Virtual Prototype Technology-Based Vehicle Ride Comfort Analysis And Driving Simulation

Ride comfort is one of the leading performances parameters determining how modern and comfortable a vehicle can be. In order to evaluate the vehicle ride comfort effectively, a simulation model is built based on the multi-body system dynamics and virtual prototype technology, including front suspensions, rear suspensions, truck steering, powertrain, and tires etc., which consequently develop a system analyzing ride comfort on simulation models. In this project a pilot research work has been carried out to solve the key problems on the development of vehicle ride comfort and testify the correctness of vehicle dynamics model by application of 6-DOF parallel connection mechanism. The details are as follow:The thesis consists of six chapters. In Chapter one the background and significance of project research are presented. The research updates in the field of automobile industry both at home and abroad are introduced focusing on from development of virtual prototype technology to its application in automobile dynamics and description of research and development on vehicle ride comfort at home and abroad is also presented from the aspect of experiment and evaluation methods. The introduction analyzes the virtual prototype technology in particular the reality of application of ADAMS into the research of vehicle ride comfort, which will be discussed in detail in the body of the thesis.Chapter two focuses on the research methods---the multi-body systematic dynamics theory. A comprehensive introduction of ADAMS, a typical multi-body systematic dynamics simulation analysis software packages which enjoys an extending application is presented including its modules, design process and its analysis and calculation methods.Chapter three deals with the simulation analysis for the vehicle ride comfort. Firstly, a full vehicle dynamics simulation model of a heavy truck is built with the help of software of ADAMS/Car. The formation of simulation models is to a certain degree a simplification of the automobile system so that it can be demonstrated by mathematical models, which helps to accelerate the computing speed and get to the core of the problems. The subsystem models, including front suspensions,rear suspensions,truck steering,powertrain,cab and tires etc. are established in this experiment. All raw data except that of the tires are transmitted through Pro/E, the three-dimensional document to guarantee the accuracy and shorten the time. Secondly the simulations of the vehicle ride comfort with random inputs and pulse inputs were carried out respectively in the virtual environment of ADAMS. In the course of the analysis of vehicle ride comfort, the impute of system is mainly determined by the roughness caused by vehicles treading over the random road at a certain speed, so according to the requirements of GB/T4970-1996《The testing method of the vehicle ride comfort with random inputs》, the simulation of the vehicle ride comfort with random inputs was carried out. The final analysis indicates the heavy truck has better ride comfort when passing on random road, and is able to satisfy the requirements of comfort. Meanwhile according to GB/T5902-1986 national standard《The testing method of the vehicle ride comfort with pulse inputs》, the analysis of the full vehicle ride comfort proved it does no harm to the driver when the heavy truck passed the pulse road. The above conclusions prove Virtual prototyping technology can be used for the simulation analysis of its ride comfort in the preliminary stage of automobile design.Chapter four introduces the formation of driving simulation system briefly. The project adopts 6-DOF parallel connection mechanism as well as its control equipments provided by the engineering robots lab of JLU to complete the driving simulation. The system is divided into motion simulation system and view simulation system. The control system converts the data of automobile pose transmitted from the scene simulation system into the pose data of platform, meanwhile setting 6-DOF parallel connection mechanism to realize automobile posture in scene simulation system to fulfill real-time somatosensory in the course of the driving simulation. Chapter five details the experiment of driving simulation. The experiment goes through every basic operation of a heavy truck driving simulation, for example from starting, braking, acceleration, deceleration, to steering and so on, which validate the interactivity and immersion of the system and complete the driving simulation of a heavy truck in the bumpy road. When there were fluctuations in the terrain, it could simulate the automobile jolted state, and reflect the movement of the driving cab, which further verified the vehicle dynamics model by former establishment.In Chapter six the conclusions are drawn and anticipations are made as to the future research prospects. This project successfully applied the virtual prototype technology to the simulation and analysis of vehicle ride comfort. However a lot more work needs to be done to perfect this theory and its application theory, such as vehicle vibration problems in the virtual environment, the interface between ADAMS and virtual scene, ect.In summary, it is feasible to apply the digital virtual prototype technology into the vehicle system and to conduct simulating analysis by formulating the detailed digital three-dimensional solid model on the computer. With the development of computer technology and softwares the virtual technology centering on the multi-body systematic dynamics will play an increasing role in the research and development, design, comfort analysis and manufacture of the automobile products.