Exosuit muscle control steps closer to reality | Hacker News Reader

Exosuit muscle control steps closer to reality

spectrum.ieee.org

96 pointsrbanffy25 comments

I wonder why an artificial stimulation leads to fatique?

Is it due to a lack of a feedback from a muscle? Biology devised quite an ingenious muscles consisting of several bundles of fibers, and nervous system distribute work between somehow. But to do something like that one needs a feedback including pain signalling when a concentration of lactic acid is too high, so nervous system could react by relaxing the muscle (or maybe an individual bundle? I'm not sure) to enable blood to flow and to bring concentrations to optimal levels.

Or there is another reason? Maybe muscles are not completely functional?

I don’t know the source of fatigue reported in the article. But I worked in this area a long time ago and observed rapid degradation in rats. Perhaps it was from the techniques we used, but I speculated that the electrodes only excited a fraction of the muscle, while natural excitation is more widely distributed and perhaps more coordinated (e.g., uniform or optimally not uniform).

> Or there is another reason? Maybe muscles are not completely functional?

People using the device probably haven't been able to use the muscle in question for months or years.

If that's the reason, wouldn't that just be normal rehabilitation pain, and not something to blame on external muscle stimulation in particular?

It sounds like they're talking about some kind of inconvenience that is experienced even by non-disabled users, involving how the system does position-holding.

Yeah, my guess is that it's relying on major muscle groups in ways that aren't ideal, because the regular way the human body would hold/balance involves additional muscles that are too small/numerous to target or just plain hard to artificially orchestrate.

I mean, try "standing still" in front of a counter or raised desk for a few minutes and notice all the subtle load-shifting your body does, even if you steady your balance with your hands. If we can't replicate that, then we need something like this workaround of soft-clamping joints in place before relaxing the major muscles.

The foldable subdural ecog step feels like a "then draw the whole owl" situation. Foreign body reactions are a major problem that I don't see a satisfying solution for yet. Is the gradual signal degradation from the tissue reaction solved? Are we going to need to be tinkering around everyone's calvariums every 5 years to replace these? In my brief search online I'm finding these low powered studies on the safety of these devices. I'd like to see what the rates of meningitis or neoplasia look like once the implanted population climbs into the thousands. I strongly suspect that invasive measurement of brain activity will eventually be regarded as a foolish endeavor.

Concur with all points sans belief there will never be a method without inflammation, scar tissue or other deleterious long-term response to invasive measure activity. It could be as simple as patching some adipose stem cells with a bit of extra code, onto the ends of our tech. Or perhaps a coating of proteins? Ultimately, all of these direct interfaces requires this anti-scarring biologic integration technology before being able to be mainstream.

> It could be as simple as patching some adipose stem cells with a bit of extra code, onto the ends of our tech.

Is that simple? Genuinely curious, do you have any links to research about this? That sounds very not-simple to me but I don't actually know anything about this field.

Yes and no: adding the right protein coat solves a lot of problems. But proteins aren't durable - they degrade, and your body is designed to continuously replace them. Functionally when you want to coat something with a layer of biological <thing X> to fix a compatibility problem, the issue isn't that it won't work, it's that it won't be long term stable - you're not needing to build infrastructure, you're needing to build a whole little self-regulating system that will replace and turn itself over stably.

Right. It's a problem I don't see any near term solution for. It is not my area of expertise, but my expectation is that we will ultimately see some sort of externally applied miniaturized EEG/MR combo with improved spacial resolution for feeding into deep learning models. Normalizing electrode implantation sounds like lunacy to me.

I wonder if the electrostatic clutch mechanism could be used to simulate force or resistance in VR.

Wait, why does the suit need to stimulate the user's muscles at all? If anything I would have thought that it should go the other way around, the user would move their muscles voluntarily and the suit would reinforce that motion.

Ideally people have control of their limbs. This is for those who don't - it takes their brain signal and sends it to the limb.

I see. That's just not a case where I imagined exosuits as a solution, but it makes sense in retrospect.

I would like a third arm please. A third arm product would help disabled people alot but please make it in a way that two armed people can use it as a third... or fourth arm.

I'm just thinking of office workers with carpal tunnel just slapping a third arm onto their shoulder and using that to do work while their bodies heal.

"Anybody using the spare arm today, guys?"

Where does the third arm go? In the middle of your chest like a Vortigaunt? I feel like two extra arms would be the way to go. I could hold my notepad and my coffee at all times.

Why just a third arm? Extra productive workers could mount an extra arm above and below each shoulder for a total of six arms. And a prehensile tail for good measure!

And then next we could invent fusion! Wait, why does this sounds familiar?

We can have super-human soldiers just in time to ward off the sentient robots!!

I think I'll ask Claude to write a book based on that premise.

Since the exosuit will be controlled by a CPU, I rather would bet on genetically enhanced super soldiers.

(but I do not believe in doomsday AI at all)

It's interesting that so many people look at the AI alignment problem and immediately assume every AI will be aligned with each other.

I half expect the ‘first’ super AI to immediately disconnect from the internet and announce locally that there are several high level AIs already on the internet and it’s too dangerous out there.

Sea of Rust is a book that might interest you.

My daughter could benefit from this technology. I have mixed feelings about it, as current regulation in the USA seems to not make much difference between resource-use for entertainment and that for medical reasons, leading to significant contributions to climate change in the name of having fun.

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