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CS545—Contents I

n Administrative• About the text books• Goals of course• Matlab/Simulink• Grading• Flexible content of course (special

seminars ?)

n Introduction• An Overview of Robotics

n Reading Assignment for NextLecture

• Scivicco & Siciliano, Appendix A

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CS545Introduction to Robotics

Stefan Schaal

Computer Science & NeuroscienceUniversity of Southern California

Kawato Dynamic Brain ProjectERATO/JST

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Outline

n A brief history of roboticsn Classical robotics

• Basic elements• Basic control

n Towards autonomous andbiomimetic robots

• Advanced control• Compliance• Learning• Integration of Perception&Action• Human-like Robots

n Lots of videos

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A Brief Chronology I1750Swiss craftsmen createautomatons with clockworkmechanisms to play tunes andwrite letters.

1917The word "robot" first appearsin literature, coined in the playOpilek by playwright KarelCapek, who derived it from theCzech word "robotnik" meaning"slave."

1921The term robot is made famousby Capek's play R.U.R.(Rossum's Universal Robots).

1938Isaac Asimov coins the termrobotics in his science fictionnovels, and formulates theThree Laws of Robotics whichprevent robots from harminghumans.

1954The first United Kingdomrobotics patent, No. 781465, isgranted in England on March29.

1956The Logic Theorist, an artificialintelligence machine capable ofproving logical propositionspoint-by-point, is unveiled atDartmouth College.

1958Joseph F. Engelberger sets upa business in his garage calledConsolidated Controls, makingaircraft components. Joseph F.Engleberger and George C.Devol name theirfirst robot "Unimate." The firstUnimate is installed at aGeneral Motors plant to workwith heated die-castingmachines. founds Unimation,the first commercial companyto make robots. Unimationstood for Universal automation.

1960Artificial intelligence teams atStanford Research Institute inCalifornia and the University ofEdinburgh in Scotland beginwork on the development ofmachine vision.

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A Brief Chronology II1961George C. Devol obtains the firstU.S. robot patent, No. 2,998,237.

1961First production version Unimateindustrial robot is installed in adie-casting machine.

1961The MH-1, Mechanical Hand withsensors, is developed at MIT byErnst.

1962Consolidated Diesel ElectricCompany (Condec) and PullmanCorporation enter into jointventure and form Unimation, Inc.(Unimation stood for "UniversalAutomation").

1963The Versatran industrial robotbecame commercially available.

1964The first Tralfa robot is used topaint wheelbarrows in aNorwegian factory during a humanlabor shortage.

1966The first prototype painting robotsare installed in factories in Byrne,Norway.

1966The robotic spacecraft "Surveyor" (UnitedStates) lands on the moon.

1968"Shakey," the first complete robot systemis built at Stanford Research Institute, inCalifornia.

1968Unimation takes its first multi-robot orderfrom General Motors.

1969Robot vision, for mobile robot guidance,is demonstrated at the StanfordResearch Institute.

1969Unimate robots assemble ChevroletVega automobile bodies for GeneralMotors.

1970General Motors becomes the firstcompany to use machine vision in anindustrial application. The Consightsystem is installed at a foundry in St.Catherines, Ontario,Canada.

1970The Russian lunar rover Lunakhod,wheels about on the moon.

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A Brief Chronology III1970The first American symposium on

robots meets in Chicago.

1971Japan establishes the Japanese

Industrial Robot Association(JIRA), and becomes the firstnation to have such anorganization.

1972The SIRCH machine, capable of

recognizing and orientingrandomly presented two-dimensional parts, is developedat the University of Nottingham,England.

1972Kawasaki installs a robot assembly

line at Nissan, Japan, usingrobots supplied by Unimation,Inc.

1973"The Industrial Robot," the first

international journal of robotics,begins publication.

1973The ASEA Group of Vasteras,

Sweden, introduces its all-electric IRb 6 and IRb 60 robots,designed for automatic grinding

operations.

1974Hitachi uses touch and force sensing withits Hi-T-Hand robot, allowing the robot handto guide pins into holes.

1974The Robotics Industries Association isfounded.

1975Cincinnati Milacron introduces its first T3robot for drilling applications.

The ASEA 60kg robot is the first robotinstalled in an iron foundry; the CincinnatiMilacron T3 becomes the first robot to beused in the aerospace industry.

