SIMULINK S-functions

The CAMPG and SIMULINK S-Functions for Complex Nonlinear Systems... 

SIMULINK S-functions generated from CAMPG are used for the simulation of complex nonlinear systems. The explanation here is a summary of the necessary parts of an S-function which are necessary to simulate nonlinear systems using a combination of bond graph modeling and the tools in SIMULINK. There are four basic sections to an S-function. These four sections are the main section, initialization section, derivative section, and Output section. Reference [13] presents a more detail description. 

Once the bond graph has been entered, selection of the SIMULINK interface will generate a SIMULINK S-function campgsfn.m and an initialization file campginum where the parameters numerical values need to be entered. The files generated by CAMPG contain a set of question marks that point to the variables that need to be... 

The STMT IT,INK model in the form of an S-function was generated by CAMPG automatically as shown in Fig. 11.49. The 4-way valve and ram model becomes a SIMULINK S-function block with the CAMPG-generated function underneath. 

These equations are used by CAMPG to produce the SIMULINK-compatible block diagrams and the SIMULINK S-functions. The latter are SIMULINK s link to the bond graph non-linear elements equations because S-fimctions can be programmed based on specific structures that are defined in a SIMULINK block. CAMPG takes advantage of this fact to produce such functions. 

Nonlinear bond graph models may be created and processed by CAMP-G in conjunction with Simulink and S-functions. Bond graph elements may be hnear or nonlinear. Nonlinear constitutive element equations will have to be added to files generated by CAMP-G before a simulation mn can be performed by Simulink. 

The simulation was compared to that in [19], which was developed by an entirely different method. Using the physical parameter values, the simulation was verified. Using the S-function created by interfacing CAMPG with SIMULINK, the following plots are created. 

All models should be integrated and connected in a virtual environment that provides a robust tool and is flexible enough to be adapted quickly or coupled with other simulation tools. At Daimler, an exhaust aftertreatment simulation tool called ExACT (Exhaust Aftertreatment Components Toolbox) has been developed in-house. It is based on MATLAB/Simulink, while the Fortran-based models themselves are integrated as S-functions. 

In this section, we show how to perform closed-loop simulations for various digital controllers. Although the controller is represented by a discrete transfer function, all other components of the control loop (models for the final control element, process, sensor, and disturbance) will normally be available as continuous transfer functions, which can be directly entered into a Simulink block diagram as functions of s. To... 

The kinematic model of the mechatronic system under study was implemented using S-flinction features within the built-in MATLAB Simulink blocks. Figure 15 shows the implementation of the function of the kinematic model of the mobile robotic system. 

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