The paper proposes the implementation of a control system for a variable-geometry suspension to achieve steering functionality. The implementation is performed in a Hardware-in-the-Loop (HiL) simulation environment with a unique suspension test bed. The purpose of the control system is to achieve path-following functionality for the vehicle with automatic steering based on the proposed system. The

ABSTRACT Rail accelerations can be used on the defect detection and health monitoring of railway vehicle and track components; therefore, mathematical models that predict this response are of interest for reproducing its behaviour in a wide range of situations. The numerical track models based on the Timoshenko beam theory introduce a non-physical response, which is especially noticeable in the rail

The drive torque for each motor can be performed independently for the distributed drive electric wheel loader (DDEWL). On the shovelling condition, the torque distribution can be optimised according to the tire load. Then the parasitic power and wheel slippage can be reduced, and the tractive force and efficiency are improved. In this study, the singular value decomposition unscented Kalman filter

The road condition is complex and variable during driving; hence, the suspension system cannot easily suppress the vertical vibration of the vehicle. To effectively improve the vehicle dynamic performance under different road conditions, this study proposes a switching control strategy for the semi-active suspension based on the road profile estimation. First, the mapping relationship between different

ABSTRACT This study deals with drifting as one of the most important nonlinearities in vehicle dynamics. A four-wheel vehicle model is used to calculate the equilibria in planar motion, numerically, by introducing an assumption on constant longitudinal tyre slips. Other than the unstable drifting points that were reported by previous researchers, a new pair of drifting equilibria are identified and

The draft gear is a key component in a railway train system. The stochastic feature of dry friction in the draft gear has been observed by many researchers, however, characterisation studies in this regard have not been published. This paper used a state-of-the-art laboratory testing rig to measured draft gear forces and deflection responses to sinusoidal force inputs. Measured data were then inversed

Development of railway transportation capabilities towards high-power, high-speed and heavy axle-load makes the dynamic interactions between the electric drive subsystem and the mechanical subsystem of a locomotive more intensive and complicated, which may threaten the locomotive operational safety. However, the included dynamics mechanism and influencing law have not been revealed completely. Based

ABSTRACT For modern electrical rail systems, the pantograph-catenary dynamic performance is one of the most critical challenges. Too much fluctuation in contact forces leads to either accelerated wear of the contacting components or losses of contact and, consequently, arcing. In this work, inertance-integrated pantograph damping systems are investigated with the objective of reducing the contact force

Railway track models with sloped subgrade ends, are commonly used in studies of train. In the present work, the effect of subgrade-end slope under a yaw angle of 30° was investigated by delayed detached eddy simulation (DDES) using one-eighth-scale train and single-track rail models. The obtained results were validated with wind tunnel tests. Time-averaged aerodynamic coefficients, pressure distribution

Reducing derailments of freight trains is of utter importance for improving railway transportation since derailments lead to large service disruption, economic losses and risk related to transported goods. The present paper studies low-speed (below 30 km/h) derailment of freight trains, performing experimental full-scale tests, using an instrumented wagon equipped with a commercial derailment detector

A method called modified modal superposition method (MMSM) for calculating the vibration fatigue dynamic stress of carbody under shaking condition is proposed. In MMSM, each external load is divided into low frequency component and high frequency component according to critical frequency (CF), which is used to separate whether the external load causes resonance effect of the structure, then traditional

This paper aims to develop an integrated adaptive control strategy to control vehicle lateral dynamics. A hierarchical control scheme consisted of two control levels is designed to keep the vehicle handling and improve yaw stability control using the coordination of active front steering (AFS) and direct yaw moment control (DYC). At the upper control level, the desired yaw moment and additive steering

ABSTRACT A method to solve minimum-lap-time problems using quasi-steady-state models and free (i.e. not predetermined) trajectory on two-dimensional tracks has been recently proposed. This work describes the extension of the method to three-dimensional tracks and builds upon g–g–g diagrams (instead of the standard g–g), to account for the effects of three-dimensionality. The main features of car and

Wheel flat is a form of wheel tread defect that reduces the service life and running safety of trains and tracks. Based on the multi-body system dynamics theory, a rigid-flexible vehicle-turnout dynamic coupling modelwas established, and the wheel diameter-varying flat simulation method used to create wheel flat models of different sizes. The most unfavourable phase of flats on the wheels of a vehicle

