Robotics Demystified. McGraw-Hill

EDWIN WISE

Robotics Demystified

PREFACE
This book is for people who want to learn the basic concepts of robotics without
taking a formal course. This book seeks to give you an intuitive grasp of
the various technologies that make up the field of robotics. There is no one
‘‘robot technology,’’ so this book breaks the study of robots down into technology
categories: the mechanics and framework of the robot, the electronics
that make up its brain and nerves, and the control systems and programming
that gives the robot life.
To aid you in your learning, this work contains short quizzes that review
the main concepts in each chapter. Answers to the quizzes are given in the
back of the book.
This is a hands-on book, and it contains a number of experiments to
illustrate the concepts described in the text. These experiements can be
completed with easily found materials.
Though this is a hands-on book, it is not a ‘‘how to’’ book. Since it covers
several complex topics, it can only go so deep into each one.

Edwin Wise

ACKNOWLEDGMENTS
Of course, I have to acknowledge my wife Marla for letting me take the time
to write this book. My reviewers, Bob Comer and Matt Pinsonneault with
help from Nikolas Wise, helped me to remain coherent and stay on track.
The text was written in Microsoft Word, and the graphics and diagrams
were created and edited with Adobe’s Photoshop, Midnight Software’s
DeltaCAD, CadSoft’s Eagle electronics layout editor, Pacestar’s ever useful
EDGE Diagrammer, and MFSoft’s Equation Grapher. Facts were
checked against the Oxford English Dictionary and the Wikipedia at www.wikipedia.com
both of which are excellent sources of information.
Special appreciation goes out to the fine people at www.lugnet.com and
the tools their members have created, without which this book would look a
lot less interesting. MLCad by Michael Lachmann let me draw all of the
LEGO designs and LPub by Kevin Clague processed these models, using
geometry in Luts Uhlmann’s LGeo library, for rendering.
Electronic layout to POVRay model conversion was handled by Eagle3D,
which was written by Matthias Weisser. Eagle3D can be found on his
homepage at http://www.matwei.de/. All rendering was done by POVRay,
from www.povray.org.
LEGO is a trademark of the LEGO Group of companies, who reserve all
rights to their names and logos. This is not a LEGO book, a book about
LEGOs, nor is this work endorsed by LEGO. We do, however, use the
LEGO construction system to provide mechanical examples. These little
plastic blocks are available everywhere, and provide a familiar context for
our exploration. The LEGO Mindstorms system also provides motors and
computers that we use to learn about robotic systems.
All other product names are the trademark of their respective companies.

E. W.

Introduction

Robot
1.a. One of the mechanical men and women inCˇ apek’s play; hence, a machine
(sometimes resembling a human being in appearance) designed to function
in place of a living agent, esp. one which carries out a variety of
tasks automatically or with a minimum of external impulse.

b. A person whose work or activities are entirely mechanical; an automaton.
Oxford English Dictionary, Online Edition
KarelCˇ apek used the word Robot in his 1921 play Rossum’s Universal Robots,
derived from the Czech word robota, meaning ‘‘forced labor.’’ These Robots
were created to replace man and, in their simplified form, as cheap labor.
Robots had perfect memory but were incapable of thinking new thoughts.
They mirrored the Hebrew legends of the golem, a clay statue that has had
life breathed into to by mystical means. And, of course, this all sounds a lot
like Dr. Frankenstein’s monster, reanimated from the bits and pieces dug up
from the local graveyard.

One thing these stories have in common is that the creation is ultimately
the downfall of their creator—robots, golems, and reanimated flesh mean
trouble. They are an illustration of what happens when we reach too far and
are bitten by the unintended consequences.

We, however, are interested in the robot as an agent that carries out its

tasks automatically or with a minimum of external impulse rather than a

recreation of life itself. A smart machine.

In this chapter, we first look at some of the history behind the robot. From

there we explore the technologies that make up a robot, laying the groundwork

for later chapters on how these technologies work. Once we have a good

sense of what a robot is, we peek into the future to see what robots might

someday be like.

