Over-constrained mechanism + number of joints

[Anonymous]

Hello everyone,

I am new on this forum and I hope that my question are relevant (and that you could help me).

• I am working on a robot assembly and I have some issues. I made this assembly and then I go to environment- Dynamic simulation, the software tells me that the mecanism is "over-constraint by 4-degrees". I don't know where to find the solution (which constraints create problem) and I don't know how to change them in order to keep the same "movment" of my mechanism.
• I also have another problem : I only grounded 1 element but in the assembly it tells me that  many parts of my assembly are grounded. What is the problem ?
• Finally I also have an issue : why are there so many standard joints ? People who work on the same project told me that they have less than 10 joints 

Thank your very much in advance for your answers

[CGBenner]

@Anonymous 

Welcome to the forums!  We're very glad to have you, and as long as you stick to the Inventor topic... your questions will be very relevant.  I hope you can find your answers. 

[JDMather]

An assembly must, of course, include parts.

In Inventor, parts are in the form of *.ipt files.

Without the *.ipt part files, the assembly *.iam file is completely useless.

(72) DSG 421 - YouTube

If automatic conversion of assembly constraints to Dynamic Simulation Joints is turned off - you will see a much larger list of Joint types.  If automatic is turned on - there is generally no need to see this expanded list of Joints.

Zip and Attach the folder of your entire project (including parts).

[Anonymous]

Thank you for your answer 

Sorry I forgot to put the parts. Here is the zip .

I just checked and the "automatic conversion of assembly constraints to Dynamic Simulation Joints" is on 

[JDMather]

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@Anonymous wrote:

Here is the zip . 

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You cannot Attach files via email Reply.  You must go to the web forum to Reply and Attach your zip folder - then double check to verify.

[Anonymous]

Sorry for my mistake

[JDMather]

In the real world - many of your components would be in sub-assemblies.

That is the first thing I would do with this assembly -- group components into logical sub-assemblies.

This will significantly reduce the number of Joints that have to be solved and make it easier to avoid over-constrained condition.

[Anonymous]

Thank you I will try to do that ! 

[JDMather]

Example - this should be one sub-assembly.

and this should be one sub-assembly.

Some of these sub-assemblies are probably also comprised of logical sub-assemblies.

Just like in the real world.

[BrendanG4AEBE]

I am getting the same error.

I am used to doing FEAs where I have to define the constraints.  Why does the dynamic environment tell me that I have this error as soon as I open up the dynamic simulation environment, before I have told it to do anything?  I have looked at a couple tutorials on youtube for the dynamic simulation, and I'm unable to follow because I get this error before the tutorials do step #1.

[CGBenner]

@BrendanG4AEBE 

Hello.  Since this is such an old post, would it be possible to elaborate on what errors you are seeing?  Maybe share some screen shots?  If possible, Pack & Go a small assembly that exhibits this behavior so the experts here can have a look.

Good luck!

[BrendanG4AEBE]

Looking at the tutorials, it seems like dynamic simulation is meant for pieces that are actually supposed to move, like pistons.  I am interested in a rigid body under vibration.  I asked ChatGPT about this, and it says that full analysis of forced loads is not possible in inventor.

This is the first time I tried to use this environment, and I guess I didn't understand what it was actually for.