Yeah, it's a bit of a kook filter across all fields ...
Also, having heard the description of SynthMuscles, they _do_
sounds a lot like linear motors, perhaps ultrasonic ones.
In which case I have to ask ... what is all that per-muscle
CPU power doing?
I'm sorry for my bad terminology. I don't know what else to call
the darn thing. Ribbon wench (not a wench), linear motor (not a linear
motor),....what does it do, well it is suppose to be a "simple man's
attept" at a synthetic muscle. Tell me what to call it and I will only
use that term.
The extra processing is there because power output is given as a
set of coefficents of a quadratic equation and range for a given time.
Also, the pulses must be aligned with the given step, so the must
function as expiratory. There is probably a better way, but it works.
The Joint Controller, just a PIC regulating two or more "thingys"
(SynthMuscles), also check position and are trying to constantly
readjust to keep in a range that is acceptable. The Joint controller
is given coefficients and range for a given time of a quadratic
equation, plus a tolerance, that is the position that joint is suppose
to be near.
The communication is a plan-attempt-succeed/fail-replan
interation. There is probably a better way, that is the reason for the
G'day Bruce, it's not that there's anything _wrong_ with calling
it whatever you want. People, myself included, just tend to be
very cautious about new ideas, especially new ideas that are
totally out of the blue.
The other scary thing is that the scope of your project is just
so enormous, all the way from a new motor technology right
through to a very advanced application. Maybe it'd be better
to concentrate on one thing at a time, eg: getting a single
SynthMuscle set up lifting and lowering a weight a million
or so times on the test bench.
Yes, the scope is huge...some of the approaches are new...but it
is not impossible (maybe highly improbable, but not impossible). I
make no illusions to the difficulties.
The SynthMuscle has been through a bunch of tests and abuses. It
hasn't hit that 1 millionth lift, but thanks for the idea.
A group can have subgroups all focused on one thing that together
make George 1.0. The "open source" approach is for everyone's benefit
and is the only way this thing could be made shy of 20million.
Also, if we don't try, then we are all just sitting around talking
about how great it would be if someone would try.
Hmmm...good questions. A preposition makes that question from
impossible to highly improbable. Do you beleive a man walked on the
To me, if someone was saying, "Hey, let's put a man on the moon",
would sound completely nuts even with today's technology. But they did
it how long ago? 34 years.
Those men and women involved in that project were true
visionaires. They focused on whatever would work and kept positive.
They did it despite all those against them (engineers, chemists,
mathematicians, physists, and the astronauts are heros in my book and
I don't give a damn who thinks otherwise :o). There are even nuts
today who beleive it never happened because they can't conceive of it.
I'm no visionairy. I am trying to build a "hammer" and I need
help to do that. The real question becomes, "Can you see someone
building a hammer?".
No worries. What kind of overall efficiencies are you getting out of
it in practice eg: how much power goes in to lift 1 kg 1 meter?
Then just leave it doing pushups in the shed 24/7, you'll
learn a lot about its wear characteristics.
Can it compete with a gearhead motor pulling the kevlar strap?
Bear in mind that for a mobile robot, the power has to come from
somewhere, so saving 1kg of motor but adding 10kg of battery isn't
much of a tradeoff.
I quite like the 'winch' idea ... did you look at the designs of
ultrasonic motors? It's not that dissimilar in method, but the
ultrasonic ones use travelling waves in a machined bit of metal
to do a similar thing ... which means they've got a lot more clamps,
but a lot less moving parts (well, a lot less discrete moving
The efficiencies suck....around 40% at best (about like a
stepping motor but much lighter...but the power-to-weight is
great...hot, but great). It needs work to minimize power. Also, for
power...think utility. :o)
I have a friend trying to get hold of a used magnetic-bearing
microturban (5kW). Now, I know this isn't the thing you want bringing
you a cup of tea in the evening, but think "Utility Class". Yes, the
images just blow you away (actually the new systems are quiet and not
quite how the imagination portrays them ;o)
To make up for immediate power, looking to lithium ion batteries
that can be charged off the generator. Working those final details out
will take some time. Know any good sources?
I like the idea of the pushups, but I am going to just program
the PIC to run it to failure as soon as time permits.
