modeling tendons/cables

[2ms1]

Is there any way to model a cable? I have cables in my artificial
hand design that function like tendons running through teflon sheath
and going over a pulley or two. I would like to be able to model
how input/pull on cable results in curling of fingers but dont see any
way to do it. This surprises me just b/c well cables are so
common in engineering, I mean half of all the exercise problems or
examples covered in traditional Dynamics class in engineering school
involve cables and pulleys.



Someone I know said he tried using incredible number of tiny ball
joints to duplicate characteristics of cable but that it didnt work b/c
too much for computer to handle.



Has anyone here ever achieved functional model of cable?

 

[Israr]

use Pro/Cabling.


Israr

 

[2ms1]

My understanding is that Pro/Cabling is for electrical systems.
As in wiring harness design. Are you sure it is the way to
achieve dynamic, load-bearing cable design in mechanical systems?



But anyway, my department (ME department of grad school) doesn't have
Pro/Cabling readily available. I would like to achieve this in
Pro/E if at all possible.

 

[Zaki]

< = defer>


What type of cable u wanna model man?? just like a twisted steel wire rope of what??

 

[2ms1]

it's ptfe coated wire rope .026" thick. But I dont care about
exactly mimicking its flexibility, internal structure, friction, or
anything like. I just want it to pull through mechanism with
10lbs force as idealized cable. So when give input (pulling of
cable) of 10lbs force and couple inches displacement by external
actuator, finger curls.

 

[Zaki]

Sorry bro


I dont have sufficient knowledge for analysis and related problem. I think Israr may help u

 

[t_spraker]

I dont know if this will help but it is a simple sweep following a sketched datum curve chain as the trajectory. I set a relationmakingthelengthof d12 dependant on how d13 changes in length and thus the position of the block. For a more complicated pulley system you would have to calculate how lengths and or position of pulleys would change and make relations to control them. If you make the cable a separate part in an assy youwould have to be reference it to the pulleys.How it drives your model woulddepend on how it was assembled. Another posibility worth exploring mightbe to make the cable a flexible part.


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