A Brief Tour of Robotics

AUTOMATA AND ANIMATRONICS

An automaton is a device that has the ability to move under its own power.

The mechanism of the motion is normally hidden, giving the illusion that the

device is self-motivated or alive. While this definition can apply to something

as mundane as a mechanical watch, automata are usually mechanisms that

try to mimic the look and behavior of living creatures.

We humans have long been fascinated by the workings of our own bodies

and the animals around us. With this fascination has come the urge to

recreate these things, to step into the role of divinity and try our hand at the game of life.

The ancient Greeks, at around 400 B.C. and continuing on into the common

era, are reputed to have used steam and water power to animate statues

or drive various mechanisms in their temples. Automatically opening doors,

statues that appear to drink offerings of wine, singing birds, self-lighting fires,

and other wonders are documented in the few remaining writings of that time.

There are hints of similar Egyptian and Chinese devices from that era as well.

Most of these technologies, the accumulated knowledge of ancient civilizations,

were lost until relatively recent times. During the Renaissance, Europe

started to drag itself out of the Dark Ages and began discovering (or, in

many cases, rediscovering) all manner of ideas, art, technologies, and sciences.

Among these, combining both art and technology, were the automata.

Some wild stories tell us about an iron fly and an artificial eagle made

of wood, constructed by Johannes Muller in the 1470s. In the fourteenth

and fifteenth centuries, automata were the playthings of royalty. Leonardo da

Vinci made an animated lion for King Louis XII, Gianello della Tour of

Cremona built a number of mechanical entertainers for Emperor Charles V,

and Christiaan Huygens created a robotic army sometime around 1680.

The first documented automaton in human form, or android, was made

by Hans Bullman in the early sixteenth century. Androids have been a

popular subject for automata builders ever since. Inventors built machines

to play musical instruments of all kinds, draw, write, and even play chess—

or at least, pretend to play chess.

The eighteenth century was the golden age of automata, with many intricate

machines. These were driven by clockwork gears and cylinders containing

hundreds, if not thousands, of complicated control tracks. These tracks

were composed of sequences of rods of different heights fixed to a cylinder, or

individual cams with complex shapes, that pushed on levers that moved rods

that adjusted the automaton creating a specific sequence of actions.

The Turk was a world-famous automaton from this time. Built in 1770 by

Wolfgang von Kepelen, and later purchased from Kepelen’s son by Johan

Nepomuk Maelzel in 1804, the Turk toured Europe and America amazing

audiences by playing chess!

By the time the Turk was on tour, audiences were familiar with the

workings of automata and had been exposed to many fine machines. But they

were also confident that these machines were just that, simple collections of

gears and levers whose rote actions were no challenge to the human intellect.

The automata may appear to be alive, but they are only vague shadows of

life. They couldn’t think.

The Turk challenged this view. It played, and often won, games of chess

against any number of famous figures of the time. Napolean, Charles

Babbage, and Edgar Allen Poe all took their turn against this mechanical

savant. Of course, it turned out that the machine could not play chess at all.

Instead, it provided cramped quarters for a human chess player who in turn

ran the machinery that made the Turk move.

One very complex automaton wasn’t an android, but a duck. Jacques

Vaucanson created this avian automaton in 1738 and then went on tour with

it. At the price of a week’s wages, audiences were invited to see this creation

move around, adjust its wings, preen, drink water, and even eat food, digest

it, and then defecate. All of this required thousands of moving parts within

both the duck and its large base. And yet, automata were just a hobby of

Vaucanson’s. He sold his collection in 1743 and went on to direct the stateowned

silk-mills in France. Among other innovations, he developed a way

to weave silk brocade using a machine guided by perforated cards. Owing to

hostility among the weavers of the time, his advances in factory automation

were ignored for decades.

In 1804, Joseph-Marie Jacquard improved and reintroduced the technique

and was later credited with its invention. While the automatic loom was still

despised by weavers, who went as far as burning down automated factories,

its improved efficiency led to its ultimate acceptance and led the way into the

industrial revolution.

