基于ADAMS/Car汽车动力学仿真

随着计算机技术及计算方法的不断发展,汽车动力学仿真研究经历了由开环研究到闭环研究的过程。在这一过程中,人们根据不同的研究目的,建立了复杂程度不同的汽车模型。同时为了实际应用的方便性,相关科研人员编制了多种专门用于汽车动力学分析的软件,ADAMS/Car是众多软件中最具代表性的一个软件。通过介绍了ADAMS/Car,然后在ADAMS/Car中对某一具体的车型进行虚拟过弯道后撒手运行,并用ADAMS/Car所提供的后处理功能对运行过程中汽车轮胎受力进行分析。     

沥青混合料转运车螺旋搅拌器机理的研究

运用理论力学的分析方法,研究在沥青混合料转运车搅拌器匀速转动过程中,沥青混合料的运动及受力情况.通过对滑移过渡界面的受力分析,表明当物料堆积角θ与翻滚角α的和接近180.时,物料就可能从螺旋的一边翻滚到另一边.因此,为了使物料能可靠的输送,应控制θ α的值小于180.,这样才能保证生产效率.     

高速大功率柴油机活塞可靠性研究

在高速大功率柴油机研制过程中,通过对整体重力铸造活塞内冷油道、型线与配缸间隙、环槽等细节结构的优化设计、混杂增强铝基复合材料的应用、热机耦合计算分析以及试验验证等4个方面的技术研究,解决了活塞结构可靠性问题,分别通过了部件、台架耐久性考核、道路以及整车环境适应性等试验验证,同时指出了铝合金活塞进一步强化的研究方向。     

半挂车牵引车驾驶室悬置隔振仿真研究

介绍了全浮式驾驶室半挂列车的悬置隔振的仿真研究。在ADAMS中建立了基于整车的驾驶室悬置系统的多刚体动力学模型，并进行了仿真分析。     

Understanding the limitations of different vehicle models for roll dynamics studies

An accurate and realistic vehicle model is essential for the development of effective vehicle control systems. Many different vehicle models have been developed for use in various vehicle control systems. The complexity of these models and the assumptions made in their development depend on their application. This article looks into the development and validity of vehicle models for prediction of roll behavior and their suitability for application in roll control systems. A 14 DOF vehicle model that includes dynamics of roll center and nonlinear effects due to vehicle geometry changes is developed. The limitations, validity of simplified equations, and various modeling assumptions are discussed by analyzing their effect on the model roll responses in various vehicle maneuvers. A formulation of the popular 8 DOF vehicle model that gives good correlation with the 14 DOF model is presented. The possible limitations of the 14 DOF model compared with an actual vehicle are also discussed.     

The perspectives of research for enhancing active safety based on advanced control technology

This paper considers the scope and the methodologies for enhancing active safety of road vehicles by sensing and control technologies. The first part of this paper introduces statistical data of traffic accidents in Japan, and describes the development of the drive recorder for accident/incident survey and analysis. Based on vehicle dynamics data, the algorithm of the drive recorder for capturing near-miss incident data is introduced. The second part of this paper reviews control problems of vehicle dynamics on micro-scale electric vehicles for enhancing vehicle dynamics and driving assistance function. In particular, the direct yaw moment control using in-wheel-motors and the active front steering control algorithm are described. The third part of the paper introduces the advanced driver assistance system adapted to driver characteristics and traffic situations. This part mainly describes an adaptive system, which adjusts the assisting manoeuvre depending on individual driver behaviour and situation, and some experimental investigations using the active interface vehicle and driving simulator. Finally, some perspectives and new challenges for future research on vehicle control technology are mentioned.     

Wheel/rail interface management in heavy haul railway operations—applying science and technology

The primary objective of the paper is to review science and technologies that have been developed by various scientists and engineers over the years and that have made it possible to push the limits within the wheel/rail interface in the heavy haul railway environment. After describing the wheel/rail stress-state and its consequences, preventative and corrective measures that can assist in optimising wheel and rail life, and thus reduce costs, are reviewed. The significant contribution of measurement and monitoring technologies to quantify the stress-state of the wheel/rail system is highlighted. Finally, a brief review of the fundamentals of contact mechanics, vehicle dynamics and wheel/rail interface analysis software is given.     

Real-time capable vehicle-trailer coupling by algorithms for differential-algebraic equations

The real-time simulation of vehicle trains requires an accurate and numerically feasible representation of the vehicle-trailer coupling. Although the equations of motion for the chassis instances can be reduced to systems of ordinary differential equations, additional constraints on the relative motion of vehicle and trailer are introduced when considering the hitch. In this article, we present a strategy for the simulation of vehicle-trailer combinations, where the algebraic constraints of the coupling are treated explicitly. Although this approach allows exact modeling of the respective joint geometry and realistic calculation of the coupling forces, a suitable numerical algorithm is required in order to solve the resulting differential-algebraic system of index 3 in real-time. The implementation in a commercial vehicle dynamics program is discussed and real-time simulation results are shown, which prove its feasibility for different coupling joints and demanding driving maneuvers.     

Human body modelling for traffic accident analysis

A traffic accident is a complex phenomenon with vehicles and human beings involved. During a collision, the vehicle occupant is exposed to substantial loads, which can cause the occupant injuries that depend on the level of passive safety, as well as on the occupant's individual characteristics. Correct estimation of injury severity demands a validated human body model and known impact conditions. A human body modelling procedure for the purpose of accident analysis is introduced. The occupant body has been modelled as a multibody system with rigid body segments connected. Geometrical and inertial properties of individual body segments were estimated using computed tomography. Frontal impact conditions were simulated on a sled test facility, while the human body dynamic response was measured. Comparison of experimental data and computer simulation revealed an influence of joint resistive properties on the occupant motion in collisions. The difference between measured and simulated response was minimised using optimisation method. Individualised human body modelling procedure enabled better prediction of the occupant motion during vehicle collision and thus more precise estimation of possible injuries in real-life traffic accidents.     

Nonlinear PI front and rear steering control in four wheel steering vehicles

Vehicle steering dynamics show resonances, which depend on the longitudinal speed, unstable equilibrium points and limited stability regions depending on the constant steering wheel angle, longitudinal speed and car parameters.

The main contribution of this paper is to show that a combined decentralized proportional active front steering control and proportional-integral active rear steering control from the yaw rate tracking error can assign the eigenvalues of the linearised single track steering dynamics, without lateral speed measurements, using a standard single track car model with nonlinear tire characteristics and a non-linear first-order reference model for the yaw rate dynamics driven by the driver steering wheel input. By choosing a suitable nonlinear reference model it is shown that the responses to driver step inputs tend to zero (or reduced) lateral speed for any value of longitudinal speed: in this case the resulting controlled vehicle static gain from driver input to yaw rate differs from the uncontrolled one at higher speed. The closed loop system shows the advantages of both active front and rear steering control: higher controllability, enlarged bandwidth for the yaw rate dynamics, suppressed resonances, new stable cornering manoeuvres, enlarged stability regions, reduced lateral speed and improved manoeuvrability; in addition comfort is improved since the phase lag between lateral acceleration and yaw rate is reduced.

For the designed control law a robustness analysis is presented with respect to system failures, driver step inputs and critical car parameters such as mass, moment of inertia and front and rear cornering stiffness coefficients. Several simulations are carried out on a higher order experimentally validated nonlinear dynamical model to confirm the analysis and to explore the robustness with respect to unmodelled dynamics.