Creating A Roll Curve

[JMorton]

Hello,

I am trying to create a sliding door that rolls on a mechanism with two wheels. I am having trouble creating the kinematics for it. I simplified the modeling, but am unable to get the mechanism to roll along the rail. I have one degree of freedom but do not know what it is. Each wheel has a roll curve, only one has the command. there are revolute joints from the wheels to the link. The planar joint is between the link and the rail. I have attached a screen grab. The rail is fixed. If I add a command to the second wheel my DOF goes away, but I am unable to figure out a way to make both commands move at the same time. The rail is simplified. The actual rail will have curvature. Thank you if anybody can help me.

http://files.engineering.com/getfil...4b44-8b09-6f7a13c62b0d&file=ScreenShot012.jpg

 

[jackk]

Do you really need to see the wheels turning and the door slides on the track? Just make a prismatic joint between the door and the rail, and get on with a more productive use of your time.

 

[JMorton]

How would you make an object follow a curvature with a prismatic joint? It only allows for lines to be chosen.

 

[JMorton]

Part of the reason I need to do the simulation is to view the movement of the assembly to see if it clears a narrow gap the door must fit through. So it must be simulated how the link moves as it goes through the rail. Also it is a good thing to show to demonstrate how the apparatus functions.

 

[itsmyjob]

From your picture the rail is not curve, should we consider the rail to be curvy?

Eric N.
indocti discant et ament meminisse periti ​

 

[jackk]

Please attach a picture showing exactly what you are trying to simulate.

I'm guessing two points that follow a curve will give you what you need, but you'll have to add one or two other joints to keep the door vertical.