overdefined mates w/flexible subassemblies 1

[KyleWilcox]

Hi guys. Check out this pic:

http://s92.photobucket.com/albums/l7/kylewilcox/trailer.jpg

What you see is a door on hinges, supported by two cylinders. The cylinders are (right now) made out of flexible subassemblies with a limitdistance mate for extension. With one cylinder it works fine... and with two cylinders it works fine (able to drag door open/shut with the cylinders extending/retracting quite nicely)... but with two, SW thinks it's overdefined and fills the feature tree with errors.

this is no big deal as I can do all the geo design with just one side, and I'm betting if I put the raw cylinder parts into the top level assembly it would work (by killing off those god-awful flexible subassy's), but for academics, I'm just curious how other people might assemble something like this?

apologies if harder searching would have given me some solutions...

-Kyle

 

[JMirisola]

Try creating a second configuration of the cylinder and kill off the limit distance mate in it. Switch one of your cylinders in the assembly to this second config and give that a try.

Jeff Mirisola, CSWP

http://designsmarter.typepad.com/jeffs_blog

 

[KyleWilcox]

Good thinking - Works like a charm! I tried a second config but didn't think of suppressing the overdefining mate in one of them (when I word it that way, it seems way too obvious... smack forehead). Thanks!

 

[drillrig]

Kyle,

This has been a thorn in my side for a long time now, since we use pairs of hydraulic cylinders all the time. I still haven't found a solution. I've tried various combinations of configurations, mate scenarios, etc. all to no avail. I also have problems with the cylinders "flipping" end to end for no apparent reason.

- Chris

Chris C. Mechanical Engineer
SW07x64 SP4.0
Dell 490, Xeon Dual Core, 8GB ram
Nvidia Quadro FX3500

 

[CakeMaster]

I've always had trouble with Limit Mates.

Whenever I create a subassembly of a cylinder, I make three configurations:

1) Fully Extended
2) Fully Retracted
3) Flexible

In your case, you could have one cylinder drive the position of the door by using the "extended" or "retracted" configuration. The second cylinder can just always be kept on the "flexible" configuration and *should* just follow the lead of the first cylinder. This usually works pretty good for me.

 

[KyleWilcox]

JMirisola's solution works fine for me; one cylinder has a limit mate (which effectively "constrains" that degree of freedom, the other cylinder has its own config with suppressed limit mate (so it doesn't further "constrain" things))

I had some trouble with SW not updating the flexible assemblies which made it seem like it wasn't going to work--I made another cyl config and suppressed the mate, but in the parent assembly the flexible cyl refused to update itself and the mate remained active(probably related to how it says, Flexible Assemblies cannot be edited in-place...) I had to suppress -all- cylinders and unsuppress them to make the assembly reload it and have the mate suppressed in one config.

They work gorgeous now.