DMU Kinematics - How to move a kinematic joint

[Superwoman]

Hi,
Let's say for an example that I have a spherical joint connected to two points. I would like to be able to move the points to another position and that the mechanism joint would follow. But as it seems to work now; the joint remains in it's original position. It may still work, but the mechanism joint is located in the old position where the points were before, even though the points it is referred to is moved. This then causes incorrect motions of course, when the mechanism joint is not in the "real" ball joint in a linkage. So this means that I have to redo the mechanism joint by deleting it and make a new one. Which I really do not want to do! It is very time consuming when you have complex and big mechansim. Also, as all engineers, we update everything all the time... So we don't have time for this! Anyway, since I am editing the reference joints the link to them as reference should mean that the joint is updated to the new position as well. Is there anyone who have a solution for this?

Thank's for your support!

 

[MrCATIA]

First step: verify that the Joint is defined by the points you are moving, and those points belong to their respective part.

If the points are modified, the Joints should automatically follow, since they are defined based on Point.N and Point.M

 

[Superwoman]

First step: verify that the Joint is defined by the points you are moving, and those points belong to their respective part.

If the points are modified, the Joints should automatically follow, since they are defined based on Point.N and Point.M

Hi mrCATIA, thanks for your reply! Yes, I have checked that. Have you tested this and got it to work? What version of catia do you use? I was using V5 revision 20.

 

[MrCATIA]

Yes, I did a little test to verify that the Kinematic joint updated when the point was modified. I'm using V5R21.

Could you attach a screen shot of your mechanism, along with the tree branch showing the Joints?

 

[MrCATIA]

Superwoman, I did another little test today (4-bar linkage) and I had the same results as you. I opened one part in a new window and moved two points and one line. When I returned to the Kinematic window, I could see the geometry changes, but the mechanism was no longer connected. I noticed several update icons in the tree, in front of the assembly constraints and in front of the joints (one revolute and one spherical). Also, there was a Update icon in the Kinematic workbench menu, and UPDATE reattached the modified joints. (I could also right-click on each Joint and UPDATE one at a time)

I haven't done much kinematics for several years, so I'm a little rusty.

 

[Superwoman]

Thanks mrCatia! It works sometimes actually! I will have to look into my mechanism a little bit deeper, because it doesn't seem very reliable. Anyway, thanks a lot for you support!