Model Interconnection

Series, parallel, and feedback connections; block diagram building

Interconnecting models of components allows you to construct models of control systems. You can conceptualize your control system as a block diagram containing multiple interconnected components, such as a plant and a controller connected in a feedback configuration. Using model arithmetic or interconnection commands, you combine models of each of these components into a single model representing the entire block diagram.

Functions

`feedback`	Feedback connection of multiple models
`connect`	Block diagram interconnections of dynamic systems
`sumblk`	Summing junction for name-based interconnections
`series`	Series connection of two models
`parallel`	Parallel connection of two models
`append`	Group models by appending their inputs and outputs
`blkdiag`	Block-diagonal concatenation of models
`imp2exp`	Convert implicit linear relationship to explicit input-output relation
`inv`	Invert dynamic system models
`ctranspose`	Conjugate dynamic system model
`lft`	Generalized feedback interconnection of two models (Redheffer star product)
`connectOptions`	Options for the `connect` command

Topics

Model Interconnection Basics

Why Interconnect Models?
Interconnecting models of system components allows you to construct models of control systems.
Connecting Models
This example shows how to model interconnections of LTI systems, from simple series and parallel connections to complex block diagrams.
Numeric Model of SISO Feedback Loop
Interconnect numeric LTI models to build a single model of a closed-loop system.
Control System Model with Both Numeric and Tunable Components
Interconnect fixed components and tunable components to build a tunable control system model.
Multi-Loop Control System
Build arbitrary block diagrams with any number of control loops by interconnecting models using the connect command.
MIMO Control System with Fixed and Tunable Components
This example shows how to build a MIMO control system using connect to build a dynamic system model representing a block diagram with both fixed components (Numeric Linear Time Invariant (LTI) Models) and tunable components (Control Design Blocks).
MIMO Feedback Loop
Obtain the closed-loop response of a MIMO feedback loop three different ways.
Using FEEDBACK to Close Feedback Loops
This example shows why you should always use FEEDBACK to close feedback loops.

Analysis Points

Mark Analysis Points in Closed-Loop Models
Insert analysis points at locations of interest when you build control system models. Use analysis points for extracting system responses from the model.
Control System with Multichannel Analysis Points
Build a control-system model with analysis points for extracting responses at different points in the system.

More About Model Interconnections

Catalog of Model Interconnections
Block diagram connections correspond to model interconnection commands or arithmetic expressions.
How the Software Determines Properties of Connected Models
When you interconnect models, the resulting model’s properties depend on the properties of the models you are connecting.
Rules That Determine Model Type
Precedence rules determine the resulting model type when you interconnect models of different types.
Recommended Model Type for Building Block Diagrams
Choice of model type can affect numerical accuracy when you interconnect models.
Preventing State Duplication in System Interconnections
This example shows guidelines for building minimum-order models of LTI system interconnections.