Getting Started

Chapter 2
Building Models

This chapter discusses how to build models of linear, time invariant (LTI) dynamical systems using functions from the Control System Toolbox. It begins by developing a simple single-input, single-output (SISO) model of a DC motor and describes the various model representations possible, including:

• Transfer functions
• State-space
• Zero/pole/gain
• Frequency response data

This chapter then describes how to build multiple-input multiple-output (MIMO) models by presenting a jet transport model. It also discusses topics related to creating general LTI models, including:

• How to access model characteristics
• Conversions between model representations
• Building larger models from smaller ones
• Accessing and manipulating I/O pairs
• LTI objects, which are MATLAB objects that store multiple linear models in a single variable

This chapter also discusses discrete-time systems, including analog to discrete-time conversion, sample time specification, and how to introduce time delays in your linear system. The last section describes functions that perform model order reduction and presents an example of how to perform a model order reduction.

Typographic Conventions

Linear Models