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Fly by wire

Date: 2002-9-24 Author: Chris Wenham Best permanent link

Summary: When Gary Krier test piloted the F-8 thirty years ago, he ushered in a world of computer mediated experiences, with a slight disconnection from reality being the price.

On May 25th, 1972, Gary Krier took off from Edwards Air-Force Base, California in an F-8 that bore the tail number “NASA 802”. Unique to this flight was that every command Krier gave to the aircraft went first from a joystick and through a digital computer before being relayed to the hydraulic systems that operated the control surfaces: flaps, elevators, rudder, thrust and so-on. This aircraft was the first experiment in Digital Fly-By-Wire but it was already hip deep in the idea: without the computer, Krier would have had extreme difficulty controlling the aircraft because the designers had sacrified stability for speed and maneuverability. So began a one-way migration away from direct human control of things and towards computer mediated control. It began with warplanes, and may yet end with people.

Adding a computer between the pilot and the plane was like sprinkling magic pixie dust: you got all of the benefits with hardly any drawbacks. Fly-By-Wire makes the aircraft lighter because it eliminates the bulk of the hydraulic systems. It makes it more maneuverable because the computer can perform hundreds more adjustments per second than a human. It makes passenger aircraft fly smoother, and with greater fuel economy. Plus on warplanes, wires were even less vulnerable to battle damage than regular control lines. Throw in enough redundancy and it even becomes less susceptible to failure than a traditional mechanical control system. Fly-by-wire's advantages were so obvious that designers were thinking about it in the 60s, and it was only computers they waited on to get small and powerful enough to fly a plane.

And so the F-8's children now include every modern warplane and every passenger aircraft, and has begun to include your car as well, starting with antilock brakes. A fly-by-wire system is built to interpret the pilot or driver's intention and translate it into action, where the translation process will take environmental factors into account first. On old aircraft the act of pulling back on the control column would raise the elevator flaps in direct proportion to how far the pilot was pulling, but on a fly-by-wire system they usually raise in direct proportion, but the computer could make subtle changes to account for turbulence. The ratio between the control column that's in the pilot's hands and the flaps on the wing is not 1:1, it's not a direct influence.

The other reason for DFBW was to correct for something called Pilot Induced Oscillations (PIO), which is where the pilot over-controls the aircraft and a sustained oscillation results. What's interesting is that it also revealed the other hidden advantage of DFBW: PIO wasn't accounted for on the first flight of NASA 802, but began to show-up on test flights of the Space Shuttle. In response, the computer programmers wrote a filter for it and tested it out on the F-8, making it probably the first piece of hardware to ever be enhanced by a software upgrade.

On a modern car, there's a computer in between your brake pedal and the brake pads, which will detect an anomalous condition (locking wheels) and release the brake in controlled bursts to get the wheel spinning again and return control of the car. The idea is to use a computer to take the driver's intent (to brake sharply), and translate it into actions that reflect reality (slippery roads). Although it's not true fly-by-wire becuase the steering column still has direct control over the wheels, it has the same kind of pixie-dust magic benefits with hardly any drawbacks. Now considering how cars will evolve in the future, true Drive-By-Wire is inevitable.

General Motors has already come out with a prototype fuel-cell chassis upon which cars of the future could be built. Nicknamed “The Skateboard” for what it resembles, their chassis looks like a low-slung metal sandwich with wheels on its corners. But inside that sandwich is a fuel-cell stack and electric motors. There is no single large engine occupying all of the front or back, and no steering column, brake or accelerator pedals, either. It is all Drive-By-Wire.

The design of the “Skateboard” is radical in many other ways, though. Without an engine or steering column the interior of the car can be arranged any way you like, such as putting the driver and passenger seats all the way up to the front, or providing “furnishable boxes” that can have the seating arranged any way you like. The controls could then be a joystick, or a computer that follows a track in the road. Anything is possible.

But with a Drive-By-Wire system in place, the act of driving can evolve dramatically and become far safer. Antilock brakes were just the beginning, because with computer mediation there's almost no road condition the computer can't translate into a uniform experience for the driver. Driving on slippery roads can be made to be almost indistinguishable with driving on dry roads. If you turn and the wheel is slipping, the car's computer can make hundreds of adjustments on-the-fly to compensate and smooth-out the difference.

Another way of describing Drive-By-Wire is with the phrase “Do What I Mean” (DWIM), which is how software developers refer to it. A computer with DWIM features will see you type in “lust” or “lost” but know from the context that you meant to type in the command “list” and your finger just slipped, so it just runs the command “list” instead. (Most DWIM systems are programmed not to be too helpful and execute irreversible commands, just in case of misunderstandings.) Like the system that filters out PIO on aircraft, DWIM systems help the operator avoid errors invisibly. A DWIM phone will dial the right number even if your finger slips on a digit. And DWIM word processors already correct common typos such as “teh” when you meant to type “the”.

And sometimes it's to the user's great annoyance. While Drive-By-Wire stands to make cars safer and much more fun to drive, they also put an extra cushion between you and the road, perhaps not causing you to make mistakes, but dulling your senses with its sugar-buffered translations of intent to action. Drive-By-Wire makes the whole world into a video game, where the laws of physics pass through an extra interpreter who'll filter out undesirable fluctuations and annoyances. Already, anybody who learned to drive in an ABS equipped car is dangerous in a model without it.

No matter how clumsy your linguistic skills, Write-By-Wire can make you sound like Shakespeare

On warplanes Fly-By-Wire was meant to make aircraft do things they physically couldn't do before because the pilot, being a human, couldn't possibly learn the reflexes necessary to keep it under control. But on consumer vehicles, Drive-By-Wire is primarily a convenience and doesn't really make the car do anything more than we could already learn how. Its safety gains come mostly from the fact that our roads are full of people who didn't learn how to drive properly—the kind who jam on brakes instead of pumping them—and the computer will override their poor judgment. They do the opposite of the simulation machines we described last weekA; instead of providing an accurate depiction of the real world, they dull and smooth it over. It's not unreasonable to believe this could have an impact on our perceptions.

