Frontiers in Computing and Intelligent Systems 
ISSN: 2832-6024 | Vol. 4, No. 3, 2023 

 

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QT	and	Simulink	Mixed	Call	Implementation	
Xingxing Chen  

College of Electrical Engineering, Southwest Minzu University, Chengdu 610041, China 

 

Abstract: In order to give full play to the advantages of Qt and Simulink, this paper puts forward a mixed programming 
method of Qt and Simulink, through the mixed programming technology of VC++ and Simulink, the code generated by Simulink 
model simulation is called by Qt, and it can be displayed vividly by ui interface. The mixed call of the two can greatly reduce 
the difficulty of manually writing the algorithm, thus improving the efficiency of the project to a great extent. 

Keywords: Qt; Simulink; Mixed Call.  
 

1. Introduction  
Qt is an efficient and cross-platform application solution. 

Qt supports Microsoft operating system, Mac OS and Linux 
operating system and supports most commercial Unix 
operating system and Linux embedded operating system [1]. 
Since its birth as a cross-platform graphical user interface 
toolkit, Qt has expanded to almost all areas of programming 
today, including portable devices. Because of the wide 
adaptability and good portability of Qt, as long as the code 
has been written once, it can be reused in other different 
operating system platforms by compiling it again.  

Qt is a fully functional, high-performance, multi-platform 
client / server attached C++ graphical user interface 
application framework [2]. Qt contains a rich and extensible 
class library, a powerful GUI layout and form constructor, a 
set of tools to remove obstacles to international workflows, 
and a completely customized, reassigned help document or 
document browser, but it provides limited mathematical 
functions and is inadequate in dealing with complex 
mathematical calculations.  

Simulink has the advantages of wide adaptability, clear 
structure and flow, fine simulation, close to reality, high 
efficiency, flexibility and so on. Based on the above 
advantages, Simulink has been widely used in complex 
simulation and design of control theory and digital signal 
processing. At the same time, there are a large number of 
third-party software and hardware that can be used or required 
to be applied to Simulink.  

Simulink can be modeled with continuous sampling time, 
discrete sampling time or two mixed sampling times [3]. It 
also supports multi-rate systems, that is, different parts of the 
system have different sampling rates. In order to create a 
dynamic system model, Simulink provides a graphical user 
interface to create a block diagram of the model, which can 
be completed by clicking and dragging the mouse. It provides 
a faster and more straightforward way, and users can 
immediately see the simulation results of the system.  
  Simulink is a multi-domain simulation and model-based 
design tool for dynamic systems and embedded systems. 
Simulink provides an interactive graphical environment and a 
customizable module library for design, simulation, 
execution and testing of a variety of time-varying systems, 
including communication, control, signal processing, video 
processing and image processing systems.  

Other products built on top of Simulink extend Simulink's 
multidomain modeling capabilities and provide tools for 

design, execution, verification, and validation tasks. Simulink 
is closely integrated with MATLAB and has direct access to 
a large number of MATLAB tools for algorithm development, 
simulation analysis and visualization, batch script creation, 
modeling environment customization, and definition of signal 
parameters and test data.  

2. The Raising of the Question  
The background of the research to realize the mixed call of 

Qt and Simulink is that the algorithm programming is 
complex and astringent, which leads to the scarcity of 
algorithm engineers in the market. The algorithm generation 
function in Simulink can solve this problem very well, and 
then use QT language programming design to show the 
function of the simulation. Therefore, the interface 
implementation of mixed programming between Qt and 
Simulink is of great significance to the whole project.  

The common practice of mixed programming in multiple 
languages is to first select a host language according to the 
needs of the application. Most applications will require to 
choose a high-level language or application language as the 
main language to express the top-level structure of the 
program [1]. Under the Windows system, the project software 
chooses Qt as the main language program to implement some 
modules or processes in Simulink.  

