YALTA and YALTAPy are MATLAB and Python toolboxes, respectively, dedicated to the stability analysis of (possibly fractional) delay systems with commensurate delays
given by their transfer function. YALTAPy can also be used through YALTAPy_Online, a graphical user interface based on Jupyter Notebook widgets and available for online use thanks to the Binder service.
The questions YALTA and YALTAPy can answer are:
- In the case of neutral systems
- Find the position of asymptotic axes.
- If the imaginary axis is asymptotic axis, find if the asymptotic poles of the chain are left or right the imaginary axis.
- In the case of retarded systems or of neutral systems with asymptotic axes in {Re(s) < 0}, find:
- For a given delay, the number and the position of unstable poles.
- For which values of the delay the system is stable.
- For a set of values of the delay, the position of unstable poles (root locus).
- Find (for non fractional systems) the coprime factors (N, D) of the transfer function as well as an approximation (Nn, Dn) in H∞-norm
