Assembly Constraints Question

[Laurel]

I'm designing a part that can be likened to the arms on a clock, in that an arm is pivoted on one end to rotate around a face plate. I've constained everything ok in order to achieve this.

 

Now imagine the clock with a peg on 6, so that the arms of the clock rotate around until they meet the peg, where they cannot pass and therefore stop.

 

At the moment, my model simply rotates around the pivot, but passes through the peg. Is it possible, or even genarally desirable, to place a constraint so that the arm stops when it reaches the peg?

 

Thanks in anticipation!!

[shift1313]

you can turn on the contact solver which will make it stop on impact. What are you trying to get out of the model? Do you want an animation showing this motion?

[JD Mather]

Contact solver will give you basic results - if you are after something more sophisticated you might need 2d or 3d contact joints in dynamic simulation (Inventor Professional).

[Laurel]

Thanks very much for the replies. I knew there was a reason why I considered you both my most reliable forum members

 

I've never come across the Contact Solver or the Drive Constraint option before - it looks very interesting, but it's not quite what I had in mind.

 

When I make my assembly and apply constraints, it is possible for me to 'grab' and 'drag' a part, and watch its motion in relation to constraints I have applied. As I drag the arm, it rotates around the pivot, but passes through the peg. Unless I am mistaken, I can only use the contact solver as part of the 'drive constraints' option, and not when I grab and drag as described above.

 

Is this collision detection while manually manipulating the model possible?

[shift1313]

in your assembly window you can grab and drag any part you wish(thats not grounded) and the assembly constraint will act like they should. If you turn the contact solver on, when you hit a solid object(thats defined as a contact set) it will stop. For instance if you drew two boxes that were only constrained to a plane, and you moved one box around it would push the other one.

[Laurel]

Thanks again for the help Shifty.

 

The picture shows my assembly, which is a device for measuring the angle at the corner of a window frame. The upper part rotates upon the lower part. The angle can be read from the graduations on the lower part. If the upper part rotates far enough around, it will collide with the extrusion on the lower part.

 

In this case, the assembly is part of a college project. I want to be as complete and accurate as I can when I submit the model, and so want to constrain it so that the upper part stops when it hits the lower part.

 

I've looked into the contact solver settings you recommend, and I seem to be having problems. When I select 'activate contact solver' from the tools menu, nothing seems to happen. Not even a tick next to 'activate contact solver' to indicate it is on. Neither can I find an 'Interactive contact' option as described on this page...

 

leake.ge.uiuc.edu/AI8/Autodesk%20Inventor%208%20Materials.doc

 

on the assembly tab of the application options window, as shown in the attached picture. I acknowledge that the doc linked above is for inventor 8, but the 2009 help (search for 'component collision and contact') also refers to the same option.

 

Any suggestions?

[shift1313]

in the feature manager you need to right click on the name of each part you wish to make part of the contact solver. In the pop up menu down where you have Grounded, Flexible, Adaptive and so on there will be a Contact Set option. You need to tell Inventor which parts you want to include for the contact set. After you have selected both pieces(the stationary one and the rotating one), turn on the contact solver and see if that works.

[JD Mather]

If you can't figure out Contact Sets and the Contact Solver (not the Collision Detection in Drive Constraint) attach your assembly here.

[Laurel]

Thanks once again, Shifty and JD for your help. Very appreciated as always

 

Your comments helped to clarify the situation, and I am now (more) familiar with the contact solver and contact sets.

 

My unfinished work has been graded as heading for a A grade, so I must be doing something right - With your help!