Tfest

Transfer function estimation with frequency response. Python equivalent of MATLAB tfest (but the algorithm is not exactly the same)

Only works with SISO systems for now.

Installation:

pip install tfest

Example:

To get a scipy transfer function:

import tfest
# u: input
# y: output
te = tfest.tfest(u, y)
# n_zeros, n_poles
te.estimate(3, 4, time=1)
te.get_transfer_function()

"time" is simulation length in seconds. To plot its bode diagram:

te.plot_bode()

Default method to calculate the frequency response Y/U is H1 estimator, if you want to use H2 or frequency/frequency just set the method to "h2" or "fft" and specify the time length of the simulation (in seconds, default is 1):

te.estimate(3, 4, method="h2", time=1)
te.estimate(3, 4, method="fft", time=1)

To use L2 regularization set the value of lambda l1 (default l1=0):

te.estimate(3, 4, time=1, l1=0.1)