Print publishers are invited to contact the author for a license to publish. Literary agents are invited to contact the author.
You need neither science nor math nor need you be "mechanically inclined" to enjoy this book. It is a reading book, not a study book, and I promise that you will have no trouble understanding it. Also you will learn a few jargon words which will impress your friends.
I say these things with some confidence because of how the book came about. When I was running a robot company I was asked to talk to a university alumni organization about robots. They were bright people with liberal arts degrees but most with no science or math that they used or even remembered very well. I spoke on "Smart Machines" with robots as a sub-topic. We all had a wonderful, animated evening and thence this book.
The book describes the many, many ways machine "smartness" both enriches our lives and threatens our lives. As you read, you will see things in our environment you never noticed before, you will recognize the effects of things we cannot get to see, and you will see through some of the self serving, hi-tech hype which is propagandized at us.
You will gain insight into the relative capabilities and limitations of people and machines and you will understand why each is better at different kinds of task. And you will become more aware of the effects of smart machines on the structure of our society.
Machine "smartness" is how machines do, without immediate human control, what they could do while under human control, except much better. Some of the things they do are physical.
For example, my home furnace is turned on and off by its thermostat without my being there to turn it on and off myself. My furnace and its thermostat comprise a rudimentary smart machine.
Some of the things smart machines deal with is information, like finding a file, or computing our income taxes, or relaying our conversations via a satellite which is 22,000 miles above the ground.
For examples, a computer is recording what I am now typing and it will make it very much easier for me to make changes than if I used an old fashioned typewriter. Another computer keeps track of my bank account and prints my monthly statement.
A "machine," here, is any contrivance made by people to help them do what they want done. It may be mechanical, electronic, hydraulic, or a combination of these and it may be powered by a human or by an engine. Screwdrivers, chain saws, computers, airplanes, and chemical plants are all machines.
The book deals primarily with the smartness which is itself part of machines, but many machines use the smartness of people as part of the overall smartness of machines; for example, a car having automatic cruise control and an automatic transmission but being steered by a person.
In the past many machines were powered by animals, but by the time machine smartness evolved, windmills, water wheels, and steam engines had arrived, followed by internal combustion engines and electric motors. No animal powered smart machines have been made insofar as I know. (However dog sleds use both the power and the smartness of animals in following a trail.) People power hand tools, of course, and the hand cranked kitchen apple peeler, human powered, has a class of smartness in following the contour of the apple which we will examine in some detail later on.
We will consider machines whose smartness in some ways greatly exceeds that of people, in other ways may be similar to that of people, and in other ways is far inferior to that of people.
Smart machines is a highly emotional subject. Smart machines affect jobs, markets, money, standards of living, education, health, and war; this book will deal with all of these. Smart machines are not used directly in sex, politics, or religion but their indirect effects, via TV and film for example, is enormous. We will examine all these effects of smart machines on society as an introduction to an enormous body of information and opinion. There is both love and hate. I will try to spell out both, but I apologize for whatever imbalance I commit.
The book will tell how smart machines came about and it will tell some stories of engineers and scientists who brought them about. The treatment of biography and anecdotes is intended to add some real life to an examination of machines which only emulate life. The book is not a full history of science and engineering; it gives only enough chronology to understand the major events and trends in the evolution of smart machines. However the references provided will start the interested reader in pursuit of all of these subjects to whatever degree of exhaustive scholarship is desired.
The descriptions and explanations of machines and their technology are as correct and complete as I can make them in a popular book, although a full catalog of smart machines is not included - it would be an encyclopedia.
I have italicised descriptions of examples and of parenthetical musings so the flow of description is not interrupted.
Lets go.
We will examine different kinds of automatic clocks which control very complicated sequences of action in many kinds of machine. We will also examine SERVOMECHANISMS which make airplanes fly straight, keep our homes at the desired temperature, and turn petroleum into gasoline.
In this book, radios, heaters, guided missiles, artificial hearts, robots, oil refineries, and airplanes are all called MACHINES and we will be concerned with automatic, or SMART, machines.
Smart machines create some kinds of job and eliminate other kinds of job. Smart machines affect education, the qualifications for work, and the social conditions which affect both. Smart machines affect competitiveness, markets, profits, standard of living, pollution, and prosperity. Smart machines affect us all.
Some smart machines are helpful to people (e.g., electro-cardiographs), some are hurtful (e.g., machine guns), some are both (e.g., cars). I shall not moralize here, although I have my own moral judgments, but I do intend to give some insight into the world of smart machines which may aid you in forming your own judgments and perhaps in taking your own actions.
If I go camping, and my tent is too cold, and I turn up the fuel knob on my kerosene heater, and the tent gets warmer, and then gets too warm, and I turn down the fuel knob, etc. I am doing MANUAL CONTROL of the temperature. If my home is too cold and I reset my thermostat it will do AUTOMATIC CONTROL of the new temperature without my doing anything else about it. My heater and thermostat together make up a smart machine. The following chapters describe automatic control devices which do many, many kinds of automatic control of many, many kinds of machine. Each control device, combined with its controlled machine, comprise a smart machine.
AUTOMATION is all kinds of control which is AUTOMATIC. There is now a tremendous amount of automation in the world which affects our lives; automation is what this book is about. Because it is so closely related, I have included the subject of REMOTE CONTROL. A radio garage door opener is a remote control device, as is a telephone answering machine which plays back its messages to us over a telephone line when we have given it the proper signal, as is the equipment to manage a satellite in orbit.
As with everything, there is good news and bad news. The good news is that automation has been, and will continue to be, a source of rising standard of living.
Among the bad news is that we will not get robots to do our housework. We cannot appreciate how complex our tedious and boring housework really is, and how complex a real person is, physically and mentally, until we have both done housework, as I have, and struggled to replace human labor with machine labor, as I also have. Robot servants remain a science fiction fantasy.
Automation replaces some jobs with smart machines in order to do the work at lower cost and, sometimes, do it better. On the other hand it creates skilled jobs in designing, producing, controlling, and maintaining the smart machines. These machines are more complex than the non-automatic machines they replace.
One can argue that automation is merely a continuation of the industrial revolution which started in 18th century England with automatic textile machinery and automatic steam engines. (The original steam engines had valves which were manually operated for each stroke. That bit of automation, done with string when he was a boy hired for the job, was James Watt's first contribution to the industrial revolution.)
It is a paradox that the two greatest areas of automation are in manufacturing machines, which produce, and in weapons, which destroy.
Not all the economic, political, and social consequences of automation are obvious. Chapters 14 and 15 will discuss them at some length and Chapter 16 will survey predictions of what is to come.
Automation is the smartness of smart machines. It is used in our homes and in our cars:
Temperature is automatically controlled in our living space, our hot water, our dishwasher, clothes washer and clothes dryer, our car engine and car interior.
The speeds of our VCRs, audio tape recorders, and CD players are automatically controlled. If our cars have cruise control the car speed is automatically controlled when we want it to be.
The loudness of our radios and TVs is automatically held at the level we set. There are automatic circuits in them which control tuning and picture quality.
Our kitchens may have any of a multitude of gadgets with automatic controls: microwave oven, toaster, can opener, convection oven, mixer, etc.
Our cameras may have automatic controls for focussing, exposure, self timing, flash, and film winding.
The commercial utilities which we use have different kinds of automation in electric, gas, telephone, and water supplies. (Some is devoted to minimizing pollution.)
Our transportation services use automation in trucks, buses, railroads, and to an extreme degree in airplanes.
The warehouses which supply our merchandise use automated conveyor systems.
The entertainment sources we use: radio, TV, movies, bowling alleys, theme parks, boats, theater and concerts, all use automatic equipment.
Our information sources: books, newspapers, magazines, brokerage, radio, schools, TV, Internet, depend heavily on automated information handling, displaying, and typesetting.
Our own offices and the offices of the business, legal, medical, accounting, banking, and other services we use depend utterly on automatic telephones, facsimile machines, photocopiers, word processors, and data handling computers.
Our purchased products, from toothbrushes to clothes to cars, are manufactured in factories using ever increasing amounts of automation.
Our government services: police, fire, information (census, statistics, etc.) rely heavily on automated equipment.
Our health is maintained and restored with a multitude of automated machines including blood testers, X-ray machines, breathing testers, and exercisers, heart-lung machines, and blood processors.
Our military establishment, once it started, is the nation's most aggressive promoter and user of automation. It started with machine guns in the late 19th century and now has a broad spectrum of implements of war from guided missiles to advanced communications. It is a philosophical paradox that much civilian automation is a by-product of military research and development.
Smart machines affect the kinds of jobs we can get, the kinds and quantities of products we can buy, our security from crime and war, our health, and our prosperity.
All of these subjects are discussed on the following pages.
We live with phenomena we do not really understand: the behavior of the economy and of government, health and sickness, complicated cars, smart machines. I can't help you with any of these except the last one, but when you have read this chapter you will really understand the basic principles of smart machines.
MECHANIZATION is doing things by machine instead of by hand. It includes both person operated machines such as old fashioned machine tools with hand cranks, and smart machines such as computer controlled machine tools. In this book on smart machines I will describe person operated machines only as a background to their smart versions. I will also include machines which are remotely controlled by people, because much of the technology is the same as in smart machines and because most such machines also include fully automatic portions.
Smart machines replace some jobs with automatic machines. On the other hand they create skilled jobs in designing, producing, and maintaining the smart machines. These machines are more complex than the non-automatic machines they replace, so there are higher qualifications for, and more advanced training of, those who work with them. As one specific example, a maintainer must be able to read and understand written manuals which bear little relationship to comic books. Those who are lubricated through public school and graduate without a real ability to read, will not qualify regardless of whatever social, quota, and ethnic laws may be written. You can't fool mother nature. Designs either work or not. A maintained machine either works or not. No ethnic or cultural arguments will make any difference.
In the course of the book a number of buzz words will be introduced which are useful to learn. Their first appearances will be capitalized.
There are three words which mean substantially the same thing: SMART, AUTOMATIC, and ROBOTIC. "Smart" started as engineers' slang, but is so apt that it is now common usage; even the military have the "smart bombs" which played such a large role in winning the war with Iraq.
Engineers sometimes speak of "intelligent" machines, meaning computers which approximate human thinking - perhaps. I will avoid the science fiction implications of that suggestion and not use the word. However EXPERT SYSTEMS are real and useful, although the word was chosen to suggest an artificial human brain instead of a means to build and use logic trees, which is what they are.
