Optimization Of Suspension Hard Point Based On Complete Vehicle Handling Stability

With the popularization of automobiles and improvement of speed, the traffic accidents increase year by year and the safe driving problem of automobiles becomes one of the problems of big concern. However, the handling stability of automobiles is the important cause for the traffic accident. Based on the project "independent research and development of a type of vehicle of Chinese Automotive Technology & Research Center", the influence of suspension hard point on the operation stability is researched, and based on the complete vehicle operation stability, research is conduced on the optimization design of position of suspension hard point.First, the evaluation method of the complete vehicle operation stability is introduced and analyzed, and after comparative research, it is determined to adopt the operation stability evaluation system based on the total square division method, and the double land-change test and slalom test roads involved in this evaluation system are designed, in which the setting of double lane-change test road is by reference to ISO/3888 standard, and the setting of slalom test method is by reference to GB6323-94 standard.Then, the multi-body dynamics simulation model of subsystems like suspension system, tire system and steering system is established, and the subsystem model established is tested and verified accordingly. The models of tested suspension, tire and steering systems are assembled together to establish the multi-body dynamics simulation analysis model of the complete vehicle system. Through the test of real vehicle, the test is compared with the simulation analysis result, and it is verified that the complete vehicle model meet the accuracy requirements.Finally, perturbation method is used for sensitivity analysis to the key hard points of the front and rear suspensions based on the complete vehicle stability, and the coordinates of hard points with a great influence on the complete vehicle stability are obtained. On this basis, the hard point coordinates of the front and rear suspensions are optimized through the joint simulation of ISIGHT and Adams. The optimization algorithm is multi-island genetic algorithm and the optimization objective is to obtain a better operation stability of vehicles. Through the comparison the vehicle body side rake angle and yaw velocity before and after optimization of hard point coordinates under the work conditions of double-lane test and slalom test, it can be seen that after hard point optimization, the operation stability of the complete vehicle is improved.The joint simulation of ISIGHT and Adams is attempted to adjust the suspension hard parameters on the level of complete vehicle, and through the comparison of performance parameters before and after optimization, the correctness of this method is verified, which provides certain reference value for the reasonable layout of suspension hard point and improve the operation stability of the complete vehicle in project.