Mechanism

[jiabao]

Dear Friends,


I have Mechanism which are composed of linkages. My query is that how to make one of my linkage stop when it touch to a circular surface. I'm just dragging the linkages and one of the linkage will touch to the circular stopper and what's going on is it continue to move?


Thanks in advance.

Jiabao

 

[Guest0527211403]

Jiabao

There are two ways to do this:

1) Use a Cam connection
-The Cam connection is in Mechanism mode. You need to specify the two surfaces which are to collide. This will not work if your circular stopper is actually spherical. Cam connections only work on surfaces that are curved in one direction, or flat surfaces. You also need to specify that you want to allow liftoff (in the cam connection dialog box). The coefficient of restitution determines the relative amount of energy lost in the collision. This only matters with Dynamic analysis (with forces), and not kinematic analysis (just velocities and accelerations).

2) Set Joint axis limits
- In mechanism mode, you can set the limits of a joint axis (the little yellow icons that show up where the parts are connected). If you limit the motion of the right axis, you can effectively simulate a collision.

Hope it helps
Mark

 

[mloew]

Jiabao,

As usual, Mark has given two excellent suggestions. The cam is preferential if you can live with the limits he detailed. Setting joint limits is good, but if the geometry changes, the limits are not yet parametric in Wildfire 2.0.

An additional way might be in using MDO (Mechanism Dynamics Option) functionality. You may be able to create a custom load that will approach infinity as the distance between the objects gets close to zero. This would have the effect of stopping the motion at that point.

Good luck!




Best regards,

Matthew Ian Loew


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