Re: that. Can you peak-and-hold the solenoids to reduce power
Okay, but what does a "utility class" robot (was this thing meant to
be a biped?) _do_? If it's going to be burning 5kW, it'd better
be doing something valuable.
Is it meant to just move stuff around? What can it do that a forklift
with a PUMA bolted to the top won't do better? Or, for that matter,
what can it do that you can't hire for minimum wage?
Yes, that is part of what the PIC is helping control. Part of
that is an expiratory PWM.
It is to be a biped. And the 5kW is overkill (haven't found
anything smaller :o).
This is just a stepping stone, nothing more. It is an "open
source" baseline. What good is an Asimo? What good is a SDR-4X?
Hopefully, at least George 1.0 can be of some use.
Remember, there is a reason the name has "1.0" in it. Maybe
around "4.0" it will be more what we all want.
Oh, right. 'Expiratory' isn't a term I'm familiar with.
What good are they? Bugger all. They're PR stunts and tax sinks
for large R&D organizations.
Autonomous bipedal hominids are a waste of time, because the
planet is already overrun with self-repairing, self-maintaining
ones. What on earth is the point imitating them?
Prosthetics, though, that'd be a worthwhile field for your
For prosthetics, that is the first place they are being used. A
friend of mine is quadraplegic. There is a version Limb Controller is
built with a USB port (via a National 9603). It provides the PID
A notebook will serve as the interface between the Arm and his
mouse (specialized and mounted to his chair). He can change the
programming through a VB program acting as the Central Controller.
There is a great need to a Utility Class droid. There will be bad
uses, there will be great uses. It is just a tool, like a hammer.
Please, don't apologize. If anyone should, it is me. My
communication skills leave a LOT to be desired. I have spent way too
much time in the workshop and very little time with people. I
sincerely apologize for my structure of speech and crude language. And
I really do appreciate what you have said.
There are many problems with the initial design. But it is only an
Yes, there is way more processing power in the SynthMuscle
(probably a bad term, but that is the function it is doing...linear
motor doesn't describe it...ribbon wench doesn't describe it...I don't
know what else to call it...I'm sorry) because it also does
calculations for rate of power output over time. Also, when pulling on
the ribbon, the algorithm must be an expiratory pulse (not just an
arbitratry pulse but aligned with the current function).
The bus (I call it AFAP because it allows all of the clients and
hosts to operate "As Fast As Possible" with varying data paths
1,2,4,8...again probably a bad term but there isn't another name I can
find that describes it) it integral to allow localized iteration for
movement. It basically synchronizes using a few lines to allow
broadcast and localized communication (such as flashing all the PICs
for updates) for clients that are interrupt and non-interrupt driven.
And this is only for motion control. We are planning a discussion for
September 6th at 11am EST just to cover the bus.
Certain parts, such as the big processors will need to be water
cooled. The rest is planned for running low pressure air lines (crude,
Let me state very clearly, this is not a "synthetic human", this
is not an "A.I. wonder", this is not a
"what-ever-you-might-fancily-call-it-over-glorifier". This is a
"Utility Class" droid. Some keep trying to make George 1.0 out as a
robotic version of a F-50 Ferarri...I'm thinking hammer. We could all
use a good hammer.
The SynthMuscles do create a number of problems. But, they also
solve so many other problems that are otherwise unsolvable with
conventional technology. I think you will come to find out that SCALE
is a all important aspect of design. (unless you think ants scaled to
the size of elephants could hold themselves up ;o)
The use of SynthMuscles actually take up much less space and
weight, but are more than twice as numerous. They also have a much,
much higher power to weight ratio. They do use some very unique
materials with specifications that seem unlikely (at least it seemed
impossible until they were found...a set of materials to fit the
As for naming it, "George 1.0" is just a starting point. Within
the team there are some that are debating the name right now. For me,
I leave the name to the team. Some have also suggested a humanoid
Personally, I no interest in making George 1.0 a friendly, human
acting droid. My goal is a usable utility class droid.
firstname.lastname@example.org (Bruce) wrote in message
Ah...do these SynthMuscles use the "quantum cavitation" phenomenon
that was observed a few years back? A carefully balanced arrangement
of materials such that electron injection upsets the stability of the
outer electron shells, switching to covalent bonds which results in
compression of the material in the direction of electron flow?
