How does this compare to Octave? (https://www.gnu.org/software/octave/)
Scilab is one of the two major open-source alternatives to MATLAB, the other one being GNU Octave.[1][2][3][4] Scilab is similar enough to MATLAB that some book authors (who use it) argue that it is easy to transfer skills between the two systems.[5] Scilab however puts less emphasis on (bidirectional) syntactic compatibility with MATLAB than Octave does.[1][6][7]
I'm a control engineer by training, and to be honest there's really no equivalent to Matlab/Simulink right now for control system design. Fortunately I'm currently working on statistics/sensor-fusion related stuff, and Python works just fine for that.