Modeling And Simulating Of 4WD Vehicle Driveline Object To Structure On ADAMS

When driving on roads like slopes, fields and icy roads, cross-country vehicles become drivers'first choice for their excellent starting acceleration, transition and grade climbing ability. The collocation form of cross-country vehicle driveline is mostly 4WDl drive. In the design of its driveline, the method often adopted is to evaluate the design by setting up the multi-body dynamics model of driveline through virtual sample machine technology and simulation analysis.At present, the setting up of multi-body dynamics model of driveline is mainly function oriented, i.e. to make certain that the various parameters of the model set up are in accordance with the driveline designed, and pay little attention to its structure. With the spread of simulation software ADAMS in dynamics and researches on the setting up of models in dynamics, however, the multi-style dynamics model which is structure-oriented becomes extensively applied for its visual and precise features. The present research concentrates on the study of the driveline with four-wheel drive and sets up the multi-body dynamics model which is structure-oriented. The main tasks are as follows:With a certain 4WD vehicle as the main research object, the present research tries to make certain its key position point through the 3D-digital model. To simplify the actual driveline model on the premise that it will not affect its actual function. The simplifying process adopts the method of laying equivalent restriction, i.e., to analyze the movement essence of the structure to be simplified in order to lay restriction on it and get rid of redundant complicated rigid bodies. In this way, abstract movement can berealized and the number of rigid bodies is reduced to improve the effectiveness of modeling and simulation. Finally, the research will make certain the concrete parameter of the driveline set up according to the related actual parameter.Under the ADAMS/Driveline, the present research will set up the model of driveline with four-wheel drive. The existing modules of engine, gear-box and clutch in the software will undergo a hard point amendment according to the key position point in the 3D-digital model. The performance parameter of the modules will be amended according to the related actual parameter. Besides, the research will reset up the communicators by analyzing the connecting relation among various parts. The modules which are not included in ADAMS/Driveline such as reducer, torque divider,wheel reducer and transmission shaft should be set up independently: to set up new structural rigid bodies in the right position according to the simplified structure, and to lay equivalent restrictions on the rigid bodies properly. In order to realized the transmission route of the driveline with four-wheel drive, after setting up the rigid bodies and restrictions, the former transmission route of AWD modules should be cut off and new communicators and restrictions should be reset. Finally, the various modules set up will be connected by the communicators to form the model of driveline with four-wheel drive, and the model will undergo a freedom-restriction analysis.At the initial stage in simulation, the research will take a simulation test on the working state of the reverse gear and the clutch of the driveline. The test will be based on the obverse and reverse input and disconnection-connection of the clutch provided by the system. Then the research will set up the typical working situation of starting acceleration, icy road and slopes by amending the input moment and road surface parameter under the ADAMS/Driveline simulation environment. In order tomake the simulation process comparable, the research adopts the sample vehicle with rear wheel drive. The parameters of transmission scale, whole vehicle weight and tire structure of the sample vehicle are amended in order to make the model in accordance with the sample vehicle in the parameters except for the collocation form of the driveline. After the simulation comparing between the sample vehicle and the model in every typical working situation, the findings are got suggesting that the structure movement of the setup driveline with 4WDl drive is in accordance with practice; the driveline has advantages over the sample vehicle with rear wheel drive in performance; and the driveline is more suitable to the actual structure and performance of 4WD vehicles.