AUTOMATION, the technology of automatic devices, is an older word for smart technology but it sounds too formidable and discourages many people. ROBOTICS, the technology of robots, sounds glamorous; however it smacks of the hype produced by the ignorant enthusiasm and self-serving overselling of the 1980's. Chapter 9 will tell you about real robots, how they evolved, and the people who developed them (I was one.).
I like simple language so I use SMART and AUTOMATIC.
This is a book of science fact, not a book of science fiction. I will go out of my way to distinguish between science fact and science fiction in order to de-bunk some of the hype issued by self serving publicists. This hype is usually a distortion or the use of misleading and suggestive words rather than outright fabrication.
Some engineers and inventors believe that science fiction is a stimulant to the creation of science fact. Whatever works for them, but it is fraud to present fantasy as fact to the lay world in order to get from them either prestige or profit.
An action is automatic, or smart, if it happens without a person making it happen, right then and there.
There are several kinds of smart behavior in machines. The simplest is the TRIGGER.
For example a mouse trap automatically snaps shut on a mouse when the mouse nudges the lever bearing the cheese. There are several kinds of trigger traps. Each has stored energy which is released by a trigger. The traps may use metal jaws, a dropped box, a noose, or a deadfall. The energy store may be a metal spring, the raised weight of the box, a bent sapling, or the weight of the trapped animal falling into the deadfall.
The naval mine and the land mine and booby trap are modern versions of traps, in which the energy store is an explosive charge which also replaces the jaws. Some smarter naval mines count and ignore several trigger inputs before they explode, in order to prevent successful mine sweeping, and others are even smarter. Land mines are hideous detritus of war: they maim and kill children and adults every single day.
Other examples of trigger machines are burglar alarms and fire alarms. Some of these are surprisingly smart, for example some fire alarms respond to the rate of rise of temperature so they are not affected by a hot day but trigger very soon in a real fire on a cold day.
CHAIN REACTION control is multiple step trigger control. The completion of each step triggers the next step.
The many steps in the cycle of a machine gun are a chain reaction. The overall speed is determined by the speed of the individual steps, not by a clock, although some of the steps may be time delays to permit something to happen before the next step is started. Many hydraulic and pneumatic machines use chain reaction smartness.
The jackhammer for breaking up concrete, which every city dweller has heard often and without affection, is a pneumatic chain reaction machine. When the internal hammer reaches one end of its travel it operates a valve which reverses the air pressure and drives the hammer back in the opposite direction.
SEQUENCE CONTROLLERS are a kind of chain reaction controller which issue each command upon receipt of a FEEDBACK signal that the preceding command has been obeyed. It is a separate device rather than a set of triggers built into the machine.
TIME CONTROLLERS issue commands based on a clock schedule. The clock schedule may be modified by other smart effects and by external commands from people via push buttons and the like. Time controller commands not only turn things on and off but may also set quantities for other kinds of controllers to obey.
For example, you may have time switches in your home to turn lights and radios on and off. In an industrial furnace for heat treating metals a time controller may command the rate of heating and cooling.
PROGRAM CONTROLLERS are combinations of time and sequence controllers. They command a sequence of operations, and sometimes even command the motions during an operation. They respond to combinations of time and feedback signals to determine when their commands should be issued.
Your dishwasher and clothes washer have program controllers which issue a program of commands to fill, drain, agitate, etc. The agitate commands are maintained for fixed periods of time but the fill command is maintained only until a water level sensor feeds back a signal that the desired level has been reached and the agitate command may wait until the water has been heated to a specified temperature.
You may also have a programmed home thermostat which commands different temperatures to be held at different times of the day, the furnace on-off commands being commanded by the feedback responsive thermostat itself.
SEMI-AUTOMATIC control is a combination of automatic control of a machine cycle and human control to initiate the cycle.
An "automatic" pistol is really semi-automatic since, after firing, it goes through a chain reaction, expelling the cartridge case, reloading from the magazine, and cocking the hammer, all automatically, but only once each time a person pulls the trigger.
LOGIC control responds to combinations of conditions, e.g. "Bring down the press if there is work in the machine and if there is not a hand in the way."
Some sequence controllers use very elaborate logic schemes to manage a machine without things going wrong.
TRANSFER MACHINES in factories convey a product through a series of processes; they are automatic production lines. The transferring may be smooth and continuous, like conveying cake through an oven, a surface sprinkler, and a packaging machine, or it may be intermittent, like conveying a piece of metal through a series of drilling and cutting STATIONS. An "assembly line" is a transfer machine with humans at the work stations.
ANALOG MATH. Sorry, but I must explain. In order to automatically control things in a state of change, like steering a flying airplane or maintaining temperatures in a reacting oil refinery, a controller must predict what those things are about to do at all times. It does so by operating a small model of the real thing inside itself. The model may not look like the real thing but it behaves the same way; it is an ANALOG of the real thing. The analog model must do arithmetic and calculus. Analog controllers may use electric voltage or air pressure or shaft angle to represent speed or temperature. Digital computer controllers really do analog control by computing the analog quantities digitally in real time. That's it! Phew!
DIGITAL MATH. Now we are into computers as we now know them. Mostly computers just do arithmetic and logic and move numbers back and forth into memories and displays. But by doing these simple things many times at high speed with very sophisticated programs they do complicated math, handle language, and do all the other things you have heard about, including acting like analog computers. We will be back to digital computers often before we have finished.
Let's go back to heating your home, our running example to introduce new ideas and new words. If your furnace is turned off, and left off, the temperature will keep getting colder until it is the same as outside. If your furnace is turned on and left on the temperature will keep getting hotter until the heat loss through the walls is enough to prevent further rise. Somewhere between is the comfortable temperature you want and you set your thermostat to that desired temperature. The actual temperature produced by the furnace at any time is measured by the thermostat which turns the furnace on and off.
Mark Twain tells of the man who had been writing "prose" all his life but was amazed to learn that he had been doing so. You have been using a FEEDBACK CONTROL SYSTEM to heat your house all your life and you have just found out that you have been doing so.
Here are the buzz words for your heating system. I give them to you, not to be pedantic, but because they are the general words which will occur time after time in your examination of all the smart machines which affect your life.
The OUTPUT temperature of your furnace ACTUATOR is FED BACK to your thermostat SENSOR. This sensor compares the output temperature to the temperature SET POINT and then COMMANDS your furnace to go on and off to maintain the OUTPUT at the SET POINT.
You now understand what a FEEDBACK CONTROL SYSTEM is, but if I had told you that you would at the beginning of this description I might have scared you off.
You may well ask why we do not just adjust the output of the furnace to keep the house at the proper temperature and not bother with all this feedback control complexity. The reason is that changes in the outside air temperature, the wind, the sun, and the rain all affect your house temperature in ways we cannot compensate with a fixed adjustment. A feedback control system takes CORRECTIVE ACTION to compensate for changes in outside influences beyond our control or ability to predict.
To put it all together, you generate a COMMAND INPUT by adjusting the SET POINT on your SENSOR. Your SENSOR compares the OUTPUT with the SET POINT and, if it differs, turns on and off the ACTUATOR to restore the OUTPUT to match the SET POINT. Once you have COMMANDED the SET POINT you are finished and the action is AUTOMATIC.
Norbert Wiener was a brilliant and flamboyant American mathematician of the first half of the 20th century. He contributed to the mathematics of servomechanisms, made comparative studies of physical servomechanisms and biological mechanisms, and coined the word CYBERNETICS, which he popularized in his 1948 book Cybernetics, or Control and Communication in the Animal and the Machine. He was a teacher of Claude Shannon, in MIT, and encouraged Shannon's work in the use of Boolean algebra in the analysis of electrical switching circuits and information theory.
This section is rather technical but it may be skipped with little loss.
Let's go back to heating your home, our running example to introduce new ideas and new words. If your furnace is turned off, and left off, the temperature will keep getting colder until it is the same as it is outside. If your furnace is turned on and left on the temperature will keep getting hotter until the heat loss through the walls is enough to prevent further rise. Somewhere between is the comfortable temperature you want and you set your thermostat to that desired temperature. The actual temperature produced by the furnace at any time is sensed by the thermostat which turns the furnace on and off.
Here are the technical terms for your heating system. I give them to you, not to be pedantic, but because they are general words which will occur time after time in your study of smart machines.
The OUTPUT (temperature) of your ACTUATOR (furnace) is FED BACK by your SENSOR (thermostat). The AMPLIFIER (the thermostat's contact positions) compares the output temperature to the temperature SET POINT and then COMMANDS (closes its contacts) your furnace to go on and off to maintain the OUTPUT at the SET POINT.
A design engineer may well ask why we do not just adjust the output of the furnace to keep the house at the proper temperature and not bother with all this feedback control complexity. The reason is that changes in the outside air temperature, the wind, the sun, and the rain all affect your house temperature in ways we cannot predict and compensate with a fixed adjustment. A feedback control system takes CORRECTIVE ACTION to compensate for changes in outside influences beyond our control or ability to predict.
A feedback control system is an error correcting system.
To generalize, you create a COMMAND INPUT by adjusting the SET POINT on your SENSOR. Your SENSOR compares the OUTPUT with the SET POINT and, if it differs, turns on and off the ACTUATOR to restore the OUTPUT to match the SET POINT. Once you have COMMANDED the SET POINT you are finished and the action is AUTOMATIC.
The performance of this elementary feedback control system is ON-OFF. The output HUNTS, or OSCILLATES, between two limits close to the set point as the furnace either burns or does not burn. Such simple systems are sometimes referred to as LIMIT CYCLE or BANG-BANG systems.
There are feedback control systems whose output varies smoothly between zero and full power in response to small variations in the controlled output, thereby keeping such variations small. The sensor's control signal is PROPORTIONAL to how much the output differs from the set point (the ERROR), and how much the actuator puts out is proportional to the control signal. With PROPORTIONAL CONTROL the output is maintained almost constant instead of swinging back and forth between a little too much and a little too little, which is what happens with on-off controls like your home thermostat and furnace.
Example: An automobile cruise control is a PROPORTIONAL SERVO which maintains the speed set point even while the car goes up and down hills. The sensor is an electric speedometer, similar to the visual speedometer on the dashboard. The actuator is the gas pedal and the engine. The speedometer sends a control signal to a kind of motor which moves the gas pedal up and down. (If you touch your gas pedal lightly with your foot when the car starts up a hill you can feel it move.) You would not like an on-off control which maintained an average speed of 50 by running half the time at 100 and half the time at 0.
