Questions about the PeriodicityGoal

[Alexandre Peres]

Hi everyone! I'm currently facing some problems when implementing the PeriodicityGoal on a cycling movement.

My first problem is that after simulating the first half of the cycling motion and requesting a createPeriodicTrajectory, the crank goes back to its initial position for the mirrored movement, making it behave in an unwanted way. Does anyone know how can I solve this problem other than manually changing the .sto file? I've attached an image of the crank at the end of the movement

My other problem, and it's been quite challenging, is the fact that once I create the periodic movement, my constraint forces are removed from the .sto file, making it impossible to use it as a guess for a following simulation. I've been using a file obtained from only the first half of the movement, and this one has the constraint forces. But I'm still having a hard time converging my problems. Does anyone have a suggestion on how I can obtain a better guess file?

[Nicholas Bianco]

Hi Alexandre,

The createPeriodicTrajectory utility assumes that the input trajectory is a symmetric half-period of a full periodic motion. Are you imposing symmetry in your cycling motion?

Your cycling model seems simple enough that you might consider simulating the full crank cycle while imposing standard periodic constraints.

-Nick