locked motion skeleton mechanism

[solidworm]

here's a "peaucellier" mechanism using motion skeleton.but there's a problem. rotating the red link in picture below, the point at A12 should trace an arc. but the mechanism is locked. can anybody help?(everything is connected using pin joints)

Edited by: solidworm

 

[rklatte]

I took a look at this and I think that ground references were being used accidently. I rebuilt the body skeleton models and even though I was very
careful in selecting the references Pro/E still grabbed a ground reference (axis) when it shouldn't have.

I also changed the length of the long arms to make it easier for me to figure out what was going on (from 75 to 100)

I'm attaching the model (it's in WF5, if you need in WF4 I can redo it but it'll have to wait until later

)

2010-09-15_083506_peaucellier2.zip

 

[solidworm]

thanks alot. well done.

i'll compare the models to see what went wrong.

 

[solidworm]

yes you are correct. in my model, ProE has copied A_8 and A_15 to the ground part and has made reference to them in some of the assembly joints. i removed those extraneous pin joints and it worked!
there is one other issue. because there are 2 ways to assemble this mechanism during motion simulation, ProE sometimes selects one and sometimes the other. here's the two possible motion animation: (first one is the intent)
first one
second one
is there a way to see different possible solutions when assembling mechanisms like this?



Edited by: solidworm