Automobile power steering is also a proportional servo in which you continually turn your steering wheel back and forth to control the direction of your car. Under the hood is a feedback servo using hydraulic power from a pump driven by the engine. Your steering wheel position is the command input to this proportional servo. The servo moves the front wheels to the angle which is the servo output.
Proportional servos were first developed for the power steering of ships because of the great effort required to turn a ship's rudder. Early ship steering servos used steam engines as actuators.
If you steer a boat, you know that you must anticipate its tendency to overshoot in direction so you move the rudder to compensate this overshoot. Otherwise the boat will zig-zag, or OSCILLATE. The smart controller (amplifier) of a servo does exactly that and STABILIZES the output. Much of feedback control technology deals with preventing oscillation.
Such PROPORTIONAL SERVOS are the glory of the control engineering profession. There are ways servos can get into trouble, which must be prevented, and there is a continuous effort to make them faster, smoother, and more accurate. The full mathematics of control theory is difficult - one can get a Ph.D. in the subject - but, since this is not a textbook on servo design, mathematics is not necessary for our purposes. Control theory was developed to enable control system engineers to make controls fast, accurate, and stable, despite the tendency of "fast" and "accurate" to cause "instability" and make the servo overshoot and oscillate like that boat we spoke of. Imagine the problems of manoeuvering a high speed fighter plane with power steering in all directions. The same problems, less dramatic, appear in the controls of chemical plants, of machine tools, and of automobile cruise control and power steering.
FEEDBACK CONTROL THEORY, CONTROL THEORY, SERVOMECHANISM THEORY are the words in current use for the mathematical study of such systems.
The diagram represents a FEEDBACK CONTROL SYSTEM, the SENSOR providing the FEEDBACK. Set point Outout You Amplifier Actuator Feedback loop Sensor
Notice the CLOSED LOOP in the diagram, marked FEEDBACK LOOP. All automatic controls other than trigger, chain reaction, and time and sequence controls are CLOSED LOOP FEEDBACK CONTROL SYSTEMS and can be described by some variation of this diagram.
Feedback control theory originated during the development of electronic feedback amplifiers and then was applied to mechanical systems.
Three major hardware breakthroughs made modern servos possible:
The first great breakthrough which made feedback control systems possible was the invention of sensors like that thermostat we keep talking about. Watt's centrifugal governor was the first. There are sensors for temperature, pressure, light, chemical composition, position, speed, sound, electric voltage and current, magnetism, and on and on.
These sensors, which respond to outputs, are called FEEDBACK SENSORS; they sense the outputs and feed them back to control the action. They are also called by the hi-tech word TRANSDUCERS. (In Latin, "trans" means across and "duce" means lead. Your thermostat leads information about the temperature across from one form of energy, heat, to another form of energy, electricity.) I think that "translator" would be a more descriptive word than transducer, but this is no time for a semantic quibble to rock the boat of an enormous industry.
The second great breakthrough was the invention of electronic amplifiers. They enable low power sensors to control high power actuators. These amplifiers are similar to the amplifiers in your stereo and TV. They are not the only amplifiers, but they are the most versatile and cost efficient for most purposes.
Analog computers, or their digital equivalents, and many corrective circuits are built into amplifiers.
Most amplifiers built today are electronic, but many are pneumatic or hydraulic valves controlling pneumatic or hydraulic cylinder actuators. Most hydraulic SERVO-VALVES have electrical inputs but some have mechanical inputs.
Pyrotechnic fuses and boosters are single use amplifiers.
There is a class of amplifier using a type of rotating electric generator but it has been largely replaced by electronic amplifiers.
There is still another kind of electric amplifier which uses magnetic saturation in iron core inductance coils and transformers. It is called a magnetic amplifier and is extremely resistant to ambient conditions. Chapter 9 is a detailed study of amplifiers.
An amplifier usually includes a smart controller which introduces time shifts, magnitude corrections, and various other effects to stabilize or otherwise improve the output of the servo. This controller may be only a few electronic components or it may be a digital computer. zzz
Among these effects are:
The amplifier's increase in output power over input power is its GAIN. The higher the gain the lower the error and the faster the response, but if the gain is too high the servo will oscillate. (Imagine steering a car or ship by turning the wheel too far each time.)
Most physical systems receive unwanted inputs from their environments. Radio static, sidewise bumps on front wheels, vibration from other sources, etc. The general term is NOISE. If the noise is picked up by the sensor, amplified, and gets through to the actuator, the output will exhibit still greater noise than was originally picked up.
In military systems, the enemy may generate noise or false signals to JAM the system. The noise may be RF, IR, acoustic, "window" (anti-radar chaff), visible camouflage, or decoys.
(DISINFORMATION and PROPAGANDA may be considered as kinds of false signals to jam societies.)
Servo systems usually have filters which block noise from getting through, usually by blocking frequencies outside the expected error frequencies. They are designed so that the natural frequencies of their parts differ as much as possible from the natural frequencies of the error and noise frequencies expected. To synthesize oscillation damping in servos, it is common to add negative RATE FEEDBACK of the system resonant frequencies to the amplifier.
There are many non-linearities in the behavior of physical devices. Among these are backlash, saturation, stiction, and change in internal geometry as a linkage moves along its path. Digital computers used as servo controllers can store compensating non-linear functions.
We tend to assume that the most accurate systems in the world are sophisticated feedback controls. Not so. Permit me an anecdote. I was once invited to consult with a company which had been started and built up by a most admirable man. He wanted to see if he could use feedback control, which he had just heard about, to improve his business. He had been trained as a mechanic, saved his money, become an entrepreneur, and built up a successful presswork business. He routinely punched out stampings at high speed with uniformity variations of a fraction of a thousandth of an inch. I had to tell him that his process, although OPEN LOOP, and was more accurate than any CLOSED LOOP system I knew of, and had zero problems of instability.
In process industries the principal actuator is a valve which adjusts the flow of a process fluid. Most such valves are adjusted by air pressure on a diaphragm working against a spring so that every value of air pressure produces a corresponding position of the valve stem. Pneumatic amplifiers provide this variable air pressure directly, reliably, and economically and are described in Chapter 9.
Among the many kinds of output produced by actuators (and sensed by transducers) are temperature, position, speed, voltage, pressure, loudness, and chemical composition.
Among the many kinds of actuators used in servos are electric motors, gasoline engines, hydraulic cylinders, pumps, valves, heaters, chemicals, and loud speakers.
For a variety of purposes, not just for weapons, explosives make dandy single use amplifiers with huge outputs for very small inputs.
Example: Pilot ejector seats.
Example: Bolt cutters on space launch vehicles to release satellites.
Some closed loop systems use a human actuator.
Example: A boat steered by a person who is watching a compass. (Such systems are smart systems combining smart persons with non-smart machines.)
The fourth great breakthrough in smart machines was the invention of the computer. It serves, first, as a time and sequence controller which stores and commands programs of great size and complexity, yet whose programs can be easily changed. Secondly, it serves as a smart controller, between the sensor and the actuator, modifying the error signal to compensate the undesirable effects described above.
The first servo computers used compressed air instead of electricity. Each quantity dealt with was represented by an air pressure quantity. Many are still used, particularly in the chemical industry.
The second servo computers were electrical ANALOG computers in which each quantity dealt with was represented by an electric voltage or current proportional to the quantity. Most servo computers are still analog computers.
The third servo computers were electrical DIGITAL computers in which each quantity dealt with is represented by a number. (Business computers, personal computers, and pocket calculators are also digital computers.) The digital computer can do many things that the analog computer cannot do and is the basis of the most advanced servo systems. A single computer can control many servos at the same time and can also act as a time and sequence controller.
A complex automatic machine such as a robot or an oil refinery may have one or more computers and may use trigger control, feedback control, time control, sequence control, and chain reaction control.
Another word for feedback control system is SERVOMECHANISM, which literally means slave machine. In fact the words MASTER, SLAVE, COMMAND, and OBEY are all commonly used in language about smart machines and are taken directly from person-person relationships and applied to person-machine and machine-machine relationships. (We assume that there is no moral opprobrium in having a machine as a slave.) The first, fictional, robots were artificial persons; robots were mechanical slaves to human masters. The word SERVOMECHANISM is usually contracted to SERVO.
The word "robot" was coined by a Czeck playwright, Karel Capek, in the early 1920's. He wrote a play called "R.U.R.: Rossums's Universal Robots" in which he used the word which he adapted from the Czeck word for work. The play is an ordinary Sci-Fi opus in which the mad scientist invents artificial people, which he called robots, lacking only souls, to do the world's work. The robots rebel, but the good guys win. The play died but the word lived and is now the same in all languages. Science fiction also lived and there have been innumerable similar scripts for books and plays and movies. Even the ballet Copellia is about a robot girl with whom the living hero falls in love, and Pinochio is a living wooden boy.
Chapter 9 will tell you much more about both fictional and real robots.
Among the many kinds of output produced by actuators and sensed by transducers are temperature, position, speed, voltage, pressure, loudness, and chemical composition.
Among the many kinds of actuators used in servos are electric motors, gasoline engines, hydraulic cylinders, pumps, valves, heaters, chemicals, and loudspeakers. For a variety of purposes, not just for weapons, explosives make dandy single use amplifiers with huge outputs for very small inputs. Some closed loop systems use a human actuator, for example a boat steered by a person who is watching a compass.
Often the actuator is preceded by an AMPLIFIER which receives a low power signal from the sensor and converts it to a high power signal to energize the actuator. An amplifier usually includes a smart controller which introduces time shifts, magnitude corrections, and various other tricks to induce stability. Electronic amplifiers are now the most common type, but there are electrical rotary amplifiers, mechanical, pneumatic, pyrotechnic, and hydraulic amplifiers.
The performance of an elementary feedback control system may be on-off, as in the case of a home furnace controlled by a simple thermostat. The output HUNTS, or OSCILLATES, between two limits as the furnace either burns or does not burn. Such simple systems are sometimes referred to as BANG-BANG or LIMIT CYCLE systems.
It is also possible to make feedback control systems whose output varies smoothly between nothing and full power in response to small variations in the controlled output, thereby keeping such variations small. The sensor's control signal is proportional to how much the output differs from the set point, and how much the actuator puts out is proportional to the control signal. With proportional control the output is maintained almost constant instead of swinging back and forth between a little too much and a little too little, which is what happens with on-off controls like your home thermostat and furnace.
