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The problem of inaccurate results was presented based on irregular shell finite element analysis using traditional modeling methods,a finite element modeling method was presented based on simplified of transmission components. The paper introduced the bearings,gears and fasteners of simplified model method. For example,finite element analysis of automobile main reducer shell based on finite element software environment. Two finite element analysis models were established based on traditional method and simplify component method; Comparing simulation results of the two models found: stress distribution on the overall trend of automobile main reducer Shell was the same,but the value of the local area to install the bearing stress positions were quite different. Stress tests show in 100 N. m,200 N. m and 400 N. m of input torque main reducer: Simplified model approach closer to actual value of test results,verify the correctness and accuracy of the method.

With the application of active control technology in vehicle, the performances of vehicle such as riding comfort, active safety and handling stability were greatly improved in recent years. However, most of these control systems were aimed to improve individual performance of vehicle respectively. In fact, the improvement of the overall vehicle dynamics performance not only depends on the cooperative work among these various control subsystems but also depends on the coupling interferences of the mechanical structure and control system of vehicle in the running process. In order to remove the coupling interferences between the mechanical structure and control system of vehicle chassis system and to further enhance the overall performance of vehicle, the method of simultaneous optimization of mechanical structure and controller parameters of vehicle chassis system based on Particle Swarm Optimization Algorithm is presented in this paper. According to the fundamental principle of vehicle dynamics, a half car mode of active suspension system and anti-lock braking systems established at first. Then the linear quadratic gauss controller of the active suspension system and sliding mode controller of anti-lock braking system are designed. Taking controllers designed for active suspension system and anti-lock braking system as bottom controllers, the upper coordinated control logic of the systems is put forward and the upper PID coordinated controller is designed on the basis of analyzing the coupling conflict between active suspension system and anti-lock braking system. Finally, a Particle Swarm Optimization Algorithm was adopted for simultaneous optimization of mechanical structure and controller parameters of vehicle chassis integrated control system, because the traditional design method of a vehicle system is always to design control parameters following structure parameters and it can not obtain the global optimal performances for the system. In order to verify the effectiveness of the algorithm, the simultaneous optimization program is developed based on Particle Swarm Optimization Algorithm in MATLAB environment while the mechanical structure and control parameters of chassis control system are set as optimization variables and the overall vehicle dynamics performance is set as objective function. Simulation result shows that the pitching angular acceleration of vehicle is reduced and vehicle riding comfort performance is improved after optimized. Braking distance and dynamic load of front and rear wheels of vehicle are also reduced significantly which indicating vehicle active safety is improved dramatically. The vehicle road test was also carried out based on integrated controller is development of anti-lock braking system and active suspension system using ARM7 when vehicle speed is 40 km/h under braking condition. The road test also shows that the dynamic load of front and rear wheels of vehicle are reduced by 34.20% and 34.10%, braking time and braking distance of vehicle were reduced by 2.31% and 4.50% respectively, the response of vehicle pitching angular acceleration at braking condition is decreased by 15.10% after optimized, and both vehicle active safety and riding comfort are improved at different levels. [ABSTRACT FROM AUTHOR]

