Learning the Quirks of DOF... Universal Joints

[jhVWRLB]

Hi Guys... Please can you help a newcomer to Fusion.  Struggling to get the joints connected for animation through a universal-joint.  Fine through the main joint, but cannot figure out how to constrain the flailing end without locking motion.  I'm hoping there is a better solution that setting many points in a 'motion study', which I did to approximate the result I wanted. Here is a link to the work-in-progress... Universal Joint Motion

[sachlene.singh]

@jhVWRLB 

Firstly, our apologies for the delayed response on this question.

I just wanted to let you know that we're working on it. A few of us have put our heads together and are working on what the best solution might be here. In the mean time, thank you for your patience.

[Anonymous · Accepted solution]

Wow, this is an awesome idea!  So I deleted all your joints and joint origins, then deleted some cylinder in timeline that turned red (not sure what that was).  And just applied as built revolute joints, and it works great!  Remember, when making an in place joint, to keep things simple first select the component that is to move relative to the other. For the joint position just be sure it's on the rotation axis in the right orientation. 

Let me know if you have any questions.  I can't get over how cool that universal joint looks working!

Jesse

[joel.palioca]

Hello,

It looks like @Anonymous has already provided a potential solution for your design, but I thought I would throw in what I worked out since it is a little bit different.

What I did was leverage the cylindrical joint for 3 of the 4 joints and used a revolute joint to provide the rotation while at the same time locking in the translation of the model.  Optimally I would have liked to use 3 revolute joints and only a single cylindrical joint, but I found a small problem that I will bring up with our team to work on resolving.  This should setup the design for its intended movement.

Cheers,

[Anonymous]

That's really interesting letting the joints be a little more forgiving, I even see a linear undulation in yours of that collar and less so of its shaft.  It did take two tries to get my exclusively revolute joints to not just bind up, so without cylindrical joints it's definitely on the edge of being functional.

Jesse

[jhVWRLB]

Thanks Jesse / Joel.  Really appreciate your responses.  I think one of the tricks I missed was applying the joints in order [ from drive to driven ] once the geometry was bedded in.  Somewhere in the process I tried to join each yoke with the swivel 'As-built' and then attach to the rigid frame, but that went nowhere.