Wuhan University of Technology Undergraduate Graduation Design (Thesis)

Real-time simulation of automobile mechanism motion based on Unity3D

School: School of International Education

Specialty amp; Class: Automotive Engineering gj1602

Name: Kou Yiqun

Tutor: Jiang Tao

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Abstract 

With the approaching of Made in China 2025 and the adjustment of China's manufacturing industry, digital simulation technology is increasingly used in the manufacturing sector. The 3D engine has gained more and more attention in the field of industrial simulation by virtue of its advantages such as efficient rendering pipeline, good visual display effect and the ability to meet the customized needs of enterprises.

This article realizes the application of Unity3d engine in the field of industrial simulation, using two examples of automobile closures parts and passenger car steering mechanism to show. In the process of implementation, 3ds max software was used to complete the construction of a Toyota car body model, and completed the assembly of the interior and exterior. And with the help of Unity3d's physics engine component and C # control script, the motion simulation of the car's closures parts was completed. At the same time, this paper also completed the real-time motion simulation of the passenger car steering mechanism. First, Catia was used to complete the modeling and assembly of the steering mechanism model, and then the model was imported into 3ds MAX to modify the position of the part coordinate system. Subsequently, the motion simulation of the steering mechanism of the passenger car was completed in Unity3d, and the design of the human-computer interaction interface was completed. This design has fulfilled the predetermined requirements, and the Unity3d engine can solve various design, motion, and display problems encountered in production through simulation in all aspects of industrial production. It can also play a huge role in the adjustment and upgrading of industrial structure, and has a broad application prospect.

Key Words：Unity3d; 3D design; motion simulation

Content

Abstract 

1 Introduction

1.1 Research background

1.2 Comparison of Chinese and Foreign Research

1.2.1 Research status abroad

1.2.2 Research state in China

1.3 The significance of research

1.4 Main research content and process

2 Introduction to modeling theory and development platform

2.1 Introduction to 3ds modeling software 3ds MAX

2.1.1 Advantages of the 3D modeling software 3ds MAX

2.1.2 3D modeling software 3ds MAX geometric modeling method

2.2 Introduction to the 3D engine Unity3d

2.2.1 Advantages of the 3D engine Unity3d

2.2.2 Unity3d's physics engine

3 Motion simulation of automobile closures parts

3.1 Design and modeling of 3dsmax car body model

3.1.1 3dsmax car body model design and modeling steps

3.1.2 Summary of model construction

3.1.3 Display of the results of model construction

3.2 Unity3d real-time simulation of the door mechanism

3.3 Program release and testing

3.3.1 Release of the program

3.3.2 Simulation program performance test

4 Motion simulation of passenger car steering mechanism

4.1 Model construction of automobile steering mechanism based on Catia

4.1.1 Component modeling

4.1.2 Assembly of parts

4.2 Model coordinate system adjustment

4.3 Simulation of the passenger car steering mechanism in Unity3d

4.3.1 Setting of auto steering mechanism parts

4.3.2 Compilation and release of steering mechanism motion simulation script

5 Summary and Outlook

5.1 Summary

5.2 Outlook

References

Thanks

1 Introduction

With the development of China's manufacturing industry and the industrial adjustment and structural upgrading of China's manufacturing industry, China's high-end manufacturing industry needs to use more digital design methods and research methods^[1]. With the rapid development of information technology, computer simulation technology is widely used in all aspects of automobile design, production, sales and maintenance. At the same time, various automobile organizations have become increasingly complex, and the degree of integration and intelligence is constantly improving. This also makes the organization's difficulty in design, testing and maintenance greatly increase, which puts forward higher requirements for the comprehensiveness of the data displayed in the simulation technology, the timeliness of the abnormal feedback and the freedom of simulation. At present, the proportion of digital prototypes and real-time simulation technology in high-end manufacturing will continue to increase, and 3ds MAX, Catia, Unity3d, as the current advanced 3D design software and 3D engine, have been widely used in the production of high-end advanced machinery and equipment. At this time, 3D engines including Unity3d gained wide attention in the field of real-time simulation due to their efficient rendering technology, excellent multi-platform production features, and the ability to meet the customization needs of enterprises.

1.1 Research background

In recent years, industrial real-time simulation technology based on motion mapping technology and real-time database technology has attracted the attention of researchers at home and abroad. Real-time simulation technology is a process that uses real-time data or commands to drive rigid body motion or flexible motion of the model according to preset mapping rules, thereby completing real-time monitoring, planning evaluation, simulation verification and other purposes. Compared with traditional industrial simulation, it has better visualization and real-time feedback capabilities.

Real-time simulation technology mainly includes three parts: scene modeling, data-driven, real-time rendering, hardware display. Scene modeling is to establish a three-dimensional model of the environment in which the simulation is located and the objects involved in the simulation. In the process of building a three-dimensional model, it includes confirming the geometric dimensions of the established model, setting the parent-child relationship between the models, and defining physical parameters such as the material and gravity of the model. Data driving is to drive the model movement of the mechanism by using the set behavior through data input. Real-time rendering is different from pre-rendering after a period of time. It is based on the dynamically changing data of the model's actions and positions, and uses the frame as the rendering cycle to output the rendered image. The choice of display hardware is closely related to the presentation of the final interactive design of real-time simulation. High-performance displays have good picture display capabilities, mobile phones and tablets have more portable presentation capabilities, and VR glasses and somatosensory handles have better Immersive experience. Different hardware devices bring a wealth of choices to the display and interaction form of real-time simulation.