In order to investigate the characteristics of air-oil two-phase turbulent flow inside the shell of transfer case, the research method to combine test and numerical simulation is proposed to take analysis. The fluid-structure interaction theory (FSI) is a science to research the interaction and influence between fluid and structure fields, and is applied to research single-direction influencing characteristic from gears rotation to air-oil field flow. The gears of the transfer case transfer power via meshing and rotating, their movement is imitated by dynamic mesh technology is fluent. Fluent UDF definition is used to define the parameters of dynamic mesh control. The fluid field inside the shell of the transfer case has two phases: air and oil. It starts to move and show its fluid characteristics in close relationship with the motion trail of gears. The air-oil fluid field belongs to a two-phase model. It is simulated by the VOF model is fluent. The interface of gas and liquid is defined by fluent UDF definition. High speed photography is the application of advanced photographic technology for high-speed motion characteristics of a clear picture. It is used to observe high-speed motion characteristics. With a transparent shell, the transfer case assembly is installed on the test bench for the observation test. The movement of air-oil fluid field has been observed after high speed photography. The results show that, during 0-0.5T moment, driven gear to rotate with oil plays a main role in the meshing zone lubrication; at 0.25T moment, gears start to mesh and rotate, oil fluid field wave; at 0.375T moment, the gear meshing area is filled with lubricating oil; at 0.5T moment, the continuous oil inflow meshing zone above, and cover the gear meshing area of tooth surface, achieve initial lubrication. The vortex phenomenon appears near the meshing zone in the velocity streamline. The speed near the wall is higher than the other zone. The velocity streamlines into and out of the meshing zone more effectively. After the pressure field stabilizes, the flow field pressure maximum value appeared in the gear meshing area; two phases of flow field in the shell are uniform, the middle of the fluid pressure is relatively small; negative pressure appears below the driven gear part. The numerical simulation results coincide with the test. The analysis results are true and valuable. [ABSTRACT FROM AUTHOR]

A controller for vehicle electronic stability program (ESP) based on direct yaw-moment control (DYC) strategy is designed with nonlinear H∞ feedback control adopted as DYC algorithm. A nonlinear observer is built for accurately estimating the longitudinal and lateral velocities of vehicle. An actuator allocation module is also designed to distribute actuator resources for all sub-controllers to prevent conflict in operation between DYC and ABS or ASR systems and ensuring the normal execution of multi-functions of ESP. An ESP controller is autonomously developed based on processor ARM7 and a platform for hardware-in-the-loop (HIL) test is constructed. The results of HIL test verify the effectiveness of the control strategy. [ABSTRACT FROM AUTHOR]

A virtual prototype model for four-wheel-steering vehicle is built with ADAMS/Car software and a hybrid control system is designed based on yaw rate feedback and neural network adaptive control. The system effectively solves the nonlinear problem of tire at large sideslip angle, Speeds up and facilitates the on-line correction of weighting coefficients of neural network and endows the system with self-adaptive ability. The results of theoretical analysis and simulation show that the hybrid control system built for four-wheel-steering vehicle is feasible and the ADAMS / MATLAB co-simulation method adopted is effective. [ABSTRACT FROM AUTHOR]

A new type of solenoid-actuated shock absorber with continuously variable damping is studied. Its structural features and working principle are analyzed, the hydraulic model and the mathematic model for compress and rebounce strokes are established and its damping characteristics are simulated. Meanwhile a corresponding test is also conducted on a single-channel electro-hydraulic servo tester. The results of simulation agree well with test data, indicating that the model established for solenoid-actuated shock absorber is relatively accurate and can be used for the research and development of solenoid-actuated shock absorber with continuously variable damping. [ABSTRACT FROM AUTHOR]

The characteristics analysis and decoupling study on the active mount system of powertrain are conducted in this paper. Firstly, the approximate linear model and analytic model for the active mount system of powertrain are set up and verified. Then with the complete response decoupling in torque roll axis direction at idle speed and the rational allocation of natural frequencies as objectives, and using Pareto genetic algorithm, a decoupling optimization on the parameters of the passive part of active mount and the position and stiffness of each mount is performed. Finally the results of optimization are verified by simulation, indicating the effectiveness of decoupling scheme adopted. [ABSTRACT FROM AUTHOR]

In view of the problems of high order and difficulty in engineering implementation of vehicle suspension controller, a 7 DOF active suspension model is built, and with consideration of the sensitive frequency range of human body to vibration, the weighted H∞ controller is designed to ensure the good stability and disturbance rejection performance of closed-loop system. By using minimum information loss method, the order reduction for 20 order active suspension controller is studied. The results of comparison between active suspension closed-loop control systems before and after order reduction in terms of frequency characteristics and ride comfort demonstrate that with the controller order of active suspension system reduced from 20 to 8, the sum of controllable and observable state information loss is less than 50 % while the control performance of controller kept basically similar. [ABSTRACT FROM AUTHOR]