Learning Roomba

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Learning Roomba

• Module 2 - Robot Configurations

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Outline

• What is a Robot Configuration?
• Why is it important?
• Several types of Configurations
• Roomba Configuration

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What is a Robot Configuration?

• Describes how a robot can move and where it can
  go
• Includes
• Physical shape of the Robot
• Model of how the Robot can move in the Environment

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What is a Robot Configuration?

• Holonomic vs. Non-holonomic
• Holonomic Robots can move in any direction
• Non-holonomic Robot is contrained to certain
  types of movement
• Example A Car is non-holonomic

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What is a Robot Configuration?

• For ground robots, the Configuration often
  describes how it
• Rotates (How the robot turns)
• Translates (How the robot moves forward or
  backward)

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Why is it important?

• With the Configuration you can tell how a Robot
  will operate prior to controlling it
• Important to understand a Robots limitations
  while designing it

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Several Types of Configurations

• Wheeled Robots
• Differential Drive
• Ackerman Steer
• Tricycle Drive
• Synchro Drive
• Skid Steer
• Roller Wheeled
• Legged Robots
• Flying Robots
• Fixed-wing
• Rotorcraft

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Differential Drive

• 2 Wheels
• Independently powered
• in-line with each other
• Usually in the center of the robot
• Often has 1 or 2 casters
• Non-powered
• Swivel in any direction
• Add stability

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Differential Drive

• Advantage
• Simple Design
• Can go anywhere the robot can fit
• Disadvantage
• Has difficulty with uneven terrain (both wheels
  need to touch the ground to work)
• Has to rotate before traveling in a new direction

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Differential Drive

• Shape matters
• In this example, the Circle robot can turn freely
  while the Square robot cannot

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Ackerman Steer

• Like a Car
• 4 Wheels
• 2 Rear wheel are powered, fixed-rotation
• 2 Front wheels are non-powered that turn
• Turn at different Angles

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Ackerman Steer

• Advantage
• Drive and Rotation functionality are separated
• Typically more stable
• Disadvantage
• Mechanically complicated
• Often complicated maneuvers (non-holonomic)

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Tricycle Drive

• Similar to Ackerman Steer
• Only 1 front wheel that turns

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Tricycle Drive

• Advantage
• Mechanically Simpler
• Disadvantage
• Similar motion limitations as Ackerman Steer
• Less Stable

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Synchro Drive

• At least 3 wheels
• All rotate together
• All are powered together

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Synchro Drive

• Advantage
• Can travel in any direction without turning the
  top base
• Separate motors for turning and driving
• Disadvantage
• Very Mechanically Complicated
• Top base cannot face another direction

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Skid Steer

• Like a tank
• Several wheels on each side or tank treads
• Turning Requires skidding

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Skid Steer

• Advantage
• Can handle uneven terrain well
• Disadvantage
• Poor odometry due to skidding

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Roller Wheeled

• 3 Wheels
• Arranged around the circumference of the robot
• Wheels are Roller Wheels (Next Slide)
• Non-Steering
• Independently Powered

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Roller Wheeled

• Roller Wheels
• Includes Rollers
• Perpendicular to the Wheel
• Around the wheel
• Non-powered

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Roller Wheeled

• Advantage
• Can go in any direction without first rotating
• Can go anywhere the robot can physically fit
• Disadvantage
• Tracking position through odometry is difficult

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Legged Robots

• Uses legs instead of wheels
• Any number of legs

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Legged Robots

• Advantage
• Can travel over rugged terrain
• Disadvantage
• Mechanically complicated
• Hard to control

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Fixed Wing Aerial

• Like a Plane
• Not Restricted to the ground

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Rotorcraft Aerial

• Like a Helicopter
• Not Restricted to the ground
• Can take-off vertically

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Other Configurations

• Many other Configurations
• Robots are not restricted to Ground (or even Air)
• Can be manipulated in many different ways

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Roomba Configuration

• Wheels
• 2 Wheels
• Independently Powered
• Non-Steered
• Arranged at approximately the center of the robot
  on opposite sides of each other
• Shape
• Circular
• Few inches tall

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Roomba Configuration

• Round Differential-Drive Configuration
• Can travel anywhere the Roomba can fit and get to
• Can move in any direction, but first need to turn
  to that direction

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Questions?