Chapter 36 7.2 Maturity of the mechanical self

Helen's regulator, Dreybel's thermostat, and Watt's regulating device injected self-control, sensory awareness, and longing awakening into their own veins.Adjust the system to perceive its own attributes, and pay attention to whether there are some changes in itself that are different from the last time it was checked.If there is a change, adjust yourself according to the established goal.In the particular example of the thermostat, a test tube filled with alcohol senses the temperature of the system and then decides if action should be taken to adjust the heat to maintain the system's established temperature target.Philosophically speaking, the system has a purpose.

Although this may be obvious to people nowadays, it took the best inventors in the world a long time to transplant even the simplest automatic circuit, such as a feedback loop, into the field of electronics.The reason for this delay is that electricity, from the moment it was discovered, was first seen as energy rather than as a means of communication.In fact, in the last century (nineteenth century), Germany's top electronic engineers have realized that the nature of electricity is actually two-sided, and this budding awareness of difference is to divide related electricity technologies into strong electricity and weak electricity. two kinds.For the energy required to send a signal is so implausibly small that electricity must be imagined as something quite different from energy.For those wild German signal scientists, electricity was brothers to the speaking mouth and the writing hand, and had the same function.The inventors of these weak technologies (we will now call them hackers) brought us a perhaps unprecedented invention - the telegraph.It is because of this invention that the communication between human beings can spread rapidly through the invisible particle carrier like lightning.And it is because of the offspring of this amazing miracle of electricity, the weak electricity, that we have reimagined our entire society.

Although these telegraph operators kept the weak electric model in mind and implemented subtle innovations, it was not until August 1929 that Bell Labs telephone engineer Blake tuned an electronic feedback loop.Blake was trying to figure out a way to make long-lasting line repeater amplifiers for long-distance telephone lines.Early amplifiers were made of natural materials, and such unprocessed materials tend to gradually decompose during use, resulting in a loss of current.An aging repeater will not only amplify the telephone signal, but will mistakenly mix in the signal any slight deviations in various frequencies that it picks up, until these bulging errors fill the system and completely destroy it.So, something like Helen's adjustment device is needed here, which can generate a reverse signal that constrains the main signal, and buffers the effects of the repeated cycle.Luckily, Black devised a negative feedback loop that counteracts the snowball effect of the amplifier's positive loop.From a conceptual point of view, this electrical negative feedback loop is exactly the same as the flushing system or thermostat of a toilet.This circuit, which acts as a brake, can keep the amplifier in a stable amplification state during constant fine-tuning, and its principle is the same as that of a thermostat that can be kept at a specific temperature through constant fine-tuning.It's just that the thermostat uses a metal brake lever, and the amplifier uses some weak currents of electrons that communicate with themselves.Thus, in the channel of the telephone switching network, the first electrical self was born.

From the beginning of the First World War to the post-war period, artillery shell launchers have become more and more complex, and at the same time, those moving pre-attack targets have become more and more sophisticated. The calculation of ballistic trajectories is a test of human intelligence. .In between battles, calculus, known as calculators, calculated the various parameter settings of those cannons under various wind, weather and altitude conditions.The results of the calculations are sometimes printed on pocket-sized forms for use by artillerymen at the front; or, if time permits and it is common artillery, these forms are coded into the artillery installation, which is commonly called automatic operating device.In the United States, all activities related to artillery calculations are concentrated at the Navy's Aberdeen Proving Ground in Maryland, where a room full of human calculators (nearly all women) uses hand-cranked computers to perform calculations sheet.

By World War II, German planes—what the artillery was trying to bring down—were flying almost as fast as cannonballs.So faster real-time calculations are needed.Ideally, the guns would be fired whenever the newly invented radar scanning device detected data on aircraft in flight.In addition, naval gunners had a critical problem: how to turn these monsters and keep them on target based on the precise data provided by the new firing tables.The solution was at hand, right at the stern: a giant ship that controlled its rudders through some special kind of automatic feedback loop, a servo mechanism.

The servo mechanism was independently invented by an American and a Frenchman at the same time around 1860, separated by an ocean.The Frenchman Leon Falco has a mouthful name for this device: the servo motor.As ships grew larger and faster over time, the force humans applied to the tiller was no longer sufficient to resist the surging currents underwater.Navy technicians came up with various oleo-hydraulic systems to amplify the forces acting on the tiller, so that just a slight shake of the small tiller in the captain's rudder well had little effect on the huge rudder.According to different ship speeds, water lines and other similar factors, the repeated shaking of the small rudder stock is reflected in the rudder to show different rudder effects.Falco invented a communication device that links the position of the large underwater rudder with the position of the small rudder that can be easily maneuvered - that is, an automatic feedback loop!In this way, the rudder stock can indicate the actual position of the rudder, and through this circuit, the indicator of the rudder stock is moved—that is, the entity of the rudder is moved.In the jargon of the computer field, this is the so-called WYSIWYG!

The barrels of heavy artillery during World War II also operated in this way.A hydraulic line containing hydraulic oil connects a small turning lever (small tiller) to the piston of the barrel steering gear.When the gunner moves the lever to the desired position, this small turn squeezes a small piston, causing the valve to open, releasing hydraulic oil to jack up a large piston, which in turn swings the huge, heavy gun barrel.In turn, when the barrel swings, it pushes a small piston which in turn activates the manual lever.So, when the gunner tries to turn the little rudder, he also feels a kind of mild resistance produced by the feedback of the big rudder he wants to move.

Back then Bill Powers was a young assistant electronics technician tasked with manning the Navy's automatic guns.He later explored the mysteries of biology by studying control systems.He describes the false impression that ordinary people can get when they read about servomechanisms: The way we speak or write tends to stretch out the whole act and make it seem like a series of distinct events.If you were trying to describe how a gun aiming servo works, you might start something like this: "Suppose I depress the barrel to create a differential. This differential will cause the servo motor to generate a counter-depression." The greater the downforce, the greater the resistance." That description seems clear enough, but it simply doesn't fit the truth.If you actually did this demo, you'd say something like, "Suppose I depress the barrel, and there's an offset... wait a minute, it's stuck."

No, it's not stuck.On the contrary, it is an excellent control system.When you start to press down, a small shift in the sensing position of the barrel is applied, causing the servo motor to turn the barrel up against the force of your downward pressure.And the offset required to create a resistance equal to your downforce is so small that you can't see or feel it.In this way, the gun barrel feels as stiff as if it was cast in cement.Because it weighed 200 tons, it felt as immovable as those old-fashioned machines; however, if someone cut the power, the barrel would immediately smash to the deck.

Servos added such a mysterious and ingenious power to steering that we still use it (with an upgraded version) to navigate ships, control the ailerons of airplanes, or fiddle with remote-controlled machinery that handles toxic or radioactive waste. arm fingers. Falco's servomechanism goes a step further than other purely mechanical selves, such as Helen's valves, Watt's regulators, and Dreybel's thermostats, and opens us up to another possibility: the human-machine The possibility of symbiosis – the possibility of merging two worlds.The driver is fused with the servo mechanism.He gets power, it gets substance.They are at the helm together.Control and symbiosis—two aspects of servomechanisms that inspired one of the more colorful figures in modern science to discover the patterns that can tie these control loops together.