In the nineteenth century improved manufacturing techniques brought

simple automata to the masses, typically in the form of toys, fancy clocks,

and other novelties. Clockwork mechanical toys were popular well into the

twentieth century. Today the springs, gears, and cams in toys have been

replaced by tiny motors and electronic controls.

The skills and techniques developed by the automata makers during the

Renaissance provided a foundation for the industrial revolution that

followed. Today, you can still find automata for sale. Automata are now in

the domain of the artist and pieces from modern craftsmen and artists can be

found for as little as a few dollars, up to hundreds or thousands of dollars.

Another use for these magical machines is entertainment. Walt Disney

introduced mechanical actors in the displays of his amusement park and

christened them Audio-Animatronics. This cumbersome name is normally

shortened to simply ‘‘animatronics.’’ Animatronics are machines driven by

motors and hydraulics and synchronized with an audio track to give the full illusion of life.

From the simplest Egyptian trick with water to the modern miracles of

Disney’s animatronics, these machine all share one characteristic. They can

only reproduce a preset sequence of motions.

FACTORY MACHINES

Ever since the advent of factories during the industrial revolution, specialized

machines have had an important role in creating the products of

civilization. The most common machine was the underpaid, overworked

citizen—men, women, and children. Early factory conditions were dangerous,

but the wages were good and nobody could argue with the efficiency

factories brought.

Water and steam power, and later gas and electric power, replaced and

enhanced human power, allowing us to make our products even faster

and cheaper. Complex machines were created to take over many aspects of

manufacture. The automatic loom is well known, but even today there are

specific machines for many tasks.

You don’t normally think about it, but there is a complex machine whose

only purpose is to bend wire into paperclips. There is another machine,

perhaps in the same factory, that makes nails. Other machines perform other

tasks. These machines, invaluable as they are for industry, are still forms of automata.

be programmed. But there is still a large gray area. Take that nail-making

machine and add a bunch of controls to it so it can make nails from different

sizes of wires, with different types of points, and different types of heads.

Is it an automaton or a robot? Does it make a difference if the controls are

mechanical levers and knobs or electronic circuits?

In the early factories, working alongside a machine made your job more

dangerous even if it made it less arduous. These early machines were large

assemblies of spinning, whirring, moving parts that continued to spin, whir,

and move even if a finger, foot, or other body part intruded into it. Even

today, people working with machines in factories and food-processing plants

face special risks. Machines are designed to be as safe as possible, but there

are limits to what can be done to a metal sheer or punch press, for example,

and have it remain useful.

As machines improved into robots, they made some aspects of factory

work safer. A robotic painter, spot welder, or assembly machine can operate

in an empty space without any help at all. A supervisor stands safely outside

its range of motion while the robot does the dirty and dangerous work

(Fig. 1-1).

The most visible type of factory robot is the robot arm (Fig. 1-2). These

can be given any type of specialized ‘‘hand’’ needed for their job (Fig. 1-3)

and programmed to perform complex activities. One arm, with a set of

different hands, can be programmed to perform any number of tasks. These

are the robots that we recognize as ‘‘smart’’ machines, beginning to realize

the dream promised to us by Kepelen’s Turk.

Screenshot

Purchase Now !
Just with Paypal

Product details

Price
File Size	6,684 KB
Pages	333 p
File Type	PDF format
Print Version	0-07-143678-2
Copyright	2005 by The McGraw-Hill Companies, Inc