If you steer a boat, you know that you must anticipate its tendency to overshoot in direction and you move the rudder to compensate this overshoot or the boat will zig-zag, or OSCILLATE. The smart controller (amplifier) of a servo does exactly that and STABILIZES the output.
Proportional servos were first developed for the power steering of ships because of the great effort required to turn a ship's rudder. The early ship steering servos used steam engines as actuators. The word "Cybernetics," above, was derived from the Greek word for steersman.
For example: an automobile cruise control is a proportional servo which maintains the set point speed even while the car goes up and down hills. The sensor is an electric speedometer, similar to the visual speedometer on the dashboard. The actuator is the gas pedal and the engine. The speedometer sends a control signal to a kind of motor which moves the gas pedal up and down. (If you touch the gas pedal lightly with your foot when the car starts up a hill you can feel it move.) You would not like an on-off control which maintained an average speed of 50 by running half the time at 100 and half the time at 0.
Automobile power steering is also a proportional servo in which you continually turn your steering wheel back and forth to control the direction of your car. Under the hood is a feedback servo using hydraulic power from a pump driven by the engine. Your steering wheel position is the command input to this proportional servo. The servo moves the front wheels to the angle which is the servo output.
FEEDBACK CONTROL THEORY, or just CONTROL THEORY, are current words for the mathematical study of such systems.
Such PROPORTIONAL SERVOS are the glory of the control engineering profession. There are ways servos can get into trouble, which must be prevented, and there is a continuous effort to make them faster, smoother, and more accurate. The full mathematics of control theory is quite difficult - one can get a Ph.D. in the subject - but, since this is not a textbook on design, no mathematics are necessary for our purposes. The reason for the development of control theory is to enable control system engineers to make controls fast, accurate, and stable. Imagine the problems of manoeuvering a high speed fighter plane with power steering in all directions. The same problems, less dramatic, appear in the controls of chemical plants, of machine tools, and of automobile cruise control and power steering.
Some of the great pioneers of servo theory are ---Bode and ---Nyquist. [Bios and history]
Three major hardware breakthroughs made modern servos possible:
The first great breakthrough which made feedback control systems possible was the invention of sensors like your thermostat. Watt's centrifugal governor was the first. There are sensors for temperature, pressure, light, chemical composition, position, speed, sound, electric voltage and current, magnetism, and on and on for a list so long it would bore you. Making sensors is a large industry.
These sensors, which respond to outputs, are called FEEDBACK SENSORS; they sense the outputs and feed them back to control the action. They are also called by the hi-tech word TRANSDUCERS. (In Latin, "trans" means across and "duce" means lead. Your thermostat leads information about the temperature across from one form of energy, heat, to another form of energy, electricity.) I think that "translator" would be a more descriptive word than transducer, but this is no time for a semantic quibble to rock the boat of an enormous industry.
The second great breakthrough was the invention of electronic amplifiers. They enable low power sensors to control high power actuators. These amplifiers are similar to the amplifiers in your stereo and TV. They are not the only amplifiers around, but they are the most versatile and cost efficient for most purposes.
The third great breakthrough in smart machines was the invention of the computer. It serves, first, as a time and sequence controller which stores and commands programs of great size and complexity, yet whose programs can be easily changed. Second, it serves as a smart controller, between the sensor and the actuator, which modifies the error signal to compensate the undesirable effects described above.
The first servo computers used compressed air instead of electricity. Each quantity dealt with was represented by an air pressure. Many are still used, particularly in the chemical industry.
The second servo computers were electrical ANALOG computers in which each quantity dealt with was represented by an electric voltage or current proportional to the quantity. Most servo computers are still analog computers.
The third servo computers were electrical DIGITAL computers in which each quantity dealt with is represented by a number. (Business computers, personal computers, and pocket calculators are also digital computers.) The digital computer can do many things that the analog computer cannot do and is the basis of the most advanced servo systems. A single computer can control many servos at the same time and can also act as a time and sequence controller.
A complex automatic machine such as a robot or an oil refinery may have one or more computers and may use trigger control, feedback control, time control, sequence control, and chain reaction control.
Inside our bodies there are many feedback control systems. The nervous system provides sensors and feedbacks, the brain or spinal cord are the controllers, and involuntary muscles, hormones, and other chemicals are the amplifiers and actuators.
For example, when we are cold our temperature sensing nerve endings signal the brain which commands muscles to constrict our skin capillaries, which reduces our heat loss to the atmosphere.
The many ways these biological systems can go wrong provide job security for internists, neurologists, and endocrinologists.
Many parts of society are feedback control systems.
For example the business cycle is an oscillating system in which, among other effects, economic data are fed back to the Federal Reserve Board which is an actuator, in this case a money lender, and which varies its interest rate to resist the oscillation.
Other feedback control systems exist in employment, education, business, and politics. You may find it a mind stretching exercise to think out some of them and to devise better ones.
REMOTE CONTROL enables a person or a smart controller to command a machine which is a long distance away and to receive sensor information back from it.
Remote control may be as simple as a radio garage door opener or a telephone answering machine which repeats its messages to a remote telephone. It may be as complex as managing the motions and sensors of a satellite millions of miles away. (We will consider remote control in more detail when we discuss the space program and man-in-space.)
Most remote controls use electricity over either wires or radio waves. Some use ultrasonic waves, infrared waves (e.g., your TV remote control), or light waves. Light waves are transmitted either through the air or through fiber optic cables.
Remotely controlled machines are not necessarily smart in themselves but have the smartness of the person controlling them; although there may be smart portions of the overall control system. Remote controls use actuators and sensors to produce outputs and to feed back information, and many remotely controlled machines have automatic feedback controls which obey the commands sent by remote control. Therefore it is appropriate to include remote control in a book on smart machines.
You have now waded through the most difficult part of this book. I will wait to include some details of robotics where they appear in use instead of piling them all into this theory chapter.
The following chapters describe different worlds of human activity in which smart machines are used, show some automation phenomena in human affairs where the word is usually not used, discuss the social and economic effects of smart machines, and offer some speculations about the future.
George Boole was a self taught mathematician of the highest order. Despite a poor childhood, little formal schooling, and working as a school teacher to support his family he rose to a Professorship of Mathematics in Queen's College, County Cork, Ireland in 1849. He generated a stream of research in mathematics, including symbolic logic, base 2 arithmetic, and Boolean algebra. As later adapted by Claude Shannon of MIT, Boolean algebra became the mathematical basis of digital computers. Little did professor Boole know that he had invented the theoretical basis for a great industry.[photo in British Museum]
Charles Babbage was born in England a hundred years too soon. He created the art of digital computers with nothing to work with but the mechanical skills of the early nineteenth century. He was no uneducated inventor; in 1816 he was elected a fellow of the Royal Society and from 1829 to 1839 he was a professor of mathematics at Cambridge.
Babbage invented other devices as well as those which made him immortal: digital computers. He started these in 1812, secured grants from Parliament, but never finished his grand designs because mechanical technology was not sufficiently advanced. His work was lost for a time, but was re-discovered in 1937, in time for electronics to make his dreams come true. [painting in National Portrait Gallery]
The dot and dash telegraph code invented by Morse is awkward for machines to use, and digital computers need such a code. Fortunately Jean-Maurice-Emile Baudot invented a more useful code in 1874. Baudot Code has a set of five elements to each character; the code is determined by which elements are "on" and which are "off." In telegraphy the elements are successive short equal lengths of time, "on" is voltage on, and "off" is voltage off. Paper tape was developed with rows of five hole position abreast, each row representing a character coded by which hole positions actually had punched holes and which did not. Machines were developed to read and to punch paper tape. Little did he know that his holes were "bits," his rows were "bytes," and his tapes were "memory." The set of five was later increased to a set of eight to provide more characters and a parity check bit to detect errors, but the principle never changed.
The thirst for ever greater speed made paper tape memories unable to satisfy the need, despite heroic feats of engineering to try to keep up. They were superceded by magnetic tapes, but the same format of a row of eight positions per character remains, only the hole has been replaced by a magnetized spot.
Shortly after the textile industrial revolution in England in the later half of the 18th century, a Frenchman named Joseph-Marie Jacquard invented a loom in which a chain of punched cards controlled which warp threads were raised or lowered for each weft thread, thereby establishing decorative patterns in the cloth. The French Revolution, in which he fought, delayed his work, but in 1805 his invention was publicized and became a commercial success, which it still is.
Jacquard's punched holes helped inspire the designs of Babbage and Baudot and Hollerith and, starting in 1949, numerically controlled machine tools had their programs punched in Baudot tape until magnetic recording took over.
The ubiquitous punched card and the vast array of information machines based on it is the product of American engineer Herman Hollerith in 1890. He developed the system of recording and reading information by representing it in Baudot-like holes in cards instead of tapes, the information in question being that of the U.S. Census. (Actually Babbage had used punched cards in his abortive digital computer and Jacquard had used them in his loom.) The census system and machines were highly successful. In 1896 Hollerith founded the Tabulating Machine Company which evolved over the years into the International Business Machine Company. IBM became an enormous success with its punched card machines and an even greater success when it replaced punched cards and mechanical computing to magnetic tapes and electronic computing.
Paper tape had a long history as a information storage and presentation medium. Samuel F. B. Morse, in his original invention of the telegraph, intended that received signals be marked on moving paper tape and was annoyed when his operators inadvertently learned to read the clicks of the writing instrument instead of watching the tape. Cross-ocean telegraphs used paper tape much longer, because the signals were not sharp and could be read only by studying the wave forms appearing on the tape. Edison used paper tape as the output display medium of his first stock ticker. (The phrase "ticker tape" was once widely used but is now forgotten.) Baudot's tape was used for many years for both transmission and reception; the sound of the tape punch could not be understood by the ear. For many years the printing telegraph produced a continuous single line of type on paper tape with a gummed back. Telegrams were delivered after the tape had been cut to line lengths and pasted to a blank form. Ultimately page printers were developed and cathode ray tubes gave visual displays. Electro-mechanical number indicators were used as displays in brokers' offices. Storage and transmission via paper tape continued until magnetic tape and disks displaced it.
The first programmed digital computer was Professor Babbage's, described above, which was never finished because the available physical technology was not available in 1812.