3. QT and Simulink Mixed Call 
Implementation 

3.1. Simulink Works  
1.First, we need to build an atomic subsystem 

 

Fig 1. Build an atomic subsystem 
 
2.Select one of the functional modules, right-click, and 

select Create Subsystem. The operations for the remaining 



 

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function modules are the same as above. 
 

 
Fig 2. Select one of the functional modules 

 
3.After the creation is completed, we will adjust the 

subsystem module to the appropriate size, straightening all 
signal lines, which seems to have no impact on the function, 
but for complex projects, more modules, more complex 
functions, this operation will be a very meaningful thing. Next 
select the Subsystem you are creating, right-click, and select 
BlockParameters (Subsystem) to create a subsystem. 

 

 
Fig 3. Create a subsystem 

 
4.In the dialog box that is displayed, set the following 

parameters. Functionpackaging must be set. If it is in the 

default state, the generated code will not change. 
Functionname can be set or not set. If Functionname is not set, 
the system automatically assigns a name, which is basically 
model name_subsystem. in actual programming, the name of 
the function is not arbitrary, and the function name should be 
as good as possible to represent the function of the function. 

 

 
Fig 4. Set the parameters 

 
5.Generate c++ code to change Type under Sloveroptions 

to Fixed-step. 
 

 

 
Fig 5. Generate c++ code to change Type under Sloveroptions to Fixed-step 
 

6. In Code Generation, change the System target file under 
Target selection to ert. tlc, set the language to C++, and check 
Generate code only under the Build process. 

 
 
 
 



 

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Fig 6. In Code Generation, change the System target file under Target selection to ert. tlc, set the language to C++, and check Generate code 

only under the Build process 
 

7. Select Create code generation report and Open report automatically in the report 
 

 
Fig 7. Select Create code generation report and Open report automatically in the report 

 
8.Change the Filepackagingformat to compact in CodePlacement. 

 

 
Fig 8. Change the Filepackagingformat to compact in CodePlacement 

 
9.Click Bilud Model or Ctrl + B to generate the code. 

 

 
Fig 9. Click Bilud Model or Ctrl + B to generate the code 



 

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3.2. Qt Works  
1.Create a project in Qt that imports the code generated in 

simulink 

 
Fig 10. Create a project in Qt that imports the code generated in simulink 

 
2.Write the code in mainwindow.cpp 
 

 
Fig 11. Write the code in mainwindow.cpp 

3.Layout in mainwindow.ui 
 

 
Fig 12. Layout in mainwindow. ui 

 
4. When the calculation result is greater than 20, the normal 

value is output; when the calculation result is less than 20, the 
output is wrong, and the result is displayed as follows: 



 

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Fig 13. Final result 

4. Conclusion  
In this paper, the mixed programming method of Qt and 

Simulink is adopted, which greatly reduces the difficulty of 
writing algorithms in Qt engineering, and the function of 

simulation model can be vividly displayed through Qt Ui 
interface. Through the project practice, the independently 
callable c++ code generated by calling Simulink has been 
well applied in the project. Of course, the complexity of 
Simulink simulation models needs to be further improved to 
meet the drawing and algorithmic requirements of different 
projects, and to provide users with a powerful development 
platform. Due to the excellent cross-platform characteristics 
of Qt and the algorithm generation function of Simulink, it is 
believed that the hybrid programming of Qt and Simulink will 
have a broader application prospect in the future embedded 
system. 

Acknowledgments 
This work was financially supported by the Southwest 

Minzu University Graduate Innovative Research Project No. 
(YB2023515) fund. 

References  
[1] Cai Zhiming, Lu Chuanfu, Li Lixia, et al. Proficient in Qt4 

programming [M]. Beijing: electronic Industry Press 2008. 

[2] Huo Yafei. QtCreator Quick start (2nd Edition) [M]. Beijing: 
Beijing University of Aeronautics and Astronautics Press, 2014.  

[3] Liu Wei. Proficient in mixed programming of MATLAB and 
Chammer + (2nd edition) [M]. Beijing: Beijing University of 
Aeronautics and Astronautics Press, 2008.