Constraints for double pendulum in SimScape

Hello,

I have a problem that a double pendulum represents quite well. I want to have constraints such that the angle (relative to the frame) of the first body is a function of the angle of the second body (relative to the first body). That would mean if I rotated the second body by applying a torque the first body would rotate by this user defined constraint. Is there a possibility to define such constraint ? Thank you for the answers.

[Lorenzo]

Hello Ondrej,

Not quite sure if this is what you need but you can "actuate" a revolute joint (which would be the joint used in your double pendulum example), by giving it an input-angle (the resulting torque will be computed automatically).

In turn the angle might be measured from another joint by using the "Sensing" field.

Does this answer your question?

Best,

Lorenzo

[Ondrej Zoufaly]

Yes I used sensing position from the joint of the second body as motion input to the first body. There was a warning because of Algebraic loop, but Matlab has some algebraic loop solvers so it worked. Nevertheless I used Algebraic Constraint to build my angle constraint (I can use scope to see if the input into the Algebraic constraint is near 0 to check that my constraint is fulfilled). It works so far so I think I figured it out. Thank you for your answer.

Ondrej.