Contents

Preface xv

Acknowledgments xvi

CHAPTER 1 Introduction 1

A Brief Tour of Robotics 2

Automata and Animatronics 2

Factory Machines 4

Fictional Robots 7

Future Dreams 8

Inside Robots 9

Tools and Supplies 10

Parting Words of Wisdom 11

CHAPTER 2 Mechanical Forces 13

Introduction 13

Energy 15

Units of Measurement 16

Position 16

Time: t 17

Length: l 17

Mass: m 18

Velocity: v 19

Acceleration: a 23

Force: F 24

Momentum: p 26

Energy: E 26

Storing Energy 27

Losing Energy 29

Summary 30

Quiz 30

CHAPTER 3 Simple Machines 32

Introduction 32

Structural Strength 33

Triangles and Squares 33

Hidden Triangles 35

Inclined Plane 36

Wedge 40

Screw 41

Levers 42

Lever Machine 42

Pulleys 44

Pulley Machine 45

Wheels and Torque 49

Gears and Sprockets 51

Summary 53

Quiz 53

CHAPTER 4 Electricity 54

Introduction 54

Pieces of Matter 55

Electrons in Metal 56

Electromagnetic Field 57

Units 59

Unit Prefixes 59

Electrical Charge 60

Current: I 61

Charge Difference 62

Electrical Energy 63

Power: P 63

Batteries and Generators 63

Speed of Electricity 64

Summary 65

Quiz 65

CHAPTER 5 Starting with Electronics 66

Introduction 66

Electronic Circuits 67

Schematic 67

Printed Circuit Board 68

Circuit Assembly 70

Prototyping Boards 70

Dead Bug and Wire Wrapping 71

Soldering 72

Suppliers 79

Resistors 80

Resistor 80

Ohm’s Law 81

Resistor Networks 83

Resistive Sensor 87

Light Bulb 94

Summary 94

Quiz 95

CHAPTER 6 Control 96

Introduction 96

Passive Control 97

Balancing Machine 98

Open-Loop Control 98

Feedback Control 99

CONTENTS vii

Centrifugal Feedback 100

Hysteresis 102

Mechanical Switch 104

Summary 105

Quiz 106

CHAPTER 7 Sequencing and Programs 107

Introduction 107

Switches and Cycles 108

Cam Control 111

Cardboard Cam 113

Card Control 113

Mechanical Card Reader 115

Programming Concepts 115

Computer Numbers 117

Computer Instructions 121

Summary 122

Quiz 123

CHAPTER 8 Joints 124

Introduction 124

Rotation and Bending 125

Rotation 125

Bearings and Bushings 126

Bending 127

Sliding 128

Complex Motion 128

Ball and Socket 128

Universal Joint 130

Robot Wrist 131

Others 134

Summary 134

Quiz 135

CHAPTER 9 Power Transmission 136

Introduction 136

Chains, Belts, and Cables 137

Gears 141

Gear Trains 142

More Gears 145

Couplers 149

Directional Transmission 150

Differential Transmission 150

Summary 154

Quiz 155

CHAPTER 10 Beyond Resistance: Capacitance 156

Introduction 156

AC/DC 157

Oscilloscope 160

Diodes 161

Signal Diode 161

Rectifier 162

Light-Emitting Diode 163

Zener Diode 163

Capacitors 165

Capacitor 165

Capacitors and Audio 168

Capacitor Networks 170

RC Circuits 171

RC Filters 172

Diode-Capacitor Circuits 176

Summary 178

Quiz 178

CHAPTER 11 Inductance and Magnetism 179

Introduction 179

CONTENTS ix

Electromagnets 180

Nail Electromagnet 181

Relay 182

Motors 182

Generators 184

Servos and Steppers 184

Inductors 185

Behavior 186

Component 186

Filters 187

Phase 187

Transformer 188

Summary 189

Quiz 189

CHAPTER 12 Semiconductors 190

Introduction 190

Conductor Physics 191

Semiconductor Physics 192

Doped Silicon 193

Diode Physics 195

Forward Bias 197

Reverse Bias 198

Electronic Switches 198

Analog Versus Digital 198

Transistor 200

FET 202

Integrated Circuits 204

Summary 205

Quiz 205

CHAPTER 13 Programming 207

Introduction 207

Programming Basics 208

RCX Programming 211

Programs 213

Simple Timed Sequence 213

Obstacle Avoidance 213

Line Following 218

Self-Calibration 221

Summary 221

Quiz 223

CHAPTER 14 Shaping Motion 224

Introduction 224

Looking Back 225

Single-Link Mechanisms 225

Two Links 228

Robotics Demystified. McGraw-Hill

EDWIN WISE

Contact Form