Transferfunktionsmodelle

Transferfunktionsmodelle beschreiben anhand eines Polynom-Verhältnisses die Beziehung zwischen den Eingängen und Ausgängen eines Systems. Die Modellordnung entspricht der Ordnung des Nenner-Polynoms. Die Wurzeln des Nennerpolynoms werden auch als Polstellen des Modells bezeichnet. Die Wurzeln des Zählerpolynoms werden als Nullstellen des Modells bezeichnet.

Die Parameter des Transferfunktionsmodells sind dessen Polstellen, Nullstellen und Transportverzögerungen.

In kontinuierlicher Zeit weist ein Transferfunktionsmodell die folgende Form auf:

$Y (s) = \frac{n u m (s)}{d e n (s)} U (s) + E (s)$

Hier stellen Y(s), U(s) und E(s) die Laplace-Transformationen des Ausgangs, Eingangs bzw. Rauschens dar. num(s) und den(s) stellen die Zähler- und Nennerpolynome dar, die die Beziehung zwischen dem Eingang und dem Ausgang definieren.

Weitere Informationen finden Sie unter What Are Transfer Function Models?

Apps

System Identification

Identify models of dynamic systems from measured data

Funktionen

alle erweitern

Erstellen eines Transferfunktionsmodells

`idtf`	Transfer function model with identifiable parameters
`tfest`	Estimate transfer function model
`pem`	Prediction error minimization for refining linear and nonlinear models
`spectrumest`	Estimate transfer function model for power spectrum data (Seit R2022b)

Modellinitialisierung und Strukturparameter

`delayest`	Estimate time delay (dead time) from data
`init`	Set or randomize initial parameter values

Extrahieren oder Festlegen von Modellparametern

`tfdata`	Access transfer function data
`getpvec`	Obtain model parameters and associated uncertainty data
`setpvec`	Modify values of model parameters
`getpar`	Obtain attributes such as values and bounds of linear model parameters
`setpar`	Set attributes such as values and bounds of linear model parameters
`addMinPhase`	Add minimum phase to frequency response magnitude (Seit R2022b)

Festlegen der Transferfunktionsmodell-Optionen

`tfestOptions`	Option set for `tfest`
`spectrumestOptions`	Option set for `spectrumest` (Seit R2022b)

Themen

Grundlagen zu Transferfunktionsmodellen

What Are Transfer Function Models?
Transfer function models describe the relationship between the inputs and outputs of a system using a ratio of polynomials.
Estimate Transfer Function Models in the System Identification App
Use the app to set model configuration and estimation options for estimating a transfer function model.
Estimate Transfer Function Models at the Command Line
General workflow for estimating transfer function models at the command line.
Data Supported by Transfer Function Models
Characteristics of estimation data for transfer function identification.

Schätzen von Transferfunktionsmodellen

Estimate Transfer Function Models by Specifying Number of Poles
This example shows how to identify a transfer function containing a specified number of poles for given data.
Estimate Transfer Function Models with Transport Delay to Fit Given Frequency-Response Data
This example shows how to identify a transfer function to fit a given frequency response data (FRD) containing additional phase roll off induced by input delay.
Estimate Transfer Function Models with Prior Knowledge of Model Structure and Constraints
This example shows how to estimate a transfer function model when the structure of the expected model is known and apply constraints to the numerator and denominator coefficients.
Estimate Transfer Functions with Delays
This example shows how to estimate transfer function models with I/O delays.
Estimate Transfer Function Models with Unknown Transport Delays
This example shows how to estimate a transfer function model with unknown transport delays and apply an upper bound on the unknown transport delays.

Fehlerbehebung für die Frequenzdomäne

Troubleshoot Frequency-Domain Identification of Transfer Function Models
Improve frequency-domain model estimation by preprocessing data and applying frequency-dependent weighting filters.

Modellinitialisierung und Strukturparameter

Transfer Function Structure Specification
Specify the values and constraints for the numerator, denominator and transport delays.
Specifying Initial Conditions for Iterative Estimation of Transfer Functions
Specify how initial conditions are handled during model estimation in the app and at the command line.

Enthaltene Beispiele

Estimating Transfer Function Models for a Heat Exchanger

Estimate a transfer function from measured signal data.

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Estimating Transfer Function Models for a Boost Converter

Estimate a transfer function from frequency response data.

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