Evaluation And Optimization Of The Ride Comfort Of Hybrid Bus Based On The Handling And Stability

The gradual increase in passenger safety and comfort requirements, leading automotive designers have put forward higher requirements for the ride comfort and handling stability. With implementing strongly the call of "saving energy and reducing emission" in the global, the automotive industry began to study hybrid vehicles (Hybrid Electrical Vehicle, referred to as HEV). The analysis, evaluation and optimization on ride comfort and handling stability of hybrid bus become research focus at present. In this paper, combining with a bus improvement to a hybrid bus, the changes of the structural arrangement and quality parameters were studied, and simulated its ride comfort and handling stability by modeling with ADAMS, and then, the ride comfort evaluation system of hybrid bus based on handling stability was built, at the same time, and the corresponding optimal design theory research were done in depth.(1) Vehicle virtual modeling techniques for ride comfort and handling stability analysisFirstly, for the most complex leaf springs in rear suspension, an improved neutral face method was proposed to build the model, and simulation values was comparatively analyzed with the test stiffness. The modeling method was more high speed and high precision.Secondly, FTire tire model was built and virtual proving ground road was reconstructed. The road roughness measurement test was completed by application of multi-function laser detector. The data was processed by interpolation method. The grid combination road model was reconstructed to provide a realistic testing ground model for bus ride comfort simulation analysis.Thirdly, the high precision rigid-flexible coupling model was established, by which the prototype bus ride comfort and handling stability were simulated respectively, and the performance met requirements.Finally, the simulation results of ride comfort and handling stability of the bus were verified by real vehicle tests that were accurate. So, it is that the vehicle model was accurate, and which provided a biable modeling method and basic reference for the subsequent hybrid bus modeling. (2) Hybrid bus structural arrangement and its effects on ride comfort and handling stabilityWhen the ordinary bus was converted to the hybrid bus, the requirements of the power, economy and energy control should be meet firstly. For the added installation parts, their size and quality were great, especially motor, motor controller, battery modules and other important components. Because of their important roles, their layout position must be designed carefully, so as to change as little as possible the hybrid bus front and rear axle load compared with the original bus, to ensure all of the vehicle performance. Particularly, seven battery modules were divided into three parts and installed respectively, by which ensured hybrid bus performance. Then based on the changes of the vehicle layout parameters, the effect on ride comfort and handling stability of the hybrid bus were analyzed respectively.(3) Ride comfort evaluation method and system development of hybrid bus based on handling stabilityThere was the impact each other between ride comfort and handling stability. Taking into account the analysis results of ride comfort and handling stability of hybrid bus, nearly 30 handling stability evaluation indexes were reduced the dimension, the 10 indexes of the cumulative contribution reached 99% were obtained, and the contribution rate of each index was as the index weight that represent in central angles, the improved handling stability evaluation network map method was proposed. The ride comfort evaluation method on hybrid bus based on handling stability was proposed by combining the weighted RMS values with the most representative of four handling stability evaluation indexes. Finally, the evaluation program was developed by VS2008 C# language, to facilitate the user evaluation.(4) Ride comfort optimization on the hybrid bus based on handling stabilityThe increase of the hybrid bus total mass mad the bus's ride to increase slightly, but the change of layout parameters mad the axle load distribution change, the mass center changing, which led to deterioration of the handling and stability. Aimed to ensure handling stability, optimize ride comfort, analyzed deeply the impact by hybrid bus improved designing and the law of the various factors. To improve the handling stability simultaneously, the front horizontal stabilizer was designed improved, and ride comfort optimization on the hybrid bus based on handling stability was implemented by using the genetic algorithm optimizing neural network method. In addition to stiffness and damper of the suspensions, two body vertical coordinals of the installationed batteries were as the optimization variables, in the premise of ensuring handling and stability of hybrid bus, ride comfort optimization program on hybrid bus was obtained. Finally, the analysis and evaluation on the hybrid bus ride comfort and handling stability after optimization were completed by simulation experiments.The innovations of this paper were,1, improved neutral surface method was proposed to build leaf spring model. When simulating leaf spring stiffness, by board-ball loading way, the stiffness could be simulated more quickly and accurately. It is the foundation of the bus virtual test.2, under the principle of ensuring front and rear axle load little difference from the hybrid bus to the original layout, the important parts added installation, such as the motor, motor controller, battery modules and so on were arranged. A program that battery modules were divided into three parts and installed in the middle frame and the right and left sides of the last paragraph was proposed to ensure hybrid bus performance.3, the improved handling stability evaluation network map method was proposed, the central angels was used to denote respectively the index weights of the handling stability, which could make the scoring of handling stability be saw more easily and intuitively. Then, the ride comfort evaluation method was proposed of hybrid bus based on handling stability. The method could simultaneously evaluate the ride comfort and handling stability easily and intuitively. By using VS2008 C#, the evaluation program of hybrid bus was developed to facilitate to the user.4, Ride comfort optimization method on hybrid bus based on handling stability was proposed by applying genetic algorithm optimizing neural network. In addition to stiffness and damper of the suspensions, two body vertical coordinals of the installationed batteries were as the optimization variables, which effectively taking into account the structure characteristics of the hybrid buses. The method considering the requirements of handling stability, try to optimize the ride comfort of the hybrid bus to accommodate the great pursuit of people's comfort.The paper provides the important simulation modeling method for hybrid bus performances analysis,for example the ride comfort and handling stability, provides a arrangement project for structural design, provides sufficient basis for improved hybrid bus ride comfort evaluation method, and provides new theory to optimize ride comfort of hybrid bus.