Mechanical calculators, starting with adding machines and extending through cash registers to desktop machines which would compute square roots, were developed through the years and were the basis for the IBM and competing lines of business machines. These typically worked to base 10, which was just as easy with mechanisms. The evolution of the modern digital computer took a different path and the mechanical calculator became largely obsolescent.
Before World War II successful digital computers were completed at Bell Telephone Laboratories and at IBM using electro-mechanical relays such as were used in telephone exchange switching. (Relays are still used in many machine controls because of their reliability and because no knowledge of electronics is needed to understand them.)
During World War II a digital computer call the ENIAC was built by Professors Eckert and Mauchly at the University of Pennsylvania. It used electronic circuits for the first time, albeit with vacuum tubes, and the modern digital computer was on its way. The original purpose of ENIAC was to compute artillery firing tables at the Aberdeen Proving Grounds, which is why government money was available during the war.
New machines and new technology came with explosive acceleration; this book will cover only a few of the key technologies.
Computer memories are keys to computer capabilities. The first memories were punched cards and punched tape, both of which we have already discussed. Then came magnetism in many forms. We have already seen magnetized spots on magnetic tape replacing punched holes in paper tape. Tape is sometimes replaced by spinning drums and discs with magnetic surfaces. Stationary memories used to be made with arrays of magnetic cores, first invented by Dr. Wang who founded Wang Laboratories. For a while they were made of solid state blocks with magnetic "bubbles," and now are made of transistor flip-flops arrayed by the hundreds of thousands on integrated circuit chips. Optical disk memories, similar to compact audio discs, are the latest form of memory, with enormous capacity.
The active elements which do the actual computing were, first, relays, then vacuum tubes, then individual transistors, and then transistors packed into integrated circuits. Research is under way to compute with light instead of electricity.
The increasing benefits of this list of techniques are lower power (and therefore less heat), greater reliability, and higher speed. One reason for the higher speed is that the distances the electrical impulses must travel are shorter and shorter along the list and thus take less time to get where they are going. (Yes, electricity does indeed travel at 186,000 miles per second as waves in free space and slightly slower along wires, but when a millionth of a second becomes an important length of time, an inch becomes an important distance.)
The obvious benefit of speed is getting more done in less time for the user and getting more productivity per dollar of investment. There is another benefit of particular interest in our subject.
You will remember that digital computers control the motions of real machines by simulating analog computers with millions of arithmetic calculations. It worked out that the vacuum tube and discrete transistor generations were not fast enough, so in industry they could be used only to monitor but not actually control. Now, with integrated circuit fast computers they can control - and do!
Meanwhile the reliability of computers also improved radically, so industry became more willing to entrust its precious machinery to the control of digital computers.
Movies, TV, Radio, Sports, Hobbies
Computers.
Detailed discussion of hardware, software, and applications
Machines and tools have been used to make products since the beginning of civilization. Early hand tools were stone axes, digging sticks, and pairs of rough stones for grinding grain. Among the earliest machines not powered by people were horse drawn chariots and ox powered water bucket irrigation pumps on the Nile.
The first machines not powered by either people or animals were for grinding grain; their millstones were rotated by windmills or water wheels. Water pumps for both irrigation and draining mines were first man powered, then animal powered, then steam powered. The English textile machines which were the start of the industrial revolution were originally driven by water wheels and later by Mr. Watt's steam engines. American textile mills in New England were located at falling water so they could be driven by water wheels.
Factories were powered directly by steam engines until the end of the 19th century when electric motors began to take over. Actually steam was still the prime mover, with an assist from falling water, either in the factories' own power plants where steam engines spun electric generators or in public utility power plants where the same occurred on a larger and more efficient scale.
The electric utility was invented by Thomas Edison. It is conventional wisdom that Thomas Edison invented the electric light. Not quite true. It was common knowledge that electric current heated its conductor and that with enough current the temperature would get high enough to make the conductor glow and give off light. Edison wanted to manufacture electric power on a large scale in a central electricity factory and ship it by wire, an analog of the illuminating gas industry of the time. Thus the electric light would compete with the existing gas lamp. His biggest problem was loss of energy (IxIxR) and voltage (IxR) in the long wires connecting the central power plant to the customers. With low voltage lamps the losses would be too great to permit a profitable business; the massive conductors having a sufficiently low electrical resistance would be too expensive and heavy. So he invented the high voltage, high resistance lamp with a long thin filament protected from oxidation by a vacuum bulb, which made the losses in permissible conductors acceptable. His target was 100 volts at the bulb and 10% line drop, whence our nominal 110 volt systems. He started a company and built the first electric power house on Pearl Street in downtown New York. Which is why we have all those Edison Companies today. Electric power applied to motors as well as lamps made it possible for each machine to be powered by its own motor instead of by a belt from an overhead line-shaft. And it provided a source of energy suitable for electrical and electronic controls and the smartening of those machines.
The earliest smart machines used simple time and sequence programing. In approximately 1729 Christopher Polheim of Sweden made automatic machines to manufacture clock gears. In 1745 Jacques de Vaucanson made an automatic loom.
Automatic feedback control was invented by James Watt in 1769. His invention was the centrifugal governor for his steam engines. The engine rotated a pair of weights around a shaft. Centrifugal force urged the weights to fly out against the restraining force of a spring. As the weights moved out, they gradually closed off the steam throttle valve, preventing further speed increase, and equilibrium was established. As load on the engine increased more steam was needed and equilibrium was re-established at a slightly lower speed and more open throttle.
Centrifugal governors were used well into the 20th century until electronic speed transducers and controllers came into use.In the 20th century the DROOP in speed due to increased load was corrected by a gradual readjustment, called RESET, of the spring or its equivalent.
Let us consider "manufacturing" as starting with the engineering of the product and its manufacturing processes. Admittedly, before engineering there is conception, market studies, organization, and finance, but for our purposes engineering is a good place to enter the process.
There are three kinds of smart machines used in engineering: computers, computer aided drafting machines, and R&D test equipment. (A fourth is surveying instruments used by civil engineers in outdoor construction.)
Computers are used in engineering for mathematics to determine dimensions, proportions, and the performance of the product and its components, for drafting, and in preparing manufacturing data.
Some of the computer output is in the form of lists of numbers, some of it is in the form of graphs; but much of it is in the form of large, multi-color manufacturing drawings of great accuracy, fine detail, and, incidentally, of much beauty. There are also lots of small, detail drawings, of course. Drawings are made on PLOTTERS which are computer controlled drafting machines. The computer output tells the factory how to make the product.
Some drafting is the modification of previous designs. Some design drafting is the preparation of accurate images which are photographically reproduced in the product, for example: printed circuits and integrated circuits. In some cases a basic drawing is reproduced many times in the same product, such as on computer memory chips. Some design drafting is not pictorial at all but is schematic, such as electrical diagrams. Computer drafting saves immense amounts of labor in all such work.
Some design computers directly generate the programs for the numerically controlled machine tools described below.
The acronyms for these processes are:
I have seen a flaw in some CAD usage. There is a tendency to send a drafter for training in CAD and to let the design engineer merely give sketches to the drafter. But the old fashioned drawing board is really a laboratory in which the design engineer draws, and therefore thinks, in actual size and shape, and is free to change and change until he gets the design to his satisfaction. If there is a second person between the engineer and the drawing machine the tendency is for the design to be frozen in its first sketched version. The solution, of course, is to train and discipline the design engineer to use the CAD equipment himself, and this is happening. Otherwise an inferior product is efficiently designed.People are much smarter designers than are machines.
There are scores of manufacturing processes from melting steel to hand polishing jewelry. More and more, these are becoming automated with smart machines. This book is not an encyclopedia of every smart machine and process, but I will describe a variety of automated machines so that you will understand what is going on and will feel comfortable even if you encounter a particular machine I have not described.
At one time low cost manufacturing was possible only in mass production. Expensive molds and dies (TOOLING) were made by skilled tool-makers and they pounded out large quantities of identical products.
Smart machines have replaced HARD TOOLING with SOFT TOOLING in the form of numerical control systems in many processes. These produce very small quantities at almost as low a unit cost as old machines produced large quantities. Smart machines have made it possible to reduce the cost of many kinds of manufacturing by replacing manual operation with automatic operation, e.g., by loading fabricating machines with robots.
In olden days metal was cut by hand using saws, chisels, and files. Then power driven machine tools were developed during the 18th and 19th centuries. The first was the lathe, which was an outgrowth of the ancient potters' wheel.
Eli Whitney invented the cotton gin, invented the milling machine, and invented the idea of making mass produced products with parts which were made so accurately that they fit together without skilled hand modification. His first application of this idea was muskets for the U.S. army.
Mechanically automated lathes were developed, initially for the clock and watch industry. The time and position control program was a set of shaped cams on a motor driven camshaft. These cams directly moved the tools of the lathe. No feedback was used; the automation was open loop.
For quantity manufacturing which cost-justifies the making of the cams, the system is unbeatable and is still in use, although mechanical clocks and watches are right in there with mechanical calculators. I have walked through factories having literally acres of "Brown & Sharpe screw machines." At present the most accurate machines of this type are made in Switzerland and are referred to, not unreasonably, as "Swiss automatics."
One of the transients in the history of machinery was the manually controlled cam making machine; it has been replaced by the numerically controlled milling machines we are about to meet.
Machine tools were then developed in which a motor moved a sensor over the surface of a template which was the program; closed loop servos moved the cutting tools along a path in the shape of the template. In effect the templates and servos acted as power cams. The template was often a hand made model of the finished part. Powerful servos permitted making very large machine tools which worked this way and many molding dies are made in this manner. Philosophically, this is analog control of machine tools.
The most dramatic machine of this type which I have seen used a small electric arc between a stylus and the template as the template sensor. I watched several tons of precision machinery follow the shape of a piece of crumpled aluminum foil without bending the foil!
In the 1950's electronic digital computers replaced the templates with lists of numbers and the modern NC (Numerical Control) systems were born. The first to be well known was made at MIT and described in Scientific American, ---. It inspired the numerical control revolution.
I well remember the excitement of reading the story. I was a consultant at Sperry Products Company at the time. They had contracted with the Allison Engine Division of GM to build a machine to automatically inspect jet engine rotor forgings for hidden defects, using their proprietary ultrasonic technology.
