CAMPG/SIMULINK

Fig. 11.46 CAMPG/SIMULINK state space and transfer function...

Let us illustrate the use of these functions and other tools utilizing the CAMPG/SIMULINK system using a nonlinear hydraulic system example. The system under consideration here is a 4-way closed-center spool valve. The valve shown in Fig. 11.47 is connected to a hydraulic ram. 

Keywords Automated modeling Simulation Mechatronics systems Computer generated differential equations Transfer functions State space CAMPG Bond graph Block diagrams MATLAB SIMULINK SYSQUAKE... 

CAMPG interfaces automatically with a simulation language (MATLAB, SIMULINK, SYSQUAKE, EASY5, ACSL, SIMULINK) or the user s own simulation program... 

The SIMULINK blocks shown in Fig. 11.45 summarize the CAMPG/SIMULtt4K... 

The CAMPG interface to SIMULINK follows the same format as the one for MATLAB. The user enters a bond graph model utilizing the menu as for the other simulation programs then SIMULINK interface is chosen under the ENTERFACE menu. 

CAMPG generates the following files for the SIMULINK interface ... 

The idea here is that using CAMPG we can let the computer derive the differential equations not only in the Cauchy form for time domain simulation, but also in state space form which can be used in SIMULINK either in the time domain or in the frequency domain. Finally CAMPG will produce computer-generated transfer functions which can also be used by SIMULINK for time and frequency domain calculations (Fig. 11.46). 

The model transferred from CAMPG to SIMULINK in the state space form follows the same order of the state space vector as the state variable vector generated in CAMPG and displayed in the campginum file and in the campgnum.m file. The rows of those matrices correspond to the rows of the state variable vector generated in those two files. The state space model in SIMULINK requires two... 

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. 

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. 

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. 

In order to achieve this goal the CAMPG approach seeks to define each differential equation as a SIMULINK subsystem connected by data store in data read and data write formats. CAMPG then adjusts to this new method presented herein in the production of system block diagrams including subsystems. The intention here is to... 

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