• POWERFUL MATHEMATICAL MODEL-BASED SYSTEM SIMULATION PROGRAM IN MATLAB ENVIRONMENT
• GRAPHICAL USER INTERFACE (GUI)
• SIMULATION OF NONLINEAR DYNAMIC SYSTEM
LINEAR/NONLINEAR CONTINUOUS/DISCRETE TIME
MULTIRATE
HIERARCHICAL MODELS
• LIBRARY OF GRAPHICAL BUILDING BLOCKS
• USER INTERFACE FROM MATLAB, FORTRAN, OR C CODE
• CAN GENERATE C CODE FROM MODELS FOR REAL-TIME CONTROL
• SIMULATION CAN BE LINKED WITH OTHER TOOLBOXES
• SIMULATION RESULTS CAN BE USED FOR MATLAB PROCESSING
• EXTENSIVE GRAPHICS CAPABILITY
Simulink [3] is basically a digital simulation program for nonlinear dynamic systems that operates in the MATLAB environment, where MATLAB is used as its computational engine. The system can be continuous, discrete time, or multirate with different sample times. Complex models can be represented by adding a hierarchy of subsystems. The system's mathematical model is to be developed first either in the time domain in terms of state-space, integral, and algebraic equations, or with Laplace transfer functions prior to simulation study. The graphical user interface permits fast simulation setups. Simulink has a graphical block library of sources, sinks, continuous, discontinuous, discrete, look-up tables, math operations, signal attributes, signal routing, etc. The blocks can be dragged into the model window and interconnected. The parameters of the block can be defined in the dialog box. An integration method is selected before running the simulation. Often, a fixed but conservatively selected time step shortens the simulation time. The running of simulation is interactive; i.e., the parameters can be changed on the fly to observe the effect of the change. The simulation results can be observed on scope or stored in workspace or files. The system design can be optimized by means of iterative simulation studies. Once the simulation is iterated for successful design, the Real-Time Workshop program can translate the controller software into C code, which can be compiled and used in DSP for real-time control. In addition, Simulink can generate VHDL (very high speed hardware description language) software for FPGA (described later) implementation of control system. This is one of the great advantages of Simulink simulation. The simulation waves can be used, for example, to plot a harmonic spectrum by using a MATLAB-based Fourier analysis program. Several example programs will be illustrated next with Simulink.