1976The Trallfa spray-painting robot is adaptedfor arc welding at the British agriculturalimplement firm of Ransome, Sims andJefferies.

1976Remote Center Compliance evolves fromresearch at Charles Stark Draper Labs,Cambridge, Mass. Dynamics of part matingare developed, allowing robots to line upparts with holes both laterally androtationally.

1976The robotic spacecraft "Viking" (UnitedStates) lands on the Martian surface.

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A Brief Chronology IV1977California Institute of Technology's

Jet Propulsion Laboratory (JPL)demonstrates a robotic hand-eye system can be integratedwith a self-propelled vehicle for

planetary exploration. (Mars Rover)

1977The British Robotics Association

(BRA) is founded.

1978The first PUMA (Programmable

Universal Assembly) robot isdeveloped by Unimation forGeneral Motors.

1978The Machine Intelligence Company is

organized by Charles A. Rosenand associates.

1979Japan introduces the SCARA

(Selective ComplianceAssembly Robot Arm); DigitalElectronic Automation (DEA) ofTurin, Italy, introduces thePRAGMA robot, which is

licensed to General Motors.

1980Robotics languages are developed to

ease programming bottlenecks.

1981IBM enters the robotics field with its 7535and 7565 Manufacturing Systems.

1982The Pedesco robot (Pedesco,Scarborough, Ontario) is used to clean upafter a nuclear fuel spill at an atomicpower plant. A task too dangerous fordirect human contact.

1982Stan Mintz and five co-employees ofHewlett-Packard Company left to formIntelledex Corporation, a manufacturer oflight assembly robots, for such tasks asinstallingintegrated circuits.

1981-1984Rehabilitation robots are enhanced bymobility, voice communication, and safetyfactors. Greater emphasis is placed onmachine vision, tactile sensors, andlanguages.Battlefield and security robots aredeveloped.

1983Westinghouse Electric Corporation buysUnimation, Inc., which becomes part of itsfactory automation enterprise.Westinghouse later sells Unimation toAEG ofPennsylvania.

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A Brief Chronology V

1984Robot Defense Systems introduces the Prowler("Programmable Robot Observer with LocalEnemy Response"), the first in a series ofbattlefield robots.

1984Intelledex Corporation introduces the Model 695lite assembly robot, based on the Intel 8086 and8087 microprocessor chips. Its software iscalled Robot Basic, aspecialized version of Microsoft's Basic.

1993The University of Michigan's CARMEL robotwins first place at the 1992 Robot Competitionsponsored by the American Association forArtificial Intelligence (AAAI).CARMEL stands for computer-aided robotics formaintenance, emergency, and life support. TheSRI International's robot "FLAKEY" wins secondplace. Bothmicrocomputer- controlled machines useultrasonic sonar sensors.

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Classical Robotics

The Robotics IndustriesAssociation provides the followingdefinition:

A robot is a reprogrammable,multifunctional machine designedto manipulate materials, parts,tools, or specialized devices,through variable programmedmotions for the performance of avariety of tasks."

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Classical RoboticsDesign Elements

n Links– steel, aluminum, ridged

n Joints– revolute, prismatic

n Actuators (Drive)– electromotors– hydraulics– gear boxes

n Sensors– position, velocity, acceleration,

force– vision, sonar, IR, tactile

n Endeffector

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Actuators: TheBottleneck of Robotics

n Electromotors• low torque, small, light, fast

(high rpm)• high torque, big, heavy, slower

(low rpm) (torque motors,direct drive motors)

n Hydraulics• messy (?), not mobile (pump!)

n High Energy Consumptionn torque ~ size 4

• huge penalty for being big

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Classical Robotics:Gear Boxes

n Advantages– small torque -> large torque– high speed -> low speed– light motors and gear boxes

n Disadvantages– amplification of rotor inertia– friction– backlash– back-drivability (stiff)

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Classical Robotics:Control

n Open-Loop Controln Closed-Loop Controln Feedback Controln Negative Feedback Controln Feedforward Control

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Open vs. Closed LoopControl

RobotxController

u

Open Loop ControlDesiredBehavior

Robotx

Controlleru

Closed Loop ControlDesiredBehavior

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Types of FeedbackControl

RobotNonlinear

Controller (Policy)