Their assumption was that the three motions of the machine which moved the ultrasonic transducer would be driven by three synchronized cams, as in the automatic screw machines, above. To their consternation they discovered that they could not predict the shape of the cams; every combination of positions had to be determined empirically. In short, they needed the finished cams in order to know how to shape the finished cams.
Serendipity raised its lovely head. I showed the chief engineer the article on the MIT machine and suggested that we used the same principle of numerical control instead of cam control. We could put counters on the three shafts, position the shafts by hand experimentally, send the numbers back as electrical codes to digital input servomechanisms on those same shafts, and presto!
He bought it, we built it, it worked, and we delivered what I believe was the first numerically controlled machine built on commercial contract.
(In the event it wasn't all that easy to design, build, and de-bug the real thing, but we really did it. Real-world engineering is the subject of a different book.[reference number to Real-World Engineering]) For me it was the beginning of a career in numerical control and automation.
"Now boys, we have got her done, lets start her up and see why she doesn't work." John Fritz
I met an engineer, once, who claimed that he had built a complex machine and turned it on and it worked. Perhaps. Everything that can happen does happen.
Numerically controlled machine tools are very quickly re-programmed as far as tool motion was concerned but were still limited by the small number of cutting tools which they could carry. These had to be changed by hand, both for sharpening and for changeover from product to product. Therefore the next step was the development of tool magazines and automatic tool changing servos commanded by additions to the same digital computer program.
It was still necessary to change the holding fixture to suit the part product being made, but in some machine tools even the fixtures have standard mountings and can be automatically changed.
The next step was to replace manual loading and unloading of the work-pieces with loading by robots, about which much more later.
The final step, as we now see it, has been to cluster associated machines into "manufacturing cells" serviced by a common robot and fed with smart conveyors.
I am sad to report that the world's largest manufacturer of numerical controls is Fanuc of Japan and that their controls are sold in the United States by the General Electric Company. And General Motors has a division which sells robot systems. With Japanese robots.
The "assembly line" is the popular image of the mass production factory, although the image neglects those portions of the factory which make the parts to be assembled.
Automatic assembly machines have existed for many years and are still under continual development. Most of them are for physically small products because the size and cost of the machine increases with the size of the product. It would not be much of a technical challenge to design an automatic machine to mount the wheels on an automobile in a car assembly line, but the machine would be huge and therefore would cost so much compared to the cost of human labor to do the job that the task is still done by people.
Most automatic assembly machines are for mass production products because the fixed cost of TOOLING with PART FEEDERS, PART GRIPPERS, TESTERS, PLACEMENT MECHANISMS, and controls is high.
Many "automatic" assembly machines include human stations along the assembly line to perform operations which are too intricate for mechanisms. The dexterity of the human hand with feed-back through the human eye and the human sense of touch can only be appreciated when you try to replace them with machines. The humans also keep an eye on the automatic stations and, in particular, clear jams in the part feeders.
One consequence of the desire for, and the limitations of, machine assembly is the effort to design parts and products which can easily be assembled automatically. This is one of the social feedbacks we have mentioned.
Automatic assembly machines also have stations for automatically testing the product. Here one of the shining benefits of automation appears: uniformity. People make oversights and mistakes and can pass a defective product with catastrophic consequences (read "product liability lawsuit.") Automatic inspection, once running properly, never makes individual errors.
There continues to be a trend in the design of automatic assembly machines to assemble the machines themselves from STANDARD MODULES. Doing so reduces their cost, makes them more cost justified, and thereby increase their sales.
There are modules to move the assembly along the assembly line, modules to orient and feed parts to the part inserting mechanisms, modules to pick up a part from a feeder module and place it into the assembly, modules to feed and screw or rivet fasteners, and many others. Standard industrial robots are sometimes used as assembly machine modules, but they often are unnecessarily complex and expensive for the purpose.
A major development has been electronic modules as the smart part of smart machines. Some modules are almost the same as desk-top personal computers. Some are special small computers programmed to seem like clusters of the electro-mechanical relays to which manufacturing engineers are accustomed. These are called Programmable Logic Controllers (PLC or PC) and have been a major contributor to cost efficient smart machines of many kinds. Most such electronic control modules are themselves assemblies of sub-modules. This practice reduces initial cost and reduces maintenance skill by reducing much of maintenance to module swapping.
I once saw a demonstration of a single robot assembling an automobile alternator. It really worked, until you took a closer look. The part feeders were really people who oriented the parts and inserted them into feeder chutes; no orientation or jamming problems. The assembled alternators were manually disassembled and the parts returned for robot re-assembly; no problems with defective parts or burrs.(In the real world, part feeding is the most trouble prone area of automatic assembly.) With these ground rules, manufacturing is a cinch!
Please note that the management motive in all of this is COST REDUCTION, not the joy of R&D. Cost is reduced by the replacement of labor with capital, by producing more uniform products having fewer rejects and repairs, and by reducing DOWNTIME, which is a combination of setup time for a new product and the time that machines are idle and awaiting loading and unloading. See Chapters 14 and 15 for a discussion of the social, economic, and political effects of this replacement.
COST-EFFICIENCY, or COST-EFFECTIVENESS, is what smart machines are all about to the managers responsible for competition and profits. We will talk a lot more about this in Chapter 14.
In machine tools the reverse of downtime is CHIPTIME, the percentage of time the machine tool is actually cutting chips. In most factories with manual loading it is woefully small.
Cost reduction by capital investment in automation is measured by ROI, as explained above.
We must compare human capabilities, including smartness, with smart machine capabilities. The most conspicuous difference is in dexterity; humans win, hands down. If you compare the number of axes of motion (count the joints and muscles), the number and subtlety of sensors (include the touch sensors in the fingertips and that incredible TV camera, the human eye), and the complex capability of even a dumb and ignorant human brain, the difference is easy to understand. Given some inexpensive training, humans can be transferred from task to task. (I speak of manufacturing tasks, not interchanging engineers and accountants.)
On the other hand, humans come in a very narrow range of sizes. If you compare a small woman with a large man, the weight handling capacity for repetitive work is less than 5:1 and the reach capacity less than 2:1. Machines can be built in a range exceeding 10,000:1 on both counts.
For displacements requiring accuracy better than about 1/8", humans must use a machine assist, although the machine may be only a simple tool. Machines are commonly built with resolutions of .000 1" and many machines shift the decimal point to the microinch range.
Humans make occasional errors. Some errors get through inspection and cause havoc later on; some errors injure humans. Machines are more consistent; when something goes wrong there is usually either a jam or a conspicuous series of identical errors. Statistical quality control is a good indicator of machine drift toward error so that corrections can be made before rejects are made.
There is an increasing trend to recognize these differences in product engineering and to design products which can be made by inexpensive machines and do not require the greater human capabilities.
In information handling, computers are many orders of magnitude faster than people and almost never make a mistake. However the handling rules must be established by a human programmer, who may make mistakes, and Garbage In-Garbage Out (GI-GO) is one of the basic laws of machine data handling.
Other management considerations favor smart machines over people. Machines do not have personality problems, or absentee problems, or commuting or family problems, or go to the bathroom, or drink coffee, or eat lunch, or get uncomfortable when it is hot or cold or dry or humid, or get sick, and do not join unions.
A damaged machine costs money, but not on the scale of human injury, and fewer safety devices are needed to prevent accidents due to violating work rules. Once bought, their capital cost is fixed and is not subject to raises. They can work 1, 2, or 3 shifts and on weekends. Their uniformity of output reduces the risk of trouble, such as poor reputation in the marketplace and product liability lawsuits. (I avoid the word "quality" which has been taken over by the advertising agencies and the sloganeers.)
On the other hand, smart machines may require a high skill level for installation and maintenance people. They cannot be laid off when business is slack to save their capital expense, whereas idle employees can be laid off to save payroll expense.
COST-EFFICIENCY, or COST-EFFECTIVENESS, is what smart machines are all about to the managers responsible for competition and profits. We will talk a lot more about this in Chapter __.
The electronics industry, which made smart machines possible, is itself a major customer for them. Automatic assembly is almost universal for mounting and connecting electronic components on printed wiring boards; these assemblies are, in infinite variety, the principal stuff of electronic products. Most of the automatic assembly of these boards is done with special purpose smart machines developed for the purpose and which are easily re-programmed to assemble an unlimited variety of patterns. (More on the semi-conductor industry)
Transfer machines in factories convey a product through a series of processes; they are automatic production lines.
The transferring may be smooth and continuous, such as conveying cakes on a belt conveyor, first through an oven, then a surface sprinkler, and then a packaging machine.
The transferring may be intermittent, such as conveying a piece of metal through a series of drilling and cutting STATIONS or a product through a series of assembly stations. The transferring path may branch, according to variations in the product specifications or to variations in the product inspection results.
A variety of smart devices are used to monitor and control fabricating, assembling, and testing.
An important and costly part of manufacturing is neither making parts nor assembling them but just moving materials, parts, and assemblies from place to place in the factory.
A class of smart machine has been developed called Remotely Piloted Vehicle (RPV) which is a remotely controlled lift truck. Wires are buried in the aisle floors and couple electro-magnetically to coils in the vehicle. The vehicle tracks the wires and also receives instructions via the wires to go to particular stations and to pick up or put down standard pallets at those stations.
A related machine is the "mail robot" which delivers mail to offices within a building.
Smart warehouses have each storage space coded; matching vehicles store and retrieve pallets or boxes at those stations. The words used are AUTOMATIC STORAGE AND RETRIEVAL SYSTEM (ASRS).
For as long as history and archaeology tell us about, people have been carving magic idols, believing them to be sufficiently alive to hear and obey the prayers of their makers. ("Magic" is the control of nature without the restrictions of what killjoy scientists call "laws of nature.")
Animism is the most primitive form of religion; it attributes life and will to "the spirits of" trees and rocks and other objects. To this day there is the feeling that machines of metal and plastic have life and will. Have you, yourself, gentle reader, ever been angry with a car or a TV and struck or kicked it to punish its recalcitrance?
A history of the development of a new computer was entitled "The Soul of a New Machine."
In the early days of the SEAC computer at the National Bureau of Standards, a famous programmer, after a long period of frustration, went into the computer room and had a long talk with the machine in which she sincerely begged for a greater degree of cooperation. (I was told this by a friend of mine, an engineer who worked with her.)
