I read an article in the feb, 2000 issue of Smithsinian magazine about this fellow, Mark Tilden of Los Alamos, New Mexico, who builds analog robots. Pretty complex ones, without computers.
Here’s a little blurb about the story;
http://www.smithsonianmag.si.edu/smithsonian/issues00/feb00/robots.html
He claims that they’re more robust than computer controlled machines, and can actually perform better.
What do all you computer geeks think?
I’ve also read a story, quite a while ago, about the potential superiorty of an analog computer.
Is such a thing feasible? Aside from our brains, I mean.
Peace,
mangeorge
The problem with sending an analog device to the moons of Barsoom is…(1) controlling it and (2)controlling it. The advantage of digital circuits is that they can be miniaturized. Well, potential computing near the speed of light carries some advantages as well.
That little blurb doesn’t make it quite clear what is meant by ‘nothing to do with computers’. I think analog vs. digital stuff is often misrepresented, often as ‘old’ vs.
new’ or something like that. In truth analog computers have been made, and they are as old as digital ones. The biggest advantage of analog computers is that they can perform operations like integration and differentiation in one step, while digital computers can only do it through algorithms that perform numerical integration, generally a lot more steps. Although the digital process can be scaled and modified much easier than the analog way.
A computer is a device that computes, simply put, and if these are learning machines then they ought to be considered computers.
Analog controllers can process most stuff that needs processing far faster than digital controllers, yet it doesn’t matter much, especially with servo motors (like on robots) which are working extremely slowly in comparison. What’s likely the advantage in this case is that the robots can be made very lightweight. It usually takes more design work to get it right, but in the end you don’t need many parts to implement it.
I’m starting to wonder if this post is any more lucid than tcburnett’s. moons of Barsoom? must be too late at night for me.
panama jack
what just happened?
Analog “computation” is great, and blows-away digital number crunching in many applications. I think it’s somewhat troubling that engineers automatically look for digital solutions when an analog solution is often faster, cheaper, and more elegant.
We still have some genuine analog computers here in our lab. They were manufactured by EAI. These things were extremely expensive when they were purchased back in the early 1970’s. We should throw them away since no one uses them, but it would be very tough to do given their original price!
But analog computation is not dead. We still design logarithmic amplifiers for some applications (using op amps). In fact, just last week I drew-up a differentiator circuit for an internal customer. Long live analog!!
Advantages of analog computation:
- Very fast
- Efficient
- Easy to implement parallel processing
- Doesn’t cause EMI glitches in adjacent circuitry (capacitive coupling)
- No quanitization error
- High bandwidth (no alaising)
- Clock signal usually not required
Advantages of digital computation:
- More reliable
- Simpler to design
- Easily configurable
- More stable over time & temperature
- Immune to noise & outside EMI
- No degradation over time
- Smaller part count
Michael Craft, EE
University of Dayton
mcraft@udri.udayton.edu
Sorry there wasn’t more info at that site. I guess Smithsonian want’s to sell back issues. It was a pretty good article, if you’re interested in that kind of stuff.
Crafter_Man’s post pretty much covers Mark Tilden’s p.o.v. Tilden’s main point seemed to be that his machines would adapt and keep on working, even if damaged. And that they didn’t require as much controlling as digital. I don’t think he was advocating the overthrow of all things digital. 
Peace,
mangeorge (Just curious)
Barsoom. Mars for readers of certain old pulp sci-fi. Dunno why you’d want to go to the moons though, they’re little more then oversized captured asteroids…
I would like to add another advantage to digital to Crafter_Man’s post of pros and cons.
It is much easier to manufacture digital circuits. One big reason for this is that they are much easier to test. Analog circuits have to be tested to see if they are as accurate as desired for every single device. This takes a lot longer if you have a $10,000,000 analog circuit tester that is useful for 2 years that is about $0.16 cents a second is the machine is operating 24/7. An extra 2 or 3 seconds can make or break the profitablity of the part.
Digital tests can be run much faster because accurate voltages do not need to be measured so the tester can be cheaper and the test takes less time.
It is missleading to say that anlaog comupters are much faster than digital computers. They can perform solve linear differential equations fast provided the answer does not need to be that accurate. They cannot however be used to balance your checkbook, play doom or wirte boring posts late a night.
In the Martian tales of Edgar Rice Burroughs (better known outside of SF circles for the Tarzan books), Barsoom is the name by which the Martians refer to their world. If you want to check out the series, the first three books are A Princess of Mars, The Gods of Mars, and A Warlord of Mars. I would recommend them, personally.
Back to the OP, as I understand it, another advantage to digital computers is that they’re more versatile in some ways. Yeah, a digital is clunky for some things like integration, but it can still be programmed to do them. On the other hand, it’s harder to program an analog computer for any task for which it wasn’t specifically designed. I may be wrong, though… If any of these other folks correct me, take their word for it.
Old pulp sci-fi? Edgar Rice Burroughs (At the Earth’s core; Fantastic worlds; The legend of Tarzan, Lord of the Apes) coined the phrase “hurtling moons of Barsoom”. Carl Sagan liked to quote the phrase.
Pulp sci-fi? Sheesh!
Didn’t they leave the analog fire control computers on the USS New Jersey?