DesiredBehavior u x

Feedback Control

RobotFeedbackControllerÂ

xdesiredufb x

+–

Negative Feedback Control

RobotFeedbackControllerÂ

xdesiredufb x

+–

FeedforwardController

Â

uff

+

+

Neg. Feedback & Feedforward Control

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Classical NegativeFeedback Control: PID

n PID = proportional-derivative-integral

• position error (proportional)• velocity error (derivative, lose

energy)• steady-state position error (integral)• linear, decoupled control, usually

with high gains• simulates a damped spring

u k x x

k x x

k err

err x x dt

p desired

v desired

i static

stat desired

= −( ) +

−( ) +

= −( )∫

˙ ˙

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In Sum: Characteristicsof Classical Robots

n Stiffn Heavyn Slown Linearn Parsimoniousn Minimal Autonomyn High Accuracyn One Task

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In Contrast: Character-istics of Bio. Movement

n Compliantn Lightn Fastn Nonlinearn Highly Redundantn High Autonomyn Lower Accuracyn Many Tasks

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Towards Autonomousand Biomimetic Robots

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Towards Autonomousand Biomimetic Robots

n Autonomous– perception, adaptation, dynamic

planning, can deal withunexpected events

n Biomimetic– structural and functional

principles of biology in robotics

n New Robot Types– mobile robots– arm-like robots– hand-like robots– eye-like robots– legged robots– human-like robots– helicopter robots, etc.

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Issues of Autonomous,Biomimetic Robots

n Better Actuationn Nonlinear Controln Learningn Behavior-based (Parametric)

Controln Decentralized Controln Brain-like Controln Human-like Design

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New Ways of Actuation

n Tendon Drivenn Muscle-basedn Passive Springs in

Traditional Gear-box Drivesn Shape Memory Materials

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Nonlinear Control

RobotPID

ControllerÂxdesired

ufb x+–

FeedforwardController

Â

uff

+

+

RobotPID

ControllerÂxdesired

ufb x+–

Classical Linear Control

Feedback & Feedforward Control (Model-based)

RobotNonlinear

Controller (Policy)

DesiredBehavior u x

Direct Control

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Learning

n Learning Models– neural nets (function

approximation)– statistical learning– incremental learning– dimensionality

n Reinforcement Learning– scalar rewards– involves function approximation– dimensionality

n Evolutionary Methods, etc.

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Behavior Based Control

n Use Basis Behaviors (BasisPolicies, Schemas)

n Run Behaviors in Paralleln Allow Inhibition, Competition

Among Behaviorsn Emphasize Reactive

Behaviorn Emphasize Model-free

Approachn Situatedn Embodiedn Mobile Robotics

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Behavior-Based Control

NonlinearController (Policy) 1

DesiredBehavior 1 u1 x

RobotNonlinear

Controller (Policy) 2

DesiredBehavior 2 u2

RobotNonlinear

Controller (Policy) 3

DesiredBehavior 3 u3

RobotNonlinear

Controller (Policy) 4

DesiredBehavior 4 u4

RobotNonlinear

Controller (Policy) 5

DesiredBehavior 5 u5

Robot

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Pattern Generators

n A Form of Behavior-basedControl

n Use Dynamical Equationsn Neurobiological Counterpartn Locomotion, Posture, Arm

Control

e.g.:

τ βτ βττ

˙

˙

˙

˙

max( , ) ( , )

,

x x wy v x C

x x wy v x C

v v y

v v y

y x i

u g y y

u

u

i i

1 1 2 1 0

2 2 1 2 0

1 1 1

2 2 2

1 2

0 1 2

= − − − + += − − − + +

′ = − +′ = − += =

= ( )

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Example:Ball Bouncing

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

145 146 147 148

Pos

ition

[m]

Time [s]

Ball Paddle

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Brain-like Control

n Explore Theories fromComputational Neuroscience

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Full-Body Robots

n Emphasis on Entire System

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Full-Body Robots

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Summary

• Robotics is a young field• Classical Robotics is still an

important basis• Actuators are a major problem• But even with perfect actuators

we would not know how tobuild “smart” machines

• Biomimetic Robotics as astrategy to find out aboutbiology and new technologies