An innovative degraded adhesion model for railway vehicles: development and experimental validation

Meli, Enrico; Ridolfi, Alessandro; Rindi, Andrea

doi:10.1007/s11012-013-9839-z

Cited by 10 publications

(10 citation statements)

References 42 publications

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“…According to the method introduced in Meli et al (2014), the transfer functions γ 1 ( p s ) and γ 2 ( E ) of each axle can be calculated, respectively, according to the test data of each axle of the train, and then the adjustment parameters λ 1 and λ 2 can be obtained based on the least square optimization method. In this paper, according to the test data of train axle speed given in Figure 1, the optimized adjustment parameters λ 1 = 5 × 10 −4 (s/ J ) and λ 2 = 2.5 × 10 −5 (1/ J ) are obtained.…”

Section: Methods and Modelsmentioning

confidence: 99%

“…Some previous preliminary papers were focused on the “global” degraded adhesion models (i.e. models involving global sliding/creepages and forces) (Allotta et al , 2014; Ridolfi and Meli, 2015; Meli et al , 2014) and the Polach theory was extended to take into account the degraded adhesion effects (Polach, 2005; Pombo et al , 2007). A new “local” degraded adhesion model is presented directly connecting local sliding/creepages inside the contact area to the local contact pressures.…”

Section: Introductionmentioning

confidence: 99%

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An improved degraded adhesion model for wheel–rail under braking conditions

Zhu

Zheng

et al. 2021

ILT

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Purpose The purpose of this paper is to develop an improved adhesion model to better reproduce the low adhesion condition of the anti-skid control for rail vehicles under braking condition. Design/methodology/approach In view of the low adhesion characteristics for rail vehicles under braking conditions, the Polach adhesion model was improved based on the sliding power and sliding energy. The wheel–rail low adhesion model suitable for braking condition was given. The analysis of braking anti-skid control under emergency braking condition was carried out through the co-simulation, and compared with the test data; the effectiveness and practicability of the improved low adhesion model were verified. Findings The results showed that the improved adhesion model is simple and efficient and the parameters involved are less, and it can be directly applied to the real-time simulation of anti-skid control in the process of train braking. Originality/value This paper can provide a theoretical reference for the reasons of change and improvement of adhesion between wheel and rail caused by the adjustment of braking force under anti-skid control, which can fulfill a need to the study of sliding energy on the contact surface, the removal effect of pollutants on the wheel–rail surface and the improvement and recovery of adhesion caused. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0244/

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Section: Methods and Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An improved degraded adhesion model for wheel–rail under braking conditions

Zhu

Zheng

et al. 2021

ILT

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“…Here, u is a unit step function and x represents change in the draft gear position. The friction coefficient is usually modeled [14] as: As a matter of the fact, too many parameters have important role in the internal draft gear interaction forces: the friction-wear interaction, Draft gears are subject to wear during their life-time and wear alters the dynamical performance of the system [20,21], effects of third body at the contact surfaces (contaminants, friction modifiers, lubricants, etc. ).…”

Section: Coupler Modelingmentioning

confidence: 99%

Effects of the change in auto coupler parameters on in-train longitudinal forces during brake application

Mohammadi

Serajian²

2015

Mechanics & Industry

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For long freight trains, the pneumatic brake systems are still used. In these situations, the cars at the end of the train brake a few seconds later than those wagons at the front. This variable braking action along the train may cause large longitudinal forces and impacts. Beside brake system parameters, auto coupler characteristics parameters have high importance in longitudinal train dynamics. Therefore, simulations of effects of the change in auto coupler parameters on in-train longitudinal forces during brake application are very important both for safety and economic reasons since longer freight trains imply higher transport costs reductions. In the present paper, effects of the change in coupling parameters such as stiffness, damping, and clearance and train speed, on the longitudinal train dynamics were investigated during brake application. The results indicate dramatic changes in the way that cars interact dynamically with each other and the magnitudes of the in-train longitudinal compression and tensile forces along the train. The freight train considered is in current use by Iranian Railways.

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“…This is an important aspect and in-time adhesion model law were used for the simulations. [26,27,36] (Figure 4) In Table 1, the main properties of the rail vehicle are shown. In Table 2 the elastic characteristics of the connection elements are displayed.…”

Section: Multibody Model Of the Railway Vehiclementioning

confidence: 99%

“…[21][22][23][24] The sensor outputs have been simulated through a 3D multi-body model of a railway vehicle, able to reproduce also the critical conditions under degraded adhesion. [25][26][27] In particular, to reproduce the motion of the railway vehicle an industrial robot with a custom IMU on its end-effector has been used: the performance of the proposed localisation algorithm have been thus evaluated. This approach permits to avoid expensive on track tests and the preliminary achieved results show a significant improvement of the position and speed estimation performances compared to those obtained with classical ODO algorithms, e.g.…”

Section: Introductionmentioning

confidence: 99%

An innovative localisation algorithm for railway vehicles

Allotta

D'Adamio

Malvezzi

et al. 2014

Vehicle System Dynamics

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In modern railway automatic train protection and automatic train control systems, odometry is a safety relevant on-board subsystem which estimates the instantaneous speed and the travelled distance of the train; a high reliability of the odometry estimate is fundamental, since an error on the train position may lead to a potentially dangerous overestimation of the distance available for braking. To improve the odometry estimate accuracy, data fusion of different inputs coming from a redundant sensor layout may be used. The aim of this work has been developing an innovative localisation algorithm for railway vehicles able to enhance the performances, in terms of speed and position estimation accuracy, of the classical odometry algorithms, such as the Italian Sistema Controllo Marcia Treno (SCMT). The proposed strategy consists of a sensor fusion between the information coming from a tachometer and an Inertial Measurements Unit (IMU). The sensor outputs have been simulated through a 3D multibody model of a railway vehicle. The work has provided the development of a custom IMU, designed by ECM S.p.a, in order to meet their industrial and business requirements. The industrial requirements have to be compliant with the European Train Control System (ETCS) standards: the European Rail Traffic Management System (ERTMS), a project developed by the European Union to improve the interoperability among different countries, in particular as regards the train control and command systems, fixes some standard values for the odometric (ODO) performance, in terms of speed and travelled distance estimation. The reliability of the ODO estimation has to be taken into account basing on the allowed speed profiles. The results of the currently used ODO algorithms can be improved, especially in case of degraded adhesion conditions; it has been verified in the simulation environment that the results of the proposed localisation algorithm are always compliant with the ERTMS requirements. The estimation strategy has good performance also under degraded adhesion conditions and could be put on board of high-speed railway vehicles; it represents an accurate and reliable solution. The IMU board is tested via a dedicated Hardware in the Loop (HIL) test rig: it includes an industrial robot able to replicate the motion of the railway vehicle. Through the generated experimental outputs the performances of the innovative localisation algorithm have been evaluated: the HIL test rig permitted to test the proposed algorithm, avoiding expensive (in terms of time and cost) on-track tests, obtaining encouraging results. In fact, the preliminary results show a significant improvement of the position and speed estimation performances compared to those obtained with SCMT algorithms, currently in use on the Italian railway network.

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An innovative degraded adhesion model for railway vehicles: development and experimental validation

Cited by 10 publications

References 42 publications

An improved degraded adhesion model for wheel–rail under braking conditions

An improved degraded adhesion model for wheel–rail under braking conditions

Effects of the change in auto coupler parameters on in-train longitudinal forces during brake application

An innovative localisation algorithm for railway vehicles

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