The end of the Drive-By-Wire road has a disconnected look to it, landmarked every few miles by another system that translates our intent into the actions that'll have the real effect. One day you'll buy a kitchen appliance that can auto-discover all your other appliances on a wireless network and organize a conspiracy to make any recipe you attempt come out perfectly; the scale will fudge its numbers to correct for any mismeasurement elsewhere, the mixer will adjust its speed and never mix too long, and the oven will never get too hot or cold. The computer mediated philosophy may even scale down to the microscopic level, giving you drugs that you can never overdose on.

Every step will be taken in the name of safety and convenience, but we'll need to watch out and make sure we don't over-pamper ourselves, least we lose touch with reality completely. If you think Television is a bad enough influence on your kids, just wait until their computer invisibly corrects homework answers and everybody is graded against “effort” instead. The most sensible thing will be to look at every computer mediation invention under a critical light to see if it's really worth giving up a closer relationship to the real world. Still, there may be an issue that forces us to adopt it, despite ourselves.

Control and abstraction over volotile environments is the point of Fly-By-Wire, and thinking about that has made us speculate on, well, non-conventional engineering applications, such as the control or influence of a society.

A well educated, democratic society, like a high-performance aircraft in turbulence, is fickle and enormously hard to control. Like how modern encryption methods keep secrets based on the principle that certain mathematical operations are fundamentally hard to reverse, the success of modern democracy depends on the principle that influence over public sentiment is fundamentally hard to sustain. Candidates can learn how to “work a crowd” but it's notoriously hard to keep them after they've left the auditorium, because there's still the onslaught of media. No candidate can learn the reflexes necessary to work all crowds under all circumstances, and a man who fares well behind a teleprompter may crack in a one-on-one interview with an attack-dog journalist, or make a slip of the tongue to the wrong minority group, or have the wrong reaction to something dredged up from his past.

Influencing groups of voters over the long-haul is hard, but it is possible, and where there's a sympathy there's a way.

Imagine someone wrote the first truly Write-By-Wire word processor. No matter how clumsy your linguistic skills, or how drunk you were that night, it can make you sound like Shakespeare. Load a different author profile into its memory and it'll make you sound like John F. Kennedy's speech-writer. Anything you type will be parsed for intent and translated into incendiary prose. And better yet, if you give it access to demographic data on your audience, it'll tailor your speech with all the gifts of the best evangelists, proselytizers and revivalists, studied and encoded by master linguists and engineers. Add biofeedback devices, and a performance modified on-the-flyA, and even Al Gore could rouse a crowd.

Social modeling is a long way from the mythic perfection of, say, Asimov's Psychohistory, but then how much edge does a candidate need? After all, it's not necessary to drive a populous the way you'd drive a car, but simply to beat the competition, and that's a much easier problem for engineers to solve. You build the teleprompter into the candidate's spectacles and train him to never say anything unless it gets beamed into his field of vision first. Then his handlers send wired volunteers out to mingle with any crowd, and who's job it is to watch faces for emotion and send signals back to HQ. A campaign advisor who's familiar with the candidate's platform will make all the decisions and express his intent to a computer that translates them into words for the candidate to say, tailored for circumstance and consistency, like weaving a highly coordinated quilt.

So the candidate falls further back into the role of a scripted actor (by as much as they aren't already), at least whenever appearing in public. He directs his campaign by chosing and indoctrinating his advisors, but once on stage, or on the street, or in a studio, he is a remote controlled man. It could make mincemeat out of any rival candidate unendowed with the same technology, because the software can be updated quickly to cope with swings in the opponent's strategy.

Assuming for a moment that we couldn't outlaw Campaign-By-Wire (maybe because the ones who'd benefit the most from it are the the lawmakers themselves), the only defense against it would be to start using Listen-By-Wire technology. Campaign-By-Wire would create an environment for a voter that tries to push and prod him from every angle and in ways he isn't expecting, exhausting his skepticism. To relieve the burden of doubt, you'd get some earphones plugged into a pocket computer that filters out anything designed to dishonestly sway your emotion. Anything you hear is a computer synthesized voice that sounds like the real thing, but is edited for content that suits the profile you've programmed the computer with. It would be a real, honest-to-goodness bullshit filter that does fact checking, invective neutralizing, and sympathy transmutation. One more step away from reality and into a computer mediated pseudo-universe, but one made necessary by an unnatural change to the environment.

On a closing note it's probably important to reflect on our own natural Fly-By-Wire systems. Everybody is born with dedicated structures in the brain that interpret reality and make hundreds of subconscious corrections for us. We think “walk forward”, but there's a biological computer we aren't aware of that knows what balance feels like and can compensate for any tip in the wrong direction, so we can sustain the act of walking for miles without spontaneously collapsing. Our artificial Fly-By-Wire systems extend the talents we already have and cut down on the burden of learning new reflexes which, as it turns out, has rewards elsewhere. It's been noted by biologists that all animal brains have dedicated structures, but humans have a higher proportion of undedicated brain matter than any other animal, and we use it for things like higher reasoning. So while most of the tools our species has invented have acted as forms of body augmentation, Fly-By-Wire technology has a much more intimate relationship with our soul: that of mind augmentation. For good or bad, and for whatever price, the ones who use it will have an edge.

Last 20 responses and inbound links

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  13. andersja's blog - Disenchanted proposes "Write-By-Wire"
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