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approaches to modeling this part?

ok... here is my one hour and 20 minute version of the tip of the finger.


terminator001.jpg



I guess if I had more time I might do more research on that bone at the tip of the finger. I did not spend alot of time with tangencies either. But this is a first run at her.
Edited by: design-engine
 
Hey Bart, looks like an excellent start. Great to see people being so helpful
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If only I had my own personal " Bart " to sit next to me for a few days
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HI !!
I think you can use also , like someone told you , the ISDX style feature in specific with some bitmap references and than use Trace Sketch to take the primary lines. It's very powerfull and easy to use , the only taught thing is scaling & positioning correctly the bitmaps.
Bye
 
hand_right_070912ab.jpg
hand_right_070912ab.jpg
I've been intermitently working on an adjustable model of a human hand. My objectives are slightly different and I'm having some trouble deciding how to sort out the thumb connection, but I started with a polygon model from http://www.cc.gatech.edu/projects/large_models/hand.html.

View attachment 4348

Here is my current Pro/E model with an the original facet data included 2007-10-29_052814_hand_right_070912ab.prt.zip

I've reduced the number of facets in my model to speed things up but I guess you could use it by removing the unwanted data and creating a surface in Restyle, or you could use a combination modelling technique by taking some cross-sections then re-create the bone using boundary blends.

If anyone can sort out the thumb joint, I'd be intereseted to hear.

All the best,

Sam
 
Interesting. The thumb will be a lot less difficult than the wrist if you really intend to make those carpals work (a bunch of cam follower and sliding connections I guess -- a lot). I'll show you what I'm doing for thumb joint once I'm done in a day or so. The thumb does have the annoying little characteristics of being able to move basically as a ball joint yet not having the rotation about center axis part, and then the thumb also sorta flips upside down during its travel (ie notice when you stick you fingers all out straight the fingernails are all on top but when your thumb is all the way don, it is flipped ofver with nail underneath). Anyway, I've got something that's working.
 
I was intending to simplify the wrist by assuming it works as a ball-joint with the pivot centre near the end of the radius where I've got a sketched circle on the CAD model.

To start with I'm just trying to get a single part that I can adjust by altering the dimensions. A mechanism would be useful in some cases, but a hand that I can alter to fit different products would be a good start.

Sam
 
I would think for a bionic hand the limbs however small would be exaggerated somewhat so silicone acting as tendon would adhere. The sinew having something to leverage if you will. I don't think the human bones are exactly what the bionic hand would evolve as. Maybe at first.




Edited by: design-engine
 
The shadow one looks nice but in reality it isn't really capable of doing anything. The mckibben actuators can only handle 60psi each and look how small they are. They're light, but they have lower power density than even steel pneumatic actuators. This means the hand is very weak and must not be able to do much more than merely manipulate (as opposed to doing any real work) very light things.


Also, mckibben actuators are highly nonlinear. 24 DOFs would be a nightmare of control problem. Throwing in the least nonlinear pneumatic actuators not such good idea.


Lastly, with all the DOFs, the pneumatic switching componentry alone (aside from the structure, actuators, etc) would never fit in the volume of an amputees limb. It's clearly only for theoretical work on some kind of testing platform. Presently, we are only able to get about 2 DOFs of input fromhuman neurology through EMG.
 
I've just come back to the human hand project I was working on and wondered if anyone else had made much progress?

Sam
 
design-engine said:
ok... here is my one hour and 20 minute version of the tip of the finger.


terminator001.jpg



I guess if I had more time I might do more research on that bone at the tip of the finger. I did not spend alot of time with tangencies either. But this is a first run at her.
Click to expand...

still, I consider Bart`s model and his approach as most accurate

pic above shows curves network, two more like this and the rest is the effort from "our(*)" side to make it by "ourselves(*)"

*these I consider as all intersted in users, like me
 
that took probably 20 or 30 minutes. www.cmu.edu was mentioned at the conference this week quite a bit. I told PTC they need help with their surfacing in the robotics department. Mayby they get some free help from some PTC guys?

Edited by: design-engine
 
another approach... video uploading now to youtube now. search bionic finger .... Did I foget to say the WF4 is bad ass


bonicfinger600.jpg


With this technique I am using the new Surface Edit tools like on the face modled in five minutes post a few days ago.

<a href="http://youtube.com/watch?v=JlItVD2oeM8" target="_blank">
http://youtube.com/watch?v=JlItVD2oeM8</a>
The video is up there. Surface Edit tools
and surface manipulation in ISDX WF4.0


Edited by: design-engine
 
we don;t sell software or anything, but I am told that design engine is responsible for a significant number of ISDX sales. VARS still hate us maybe because we actually use Pro/E ;)

Someone should still make fun of my Atlanta accent in the video.


Edited by: design-engine
 
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