FrequencyResponse

class sharpy.postproc.frequencyresponse.FrequencyResponse

Frequency Response Calculator.

Computes the frequency response of a built linear system. The frequency will be calculated for the systems specified in the target_system list. The desired frequency_unit will be either w for radians/s or k for reduced frequency (if the system is scaled). The frequency_bounds setting will set the lower and upper bounds of the response, while num_freqs will specify the number of evaluations. The option frequency_spacing allows you to space the evaluations point following a log or linear spacing.

If compute_hinf is set, the H-infinity norm of the system is calculated.

This will be saved to a binary .h5 file as detailed in save_freq_resp().

Finally, the quick_plot option will plot some quick and dirty bode plots of the response. This requires access to matplotlib.

The settings that this solver accepts are given by a dictionary, with the following key-value pairs:

Name	Type	Description	Default	Options
folder	str	Output folder.	./output
print_info	bool	Write output to screen.	False
target_system	list(str)	System or systems for which to find frequency response.	['aeroelastic']	aeroelastic, aerodynamic, structural
frequency_unit	str	Units of frequency, w for rad/s, k reduced.	k	w, k
frequency_bounds	list(float)	Lower and upper frequency bounds in the corresponding unit.	[0.001, 1]
frequency_spacing	str	Compute the frequency response in a linear or log grid.	linear	linear, log
num_freqs	int	Number of frequencies to evaluate.	50
compute_hinf	bool	Compute Hinfinity norm of the system.	False
quick_plot	bool	Produce array of .png plots showing response. Requires matplotlib.	False

run(ss=None)

Computes the frequency response of the linear state-space.

Parameters:ss (sharpy.linear.src.libss.ss (Optional)) – State-space object for which to compute the frequency response. If not given, the response for the previously assembled systems and specified in target_system will be performed.

save_freq_resp(wv, Yfreq, system_name=None, hinf=None)

Saves the frequency response to a binary .h5 file.

If the system has not been scaled, the units of frequency are rad/s and the response is given in complex form. The response is saved in a [p, m, n_freq_eval] format, where p corresponds to the system’s outputs, n to the number of inputs and n_freq_eval to the number of frequency evaluations.

Parameters:

• wv (np.ndarray) – Frequency array.
• Y_freq (np.ndarray) – Frequency response data [p, m, n_freq_eval] matrix.
• system_name (str (optional)) – State-space system name.
• hinf (float (optional)) – H-infinity norm of the system.