how to define a marker motion correclty

Nicolas_20776

I try to control the motion in global X for the red cylinder (which has contact to the gray arm). 

"Marker 0" is fixed to the cylinder and want to give a velocity in X. But no matter what velocity i give (even when i give "0") the cylinder motion is only driven by the contact and the gravity. 

Is there a guideline how to apply marker motions?

Thanks

Nicolas

GTT Adam

Hi Nicolas,

You can learn more about defining motions with markers here:

https://help.altair.com/hwdesktop/hwx/topics/chapter_heads/motions_r.htm?zoom_highlight=motion

 

Also, this constraint will only effect the TX axis, so the object is still free in TY, TZ, RX, RY, and RZ. 

 

Hope this helps!

Adam Reid

Nicolas_20776

The marker motion x=0mm should prevent the cylinder tor roll down:

 

...but it has no effect.

And  i can not see any error or warning in the .log file....

 

What is wrong with MotionSolve or my setting?

find the .mdl attached.

 

Thanks for you help

 

Nicolas

GTT Adam

Nicolas_20776 said:

The marker motion x=0mm should prevent the cylinder tor roll down:

 

...but it has no effect.

And  i can not see any error or warning in the .log file....

 

What is wrong with MotionSolve or my setting?

find the .mdl attached.

 

Thanks for you help

 

Nicolas

Hi Nicolas,

If you want to constrain the cylinder to only move in the Z axis, you can create a translational joint that connects the cylinder to ground. 

If you want to allow translation in in the Z and Y axis, then you can instead create a planar joint.

 

If you would rather use the Motion method, then only a few changes are needed:

1. Create a new marker attached to ground at the same location as Marker 0 (Point 6).
2. Change the Motion definition to instead use the marker on the cylinder as the first marker and then new marker as the second marker:

 

Hope this helps!

Adam Reid

GTT Adam

Adam Reid_21142 said:

Hi Nicolas,

If you want to constrain the cylinder to only move in the Z axis, you can create a translational joint that connects the cylinder to ground. 

If you want to allow translation in in the Z and Y axis, then you can instead create a planar joint.

 

If you would rather use the Motion method, then only a few changes are needed:

1. Create a new marker attached to ground at the same location as Marker 0 (Point 6).
2. Change the Motion definition to instead use the marker on the cylinder as the first marker and then new marker as the second marker:

 

Hope this helps!

Adam Reid

Hi Nicolas,

If the above reply answered your question, please make sure to mark it as Correct so other Users may be able to find the answer easily.

 

Thanks,

Adam Reid

Nicolas_20776

can any one help me here do define a correct marker motion please?

Thanks a lot.

Nicolas

GTT Adam

Nicolas_20776 said:

can any one help me here do define a correct marker motion please?

Thanks a lot.

Nicolas

Hi Nicolas,

I already modified your model to provide the requested Motion.

It was attached to my previous post.

If you are unable to see it, make sure you are Showing all Replies (button at top of this page).

 

Hope this helps!

Adam Reid