How to get the instantaneous step size value in variable step solver at a simulink model?

I got a problem to get the value of instantaneous step size value in variable step solver. In my simscape model there is also a runge kutta solver function that I wrote and I need a h value which is a h=step_value/10. I dont want to use fixed step solver. That is why I need to know step value for each time step.

Answer 1

[Yifeng Tang]

If you turn on data logging for Simscape, you can access the time marks in the states data for each block. Any block will give you the same time array. More details here: https://www.mathworks.com/help/physmod/simscape/ug/log-and-plot-simulation-data.html

The time information should also be available in Simulink tout variable, depending on your model settings.

One example:

ssc_mass_spring_damper_sl;  % open a simple Simscape example

Run the model. Then in the results:

time = simlog_ssc_mass_spring_damper_sl.Spring.x.series.time;      % time
X = simlog_ssc_mass_spring_damper_sl.Spring.x.series.values('cm'); % displacement in specified unit
time2 = tout;  % same time info

If you want to see which block is limiting the time steps, try the Solver Profiler: https://www.mathworks.com/help/simulink/ug/examine-solver-behavior-using-solver-profiler.html