Mechanics and Construction > Mechanics and Construction

My Advanced Realistic Humanoid Robot Project

<< < (4/8) > >>

cyberjeff:
I saw this earlier today:

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_357641_-1

PDF: http://www.jameco.com/Jameco/Products/ProdDS/357641.pdf

Haven't got the hang of  this forum yet.

 
--- Quote from: mklrobo on July 22, 2015, 02:58:44 PM --- ;D Hello!
CyberJeff has some info;
Let me propose a very old method of mechanical energy controlling various devices, the same  method used in player pianos and those circus orchestras with all the doo dads. They work on a vacuum. Pistons would not need to be metal, they could be neoprene tubes that collapse. There are various possibilities. And some leakage would not be fatal.
That reminded me of some metal cords, called Nitrinol. These metal "strings" shrink when electricity is applied. Each thickness has a certain amperage draw, and pull of torque accordingly.

--- End quote ---

artbyrobot1:
I think both of those suggestions have HUGE merit and are very exciting possibilities.  I thank you both for bringing them up!  This vacuum neoprene idea and the Nitrinol wire idea have my attention.  Maybe one of them can be a plan b?  I'm already all in with my existing servomotor and pulley system plan having already bought a lot of what I need, already tested and done proof of concept, etc.  If you brought this up a year ago I might try it, however, I have to at least give the way I have been planning for over a year a try before trying anything else ya know?  I don't see why the way I am planning wont work.  Also, I agree it will be WEAK.  I can upgrade to more powerful higher voltage motors later though if I get more $.

One of my concerns with Nitrinol which I have looked into in the past is I haven't seen many projects using it and it isn't widely available from what I've seen.  It is very experimental and expensive and could have a lot of complications in terms of heat and electrocution possibilities... hmmm...

cyberjeff:

--- Quote from: artbyrobot1 on July 24, 2015, 09:25:51 PM ---I think both of those suggestions have HUGE merit and are very exciting possibilities.  I thank you both for bringing them up!  This vacuum neoprene idea and the Nitrinol wire idea have my attention.  Maybe one of them can be a plan b?  I'm already all in with my existing servomotor and pulley system plan having already bought a lot of what I need, already tested and done proof of concept, etc.  If you brought this up a year ago I might try it, however, I have to at least give the way I have been planning for over a year a try before trying anything else ya know?  I don't see why the way I am planning wont work.  Also, I agree it will be WEAK.  I can upgrade to more powerful higher voltage motors later though if I get more $.

One of my concerns with Nitrinol which I have looked into in the past is I haven't seen many projects using it and it isn't widely available from what I've seen.  It is very experimental and expensive and could have a lot of complications in terms of heat and electrocution possibilities... hmmm...

--- End quote ---

If you have proof of concept then you should run with it. The muscle wire is expensive and I think may be too slow and energy inefficient. The vacuum idea would require building things that are not off the shelf that have never been done. The advantage that air, or vacuum has is that it has energy storage, you can get a huge jolt of power and then wait for recovery. In my mind this is similar to the way most people use muscles.

I have given some thought to your idea of bands and servos, not that I wish to copy your project, but rather use it for a flexible spine. The bands would run through the spine and then outside where they would be tugged on by servos. Assuming the spine returns to a straight position, the curve of the spine with one servo could be modeled on a quadratic bezier. I would need 3 servos.

Since you have no flesh your robot could be relatively light, reducing forces needed. I think you may need to compromise between speed and servo size or by setting your pulleys as a force multiplier, probably you have already done that.

What are you casting with? How is  the weight?

I'm making my simple little toy out of cypress and find the skeleton weighs a small fraction of the total. I suspect you may have substantial weight.

Good luck to you and we await to see your progress!

artbyrobot1:
@cyberjeff  Thanks for the feedback and thoughts I enjoyed the read!  I too will have a flexible spine modeled after the human spine.  Also, I WILL have realistic silicone skin.  The bones are being made via clay sculpt and then a cast pulled from that made of composite material construction.  The total weight of the bones will be in the 2-3lb range I believe they are extremely lightweight and hollow.  I show in depth how I'm making the bones on my youtube: https://www.youtube.com/c/artbyrobot1  I hope you enjoy the project as it unfolds!

cyberjeff:

--- Quote from: artbyrobot1 on August 03, 2015, 04:33:51 PM ---@cyberjeff  Thanks for the feedback and thoughts I enjoyed the read!  I too will have a flexible spine modeled after the human spine.  Also, I WILL have realistic silicone skin.  The bones are being made via clay sculpt and then a cast pulled from that made of composite material construction.  The total weight of the bones will be in the 2-3lb range I believe they are extremely lightweight and hollow.  I show in depth how I'm making the bones on my youtube: https://www.youtube.com/c/artbyrobot1.  I hope you enjoy the project as it unfolds!

--- End quote ---

Sorry, link comes up 404.

3 lbs is pretty good.

As far as the realistic skin, I watched a documentary on Ray Harryhausen last night, it is phenominal what he did with latex and armatures:

https://en.wikipedia.org/wiki/Ray_Harryhausen

What fascinated me was how he got the motion right.

I don't understand why, if you are covering all this up with skin, why the bones have to be so true to form. It seems to me that the details are pushing the complexity and time frame way up.

I've been thinking a bit about twisted string actuators:

http://www.dexmart.eu/fileadmin/dexmart/public_website/downloads/presentations/USAAR-Workshop-A3.pdf

I think for the amount of micro detail and control you need those may be useful to you as they take up little room. For my purposes, it could pull a spine into a curve. I'm saving that for later, i just got a bunch of servos and  the Arduino Due so it is time for me to see if any of my ideas work!

Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version