Linearize at Trimmed Operating Point :: Linearization (Simulink® Control Design™)

Product Documentation

Search MATLAB Documentation
R2011b Documentation → Simulink Control Design
View documentation for other releases	Learn more about Simulink Control Design

Contents

Index

• Getting Started

About This Tutorial

PID Control Design Using Robust-Response-Time Tuning Algorithm

PID Control Design Using Bode Graphical Tuning

Closed-Loop Simulation of Simulink Model

• User's Guide

• Steady-State Operating Points

• Linearization

• Linearizing Nonlinear Models

• Specify Model Portion to Linearize

• Linearize at Model Operating Point

Linearize at Trimmed Operating Point

• Linearize at Simulation Snapshots and Triggered Events

• State Order in Linearized Model

• Linearization Range of Accuracy

• Visualize Models

• Troubleshooting Linearization

• Controlling Block Linearization

Models with Pulse Width Modulation (PWM) Signals

• Speeding Up Linearization of Complex Models

• Exact Linearization Algorithm

• Frequency Response Estimation

• Designing Compensators

• Model Verification

• Model Advisor Checks

• Blocks

• Functions

Examples

• Release Notes

Linearize at Trimmed Operating Point

This example shows how to use the Linear Analysis Tool to linearize a model at a trimmed steady-state operating point (equilibrium operating point).

The operating point is trimmed by specifying constraints on the operating point values, and performing an optimization search that meets these state and input value specifications.

Code Alternative

Open Simulink model.
```
sys = 'magball';
open_system(sys)
```
In the Simulink model window, select Tools > Control Design > Linear Analysis.
This opens the Linear Analysis Tool for the model.
In the Operating Point list, select Trim model....

This action opens the Trim Model tab.
Click Specifications.
By default, all model states are specified to be at equilibrium (as shown in the Steady State column).
In the States tab, select Known for the height state.
The height of the ball should match the reference signal height. This height value should remain fixed during the optimization.
Enter 0 for the minimum bound of the Current block state.
Click to compute the operating point.

A new variable, op_trim1, appears in the Linear Analysis Workspace.
In the Simulink model window, define the portion of the model to linearize for this linearization task:
- Right-click the Controller block output signal (input signal to the plant). Select Linearization Points > Input Point.
- Right-click the Magnetic Ball Plant output signal, and select Linearization Points > Output Point.
- Right-click the Magnetic Ball Plant output signal again, and select Linearization Points > Open Loop.
In the Linear Analysis Tool, select the Exact Linearization tab. In the Operating Point drop-down list, select op_trim1.
Click to linearize the model at the specified operating point.
(Optional) Click Generate MATLAB Code in the Linearize drop-down list to automatically generate a MATLAB script.
The generated script contains commands for linearizing the plant for this example.