Application of the hottest virtual reality technol

Editor's note: with the development of virtual prototype and virtual reality technology, a revolution has been caused in the automotive industry. In this paper, virtual prototype technology and virtual reality technology are applied to the vehicle performance test, the vehicle virtual test system is designed, and the vehicle handling and stability test is taken as an example for development and research. The results show that, With virtual instruments and virtual environment, virtual test breaks through the shortcomings of the original evaluation of simulation curves. Through stereo vision equipment, people can immerse themselves in the environment and experience the performance of vehicles in a closed-loop way, breaking through the current way of vehicle performance evaluation

1. Introduction

virtual prototype technology and the use of high molecular materials marked by plastics as much as possible is the most effective and powerful way to achieve vehicle weight reduction. The emergence of virtual reality technology has improved the traditional vehicle design and test methods. The digital vehicle designed by using the virtual prototype technology is combined with the complex and changeable virtual test environment, and the real driver is used to simulate the driving, which acts on the user with vision, hearing, touch and so on, so as to produce an immersive immersion and interaction feeling. The human vehicle environment is integrated, and the vibration, tilt, noise and other effects of the vehicle can be directly felt. Without danger and damage, limit tests such as collision and rollover can be carried out, It improves the abstract numerical curve simulation, breaks through the complex driver's feelings and reactions that are difficult to express with mathematical models, finds potential problems in time in the early stage of the design, makes adjustments and corrections, and realizes optimization, which has the advantages of saving money, repeatability, risk-free and so on. Typical examples are: Chrysler's new vehicle development cycle was shortened from 36 months to 24 months, and Ford also announced the development of a fully digital car at the end of 1999. Mercedes Benz automobile company has completed the digital car prototype before 1998, and realized a strong virtual reality technology, which can visually and comprehensively simulate, analyze, evaluate and improve the overall performance matching and body system layout design of the car in the design stage

therefore, on the basis of consulting a large number of materials, this paper designs the vehicle virtual test system, and takes the handling and stability test as an example to develop it. Through the comparison between the actual test and the virtual test, the virtual test has better effect than the traditional simulation data processing, and the integration of human vehicle environment provides a new method for the study of vehicle closed-loop system. Here is a detailed introduction of Mr. Li from Shijiazhuang, Hebei Province who visited our company yesterday

2. System structure design

the vehicle virtual test system is a complex system. It follows the basic principles of progressiveness, openness, reliability and so on. Based on the object-oriented design idea, it adopts the hierarchical, modular and standardized design method, so that the system can achieve the rationalization of structure on the premise of maintaining the realization of function

the vehicle virtual test system is mainly composed of input module, virtual test module and output module, as shown in Figure 1. Import the car model into the virtual environment, analyze the kinematics and dynamics of the car model according to the user's input control commands, and use the analysis data to "virtual reproduce the car test process" in the virtual scene. The user feels and experiences the performance of the car through various sensors, obtains the performance evaluation, and modifies the model parameters according to the evaluation. This process can be repeated continuously to modify the car parameters, Until the car gets the best performance. It is briefly described below

3. Development example of virtual test system

the author took the virtual test of handling and stability as an example to develop. Firstly, the digital virtual prototype of the vehicle is established by using adams/car software, and its handling and stability simulation analysis is carried out. The virtual test environment is implemented by WTK (worldtoolkit) and visual c++, and the virtual instrument part is implemented by ComponentWorks component of Ni company. The simulation data of dynamic analysis is transmitted to the virtual environment to realize the experiment visually and realistically, and the changes of data are accurately displayed through the virtual instrument. Using human-computer interaction technology, users can not only have visual and sensory experience, but also immerse in the virtual test environment through the AGC viewer g stereo observation system, truly experience the vehicle performance, so as to evaluate the vehicle performance

the following takes the single line shifting test in the closed-loop test of vehicle handling and stability as an example. Using adams/car, the author has established a digital model of a vehicle by using the clamp of the tensile testing machine now sprayed with emery, and designed a control file according to the single line shifting test method (such as track, speed, etc.). In the process of vehicle dynamics simulation, the file controls the vehicle to drive along the specified route, Then extract the data of the main characteristic parameters of handling and stability (such as steering wheel angle, yaw rate, roll angle and lateral acceleration) from the simulation analysis results, and dynamically observe the vehicle itself and the changes of parameters in combination with the scene of single line shifting test. In order to enable users to accurately know the specific parameter changes in the process of vehicle movement, the function of virtual instrument is added to the load sensor measurement experiment force, and the virtual instrument is used to cooperate with the virtual scene to dynamically display the changes of various parameters in the process of vehicle simulation. In order to realize the immersive feeling of the scene more realistically, the stereo scene display effect of two viewports is developed. Through agc--viewerg stereo observation system, you can immerse in the virtual test scene, feel and experience the test process. Figure 2 shows the results of dynamic simulation analysis (speed is 100km/h), and figure 3 shows the simulation scene and virtual instrument changes during the virtual single line shifting test

4. Summary

with the application and development of virtual prototype and virtual reality technology in the automotive industry, great progress has been made in automotive design and experimental research. The multi-body system dynamics analysis software is used to obtain vehicle performance parameters and realize the virtual test system of vehicle performance, which can fully realize the "indoor virtual test". It is an extension of the future virtual prototype system. By connecting some control equipment and combining with the virtual scene, users can feel the vibration, side deviation, side inclination and other movements of the vehicle, and people's subjective feelings can be added to the evaluation of vehicle performance, It has strong practical significance. With the development of computer, image technology, sensor and other technologies, automotive virtual test technology has a good development prospect

references

[1] Wang Chengcheng, Gao Wen, Wang Xingren The theory, implementation and application of spiritual environment (virtual reality) technology Beijing: Tsinghua University Press, 1996

[2] edited by Yang Baomin and Zhu Yining Distributed virtual reality technology and its application Beijing: Science Press, 2000

[3] Wang Shufeng