SIMULINK

Simulink (Simulation and Link) is a software add-on to MATLAB based on the concept of block diagrams that are common in the control engineering areas. It is an environment for dynamic simulation and process control. 

We can start Simulink either by clicking on the Simulink library icon on the menu bar of MATLAB or just typing 

Commonly Used Blocks Continuous ki Discontinuities Discrete 

Logic and Bit Operations b-l Lookup Tables b-l Math Operations Model Verification y Model-Wide Utilities b-l Ports Subsystems b-l Signal Attributes b-l Signal Routing Sinks s Sources 

We have three sections. The main window, to the right. The explanatory window, to the top where the description of the block can be read. The Browser shows to the left the groups of blocks available within Simulink. For each group, we can click and the different blocks appear in the main window. 

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The 11 and 22 set rulebase simulations were undertaken using SIMULINK, together with the fuzzy logie toolbox for use with MATLAB. More details on the... 

MATLAB, its Toolboxes and SIMULINK have beeome, over a number of years, the industry standard software paekage for eontrol system design. The purpose of this Appendix is to introduee the reader to some of the more useful aspeets of MATLAB, and to illustrate how the software may be used to solve examples given in the main text of the book. 

SIMULINK The Control System Toolbox does not possess a ramp eommand, but the ramp response of a first-order system (Example 3.6, Figure 3.15) ean be obtained using SIMULINK, whieh is an easy to use Graphieal User Interfaee (GUI). SIMULINK allows a bloek diagram representation of a eontrol system to be eonstrueted and real-time simulations performed. 

With MATLAB Version 5.3, typing simulink at the MATLAB prompt brings up the SIMULINK Library Browser. Clieking on the Create new model ieon in the top left-hand eorner ereates a new window ealled untitled . 

Clieking on the El icon attaehed to SIMULINK lists the SIMULINK options, and E Continuous lists the eontinuous systems options. To obtain a transfer fune-tion bloek, eliek and hold left mouse button on the Transfer Fen ieon under Continuous , and drag to untitled window. 

Fig. A1.1 SIMULINK model for the ramp response of a first-order system.

Fig. A1.3 SIMULINK simulation of CNC machine-tool positional control system.

The state-variable feedbaek solution was implemented in SIMULINK as shown in Figure A1.4. 

Fig. A1.8 Simulink implementation of inverted pendulum fuzzy logic control problem.

The MathWorks Inc. (1993) SIMULINK Numerical Simulation Software - Reference Guide, The MathWorks Inc., Natick, Mass. 

SIMULINK Workstations, Mac and PC Based on MATLAB but with improved integration routines, model building blocks and graphical interface. 

Consider Example 5.3 again and let s pick xp to be 5 min, Kp be 0.8 [unit]. Instead of using the equation that we derived in Example 5.3, we can use the following statements in MATLAB to generate a simulation for the case of a unit step change in the set point. This approach is much faster than using Simulink. 

We can use the following MATLAB statements to do time response simulations (explanations are in MATLAB Session 5). Better yet, save them in an M-file. The plotting can be handled differently to suit your personal taste. (Of course, you can use Simulink instead.)... 

This is roughly how we did it. All the simulations are performed with Simulink. First, we use Gj j and G22 as the first order with dead time functions and apply them to the ITAE tuning... 

We retain the ITAE controller settings and apply them to a Simulink block diagram constructed as in Fig. 10.12. The result is labeled MIMO in the figure. Finally, we use Fig. 10.14 and the two decouplers, and the simulation result with the initial setting is labeled MIMO with decouplers. ... 

Simulink is a user-friendly simulation tool with an icon-driven graphics interface that runs within MATLAB. The introduction here is more conceptual than functional for two reasons. One, the Simulink interface design is very intuitive and you may not need help at all ... 

Figure M5.1. Sample icons from the Simulink Block Library Window.

Figure M5.2. Sample icons for model building from the Simulink Continuous Library Wndow.

All we need is to drag-and-drop the icons that we need from the toolboxes into a blank model window. If this window is not there, open a new one with the File pull-down menu. From here on, putting a feedback loop together to do a simulation is largely a point-and-click activity. An example of what Simulink can generate is shown in Fig. M5.3. 

Figure M5.3. A sample negative feedback closed-loop generated within Simulink. This servo system has a first order process function and uses a PID controller. The output is sent to a graphing tool for plotting.

Some of the features that we use most often within the Simulink Block Library ... 

Blocksets From the Blocksets Toolboxes, choose "Simulink Extras," and then... 

All Simulink simulation block diagrams are saved as ascii files with the mdl extension. 

Simulink shares the main MATLAB workspace. When we enter information into, say, the transfer function block, we can use a variable symbol instead of a number. We then define the variable and assign values to it in the MATLAB command window. This allows for a much quicker route to do parametric studies than changing the numbers within the Simulink icons and dialog boxes. 

The control toolbox supports an extremely nice root locus design graphics design tool that is ideal for experimentation. The interface is even more intuitive and self-explanatory than that of Simulink. We take the same approach as our introduction to Simulink and have moved the not so necessary and print-intensive window display and instructions to our Web Support. A very brief conceptual introduction is provided in this section. 

The solver is implemented in Fortran, using optimized treatment of diagonal-band matrices and analytical derivatives of reaction rates to minimize computation time. The software structure is modular, so that different reaction-kinetic modules for individual types of catalysts can be easily employed in the monolith channel model. The compiled converter models are then linked in the form of dynamic libraries into the common environment (ExACT) under Matlab/Simulink. Such combination enables fast and effective simulation of combined systems of catalytic monolith converters for automobile exhaust treatment. 

Shelton M., Celik I., Liese E., Tucker D., Lawson L. (2005) A transient model of a hybrid fuel cell, gas turbine test facility using simulink. In Proceedings of the ASME Turbo Expo, Reno-Tahoe, NV, 2005-GT-68467. 

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