It isn't so elegant (and much more durable ;o). I tried a
harmonic drive system in one of the many other attempts to make a
usable SynthMuscle, but it couldn't sustain any force.
email@example.com (Garrett Mace) wrote in message
Can you provide more details about these "Synthmuscle's"? What's the
principle of operation? How are they built? How can a hobbyist or
interested collaborator get one or build one? That's the first step, in my
opinon. Validate the effector technology. Without this I don't think you
have a project. Seriously.
I think the single most important component missing from the humanoid
arsenal is a device that can be made to behave like a biological muscle.
This doesn't just mean power/weight ratio, energy storage, efficiency, etc.,
but also things like having the ability to form it into many shapes and
sizes as well as having the device conform to the operating environment.
Not to mention such things as operating noise. A humanoid with hundreds of
motors might be interesting, but, if I have to wear ear protectors while
it's fetching me a cup of coffee it's a real deal-breaker.
This is a simple device. I have been holding off details until I
could get a decent sized group started (people are the hard part...you
Bascially, the SynthMuscle is an electromechanical device. It uses
two sets of coils (pinchers) to squeeze a kevlar ribbon (1/1000th of
an inch thick, 1/2 inch wide) to generate friction. Two other large
coils pull the ribbon being held by one set of pinchers to the other.
The distances are very tiny which enables it to work (fun with
magnetic math). The actual pull distance is on average around 1/1000th
of an inch.
The ribbon was the hard part. It is 200 kevlar filaments
side-by-side bonded with a UV curable acrylic. In order for it to
work, it had to be very thin, stretch less than 1%, be very strong,
and wear resistant.
Anyone can make this thing. It is not elegant, but it does work.
I will be posting the pictures, video, schematics, and notes on making
one this week.
Like I said, not complex. Just a starting point.
I can't wait to see your pictures. But I can't help but wonder why you'd
want to use coils (heavy) and magnetism (weak) instead of plates and
electric fields. If new technology is being developed here, wouldn't it be
more promising to explore the electric field as a purveyor of force, rather
- Owen -
Let me see if I understand what you are proposing.
1- A set of coils causes a mechanism to clamp onto the ribbon.
2- Once clamped, a second set of coils is energized and moves the clamp (and
ribbon) a very small amount.
3- At the end of the motion, a new clamp secures the ribbon at the new
4- The first clamp releases and is moved to the original position
5- The process is repeated.
It's a microstepping motor.
Well, the first problem is that the power you'll be able to generate is
proportional to the strength of the magnitic field. This, in turn, is
related to how much iron you have. If designing a DC motor that's one of
the limiting factors. Bigger magnets don't get you more power without more
iron. If you are not going to have any magnets then the field strength has
to be generated by burning energy, which is not very efficient at all.
I like high performance DC motors. If properly designed and operated they
can run at efficiencies apporaching 90%. That's pretty good. Still, if
you'll need, say, 5000W to run a robot full of motors, that means that you
will be burning, at the very least, 500W in wasted energy. The number is
probably many times worst due to the fact that all the other elements
involved will not operate at 100%.
Here's the funny thing. The mechanism you are proposing is almost exactly
how motion picture cameras work. Of course, this is done off a single motor
and using sprockets. The film is clamped between two plates. Claws engage
the film's sprockets. The clamp is released. The claws pull the film down
the the next frame. The clamps are activated again. This happens over and
over again at whatever frame rate the rig is being operated at. Lookup
"Geneva mechanism" on the web. I would suspect that this approach (meaning,
a single DC motor with some mechanics) is much, much more efficient than
what you are proposing. Efficient in terms of energy in -> energy out.
On a different end of the scale, ultrasonic motors can be thought of
operating on a very similar principle. I think they are really inneficient
though. Years ago I heard that a consumer camera (Cannon) used an
ultrasonic ring to actuate focus on the lens.
I do think that the secret is in small motions. Magnetics gets interesting
as the air gap is reduced. The biggest challenge yet might be that of
manufacturing something like this that can run these
clamp-pull-move-clamp-reset cycles at thousands of times per second and
I look forwards to seeing what you are going to post. Do you have any video
of a prototype in opeartion?
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