Transcript Artificial Intelligence

Artificial Intelligence
Lecture 11
Computer Science
Robotics & AI
Outline
• What does a computer scientist do?
• Robotics
• Artificial Intelligence
What's a Computer
Scientist?
• Let's ask Jeeves first:
– Jeeves' answer
• Answer:
– Computers are a new, complex kind of tool
– Computer scientists figure out how to do
useful things with computers:
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graphics & medical imaging
networking
sharing information (the web)
robotics & artificial intelligence!
Where do CS ppl. work?
• There are basically three places that
use computer scientists:
– Academia - colleges and universities for
teaching and research
– Research institutions - NASA, plus
other companies that do research
(Microsoft, Bell Labs, etc.)
– Industry - programmers (writing the
software that people use on their
computers)
Robotics
• A robot is basically a mechanism that
operates under computer control
• The main purpose they serve these
days is to do boring, repetitive tasks
• The fun ones are research robots
Basic Robot
• Has three parts:
Sensors
Computer
Actuators
• Reads sensors to understand environment
• Computes what to do based on sensors
• Uses actuators to do it
Sensors & Actuators
• Many possible sensors:
– video cameras
– tilt sensors
– force sensors
• Many possible actuators:
– Electric motors
– Hydraulics
– Pneumatics
Mobile Robotics
• All the stuff done in the field called
Mobile Robotics.
– means that robot can move around on its
own power
– as opposed to most industrial robots,
which are giant arms bolted to the floor
• There are two types of mobile
robots:
– walking robots
– wheeled robots
Examples, examples
• We'll do this by example…
• Robots at Carnegie Mellon:
– Daedalus
– Lunar Rover (Nomad)
– Black Widow
• Robot at NASA:
– Dexter
Daedalus
• Designed to be a planetary explorer
Daedalus
• an example of a frame walker
Frame 1:
Frame 2:
Legs
Nomad
• Designed to test ideas for a
commercial trip to the moon
(LunaCorp)
Nomad
• Went to the Atacama
desert of Chile
• Searched for
meteorites in
Antarctica
• Is a wheeled robot
• Super-cool collapsible
steering mechanism
Dextre
• Dextre is a two armed robot which is
part of the Mobile Servicing System
on the International Space Station
(ISS), and extends the function of
this system to replace some
activities otherwise requiring
spacewalks. It was launched March
11, 2008 on mission STS-123.
Dextre
Black Widow
• A research project
Black Widow
• Patterned somewhat after an insect
(leg length, number of legs)
• Patterned somewhat after a crab
• Purpose was to try out walking
algorithms.
• Used neural networks for training
method
Artificial Intelligence
• Attempts to understand and build
intelligent entities
• Four different definitions of AI:
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acting humanly (the Turing Test)
thinking humanly
thinking rationally
acting rationally (this is the goal of
robotics)
Problems that require AI
• Natural Language Processing
– make a computer understand English
• Machine Learning
– change behavior based on experience
• Perception of a visual scene
– be able to pick out people, objects, etc.
• Robotics!
– navigation, accomplishing tasks, etc.
AI Techniques
• Some that you've probably heard of:
– Neural Networks
– Genetic Algorithms
– Fuzzy Logic
• Others that are popular:
– Reinforcement learning
– Probabilistic reasoning
– Search techniques
Neural Networks
• Based on animal nervous systems:
Neural Network Neuron
Weighted Activation
Sum
Function
Input Links
(from other
neurons)
Output Links
(to other
neurons)
A Simple Neural Network
Input
Output
Input
Training Neural
Networks
• That was Black Widow's neural network to
keep the body level.
• To train (decide the weights to use in the
weighted sums) a NN, you have to give it
LOTS of examples
• Traditionally, these are generated in
simulation or by people
– It made the robots do the work...
Questions & Answers
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