Applied Mechanics and Materials Vols. 494-495

Abstract: The ergonomics research of the joystick in excavator cab is a problem which requires immediately solution in our country. In this paper, we come to a conclusion that the improved cab takes shorter time and less muscle activity than the previous cab which means that the improved cab have advantage to the previous one in comfort and work efficiency.

Abstract: This paper introduced an advanced electric variable transmission used in hybrid electric vehicle, and analyzed the operating mode in hybrid electric vehicle. For the strong flux coupling of EVT, a kind of split electric variable transmission used in hybrid electric vehicle was expatiated, and the parameters of split electric variable transmission were designed. The simulation model of HEV using the split electric variable transmission was completed using Matlab/Simulink, and the experiment test bench was built. The simulation and experiment results demonstrate the feasibility of the proposed method, and it can be taken as a new theory and method for the study of hybrid electric vehicle.

Abstract: The aerodynamic characteristics of vehicle play a crucial role in steering stability, comfort and safety of vehicle. The crosswind will affect the aerodynamic characteristics of vehicle. In this paper, the aerodynamic characteristics of ASMO model under steady crosswind is simulated by XFlow software, and the changes of aerodynamic characteristics under different steady crosswind are analyzed. It turned out that the asymmetry of wake flow field is enhanced with the increasing of crosswind, and the body surface pressure of windward is amplified, the six components of aerodynamic coefficient are also increased. It is found that the vehicle aerodynamic characteristics changed obviously under steady crosswind.

Abstract: Traditional fatigue analysis approaches could not solve the structure fatigue failure caused by resonances. The time domain simulation approach which took the structural intrinsic property into account was presented to solve vibration fatigue problems. The vibration fatigue failure of the frame of vehicle equipment was studied. Broadband vibration loads were put into the finite element model of the frame as excitations, the stress power spectral density of a dangerous point was calculated. At last, the Dirlik method and the time domain simulation approach were used to calculate the fatigue life. The results show that the damage caused by the first-order vertical flexural vibration is the largest; the result of the time domain simulation approach has a good agreement with the experimental result when compared with the frequency domain method.

Abstract: It is difficult to measure the dynamic characteristic accurately. In the traditional simulation system, some parameters about dynamic characteristic usually are neglected. Aiming to the key problem, this paper presents a simulation calculation method to calculate the engine output power which considers the unstable condition of the actual running. According to the vehicle dynamic equation and actual running conditions of the vehicle, the mathematical model of dynamic characteristic is established. The vehicle dynamic simulation system is developed using the VC++6.0. Measurement experiment of dynamic characteristic of Hover H6 is performed. The experimental results agree well with the simulation results. This indicates that this method can accurately calculate the vehicle dynamic parameters and provide for scientific basis on the vehicle design.

Abstract: Fatigue driving becomes a main hidden danger for traffic safety and endangers peoples life and property seriously.This paper is to obtain the effect of alignments of mountainous highways on driver characteristics. this paper combines with all kinds of theoretical methods and research means on physiology, medical psychology and engineering psychology, then this paper models regression equation on driver's growth rate of Heart Rate and alignments index of mountainous highways, and analyses driver's heart rate variability (HRV). The results show that: when the slope of long downhill is about 3.5%, drivers growth rate of HR exceeds 40%, which is the most nervous state. And during the downhill, the value of LF / HF appears to be rising, which indicates that the more active of the drivers sympathetic nerve, the more likely to be tired. The study has a certain realistic guiding significance on mountain highways slop design and fatigue driving alarm. This acquisition system is easy to operate with high accuracy which can meet the all-weather, dynamic monitoring and real-time processing requirements. Aim at the national highway 321 that from Guilin to Longsheng, the research on the design and revise of the highway slope has a certain realistic guiding significance.

Abstract: A conjoint simulation of suspension system and brake system is proposed based on vehicle braking performance and ride stability. A half car simulation model is built applying the software of MATLAB in which the dynamic load is used to control the active force for suspension system and adjust parameter value of ABS (Anti-lock brake system). The suspension system and ABS construction of the half car simulation model is illustrated in detail. Using the simulation model, the braking distance, the stroke for suspension and the pitch angle of body are measured in three status which include the individually control for active suspension, the individually control for ABS and the integration control respectively. The simulation data show that the integral control method synchronously ensures braking stability and riding stability.

Abstract: A design method of integrated control for suspension system and steering system is proposed based on vehicle ride comfort and handling stability. A car simulation model is built applying the software of MATLAB and ADAMS. The construction and characteristic of the integrated simulation model of the suspension system and steering system is illustrated in detail which uses fuzzy method and PID method. Using the simulation model, body vertical acceleration, roll angle and yaw angular velocity are measured in three status which include no control condition, the individually control for active suspension, and the integration control respectively. The simulation data show that the integrated control method synchronously ensures the ride comfort and handling stability.

Abstract: Interlinked air suspension, which formed by interconnecting two or more air springs of traditional air suspension using switchable pneumatic pipe connections, can further improve vehicles riding comfort and driving stability. The structure and working principle of this suspension is introduced, the model of interlinked air suspension is developed and validated via experiments. Simulation results indicate that, the larger the diameter of connecting pipe, the smaller the stiffness of air springs, and interlinked air suspension can effectively reduce vehicles roll angle and vertical vibration under its first natural frequency, which greatly affects vehicles riding comfort.

Abstract: Based on the hydro-mechanical continuous variable transmission (HMCVT) of 400 house-power of Dongfanghong, the synchronization in period of contions to content to multiple period of HMCVT was established by analyzing its transmission principle, and the relation fomulas of power distributing ratio and efficiency was presented. That results showed that the characteristics of power flow at the first half and at the second half were different, when it was within the certain grade to do the boundary of e equaled with zero; while it was each grade in section points, that characters were the same; the more grades, the greater HMCVT system transmitting power and the higher the transmission efficiency of the entire system. The high efficiency features of multiple range hydro-mechanical stepless transmission, meet the requirement of tractor operation.