Odometry

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Odometry
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Basic Odometry Concept
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Common Wheel Encoders

• Magnetic Pickup used in most ABS
• Hall Effect
• Optical

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Magnetic Pickup ABS
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Incremental Optical Encoder w/ Biphase Output
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Systematic Errors

• Unequal wheel diameters.
• Average of actual wheel diameters differs from
  nominal wheel diameter.
• Actual wheelbase differs from nominal wheelbase.
• Misalignment of wheels.
• Finite encoder resolution.
• Finite encoder sampling rate.

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Non-Systematic Errors

• Travel over uneven terrain
• Travel over unexpected objects
• Wheel-slippage
• Change in tire shape over time

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Odometry Trailer
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References
http//hostingprod.com/_at_aa1car.com/library/abs1.ht
m All About ABS Carley, Larry
CarleySofware, 2000   http//www-personal.engin.um
ich.edu/johannb/index.html Personal web page
for Johann Borenstein of Univ of Michigan many
links to papers on odometry including the UMBmark
standard.