Overview of the Simulunk Tool

Simulink® software models, simulates, and analyzes dynamic systems. It enables us to pose a question about a system, model the system, and see what happens.
With Simulink, we can easily build models from scratch, or modify existing models to meet your needs. Simulink supports linear and nonlinear systems, modeled in continuous time, sampled time, or a hybrid of the two. Systems can also be multirate — having different parts that are sampled or updated at different rates.
Thousands of scientists and engineers around the world use Simulink to model and solve real problems in a variety of industries, including:
•Aerospace and Defense
•Automotive
•Communications
•Electronics and Signal Processing
•Medical Instrumentation

Tool for Model-Based Design
With Simulink, we can move beyond idealized linear models to explore more realistic nonlinear models, factoring in friction, air resistance, gear slippage, hard stops, and the other things that describe real-world phenomena. Simulink turns our computer into a laboratory for modeling and analyzing systems that would not be possible or practical otherwise.

Whether we are interested in the behavior of an automotive clutch system, the flutter of an airplane wing, or the effect of the monetary supply on the economy, Simulink provides us with the tools to model and simulate almost any real-world problem. Simulink also provides demos that model a wide variety of real-world phenomena.

Simulink provides a graphical user interface (GUI) for building models as block diagrams, allowing us to draw models as we would with pencil and paper. Simulink also includes a comprehensive block library of sinks, sources, linear and nonlinear components, and connectors. If these blocks do not meet our needs, however, we can also create our own blocks. The interactive graphical environment simplifies the modeling process, eliminating the need to formulate differential and difference equations in a language or program.

Models are hierarchical, so we can build models using both top-down and bottom-up approaches. We can view the system at a high level, then double-click blocks to see increasing levels of model detail. This approach provides insight into how a model is organized and how its parts interact.

Tool for Simulation
After we define a model, we can simulate it, using a choice of mathematical integration methods, either from the Simulink menus or by entering commands in the MATLAB® Command Window. The menus are convenient for interactive work, while the command line is useful for running a batch of simulations (for example, if we are doing Monte Carlo simulations or want to apply a parameter across a range of values).

Using scopes and other display blocks, we can see the simulation results while the simulation runs. We can then change many parameters and see what happens for "what if" exploration. The simulation results can be put in the MATLAB workspace for postprocessing and visualization.

Tool for Analysis
Model analysis tools include linearization and trimming tools, which can be accessed from the MATLAB command line, plus the many tools in MATLAB and its application toolboxes. Because MATLAB and Simulink are integrated, we can simulate, analyze, and revise our models in either environment at any point.

How Simulink® Software Interacts with the MATLAB® Environment
Simulink software is tightly integrated with the MATLAB environment. It requires MATLAB to run, depending on it to define and evaluate model and block parameters. Simulink can also utilize many MATLAB features. For example, Simulink can use the MATLAB environment to:
•Define model inputs.
•Store model outputs for analysis and visualization.
•Perform functions within a model, through integrated calls to MATLAB operators and functions.