.FailureModes.Chattering.ChatteringNoEvents2

Information

After t = 0.422, chattering takes place, due to the discontinuity in the right hand side of the second equation. The discontinuity does not generate state events, thanks to the noEvent operator.

If a variable-step-size integration algorithm with error control is used, the time step will be reduced to very small values once the discontinuity is hit, and this can be detected by monitoring the value of time at each time step.

Variable step size solvers usually allow to identify which state variable(s) give the biggest contribution to the error estimate (x, in this case), thus causing the step size reduction. The corresponding derivative shows very high frequency oscillations between two values.

The end user can then use the BLT navigation functionality of the debugger to investigate which variable/equation is introducing the discontinuity, that is, z = noEvent(if x > 0 then -1 else 1);