Autonomous control of automobiles Omar Hashmi, supervised by Uwe Zimmer

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Autonomous control of automobilesOmar Hashmi,
supervised by Uwe Zimmer
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The Goal
The goal The drift algorithm The computers The
sensors Implementation Testing

• To get a car to drift into a parking spot

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No Seriously?
The goal The drift algorithm The computers The
sensors Implementation Testing

• To get it to drift
• To control the parameters of the drift
• To have a repeatable manoeuvrer
• No so concerned about a parking spot

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But Why?
The goal The drift algorithm The computers The
sensors Implementation Testing

• Drifting is a increasingly popular motor sport
• Allows better safety and control systems
• Allows us to develop better vehicle control
  systems
• Lets face it its cool.

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How to drift a Car
The goal The drift algorithm The computers The
sensors Implementation Testing

• Remote control cars much easier to drift- no
  gears- light weight- slippery surfaces
• Four stage algorithm

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The drift algorithm
The goal The drift algorithm The computers The
sensors Implementation Testing
1) Accelerate

• The FastCar must be travelling fast enough to
  loose traction
• Friction with road will slow car quickly once
  drifting

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The drift algorithm
The goal The drift algorithm The computers The
sensors Implementation Testing
2) Steer and brake

• Brake the rear wheels hard so they quickly
  decelerate and loose traction with the road
• Turn in one direction to change the orientation
  of the car

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The drift algorithm
The goal The drift algorithm The computers The
sensors Implementation Testing
3) Counter-steer

• When the rear of the car is slipping out, reverse
  the steering
• Front wheels loose traction

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The drift algorithm
The goal The drift algorithm The computers The
sensors Implementation Testing
4) Control

• All four wheels have lost traction
• Possible to adjust the orientation by
  accelerating forwards or backwards.

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The goal The drift algorithm The computers The
sensors Implementation Testing
What is available?

• Computers
• Sensors
• No brakes (yet)

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The Computers
The goal The drift algorithm The computers The
sensors Implementation Testing

• ATMEL Atmega128
• Gumstix running Linux
• ATMEL Atmega32 (on IMU)

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ATMEL
The goal The drift algorithm The computers The
sensors Implementation Testing

• Hardware timers
• PWM outputs
• 128kB flash memory

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Gumstix
The goal The drift algorithm The computers The
sensors Implementation Testing

• Field Debugging Programming
• Unix redirect (gt), scp, ssh capabilities
• Makes programming and debugging much easier!

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The goal The drift algorithm The computers The
sensors Implementation Testing
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The Sensors
The goal The drift algorithm The computers The
sensors Implementation Testing

• Gyroscopes
• Accelerometers
• Proximity Detectors

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IMU
The goal The drift algorithm The computers The
sensors Implementation Testing

• Accelerometers tell us x y z linear acceleration
• Gyroscopes tell us x y z rotational acceleration
• Rotation around z axis turning the steering
  wheel

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(No Transcript)
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IR distance sensor
The goal The drift algorithm The computers The
sensors Implementation Testing

• Can detect objects up to 1 meter away (at best)
• Accounting for noise 60cm
• Not enough time to use past a crawling speed

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Available information
The goal The drift algorithm The computers The
sensors Implementation Testing

• How fast we are accelerating
• Turning ability
• Can use z axis gyroscope to detect slipping out
  of rear wheels.

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4 steps 4 states
The goal The drift algorithm The computers The
sensors Implementation Testing

• Accelerate
• Steer Brake
• Counter Steer
• Hold Control

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The goal The drift algorithm The computers The
sensors Implementation Testing

• Accelerate for 0.75s
• Builds up required speed
• Incremental acceleration

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The goal The drift algorithm The computers The
sensors Implementation Testing

• Reverse motor to brake rear wheels
• Turn hard left
• Transition when high angular acceleration is
  detected

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The goal The drift algorithm The computers The
sensors Implementation Testing

• Idle motor (dont want to reverse)
• Turn hard right
• All four wheels should be drifting
• Transition after 0.25s

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The goal The drift algorithm The computers The
sensors Implementation Testing

• Motor controlled by RC
• Turn hard right
• Terminate after 2s

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Testing
The goal The drift algorithm The computers The
sensors Implementation Testing

• Drifting
• Repeatability
• Parameters

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Test Track
The goal The drift algorithm The computers The
sensors Implementation Testing
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Test run
The goal The drift algorithm The computers The
sensors Implementation Testing

• Show .mp4
• Drifting
• Rotation during the drift, not just before

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Results
The goal The drift algorithm The computers The
sensors Implementation Testing

• Mean drift of 46
• Drifts on all tested surfaces (track, carpet,
  tiles)
• Repeatable maneuver
• Not the desired angle

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So long, and thanks for all the fish