HONG KONG, Aug. 11, 2022 (GLOBE NEWSWIRE) -- WIMI Hologram Academy, working in partnership with the Holographic Science Innovation Center, has written a new technical article describing their exploration of simulated driving system based on virtual reality experimental scenarios. This article follows below:
In order to solve the problems of coarse display screen and fixed driver's viewpoint in the driving simulation system, a three-dimensional high-precision model of the comprehensive automobile test track was established by software, and a virtual reality display system was built based on other software to render the complete environment of the automobile test track and VR display. Finally, the vehicle dynamics simulation platform was built, which completed the whole process of building the VR-based driving simulation system. The simulation results show that the driving simulation system developed based on the virtual reality test scene has a good display screen, and the driver has a high field of view and a free and flexible observation perspective, which effectively improves the driver's immersion. Scientists from WIMI Hologram Academy of WIMI Hologram Cloud Inc.(NASDAQ: WIMI), discussed in detail the application of the driving simulation system based on virtual reality experimental scenarios.
China has become the world's largest producer and consumer of automobiles, and the growing automotive market has brought about fierce competition in the industry, and drivers have increasingly high requirements for car driving performance. The introduction of human-computer interaction measurement means in the early stage of product development, and the use of simulation driving system for simulation testing, laid a good foundation to ensure the successful development of products and performance requirements. The automotive test track can reproduce various road and driving scenarios encountered in the process of driving, which is an important means to verify the performance of the test vehicle.
In fact, building a real-world test site for verification is costly and subject to uncontrollable factors such as time and weather. With the development of computer simulation technology, it is possible to conduct simulation tests related to automobiles through driving simulation systems in VR scenarios. Some studies have shown the necessity of studying speed limits for senior citizens driving on virtual roads through driving simulation systems. The driving simulation system using traditional view display will cause problems such as fixed display view and rough display of the screen. Therefore, a driving simulation system development scheme based on VR test scenario is proposed. The final simulation results show that the constructed driving simulation system achieves the expected development functions and requirements, and the scenes are well displayed, giving the driver a wider and freer driving perspective.
1.Comprehensive automotive test site modeling
1.1 High-speed loop modeling
The high-speed ring road in the test track can be used for continuous high-speed driving of the test vehicle. The design shape of the high-speed ring road in this paper is oblong, and the design of its three-dimensional model can be divided into horizontal and cross-sectional lines.
1) Horizontal line design. The horizontal surface profile is generally composed of straight line section OM, gentle curve section MN and circular curve section NE. The curvature of the straight section is 0, the curvature of the circular curve section is 1/r, and the gentle curve section can make the curvature between the circular curve and the straight line smoothly over, which is the focus of the horizontal line design.
2) Cross-sectional line design. As the maximum speed of the high-speed ring road is large, it is necessary to design the transverse ultra-high angle β (slope inclination) to offset the centrifugal force generated when the car is running at high speed. The cross-sectional line design of circular curve section NE. The test site set up four high-speed ring roads, the lane to the inside out, the speed of 80, 120, 160, 200km/h. For different speed, the transverse ultra-high angle is different, so this paper chooses three parabolic as the cross-section curve, so that the speed distribution between the ring road cross-section is more continuous and uniform. The first lane boundary is used as the starting point of the cross-sectional curve of the circular curve, and the first order derivative of the curve in the center line of each lane is the sine value of the lateral super-elevation angle of the lane, and the equation of the curve is solved. The cross-sectional design of the MN section of the gentle curve. In order to avoid too many curve equations, which would cause too many triangular surfaces and cause the scene rendering stutter, the cross-sectional equations were only calculated at 40m intervals from the starting point of the easing curve.
1.2 Other test road modeling
The test site also has a 300m diameter dynamic test square for dynamic steering, minimum turning radius, and right angle turning tests; a 400m long, 3-lane, 9m wide comfort road for in-vehicle noise, smoothness testing, and noise testing and evaluation; a 2-lane, 8m wide comprehensive evaluation road with a total lane length of about 4280m, including a variety of different radius curves, different longitudinal slopes. The ramp is used for subjective evaluation of vehicle performance and break-in test, etc.; the basic performance loop with a total length of about 2000m and width of 15m is used for power measurement, slip test and direct acceleration performance test.
