Derivative input is Inf

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Ibrahim Seleem
Ibrahim Seleem on 8 Sep 2015
Commented: Sofia Carvalho on 12 Apr 2017
I face a Simulink problem at the input of the integration block, which is:
Derivative input 1 of 'test_ahmed/Integrator' at time 0.003375 is Inf or NaN. Stopping simulation. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)
However,the input of the integration block is not infinity according the scope.
The model belongs to sliding mode control of biped robot in single support phase.
attached with the message simulink model..
Thank you!

Accepted Answer

MUHAMMED FASIL on 28 Sep 2015
Edited: Walter Roberson on 19 Oct 2015
Error with attached model.
  1. Use 0.000000001 or so instead of 0 in Integrator initial condition box. Try reducing or increasing number of zeroes until your model runs fine.
  2. Use a delay block in front of "division" block.
Otherwise send ur model to
Sofia Carvalho
Sofia Carvalho on 12 Apr 2017
I have a similiar error, I guess:

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