Model Error

[Connor Stapp]

While I was working on a model, I hit the simulate button at the top of OpenSim (green running dude). When I hit the button, the model would run for a short time but then an error would pop up.


The error that I would get is:

ForwardTool::run() caught exception
SimTK Exception thrown at AbstractIntegratorRep.cpp:428:
Integrator step failed at time 0.0622917597385693 apparently because:
SimTK Exception thrown at AbstractIntegratorRep.cpp:547:
Error detected by Simbody method AbstractIntegrator::takeOneStep(): Unable to advance time past 0.0622918.
(Required condition 't1 > t0' was not met.)

Could anyone explain this error to me?

[shayan moradkhani]

hi,
well i had the same problem. in my case i had prescribeFunction for one of my coordinates and my function values were not matching the coordinate ranges; so i just simply changed my function values to be in the range of my coordinate limits.
hope this points out something for you.
regards
Shayan

[Thomas Uchida]

There are a few possible explanations for an integration failure. This particular error message indicates that the (variable-step-size) integrator detected an unacceptably large change in a state variable, but was unable to prevent an unacceptably large change from occurring despite reducing the size of the time step to something tiny. Something bad is happening. You might be able to track down the issue by plotting states and other variables, and looking for values that are approaching infinity, zero, or some other prohibited value.