Problem using .mat files (containing data recorded) as input

Hello to everybody.

I am pretty new in using Matlab and Simulink, so I lack knowledge and I hope my question will be clear.

In fact, I have to model a pretty simple half car model, so I have already implemented some first-approach/simple vertical and lateral behaviors, with corresponding Physical parameters saved in a Parameters .mat file. Plus, I have several correct data recorded from a real car with a data logger (from 0 to 180s) - such as steering angle, throttle pedal, gear position and brake pressure - with the same sampling rate (10Hz). Then, I saved each of these individually in a different and individual .mat file with the sampled time (so, with a time step of 0.1s), that I load in the Matlab Workspace.

But the problem arising is the following: I want to use these as input data to simulate the driver behaviour, so I creating a "From Workspace" bloc for each of them. But I cannot run the simulation properly: it crashes when I use a fixed time step solver, such as a Runge Kutta, and it doesn't runs properly when I use a variable time step one. I made some research on the internet, but I cannot find any proper answers to my problems, apart that it seems that it may be possible that one is thing is that the steps between the simulink solver and the ones specified don't match.

Don't hesitate if you need more information.

Thank in advance to the person(s) who will take time to help me to find a solution.

Clement