chapter 1 - introduction to robotics
Post on 06-Apr-2018
220 Views
Preview:
TRANSCRIPT
-
8/2/2019 Chapter 1 - Introduction to Robotics
1/27
Introduction ToRobotics
Lecture 1
Instructor: Monica Nicolescu
-
8/2/2019 Chapter 1 - Introduction to Robotics
2/27
CS 491/691(X) - Lecture 1 2
The term robot
Karel Capeks 1921 play RUR (Rossums UniversalRobots)
It is (most likely) a combination of rabota (obligatory
work) and robotnik (serf)
Most real-world robots today do perform such
obligatory work in highly controlled environments
Factory automation (car assembly)
But that is not what robotics research about; the
trends and the future look much more interesting
-
8/2/2019 Chapter 1 - Introduction to Robotics
3/27
CS 491/691(X) - Lecture 1 3
What is a Robot?
In the past A clever mechanical device automaton
Robotics Industry Association, 1985
A re -programmable, multi-functional manipulator designed
to move material, parts, tools, or specialized devices []
for the performance of various tasks
What does this definition missing?
Notions of thought, reasoning, problem solving, emotion,consciousness
-
8/2/2019 Chapter 1 - Introduction to Robotics
4/27
CS 491/691(X) - Lecture 1 4
A Robot is
a machine able to extract information from itsenvironment and use knowledge about its world to
act safely in a meaningful and purposeful manner
(Ron Arkin, 1998)
an autonomoussystem which exists in the
physical world, can senseits environment and can
acton it to achieve some goals
-
8/2/2019 Chapter 1 - Introduction to Robotics
5/27
CS 491/691(X) - Lecture 1 5
What is Robotics?
Robotics is the study of robots, autonomous
embodied systems interacting with the physical
world
Robotics addresses perception, interaction and
action, in the physical world
-
8/2/2019 Chapter 1 - Introduction to Robotics
6/27
CS 491/691(X) - Lecture 1 6
Robots: Alternative Terms
UAV unmanned aerial vehicle
UGV (rover)
unmanned ground vehicle
UUV
unmanned undersea vehicle
-
8/2/2019 Chapter 1 - Introduction to Robotics
7/27
CS 491/691(X) - Lecture 1 7
An assortment of robots
-
8/2/2019 Chapter 1 - Introduction to Robotics
8/27
CS 491/691(X) - Lecture 1 8
Anthropomorphic Robots
-
8/2/2019 Chapter 1 - Introduction to Robotics
9/27
CS 491/691(X) - Lecture 1 9
Animal-like Robots
-
8/2/2019 Chapter 1 - Introduction to Robotics
10/27
CS 491/691(X) - Lecture 1 10
Humanoid Robots
Robonaut (NASA) Sony Dream Robot
Asimo (Honda)
DB (ATR)
QRIO
-
8/2/2019 Chapter 1 - Introduction to Robotics
11/27
CS 491/691(X) - Lecture 1 11
What is in a Robot?
Sensors
Effectors and actuators
Used for locomotion and manipulation
Controllers for the above systems
Coordinating information from sensors with commands for
the robots actuators
-
8/2/2019 Chapter 1 - Introduction to Robotics
12/27
CS 491/691(X) - Lecture 1 12
Sensors
Sensor = physical device that provides informationabout the world
Process is called sensing or perception
What does a robot need to sense?
Depends on the task it has to do
Sensor (perceptual) space
All possible values of sensor readings
One needs to see the world through the robots eyes
Grows quickly as you add more sensors
-
8/2/2019 Chapter 1 - Introduction to Robotics
13/27
CS 491/691(X) - Lecture 1 13
State
State: A description of the robot (of a system in general)
For a robot state can be:
Observable: the robot knows its state entirely
Partially observable: the robot only knows a part of its state
Hidden (unobservable): the robot does not have any access
to its state
Discrete: up, down, blue, red
Continuous: 2.34 mph
-
8/2/2019 Chapter 1 - Introduction to Robotics
14/27
CS 491/691(X) - Lecture 1 14
Types of State
External The state of the world as perceived by the robot
Perceived through sensors
E.g.: sunny, cold
Internal The state of the robot as it can perceive it
Perceived through internal sensors, monitoring (stored,
remembered state)
E.g.: Low battery, velocity
The robots state is the combination of its internal
and external state
-
8/2/2019 Chapter 1 - Introduction to Robotics
15/27
CS 491/691(X) - Lecture 1 15
State Space
All possible states a robot could be in E.g.: light switch has two states, ON, OFF; light switch with
dimmer has continuous state (possibly infinitely many
states)
Different than the sensor/perceptual space!!
Internal state may be used to store information about the
world (maps, location of food, etc.)
