7
Method of Solution

• Based on a Mark III Kit robot (pictured)
• Modifications
• Shaft Encoders on each axle
• Accelerometers added
• Scoop removed
• Marker mount added

8
Method of Solution

• OOPic Microcontroller
• Programmed using Java, C or VB
• Serial Interface
• EEPROM Onboard
• Well Defined Programming Interface

9
Method of Solution

• 600CS-ND Incremental Shaft Encoders
• Clarostat Manufacturing Co.
• Digital Output
• 128 Pulses Per Revolution
• ADXL202E Accelerometer
• From Analog Devices
• Digital Output
• 2g Range, 200 mg accuracy

10
Validation

• Need to ensure the navigation systems work at
  some minimum level before testing.
• Robot will be required to follow a simple path
  with a right and left turn and three runs.

11
Cost Analysis

• Shaft Encoders 2 _at_ 46.14
• Mark III Complete Kit 98.00
• Includes OOPic
• Accelerometer Kit 23.00
• Total Cost 360.06

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PERT Diagram
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Conclusion

• Construction
• Mark III based robot with shaft encoders and
  accelerometers
• Validation to ensure systems work at a basic
  level
• Experimentation
• Use dead reckoning navigation in trials.
• Record trials on butcher paper
• Analysis
• Numerical analysis of which navigation method
  performs better.