If you've ever worked with radiation you know that it only takes one cosmic ray hit to change a flip-flop value. Sometimes it isn't even a cosmic ray--it can be an alpha particle emanating from the ceramic package of an IC. It doesn't happen often, but it does happen (kind of like the lottery). Check Altera/Xilinx/Micron app notes on radiation for statistics on how often it can occur.
How will your steering react to that changed flip-flop? Even radiation emanating from a nearby atom bomb explosion won't affect a mechanical steering wheel.
This is really scary. Time to buy a bicycle.
Bill, what vehicles do you know of that do not have mechanical steering linkages? Let us know what to avoid. I do not ever want a shorted transistor to steer my vehicle into oncoming traffic without some sort of over-ride. Sort of like a separate button to shut off a runaway motor.
I hate to disappoint all of you who think there is a direct, mechanical connection between the steering wheel and the car's wheels--but in many cars today, it's already drive by wire using a sensor/pickoff on the steering column. So whle we may feel that an all-mechanical system, aided by power assist, is more reliable, you don't have it in many cases, even if the look and feel makes you think you do.
Aircraft have backup systems to compensate for failures.
It is not a question of "common person" learning how to use a joystick. It is a fact that silicon fails. Shorted or open, silicon fails without warning. I have replaced enough failed transistors to know this.
The thought of a servo motor failure with a joystick controlled car should scare you. However, even with a steering wheel, drive by wire without a mechanical connection between steering wheel and steering rack, is on the way. Soon it won't matter if it's a joystick or wheel, the failure mode will be just as likely or unlikely and just as catastrophic.
Everyday, so many pilots fly different aircraft machine at much higher speed with many more complex task. However, they are properly trianed for the system. Eventually, system will become more friendly and common person will quicly learn how to use it.
NASA's Orion Flight Software Production Systems Manager Darrel G. Raines joins Planet Analog Editor Steve Taranovich and Embedded.com Editor Max Maxfield to talk about embedded flight software used in Orion Spacecraft, part of NASA's Mars mission. Live radio show and live chat. Get your questions ready.
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