CoordinateCouplerConstraint Forces?

Jonathan Mortensen · Post by **Jonathan Mortensen** » Sun Jul 01, 2018 2:54 pm

I am getting surprising results using the coordinatecouplerconstraint.

When muscle A is attached to body A, it cannot apply any moment to coordinate 1.

I then created body B that connects to body A through a custom joint. Body B is constrained to rotate about body A through a coordinatecoulerconstraint according to a function of the independent coordinate 1.

I then switched the attachment of muscle A to body B. Here is the surprise: muscle A now applies a moment to coordinate 1!

This doesn't make sense to me. How can muscle A apply any moment to coordinate 1? The muscle is attached to a body that is not connected in any way that I can see to coordinate 1. If I remove the coordinatecouplerconstraint, muscle A can no longer apply moment to coordinate 1.

Does the coordinatecouplerconstraint apply moments to both the independent and dependent coordinate?