2. VR-based automotive test track display
2.1 Virtual reality-based view display system
The traditional view display of the driving simulation system has problems such as fixed display angle or rough picture. The combination of VR technology and physical simulation engine can build a viewpoint free, fine picture of the vision display system. Based on the analysis of the current VR-based scenery display scheme, the author uses the virtual reality development hardware to form a three-dimensional view through the difference in image perspective of binocular dual screens. The resolution of the dual screen is 2160×1200, the pixel density is 447PPI, and the refresh rate is 90Hz, which can meet the high-definition display of human eye vision, and convert it into a dual display for left and right eyes, output to the head-up display device, and realize the 3D stereoscopic display of the scene.
2.2 Virtual reality-based automotive test environment construction
After realizing the virtual view display, it is necessary to build a complete automotive test site environment, including natural environment, test site test road, and real-time weather system. 1) Environmental terrain. Use tools to create terrain and set ground texture maps, and switch the display model fineness according to the distance to improve the rendering speed. 2) Test track road. By modeling the road of the car test site, considering the generality of the model, it was exported to FBX format and imported into the software as prefabricated parts, which is easy to manage and build the scene in professional software. 3) Weather system. The creation of the weather system mainly uses the sky box and particle system, which can simulate the light and dark display of dusk and night, as well as the transformation effect under different weather such as rain and snow.
2.3 Virtual reality-based driver's view display
After building the VR vision display system and the car test scene, it is necessary to simulate the driver's display perspective, so as to determine the perspective display screen, and to transmit the screen to the head-up display device, so that the driver has a three-dimensional immersion visual experience. Specifically, this is divided into the following three steps.
1)The driver's view of the screen display. In order to obtain the picture that the driver sees in the car test site, it is necessary to create a simulation model. The simulation model calculates the display position of the model in the test track according to the coordinate transformation of the world coordinates, the camera coordinates, the crop coordinates and the screen coordinates, and then displays the visuals in real time. In the process of operation, the simulation model is placed at the driver's eyes to simulate what the driver sees.
2)Driver's view screen switching. As the driver's head posture changes, the coordinate information of the head-up display device is transmitted to the relevant software through special equipment, and the posture of the person is updated in real time, and the display screen in the head-up display device is changed by the change of coordinates in the car test scene, so as to ensure that the picture seen by the driver follows the head movement and changes.
3. VR-based driving simulation system development
3.1 Driving simulation system architecture design
The driving simulation system is a closed-loop simulation system in the human-vehicle-road environment. However, the VR-based car test scene cannot directly establish the car dynamics simulation model to reflect the car's motion state, and it is necessary to build a joint simulation platform of car dynamics. The driver is manipulated according to the virtual scene in the VR head-up display device, and the signals from the driver's control device are collected through the vehicle dynamics simulation platform, which is combined with the vehicle dynamics model and the virtual road to solve the real-time vehicle posture information to drive the virtual vehicle motion. At the same time, according to the head posture information and through coordinate transformation, the scene seen by the driver in the head-up display device is switched, thus forming a closed-loop simulation.
According to the standard parameters of the comprehensive automobile test site, the test site model was established in equal proportion, the development of VR vision display system was completed, the real-time simulation of automobile dynamics was completed through auxiliary equipment, and the development of a complete driving simulation system based on VR test scenes was finally completed. Compared with the traditional single-screen display of the driving simulation system, its FOV increased by 22%~83%, and the view range in front of the driver increased from the fixed view of a single screen to a free 180°, which makes the driving display view wider and more flexible and in line with the actual driving condition.
Founded in August 2020, WIMI Hologram Academy is dedicated to holographic AI vision exploration, and conducts research on basic science and innovative technologies, driven by human vision. The Holographic Science Innovation Center, in partnership with WIMI Hologram Academy, is committed to exploring the unknown technology of holographic AI vision, attracting, gathering and integrating relevant global resources and superior forces, promoting comprehensive innovation with scientific and technological innovation as the core, and carrying out basic science and innovative technology research.
Holographic Science Innovation Center
Email: pr@holo-science. com