Mechanism and multiple linkages

[mprice214]

Hi all,



I'm having a problem in WF2 with a kinematic mechanism analysis.
I'm trying to show a "pretty picture" and have different linkages move,
so I'm not doing an analysis, but just assigning motors to different
pin joints. Anyway, the problem is that I have two linkages and
the first linkage is connected with a pin join to a grounded
body. I've attached a motor to that joint and that works
fine. I have a second linkage attached to the first with a pin
joint and again have created a motor. The problem I'm having is
that when I run only the second motor, it also moves the first
linkage. In fact, I can't see a pattern to the motion of the
first linkage. The second linkage moves fine, but its the first
linkage that I don't want arbitrarily moving during the second
linkage's motion.



Any ideas?



Thanks,



Mike

 

[slashct]

Can you post an image so we can get a better feel?

 

[Mloew]

When you run only one servo motor the mechanism is underconstrained. This is a 2 DOF system; and therefore need two servo motors to obtain the motion you desire.

 

[mprice214]

Thanks Matthew. That did the trick.

 

[Mloew]

You are welcome. One trick I did not mention is you can have "extra" servo motors that are constant zero (or other fixed values). This way you can leave in the one servo motor with the profile of interest and leave the others fixed to isolate the DOF you are interested in.