Modeling, Simulation And Analysis Of Automotive Handling And Stability Based On CarSim

Presently the automobile industry in China is booming, but Chinese automobile enterprises are still weak in independent research and development. The competition among enterprises is ultimately the competition of management and technology. Therefore the outlet for Chinese automobile industry is to develop independent brand with independent key technology and improve self-development ability. In the process of automobile development, the important factors are information and virtualization, that is, the full-scale introduction of simulation techniques to realize the simulation in the entire process, the reduction of the number of testing and production cost, and the shortening of the development cycle of new cars, which altogether can ensure the improvement of enterprises' technique and competitive strength.Vehicle dynamic simulation is an essential part of automobile simulation techniques. The application software of vehicle dynamic simulation can be classified into two types: the multi-body software like ADAMS and Simpack; the property software like CarSim and CarMaker. The former type based on the theory of multi-body systems can simulate automobile-configuration directly but it needs a large amount of work in obtaining the information of hard points, mass and moment of inertia. Also the multi-body software is characterized by complicated debugging process and low simulation speed. The latter one based on the theory of vehicle dynamic needs the input of property parameters and property curves of automobile. The property software is characterized by relatively simple debugging process and high simulation speed. Presently the application of the multi-body software like ADAMS is more popular and the understanding about it is relatively deep. While the study and application of the property software like CarSim is still in infancy and needs to be improved. This study is carried out based on the experimentation and the simulation in the project of "An analysis of the chassis of a testing car". The research process and the corresponding conclusions are as follows:First, subsystem tests have been carried out. Based on the results of these tests, the CarSim model of the testing car has been built and debugged, which aims at deepening the knowledge about CarSim software modeling, obtaining more experience of building whole-car CarSim models and debugging, and preparing for further simulation analysis with CarSim software. The conclusion is drawn from the experimentation: in CarSim the obtaining of subsystem properties takes up a large amount of work; the debugging process of CarSim is more simple and the simulation speed is faster.Then, automotive handling and stability tests have been carried out and a preliminary analysis of the handling and stability has been made based on the results of the experimentation. On the one hand, the performance testing and evaluating analysis of the testing car is an important section in automobile development. On the other hand, the results of handling and stability tests can be used to make a comparison with the results of simulation. The conclusion drawn from the handling and stability tests is: the returnability of the testing car is relatively bad but the total handling and 1 stability is relatively good.Finally, the open-loop simulation of handling and stability in CarSim has been carried out and the results have been compared with those of the handling and stability tests to validate the simulation precision of CarSim models, and the diver modle has been added to carry out the close-loop simulation of some typical tests and make close-loop evaluation, which helps to deepen the knowledge about the simulation precision of CarSim software and realize the application of this software in engineering practice and further development of automobiles. The corresponding result is: CarSim software has a high level of simulation precision and can be applied in the open-loop and close-loop simulation on automotive handling and stability. To sum up, the attempt to apply CarSim software in the simulation of handling and stability can be used in further development. In the further research, software like ADAMS and SuspesionSim can be combined with CarSim for better analysis. For example, the positions of the hard points or the stiffness of the rubber lining in SuspesionSim can be changed for virtual suspension K&C tests. Due to the fast simulation speed and high degree of precision of CarSim, the results can be inputed to CarSim for the open-loop and close-loop simulation on automotive handling and stability, in which the effect of the change of suspension on the automotive handling and stability can be observed and therefore the improvement of suspension can be guided.