Using the Ideal Translational Velocity Source

I have no problem prescribing an input force to a mass/spring system in SIMSCAPE. However, applying a prescribed displacement apparently is another matter. Apparently, there is no source element that exists in the SIMSCAPE/Foundation Library/Mechanical/Mechanical Sources in the SIMULINK library. However, I can use the Ideal Translational Velocity Source. I tried this, but not successfully. I have included the model in the .zip file along with the same model that has a prescribed input force. The model using the Ideal Translational Velocity Source generates an error concerning convergence of initial conditions.

"Initial conditions solve failed to converge. ...Dynamic states at start of simulation are not consistent. Set initial dynamic states consistently (for example, parallel capacitors must have equal initial voltages, and parallel masses must have equal initial velocities)."

Can anyone suggest how to do what I am attempting? By the way I am relatively new to SIMULINK & SIMSCAPE so I have little experience on configuring the solvers so that convergence issues are avoided. So if there is any good documentation on the issue please let me know. I did not find the HELP directory very informative.

Thanks for any assistance.

Answer 1

[Jeff]

I believe I figured this out. I changed the input signal so that it is smooth at time = 0. If the initial velocity is something other than ZERO then violation of the system @ rest causes the convergence problem.