Animating 2 DOF assemblies

srinath_mallikarjunan808

How do we animate assemblies with 2 degrees of freedom in Onshape ?

For example...
A helicopter swash plate. Main rotors spin around a central axis, but swash plate can independently move up and down. As the swash plate moves up and down, pitch of the blades change.

The rotational motion of the shaft and linear motion of the swash plate are 2 independent mechanisms.. how can i animate them together ?

Even if i were able to animate the rotation of the shaft, while moving the swash-plate up and down, it would be a good step.

michael_mcclain

You may want to check out cylindrical mate. It allows rotational degrees of freedom and a Z-axis linear degree of freedom.

Or maybe use a slider mate for only the Z-axis linear movement of the swash plate and use a parallel mate to lock the swash plate Z-axis rotation with the blade rotationaround the rotor shaft Z-axis. Then you can add ball mates to each end of the linkage to have realistic blade pitch depending on the Z-axis linear movement of the swash plate.

Don't forget that you can modify a mate connector after a mate has been placed. Just go to the mate in the assembly tree and click the flyout arrow to see and modify mate connectors

owen_sparks

(a) I believe you will be able to use a gear relationship to drive the pitch of the blades relative to the position of swash plate.(Probably one gear per blade)

(b) I don't think we can animate 2 independent mates as of today.

philip_thomas

I know a little about helicopters - set the swash plate angle and the driving input is the shaft.
The blades will rotate and change pitch.  BOOM!

MBartlett21

@philip_thomas
Is that document public?
Can you share a link?

philip_thomas

@mbartlett21 - its now public

https://cad.onshape.com/documents/9024fe81f0f94c443f2725e0/w/21ab1ee7ef137b53f759693c/e/a74127d48228c26ad4a5b1c2