The word "robot" was coined by a Czeck playwright, Karel Capek, in the early 1920's. He wrote a play called "R.U.R.: Rossums's Universal Robots." In it he used the word robot which he adapted from the Czeck word for work. The play was an ordinary Sci-Fi opus in which the mad scientist invents artificial people, robots, lacking only souls, to do the world's work. The robots rebel, but the good guys win. The play died but the word lived on and is now the same in all languages.
Science fiction also lived on and there have been innumerable similar scripts for books and plays and movies. Even the ballet Coppelia is about a robot girl with whom the living hero falls in love, and Pinocchio is a living wooden boy.
Another literary robot was the monster created by imaginary Dr. Frankenstein who was created by real Mary Shelley. The good doctor modestly re-assembled existing parts instead of starting from scratch.
The earliest solution to the problem was to force somebody else to do the work. The practice was called slavery and it was used all over the world. There were a variety of rules dealing with ethnic origin, capture in conquest, people imprisoned for crime (mostly political), and the like. It worked pretty well for the slave owners and still does in some corners of the world. Hitler and Stalin were the most recent large scale European practitioners. It is largely out of fashion at present and, in the United States at least, laws against peonage tend to limit equivalent practices.
Some of the language lives on in the language of smart machines: MASTER, SLAVE, COMMAND, OBEY, SERVOMECHANISM, SERVO.
Slavery fell out of favor in the western world in the 19th century and was replaced by hiring people for pay, in money and keep. This practice is called employment and is now used all over the world. A variety of rules vary from only a legalistic distinction from slavery to a very favorable treatment indeed of the hired person. If the hired person does domestic work he or she is, or was, called a servant and if the hired person works in a business he or she is called an employee.
There are several objections to getting work done by employees. Human workers are not always energetic, reliable, docile, smart, and easily led. They are not always cheap, and those with the desired skills are not always available.
So, for as long as recorded history, people have wanted to make real artificial people to be their slaves.
In the middle ages, when clockwork mechanisms were developed, articulated models of people were engineered, powered by springs or descending weights. There was even a mechanical man who wrote a few Chinese characters on paper, made as a gift to the emperor of China; and a mechanical man, built in 1770, is still in working order in the Swiss Musee d'Art et d'Histoire. Town clocks exhibiting a parade of animated characters (JACKWORK) have been refurbished as tourist attractions in Europe and a brand new one has been built and installed near the Pompidou Center in Paris. I have watched a crowd of people enthralled by its gyrations. Disney World has lifelike machines acting out scenes from American history as well as other JACKWORK displays. Every toy store has mechanical dolls.
The ultimate dream was, and is, a mechanical person who is the slave of a real person. This is pretty easy to accomplish in the imagination and became one of the staple themes of science fiction (one of the great oxymorons of all time.) Not quite so easy for real.
The emotional appeal of robots approaches that of religion and patriotism. In 1986 I visited a research institute in China and saw some primitive robot engineering being done. When I said that China had so much cheap labor that there was no economic benefit from robots, I was answered, passionately, "China needs robots!"
For prestige, perhaps, as with national airlines subsidized by poor countries to fly international routes. After all, the United States sent men to the moon for competitive prestige after the Russians orbited Uri Gagarin for competitive prestige.
In contrast to the alchemy-like attempts by some at artificial people as mechanical slaves, others were content to engineer real machines intended merely to be machines and to do real work. These more modest folk were much more successful, since they did not have the self imposed requirement of anthropomorphism (man shape) and merely designed machines to suit their jobs.
It has became useful for commercial prestige to apply the words "robot" and "robotic" to any smart machine.
After the technology explosion during World War II, George Devol, a successful inventor and entrepreneur, met an engineer named Joseph Engelberger at a cocktail party in Connecticut. They were both bright, enthusiastic, and imaginative. Together they made a serious and commercially successful effort to develop a real, working robot.
Their concept was to use an electronic digital computer as the "brain" (i.e. program controller) and servomechanisms as the "muscles." A mechanism was designed suggestive of a human arm. (Anthropomorphism remained an article of faith.) It resembled a tank turret and cannon with additional axes of rotary motion at the outboard end of the cannon (the "wrist"). Servo actuators used hydraulic cylinders, electro-hydraulic servo valves, and electronic encoders for feed back. The controller was the digital computer. The machine was trade named the "Unimate."
The hard part of Entrepreneuring is funding. They persuaded Norman Schafler of Condec Corporation in Danbury that they had the basis of a commercial success and Unimation, Inc. was born. Ultimately Unimation was acquired by Westinghouse and the entrepreneurs' dream of wealth was achieved.
Most Unimates were sold to extract die castings from die casting machines and to perform spot welding on auto bodies, both tasks being particularly hateful jobs for people. Both applications were commercially successful, i.e., the robots worked reliably and saved money by replacing people. An industry was spawned and a variety of other tasks were also performed by robots, such as loading and unloading machine tools.
The robot idea was hyped to the skies and became high fashion in the Boardroom. Presidents of large corporations bought them, for about $100,000 each, just to put into laboratories to "see what they could do;" in fact these sales constituted a large part of the robot market. Some companies even reduced their ROI (Return On Investment criteria for investment) for robots to encourage their use.
The image of the "electronic brain" as the principal part of the robot was pervasive. Computer scientists were put in charge of robot departments of robot customers and of factories of robot makers. Many of these people knew little about machinery or manufacturing but assumed that they did; there is a common delusion of electrical engineers that mechanical phenomena are simple because they are visible. (Things like variable friction, the effects of burrs, minimum and redundant constraints, non-linearities, variations in workpieces, accommodation to hostile environments and hostile people, etc. are like the "Purloined Letter" in Poe's story, right in front of the eye but yet unseen.)
They also had little training in the industrial engineer's realm of material handling, manufacturing processes, manufacturing economics and human behavior in factories.
As a result, many of the experimental tasks in those laboratories were made to fit their robot's capabilities but had little to do with the real tasks of the factory.
My robot company was once visited by a computer science Ph.D. He had been in charge of robot applications in a major American manufacturing company, a customer of mine, and was now president of a competing robot company. After the factory tour he said, quite sincerely, that our very large machines were unnecessary because they could be replaced by integrated circuit chips.
Robots were described in anatomical language: they had arms, wrists, hands, fingers, and, of course, brains. Better mechanism designs which were not analogous to humans (not anthropomorphic) were denounced by zealots as "not real robots."
All animals have hinged joints, like elbows, and none have sliding parts, like trombones. Bugs, fish, puppy dogs, people. Probably something to do with keeping germs out and blood in. So most robot designers feel compelled to use only rotary joints and to call them "elbow," "wrist," etc., despite their many disadvantages in programming, accuracy, rigidity, and size. (Nevertheless, even the Unimate had one linear slide!) Machines designed as machines, by engineers without this compulsion, have both kinds of joints; usually using linear slides for position and rotary joints for orientation.
A convenient way to describe vector motion components in Cartesian machines is north-south, east-west, and up-down for position, and roll, pitch, and yaw (from airplane language) for orientation. Very useful on the telephone. For the mathematically pure one says +- X, +- Y, +- Z, +- alpha, +-beta, +- gamma, and speaks learnedly of coordinate transformations. (To program a jointed arm, anthropomorphic, machine its computer must really perform coordinate transformations.)
One of the benefits of Cartesian robots is ease of programming. Since the axes are at right angles to each other there is no cross coupling. For point to point work with a small number of positions, limit switches and a very simple computer are all that are needed. If many positions are needed, only a basic machine tool point to point numerical control system is needed. If continuous path motion is needed, a standard machine tool Computer-Numerical-Control will do. However if "teach mode" is needed for spray painting or the like (see Teach Mode below) there is no programming advantage.
Another advantage is the ability to make a branched configuration having two or more independent arms.
At MOBOT Corp. we designed and manufactured such non-anthropomorphic machines and sold them successfully for use in real factory jobs in major corporations, some in the computer industry. We generated credibility partly by de-bunking the hype.
On the other hand, people come in a narrow range of sizes. Between a fragile, small woman and a brawny, large man the strength ratio is less than five to one and the reach distance ratio is less than two to one. Both are equally sensitive to heat, fumes, and noise. Machines, on the other hand, range from micro-manipulators for use under a microscope to steel mill cranes and can be made insensitive to almost any environment.
MOBOT Corp. was one of the first to sell Cartesian robots, starting in 1973. As my own robot salesman I found that proposals for tasks easily done by humans were very difficult to sell, but proposals for tasks for which humans required walking, lifting heavy objects, long reach, heavy tools, etc. were much easier to sell. In short, I could sell robots to handle large, heavy loads through long distances. We enlarged our machines and succeeded. The last robot sold before the company's acquisition carried 300 pound jet engine part fixtures and loaded them with extreme precision into a row of large NC lathes spaced along a 400 foot row. Try that with jointed arms.
Pseudo robots were made which were simple machines clothed and painted to look almost human and built to do trivial tasks like delivering a drink and talking via a hidden tape recorder. They were presented with the false implication that they were capable of other tasks as well.
Real robots were, and still are, given exhibition tasks to imply capabilities beyond the truth. They have been video-taped "caring for the sick," "making dinner," etc., with all those essential parts of the job which they cannot do, left out.
These practices still generate research grants, however. My favorite boondoggle projects are walking robots. I have met a person who gets grants to emulate a horse.
The robot companies' stock prices zoomed. A major brokerage firm had an analyst who, in all sincerity, was devoted to promoting the boom. Robots became high fashion in journalism.
In the end, the phoniness served to discredit robots to serious people and the bubble burst. Why?
Hype. There was gross exaggeration, by some, of the nature and capability of robots ("electronic brains" etc.) There was the will to believe that a good thing was about to happen. There was, and is, the pervasive, and deliberately planted, confusion of science fiction and science truth.
There was an unusually high level of professional conceit among the technical promoters. There was the usual practice of hype, with wishful thinking, to promote money and careers.
A grey area exists in which hype give way to hoax; perhaps the difference is the intent of the speaker. Civilization has a long history of bubbles; the book "Extraordinary Popular Delusions And The Madness of Crowds" by Charles Mackay is a classic study.
Are robots a passing hoax, then? No. There are real, productive robots which are valuable, cost efficient, smart machines. Some are used as part handlers to load and unload fabricating machines such as machine tools. Some are used as tool handlers, spot welders, arc welders, paint sprayers, de-burrers, and sealant dispensers. Some are used in automatic assembly machines.
