CATIA V5 DMU Kinematic workbench (Resolving the over DOF=0 condition~)

3D Design
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1

Help me~
In CATIA V5 « assembly workbench » and « DMU Kinematic workbench ».
I made strut ball joint with van model.
But there is no problem after « Manipulate » in « assembly workbench ».

image

But after running simulator in DMU Kinematic workbench (Of course DOF = 0)
nothing moved~rotated~~!
(I think the root cause is maybe over constrained DOF = 0~!~
But I don’t know where is the over DOF problem~)

Help me~~~

2

Hello @B_B ,

I don't know CATIA and its " kinematics workshop", but just reading this document is revealing.

The kinematic model can be defined in two ways:

  • either by converting geometric constraints into bonds,
  • or by declaration/definition of the links.

In the first case, if superabundant constraints have been defined for the purposes of the geometric model, they are converted into connections that may prove to be incompatible with the expected motion. This seems to be confirmed by the indication DOF = 0.
And even if mobility is okay, hyperstatic nature may be difficult to manage.
The second method makes it possible to define only what is strictly necessary in terms of connections, which is much safer.

The same problems and their solutions exist with the " mechanical " applications of Solidworks...

6

Good evening @B_B ,

French from France, not from La Belle Province.
image

My SW model in 2019 version is in the attached zip, as well as a Word document to clarify certain points. I don't see what I can add...

Happy New Year's Eve, and all my wishes for the new year.
Van_Kine2_2019.zip (2.5 MB)

9

Hello

Sorry, I made a mistake when selecting the attached document.
It's fixed in my previous message, the zip file is now downloadable...

About a video: while the basic principles of modeling are similar for Catia-DMU-Kinematics and for SW-Meca3D, the practical approaches to creating mechanical entities are significantly different, and a video made with one of these applications will not be of much use to the other.
In addition, I encourage you to explore the help of Catia's cinematic workshop which seems very complete and detailed, as well as the tutorials that accompany it.

And out of caution, I don't give my email address on a public forum... :frowning_face: