Frequency Response Analysis
The Frequency Response Analysis computes the frequency response from an input analysis point to one or more output analysis points in a model. This is useful for identifying system dynamics, resonance, and bandwidth, and for validating models against experimental data.
Method Overview
Frequency-response analysis excites the system with a wide range of frequencies (chirp or multisine) and estimates the transfer function from a specified input to one or more specified outputs over the selected frequency range. The result is typically visualized as a Bode plot (magnitude and phase).
Chirp excitation: A single frequency-swept signal, fast and efficient for most systems.
Multisine excitation: Multiple experiments are performed, each one with a different frequency. This alternative is typically slower but more accurate.
Analysis Arguments
The following arguments define a FrequencyResponseAnalysis:
Required Arguments
model: The model to be analyzed.input::String: Name of the input analysis point.outputs::Vector{String}: Names of the output analysis points. Can be a single output or multiple outputs for MIMO analysis.wl: Lower frequency bound for the analysis.wu: Upper frequency bound for the analysis.
Optional Arguments
input_type::String = "chirp": Type of excitation signal, either"chirp"or"multisine".num_frequencies::Int = 50: Number of frequencies (only for"multisine").duration::Float64 = -1.0: Duration of the experiment (for chirp). If -1, use default.Ts::Float64 = -1.0: Sample time for the experiment. If -1, use default based on the frequency range.
Artifacts
A FrequencyResponseAnalysis returns the following artifact:
Standard Plot
BodePlot: Bode plot (magnitude and phase) of the transfer function from input to each output.