列车动力学模型的研究

研究了列车动力学计算模型的建立方法 ,给出了列车系统状态矩阵的构成及其计算方法 ,采用SIMULINK仿真工具 ,建立了多车编组的垂向和横向列车模型。分别对列车的垂向和横向列车动力学进行了实例计算 ,说明了在高速动车组中采用列车计算模型分析各车辆间悬挂作用的必要性和有效性。     

反吊桥主缆索张拉过程分析

以拟定的某反吊桥方案为对象 ,对张拉主缆索调整主梁应力过程及张拉主缆索过程中全桥的整体稳定性作了计算分析。结果表明 ,张拉主缆索可以显著地改善反吊桥主梁的应力。     

刚性接触网的不平顺分析

研究目的:刚性接触网的不平顺会激发受电弓和刚性接触网之间的有害振动,破坏受流,影响行车安全。在我国对刚性接触悬挂不平顺的研究刚刚起步,所以对刚性接触网不平顺进行分析是十分必要的。研究方法:对刚性悬挂不平顺进行数值模拟分析以及推导受电弓与接触网系统的计算模型。研究结果:推导出了刚性接触悬挂的受流性能由2个方面决定,一是受电弓的受流特性,二是刚性接触悬挂的接触面的不平顺值。研究结论:刚性接触悬挂的不平顺是研究受电弓与刚性接触网系统振动的基础,减少刚性接触悬挂的不平顺,受流质量将得到提高。     

New model and simulation of Macpherson suspension system for ride control applications

The main purpose of this paper is to propose a new nonlinear model of the Macpherson strut suspension system for ride control applications. The model includes the vertical acceleration of the sprung mass and incorporates the suspension linkage kinematics. This two-degree-of-freedom (DOF) model not only provides a more accurate representation of the Macpherson suspension system for control applications in order to improve the ride quality, but also facilitates evaluation of the suspension kinematic parameters, such as camber, caster and king-pin angles as well as track alterations on the ride vibrations. The performances of the nonlinear and linearised models are investigated and compared with those of the conventional model. Besides, it is shown that the semi-active force improves the ride quality better than active force, while the opposite is true in terms of improving the performance of the kinematic parameters. The results of variations of the kinematic parameters based on the linear model subject to road disturbances are compared with those of a virtual prototype of Macpherson suspension in ADAMS software. The analytical results in both cases are shown to agree with each other.     

Fault detection of vehicle suspension system using wavelet analysis

This paper presents a method based on continuous wavelet transform to detect the faults of vehicle suspension systems. The Morlet wavelet functions are employed to approach the natural frequencies of the system and the frequency components of the signal with relative maximum energy. To evaluate our method, we use a full vehicle dynamic model which has been simulated in ADAMS/CAR and validated by laboratory test results. The suspension faults have been considered due to the damage of shock absorbers (dampers) and upper damper bushings (UDBs) and assumed as the decrease in damping force and loose joints, respectively. In this paper, the incapability of the spectral analysis by using fast Fourier transform in analysis of the signals is revealed through applying the inputs that include transient characteristics and then wavelet transform employed to achieve more proper results. A swept frequency is applied as an input to the wheels that simulates the road irregularities. After detection of faulty sections of the system using signal energy distribution, the defects of damper and UDBs are distinguished from each other through observing the changes of natural frequencies and corresponding energy amplitudes.     

Multiphysic modelling of railway vehicles equipped with pneumatic suspensions

This article presents a multidisciplinary approach of railway pneumatic suspension modelling: both multibody and pneumatic aspects are taken into account. The work aims at obtaining a realistic model of the secondary suspension and coupling it with a multibody model of a train. Various components of the pneumatic circuit such as bellows, tanks, pipes and valves are taken into account. The article focuses on the bellow–pipe–tank subsystem for which several modelling approaches are presented and compared. Differences between differential and algebraic models are highlighted, and an application-dependent choice between them is suggested. A complete model of the pneumatic circuit is then obtained and coupled with a multibody model of the train. As a result, the behaviour of a suburban train equipped with a pneumatic secondary suspension is analysed, in particular undesired oscillating motions which affect the comfort. Topological modifications and improvements of the suspension are also investigated and discussed.     

Lateral Vehicle Behaviour: Comparison of Subjective/Objective Assessment Using the Choquet Integral

This paper presents an original method for the aggregation of transverse behaviour indicators obtained first from a subjective assessment then from an objective one of different vehicles tested under normal working conditions. The Choquet integral is used with respect to fuzzy measures. The main advantage of this method is to take account of the existing interactions between the indicators: redundancy, complementarity, inde-pendence. When this tool is used for subjective and objective evaluations, the computation methods of the objective indicators can be validated. Moreover, the influence of the human factor in the judgment of vehicle behaviour is easier to understand.     

悬索桥主缆成桥线形确定的有限元新算法

为提高悬索桥主缆线形确定的有限元算法的执行效率,对单悬索结构ANSYS程序找形原有算法的不足进行分析,提出模型更新位移预测和残差补偿算法。该算法通过主动预测的变步长来更新模型,并采用有效方法来处理大步长更新所带来的不利后果。采用该新算法对2座桥进行计算,结果表明该新算法找形分析的计算结果可靠,计算精度及效率高。     

A study of locomotive driver's seat vertical suspension system with adjustable damper

This paper shows that laboratory measurements can be used for the identification of structure and parameters of commercial seat vertical suspension system model. A commonly used single-degree-of-freedom suspension model does not suffice. The system model presented is based on Zener's structure and clearly describes the dynamic properties of a vertical seat suspension with an adjustable damper. The model introduced, augmented with seat cushion dynamic model, predicts the seat vertical vibration mitigation properties under field conditions with a reasonable accuracy. Optimisation of the adjustable damper setting is performed using a two-objective function optimisation technique. This enables us to optimise not only the exerted vertical vibration acceleration but also the seat relative vertical displacement (stroke). Optimisation was facilitated for the particular suspended seat without the requirement of further field measurements. In addition, a two-parameter optimisation was performed showing possible further improvement in both objectives at the manufacturer's discretion. This study could be representative of driver's seats equipped with vertical seat suspension system using an air-spring and an adjustable damper.     

Application of observer-based fault detection in vehicle roll control

This paper describes how observer-based techniques for intelligent fault detection were applied to monitoring an active suspension control system in an experimental articulated heavy vehicle. The aim was to define a practical method for detecting faults, taking into account the nonlinearities of the vehicle. The experimental vehicle was divided conceptually into subsystems, namely the passive dynamics of the trailer, the dynamics of the hydraulic actuators, and the expected response of the closed-loop system. A linear dynamic model was designed for each subsystem. A fault detection observer was then designed for each dynamic model. The observer feedback gains were chosen to optimise estimation by the observer residual of specified errors on the output measurements. The observer residuals were then normalised and combined logically to provide a fault diagnosis. The performance of the fault detection scheme is demonstrated in the case of sensor faults and changes in the operation of the active control system.