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Comment: Of course you use force control to run fast. (Score 5, Insightful) 42

by Animats (#47915427) Attached to: MIT's Cheetah Robot Runs Untethered

That article is written as if that crowd invented running using force control. Of course you use force control. Everybody in the field knows that by now. I patented that 20 years ago. The Scout II robot at McGill, developed by Prof. Martin Buehler, used that approach. Buehler went on to become the designer of BigDog, but never got much public credit for it and quit to work for iRobot.

The key to legged running in non-trivial situations is careful management of ground traction. Traction is first priority, then balance, then foot placement. Historically, everybody worried about foot placement first, but that turns out to be backwards. As soon as you get off flat surfaces with good traction, traction control dominates.

The next unsolved problem in that area is not going fast. It's starting, stopping, and turning fast. Most of the legged robots accelerate very slowly, and don't make abrupt high-speed turns. Big Dog starts by trotting in place, then extending the gait out. Starting fast, stopping fast, and turning fast are all facets of the same problem. You have to take one stride using completely different control algorithms than you use for normal locomotion. That's all I'm going to say about this for now.

Comment: Re:Renewable (Score 1) 79

by Jeremi (#47914911) Attached to: Solar Powered Technology Enhances Oil Recovery

Just as a quick jab, maybe I want poor Canadians to be paid by rich beachfront property owning Miamians? Just something to think about.

Hmm, a sort of environmental extortion racket? I like it, but somehow the Canadians don't strike me as quite the type to try it. Maybe I'm wrong about that. :)

Inflation: It would cost more today to retard economic growth and combat climate change than it will in 2025.

Are you sure? Because while the relevant technologies will have no doubt advanced by 2025, the scale of the problem will be that much larger by that time as well. It's not obvious (to me anyway) how one would predict where the "sweet spot" would be, or if there even is going to be one -- it's entirely possible that the problems will continuously grow faster than the technology needed to solve them, so that it will never be cheaper or easier to combat climate change than it is today.

Comment: Re:SF stories optimistic? (Score 1) 122

by Jeremi (#47914875) Attached to: Sci-Fi Authors and Scientists Predict an Optimistic Future

It seems that we are going to have to fight off aliens for our survival.

Er, why does it seem that?

Is it because any aliens that come here are going to want to take our resources? That seems unlikely, since any aliens capable of coming here would also be quite capable of gathering all the raw materials they need from other locations closer to wherever they came from -- avoiding interstellar freight costs is a huge incentive. (the exception might be "exotic" materials that can be found only on Earth, e.g. DNA, which might explain the cattle abductions -- but they only need samples of that since it's straightforward enough to duplicate as necessary)

Comment: Use best practices (Score 1) 240

by Jeremi (#47914785) Attached to: Ask Slashdot: What To Do After Digitizing VHS Tapes?

The standard IT solution for this problem is to encode the data as DNA and inject it into a few dozen cockroaches, which you then drive to the nearest KFC and set free.

If you ever need to restore from backup, just put some twinkies in a bowl outside your door, and some copies of your data will be available to you by morning.

Comment: Clueless (Score 1) 53

by Animats (#47911665) Attached to: New Data Center Protects Against Solar Storm and Nuclear EMPs

This keeps coming up. The effects of an electromagnetic pulse and a solar storm are completely different. EMP is a big RF pulse with a risetime in the nanoseconds. This is a risk to input transistors connected to external wiring. Twisted pair, coax, and small mobile devices are relatively immune. Fiber optics are totally immune.

Solar storms induce DC voltages across long distances of conductive landscape. This is a risk only to transformers with grounded center taps connected to long transmission lines.

Here are the PJM power grid emergency procedures for geomagnetic events. They had to be implemented for a day two years ago. Almost nobody outside of power grid operators noticed.

Comment: Re:Renewable (Score 1) 79

by Jeremi (#47908851) Attached to: Solar Powered Technology Enhances Oil Recovery

The problems I have with it are the government favoring it over a neutral policy and mandates forcing me to use it when it's not yet the least costly.

That raises the question: Least costly to whom?

If, for example, the carbon emissions from your cheap energy today are going to result in my air conditioning bill doubling next year, shouldn't you be held liable to compensate me for the costs you incurred?

Or on a larger scale, if Shell's tar-sands pollution over the next few years causes Miami to have to be evacuated in, say, 2025, should the cost of losing Miami and relocating all of its people not be somehow factored in to our calculations about what is really "cheapest"? Otherwise we're just robbing Peter to pay Paul.

Comment: Only Apple can't make sapphire work. (Score 0) 199

by Animats (#47903731) Attached to: Sapphire Glass Didn't Pass iPhone Drop Test According to Reports

Everybody who gets an iPhone immediately puts it into a rugged, generally rubberized, case.

That's pathetic. All that effort to make a super-thin device, and you have to put it another case to protect it. Nokia would laugh.

Get a non-toy phone.

It's amusing that Apple can't get sapphire-coated glass to work. Sapphire glass for checkout scanners is a standard product. Every Home Depot checkout scanner has sapphire-coated glass. People slide metal tools across those for years without damage.

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