How intelligent a robot appears is stronglydependent on how much and how fast it can sense
its environment and about itself
-
8/2/2019 Chapter 1 - Introduction to Robotics
16/27
CS 491/691(X) - Lecture 1 16
Representation
Internal state that stores information about the worldis called a representation or internal model
Self: stored proprioception, goals, intentions, plans
Environment: maps
Objects, people, other robots
Task: what needs to be done, when, in what order
Representations and models influence determine
the complexity of a robots brain
-
8/2/2019 Chapter 1 - Introduction to Robotics
17/27
CS 491/691(X) - Lecture 1 17
Action
Effectors: devices of the robot that have impact onthe environment (legs, wings robotic legs,
propeller)
Actuators: mechanisms that allow the effectors to
do their work (muscles motors)
Robotic actuators are used for
locomotion (moving around, going places)
manipulation (handling objects) This divides robotics into two basic areas
Mobile robotics
Manipulator robotics
-
8/2/2019 Chapter 1 - Introduction to Robotics
18/27
CS 491/691(X) - Lecture 1 18
Autonomy
Autonomy is the ability to make ones own decisionsand act on them.
For robots: take the appropriate action on a given situation
Autonomy can be complete (R2D2) or partial
(teleoperated robots)
Controllers enable robots to be autonomous
Play the role of the brain and nervous system in animals
Typically more than one controller, each process
information from sensors and decide what actions to take
Challenge in robotics: how do all these controllers
coordinate with each other?
-
8/2/2019 Chapter 1 - Introduction to Robotics
19/27
CS 491/691(X) - Lecture 1 19
Control Architectures
Robot control is the means by which the sensing andaction of a robot are coordinated
Control architecture
Guiding principles and constraints for organizing a robots
control system
Robot control may be implemented:
In hardware: programmable logic arrays
In software
Controllers need not (should not) be a single program
Should control modules be centralized?
-
8/2/2019 Chapter 1 - Introduction to Robotics
20/27
CS 491/691(X) - Lecture 1 20
Languages for Programming Robots
What is the best robot programming language? There is no best language
In general, use the language that
Is best suited for the task
Comes with the hardware
You are used to
General purpose:
JAVA, C
Specially designed:
the Behavior Language, the Subsumption Language
-
8/2/2019 Chapter 1 - Introduction to Robotics
21/27
CS 491/691(X) - Lecture 1 21
Spectrum of robot control
From Behavior-Based Robotics by R. Arkin, MIT Press, 1998
-
8/2/2019 Chapter 1 - Introduction to Robotics
22/27
CS 491/691(X) - Lecture 1 22
Robot control approaches
Reactive Control
Dont think, (re)act.
Deliberative (Planner-based) Control
Think hard, act later.
Hybrid Control
Think and act separately & concurrently.
Behavior-Based Control (BBC)
Think the way you act.
-
8/2/2019 Chapter 1 - Introduction to Robotics
23/27
CS 491/691(X) - Lecture 1 23
Thinking vs. Acting
Thinking/Deliberating slow, speed decreases with complexity
involves planning (looking into the future) to avoid bad
solutions
thinking too long may be dangerous requires (a lot of) accurate information
flexible for increasing complexity
Acting/Reaction
fast, regardless of complexity
innate/built-in or learned (from looking into the past)
limited flexibility for increasing complexity
H t Ch C t l
-
8/2/2019 Chapter 1 - Introduction to Robotics
24/27
CS 491/691(X) - Lecture 1 24
How to Choose a ControlArchitecture?
For any robot, task, or environment consider: Is there a lot of sensor noise?
Does the environment change or is static?
Can the robot sense all that it needs?
How quickly should the robot sense or act?
Should the robot remember the past to get the job done?
Should the robot look ahead to get the job done?
Does the robot need to improve its behavior and be able tolearn new things?
R C l
-
8/2/2019 Chapter 1 - Introduction to Robotics
25/27
CS 491/691(X) - Lecture 1 25
Reactive Control:Dont think, react!
Technique for tightly coupling perception and action to provide
fast responses to changing, unstructured environments
Collection of stimulus-response rules
Limitations
No/minimal state
No memory
No internal representations
of the world
Unable to plan ahead
Unable to learn
Advantages
Very fast and reactive
Powerful method: animals
are largely reactive
D lib i C l
-
8/2/2019 Chapter 1 - Introduction to Robotics
26/27
CS 491/691(X) - Lecture 1 26
Deliberative Control:Think hard, then act!
In DC the robot uses all the available sensory information andstored internal knowledge to create a plan of action: sense
plan act (SPA) paradigm
Limitations
Planning requires search through potentially all possible plans these take a long time
Requires a world model, which may become outdated
Too slow for real-time response
Advantages
Capable of learning and prediction
Finds strategic solutions
-
8/2/2019 Chapter 1 - Introduction to Robotics
27/27
CS 491/691(X) - Lecture 1 27
Textbooks
Lectures The Robotics Primer, 2001. Author: Maja
Mataric'
Available in draft form at the bookstore
top related