Research And Development Of Virtual Display Technology For Vehicle Braking Stability

Vehicle braking stability is one of the most important safety performances of vehicle,and a lot of researches have carried out on it until now. Among all research methods,using virtual reality technology for virtual simulation of vehicle braking stability is a newmeans of experimental simulation, and it is able to show the behavior of the vehicleduring braking through the screen intuitively. At present, researchers normally use VRMLprograming to process the virtual simulation of vehicle braking stability, which is able tocomplete the virtual display functions, but also has defects. For example, VRML filesneed a VRML browser to interpret it, while the complex three-dimensional model willreduce the speed of the browser. In addition, VRML browser is not one of the mainstreambrowser, so the portability of system is fell off. Furthermore, this kind of virtual displaysystem has the problems of singleness in function, especially cannot reflect the state ofmotion of the wheels.In order to solve above problems, in this thesis,3D game engine technology isadopted to process the virtual simulation, which is a new means and idea for virtualsimulation of vehicle braking stability. To achieve this scheme, it needs to verify whetherthe physical engine of3D game engine can control vehicles' braking or not, and to createa correct and simple model of vehicle braking stability. The main work is given asfollows.Firstly, a model of vehicle dynamics is created, in which the vehicle model uses aseven degrees of freedom model, the tire model uses G. Gim model, and the brake systemmodel uses a simplified brake system model. The simulation result shows that thephysical model of the chosen game engine is so relatively simple that it cannot trulyreflect the state of vehicle braking.Secondly, on the basis of the model, a virtual experimental scheme is proposed byusing a3D game engine. The feasibility analysis of the scheme shows that realization ofthe model with3D game engine can be achieved. Then, the model is programmed asalgorithm via difference method. By gathering the rendering rate while the virtual vehicleis braking, it is proven that this model not only keeps the image rendering speed, but alsosatisfies the real-time and continuous requirement of screen rendering for virtual display.Then, based on the virtual experimental scheme, the virtual reality simulation system forvehicle braking stability is designed and developed by using method of software engineering. System testing proves that the virtual reality simulation system is valid.Finally, on the basis of virtual reality simulation system for vehicle braking stability,the virtual reality simulation system is designed and developed for vehicle anti-lock brakesystem (ABS). The work shows that this system can interconnect with an ABS test benchto complete a hardware-in-the-loop virtual reality simulation scheme for ABS.