Robotics

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• Robotics

In which agents are endowed with physical
effectors with which to do mischief.
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Introduction

• Robot Institute of America defines robot as a
  reprogrammable, multifunction manipulator
  designed to move material, parts, tools or
  specific devices through variable programmed
  motions for the performance of a variety of
  tasks.
• Russell and Norvig an active, artificial agent
  whose environment is the physical world.
• Robots differ from Softbots whose environment
  consists of computer systems, databases and
  networks.

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The Physical World

• The physical world is very demanding, it is
• inaccessible - sensors are imperfect, only
  stimuli that are near the agent can be perceived.
• nondeterministic - a robot needs to deal with
  uncertainty
• nonepisodic - effects of an action change over
  time
• dynamic - robot needs to decide when to think and
  when to act immediately
• continuous - states and actions are drawn from a
  continuum of physical configurations and motions

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What are robots good for?

• Manufacturing and materials handling

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What are robots good for?

• Gofer robots

Bell Howell Mailmobile
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What are robots good for?

• Gofer robots

Carnegie Mellons Nomad
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What are robots good for?

• Hazardous environments

Lunokhod Moon Robot
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What are robots good for?

• Hazardous environments

Dante II Frame Walking Robot
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What are robots good for?

• Telepresence and virtual reality

The Wheelbarrow, a bomb disposal robot
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What are robots good for?

• Telepresence and virtual reality

Advanced Tethered Vehicle (ATV)
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What are robots good for?

• Telepresence and virtual reality

Advanced Robot and Telemanipulator System for
Minimal Invasive Surgery (ARTEMIS)
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What are robots good for?

• Augmentation of human abilities

Sigourney Weaver in the movie Aliens
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What are robots good for?

• Augmentation of human abilities

General Electrics Walking Truck
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What are robots made of?

• Effectors Tools for Action
• Locomotion
• Manipulation
• Sensors Tools for perception
• Proprioception
• Force Sensing
• Tactile Sensing
• Sonar
• Camera Data

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What are robots made of?

• Effectors Locomotion

Carnegie Mellons Ambler
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What are robots made of?

• Effectors Locomotion

MITs 3D Hopper
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What are robots made of?

• Effectors Manipulation

Degrees of Freedom
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What are robots made of?

• Sensors Proprioception

MITs Spring Flamingo
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What are robots made of?

• Sensors Force Sensing

MITs Phantom
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What are robots made of?

• Sensors Tactile Sensing

MITs Planar Grasper
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What are robots made of?

• Sensors Sonar

ActivMedias Peoplebot
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What are robots made of?

• Sensors Light Sensors

Grey Walters Tortoise
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What are robots made of?

• Sensors Camera Data

The Johns Hopkins Beast
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What are robots made of?

• Sensors Camera Data

MITs Fast Eye Gimbals
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Architectures

• The architecture of a robot defines how the job
  of generating actions from percepts is organized.
  It is basically the control mechanism of the
  robot.
• Classical Architecture
• Situated Automata

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Architectures

• Classical Architecture
• A robot with classical architecture is given a
  number of low-level actions (LLAs). It then uses
  these LLAs to reason about the effects of
  performing a sequence of these LLAs.
• The problem with this is that due to things like
  wheel slippage and measurement errors any lengthy
  sequence of actions is prone to fail.

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Architectures

• Classical Architecture

SRIs Shakey
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Architectures

• Situated Automata
• The process of deliberating is often too
  expensive to generate real-time behavior.
  Situated automata do not explicitly reason, they
  operate by reflex.
• A situated automata has two parts. The first
  collects sensor inputs and updates the state
  register accordingly, the second looks at the
  state register and calculates output (actions).
  Thus a situated automata does not plan, it just
  does whatever it knows to do given the state it
  is in.

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Architectures

• Situated Automata

SRIs Flakey
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Configuration Spaces

• Configuration Space is the path where robot can
  move from one position to another.
• Generalized configuration space
• Recognizable sets

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Configuration Spaces
Generalized configuration space

• Generalized configuration space includes other
  objects as part of the configuration, which could
  be movable, variable in shapes (i.e. scissors or
  staples), or deformable (i.e.string or paper).

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Configuration Spaces
Recognizable Sets

• Includes envelope of possible configurations

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Navigation and Motion Planning

• Cell decomposition
• Skeletonization
• Fine-motion (Bounder-error) planning
• Landmark-based navigation
• Online algorithms

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Navigation and Motion Planning

• Cell decomposition
• Breaks continuous space into a finite number of
  discrete search problems

Bell Howell Mailmobile
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Navigation and Motion Planning

• Skeletonization methods
• Computes a one-directional skeleton (subset)
  of the configuration space, yielding an
  equivalent graph search problem

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Navigation and Motion Planning

• Fine-motion (Bounded-error) Planning
• This methods assume bounds on sensor and
  actuator uncertainty, and in some cases can
  compute plans that are guaranteed to succeed even
  in the face of severe actuator
• partial knowledge of the environment is known to
  the system
• most of the planning is done offline
• used for planning small, precise motions of
  assembly

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Navigation and Motion Planning

• Landmark-based navigation
• This method assumes that there exists some
  regions in which the robot location can be
  pinpointed using landmarks, whereas outside those
  regions it may have only orientation information
• This method is both sound and complete
• The plan have at most n steps if there are n
  landmarks

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Navigation and Motion Planning

• Online algorithm
• The robot makes decision at run time (no need
  for offline planning
• This method assumes that the environment is
  completely unknown
• The robot cannot see anything. It can only sense
  a boundary
• The robot is equipped with a position sensor and
  knows the location of its goal.

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The End