More and more automatic or remotely controlled machines are called "robots" or "robotic" to benefit their makers and buyers with the glamor of the word "robot." All are intended to replace people at net savings to the manufacturers who invest their cost reduction budgets in robots.
Many robot tasks cannot be programmed exactly in advance because real world operating conditions cannot be predicted exactly. For example, consider the requirements to pick up the top part from a stack of parts, or put down a new part on a stack. Since the part thicknesses vary, one cannot predict the exact position of each part. The same goes for parts in a tray, the location of a conveyor fixture, etc. Means must be engineered to position the robot at the position really required. For another example, consider the problem of putting a part into a very close fitting holder such as a lathe collet, when the clearance between part and holder is less than the positioning accuracy of the robot. Adaptive means other than brute force accuracy are required.
Most robots are internally programmed and merely go through the programmed cycle when given a simple start signal. However there are many robots which combine an internal program with obedience to commands from outside. Here are some examples:
Automatic storage and retrieval robots (automatic warehouses) are commanded from outside either to transfer an object from a designated pickup point to a designated position in storage or vice versa. The detail motions are internally programmed. Such robots are made in sizes to handle "objects" from tape cassettes to pallets carrying diesel engines. The commands may come from a computer which controls a larger operation, in which case the robot computer and the computer which commands it are said to form a hierarchy.
Remotely controlled robots include satellites and space probes which send data by radio back to their human controllers ("telemetry") and receive commands by radio from their human controllers. The detail actions are internally programmed. It is argued that such remote control makes it unnecessary to sent people into space.
Mobile robots travel around under some combination of automatic control and remote control. Among them are vehicles for mail delivery, surveillance and police tasks, material transportation in factories, military tasks, and underwater tasks like inspecting pipelines and ship hulls and recovering torpedoes.
Although the word, robot, is used at almost every opportunity because of its prestige, it is usually not applied to machine tools. However many machine tools are computer controlled and the control program is replaced for each different product to be made by the machine tool.
It is possible to add sensors to the robot servos so that the final position of the END EFFECTOR is where the sensors command after a staging position which the program commands. I call such systems "active homing guidance."
Typical sensors are limit switches and proximity sensors (optical, acoustic, inductive, capacitive, pneumatic) and in some cases, television.
For the ultimate in precision positioning it is possible to make the end effector "permissive" or "compliant" so that forces on the part or its gripper displace moveable portions of the end effector assembly to permit self alignment. In many cases there is no final error whatsoever, the gripper is truly positioned where it should be, plus or minus zero. I call such action "passive homing guidance." In this case, open loop mechanisms out-perform closed loop servos. Heresy!
Examples of passive homing guidance are described and illustrated in Chapter 14 of my book, "Designing Cost-Efficient Merchanisms."
Homing guidance makes the difference between many successful robots and impossibility.
An early concept in robot development is programming by "teaching" the robot, another anthropomorphic word. The robot is equipped with a switch or other transducer assembly near its end effector. (Sometimes teach switches are separately supported at the end of a flexible cable.) The switch assembly is held by the programming person and moved along the desired motion path while the transducer outputs control the robot motors to follow the transducer assembly. The control computer records the electrical signals generated by the feedback transducers and then regenerates the motion commands.
An application of robots where teach mode is indispensable is spray painting. No one can mathematically define the path of a spray nozzle to produce a finish on a refrigerator door without runs or streaks. However a skilled human in grungy overalls and no great power of verbal articulation can move the nozzle to produce perfect results. The solution is to give this human a real nozzle connected to a set of transducers and ask him to paint a real part by hand. Once. The nozzle is then transferred to the robot which reproduces every flick and twist and sweep of the human painter's hand.
One of the hype fantasies was that a robot, being similar to a human, could be easily reassigned from one job to another merely by moving it across the factory floor and plugging in a new program, just as a human is reassigned to a new task and given a new instruction. This conceit is not just an exaggeration, it is flat out not so. Why not?
The first reason concerns tooling. You and I have standard tooling called hands and fingers, eyes and touch as transducers, brains as controllers, hundreds of muscles as actuators, and tens of joints as axes. Not only can these tools of ours do remarkable feats of dexterity but they can pick up and use extension tools like pliers and scalpels.
Robot tools are primitive in comparison and therefore must be made to suit each particular task. (Yes, there are always fatuous R&D efforts to emulate the human hand. Lots of luck from a very experienced robot tool inventor and designer.) Robot controls are primitive in comparison with human controls and robot articulation (axes and actuators) is a tiny fraction of human articulation.
The second reason is installation. The machines, conveyors, part magazines, etc. working with the robot must be arrayed in a pattern within which the robot can successfully reach and work. The robot must be accurately positioned within that pattern; it does not have eyes and a brain to adapt to it. Guards and interlocks must be provided to prevent a sudden machine defect from causing mechanical damage or human injury. A master programmer must control both the robot and the associated devices. Often the robot's own programmer is in the bottom layer of a hierarchy of controllers. In short, the robot task itself requires extensive engineering aside from the robot.
I know of no such multiple purpose robot usage.
Robots can be re-programmed easily for variations within task (e.g. spot welding different chassis); but they can not be converted from task to task except as a permanent change with a corresponding investment.
Some robots are cost-justified solely on labor savings, some are cost-justified, at least in part, by the superior uniformity of machine work over human work, and some are cost justified by the savings in not exposing people to dangerous working conditions. The cost of a robot is approximately the workman's compensation cost of an industrial accident, and there is no assurance that there will not be another accident to the replacement worker.
I have read a lot about robots which "improve the quality of life" in factories, but in all my experience I never met a manager with much of a budget to "improve the quality of life" except as a means to improve profits.
Please excuse the cold blooded but realistic language.
The real economic significance of the robot is that the robot itself is a multiple purpose smart machine, produced in quantity, and therefore more cost efficient than a special machine developed to do each kind of job.
I'm sorry you will not get a robot to do your housework. Housework is boring and far below your human capability but it is vastly too complex for any smart machine. Automatic, single purpose machines, like dishwashers, you already have and you can count on more and better as time goes by, but a housework robot? No.
The phrase "process industry" usually refers to a factory producing an amorphous product like chemicals or petroleum or metals or plastics or medicines. The product flows through the manufacturing steps in pipes or on conveyors, either continuously or intermittently in batches. Discrete products appear at the end when the product is packaged. Manufacturing automation first occurred in the process industries. One of the first automatic factories was a flour mill made by Oliver Evans in the 18th century. The pneumatic instrumentation and control art (Chapter--) was developed in and for the process industries and is still widely used, sometimes in combination with electronics, particularly for variable valve controllers. Flow rates are controlled by pump speed, conveyor speed, or valve setting. Mixtures are controlled by volume or mass flow rate for continuous processes or by weighing batches in batch processes. Temperatures are controlled by controlling flow rates of fuel or steam or electricity. Product properties and process variables are measured by transducers for temperature, pressure, viscosity, pH, optical properties, and other parameters.
It is not obvious which is the world's oldest profession, but school teaching is certainly in the running. Since ancient Egypt, thousands of years ago, children have been sent to school. Furthermore the principal curriculum has not changed very much: the three R's and some variations on what we now call social studies.
Even the physical technology has changed very little, until quite recently. A classroom, individual writing instruments and writing surface (stylus and clay or wax tablet, pen and ink and papyrus, ball point pen and paper); teacher's display writing instrument and surface (stick and sand, chalk and blackboard), the differences are only convenience. Science laboratories were added in the late 19th century when "natural philosophy" was replaced by empirical science.
Classroom activity has changed very little also: Lecture, recitation, and perhaps some discussion among the students.
University professors continue their fraud on undergraduates by hiring graduate students as "Teaching Assistants" to conduct their classes (I did not say teach), while the professors spend their time as consultants and advancing their careers with research, papers, and books, with an occasional appearance in the classroom.
One might think teaching would, by now, be a well established and non-controversial art. It is not. The profession continues to generate new theories of education and new fads. There are many journals devoted to current variations in theory and practice. A few quotations from a recent article about computer aided education will give you the flavor:
Therefore much of this chapter is in the form of speculations and questions about the use of smart machines - mostly computers - in education and about their effects on curriculum, rather than a straight-forward description of the use of a technology.
Most forms of life develop random growths which are best pruned off. In plants they are boles and suckerwood. In humans they are warts and tumors. In the educational system they are fashionable and transient theories of education created by a variety of human called, for example, "Professor Of The Teaching Of Mathematics."
When the Russians launched Sputnik these people came to the rescue of our nation; they leapfrogged the Russians by creating and imposing on our children the "New Math."
They had heard something about digital computers using base 2 arithmetic. They didn't know why, but clearly base 10 was old fashioned and base 2 was in. So they converted a large fraction of children's arithmetic education to learning how to calculate with any base number and to switch from base to base. But why, teacher? Because that is the modern way. No one knows how many potential engineers and scientists were permanently turned away by this inanity.
Fortunately this lunacy has now petered out.
Educational movies are not smart machine technology, but they were the first major technological innovation in teaching. They have been used extensively to supplement conventional classroom teaching, but hardly at all to replace it. I have actually seen a film of a famous scientist, Professor Gamow, who was also a fine teacher, delivering a lecture. Once. Why is this not standard procedure, in all subjects, with the best teachers chosen to teach? And with live teachers only for recitation and discussion? Less cost for better education. Is the answer job security and a strong union?
Video tapes and compact discs have largely replaced film projectors. They are easier to load and unload, the TV screen is a natural part of modern life, the program can be transmitted by wire to many screens simultaneously, and wire transmission eliminates transporting cans of film. The resolution of the picture (the clarity of its details) is far inferior, but we are all used to that.
During the 1960's there was a fad to develop teaching machines. A wide variety of electro-mechanical devices were designed. A style of printed matter was developed which taught with a system of short expositions, questions, answers, and explanations of wrong answers. (This technique was carried forward into computer teaching, but we are getting ahead of our story.) No revolution occurred except in language labs where sound recorders became a great asset in learning spoken language.
First came mainframe computers wired to a multiplicity of "dumb" terminals and then personal computers (small, electronic, digital computers with CRT displays, that is) showed up and the world changed. In education it became possible to write teaching programs for students who learned at their individual rates and did not depend on a teacher who might or might not be the world's best teacher. Almost any subject could be accommodated, excluding laboratory work.
In operation the computer communicates to the student visually via the screen and audibly via earphones. Depending on the sophistication, and cost, of the equipment the