assembly issues

[Anonymous]

Hi

Iam modelling an excavator type arm, iam having issues when rotating it into the different positions in assembly mode. I have set the cylinder strokes up with limit constraints, now I want to stop the cylinders going overcenter as they are in the below screenshot. would this be solved by some kind of an angular limit?

 

My other problem is with flexible hoses, I am trying to model the hoses as built, my problem is that everytime i move the assembly into a new position the hoses adjust and shorten, is there any way of keeping the hoses a fixed length so that they bend/stretch as they would in reality?

any help is more than appreciated,

Cheers.

[blair]

If the cylinders are properly modeled you should be able to control their movement with contact sets. One set utilizing the end face of the piston and the end plate of the cylinder housing. The other the rod end face of the piston and the inside end cap of the cylinder.

[karthur1]

I've seen it do that exactly that with the limits on a constraint.  About all you can do is suppress the constraint and move the parts back into their correct range of motion, then activate the constraint again.  I have not found a bullet-proof way to avoid this.

I have tried to use angular constraints too, but they get turned inside out as well.

It looks like you are probably after flexibility (so you can move the arm through its motion), but you could setup positional reps for each of the cylinders on the arm.  Make one for each cylinder fully extended and fully retracted.  Plus, the positional reps will help you when you start to document the model too.

http://wikihelp.autodesk.com/Inventor/enu/2013/Help/1310-Autodesk1310/1655-Assembli1655/1731-Represe...

[mcgyvr]

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@karthur1 wrote:

I have tried to use angular constraints too, but they get turned inside out as well.

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Not if you use the "explicit reference vector" option angular constrain. That used to happen before when they only had the directed angle option.

[Anonymous]

To solve your issue with the hydraulic hoses, try adding route points on both sides of the hinge. Set the offset of the points so they don't move relatuve to the linkage members, and the length on either side should stay the same. This may take a few iterations to get it set correctly.  You'll want to make sure you keep an eye on how close the points are to each other so you don't get an error due to the minimum bend radius.