More intensive vibration reduction measures are necessary given increasing demands for urban rail transit vibration control. While the floating slab track system remains the most effective vibration isolation measure, a large vibration reduction blind area can still be observed at low frequencies. In the present study, a general quasi-zero-stiffness vibration isolator (GQZS vibration isolator) was

ABSTRACT This paper proposes a fault-tolerant controller for active suspension to improve the bounce and pitch performance of a half-car system. In order to guarantee both the transient and steady-state control objectives, the prescribed performance control (PPC) method is applied to regulate the convergence rate, overshoot and tracking error of the closed-loop (CL) system. The system parametric uncertainties

ABSTRACT This paper presents an adaptive optimal control strategy focused on improving ride comfort by minimising the root mean square of accelerations measured at seven locations on the carbody floor. It requires preview knowledge of both the train speed and the standard track quality (not the deterministic track disturbances) and differs from other works in considering pointwise constraints (upper

Keeping a vehicle in its current lane without veering into adjacent lanes is important in hard-braking manoeuvres on split- μ roads. Whether the emergency braking is initiated by a human driver or by an AEBS, drivers have difficulty adjusting steering correctly to balance yaw moment generated by asymmetric tyre braking force. Some anti-lock braking systems reduce braking force to reduce the yaw moment

ABSTRACT The turnout is the key equipment for guiding trains to change lines in railway track, which can affect the vehicle running smoothness and limit the train speed drastically. This paper proposes an optimisation method for turnout layout of the diverging route by considering multiple curvatures or curvature changes through the vehicle-turnout dynamics, and the effect of train speed on dynamic

ABSTRACT Automobiles are becoming more and more complex as multiple control systems are integrated into the vehicle platform. This paper investigates the coordination of active rear steering (RWS) and torque vectoring (TV) – which is enabled by independent electric motors at the rear axle – in controlling vehicle lateral dynamics. The proposed controller aims at enhancing vehicle handling performance

This paper presents a novel observer-based gain-scheduling path following control algorithm for autonomous electric vehicles subject to time delay. Firstly, the lateral dynamic model of the autonomous electric vehicle is constructed by a polytope with four vertices, in which the issues of the time-varying longitudinal velocity and nonlinear tyre dynamics are accurately described. Secondly, taking the

This paper proposes a hybrid suspension system, consisting of a linear electric motor (LM) and a semi-active mono-tubed magnetorheological damper (MRFD), to improve vehicle dynamics with lower power demand. For determining the damping force directly and concisely, a modified bi-viscosity magnetorheological fluid (MRF) model that explicitly includes the current parameter is developed. The fabricated

ABSTRACT The location of wagon gravity centre (WGC) has a significant effect on the wheel-rail contact force. For the sake of improving the curving performance of a freight wagon, it is necessary to optimise the location of WGC by shifting the position of cargo or adopting the balance weight. This paper proposes a data analysis methodology that demonstrates the safe distribution scope of WGC based

ABSTRACT Vibration analysis of vehicle-bridge coupled systems has received considerable attentions over the past two decades. This work is dedicated to the stochastic dynamic analysis of vehicle-bridge coupled systems with nonlinear Hertz wheel-rail contacts subjected to random track irregularities. An explicit time-domain method (ETDM) is proposed for efficient nonlinear dynamic analysis of vehicle-bridge

In recent years, low and medium speed maglev (LMSM) transportation system has been greatly promoted in China to meet different social demands. Accordingly, a LMSM train using levitation frames with mid-set air springs has been developed, and it is necessary to investigate the dynamic characteristics of its train-track-bridge coupled system. First, environmental vibration tests were conducted on the

This technical note addresses the overturning risk assessment of high-speed trains over multi-span simply supported bridges under crosswind. A train-bridge coupled system is established to estimate the wheel–rail contact forces from which the overturning risk of train is assessed. The estimation is also compared to that without consideration of bridge vibration. The result shows that the loss of vertical

Understanding the effect of wind speed variation on wind-induced momentary discomfort is the basis to improve the train vibration comfort. This study focuses on this challenge. Firstly, the momentary discomfort evaluation index Pw is developed and proved by the full-scale test. Then, setting Pw as the critical value, a multi-body nonlinear numerical investigation of the effect of the wind speed change

ABSTRACT Friction coupling independently rotating wheelsets have advantages of both rigid wheelsets and independently rotating wheelsets. These wheelsets have self-steering ability on straight lines and large curves. They can also reduce the wear of wheels. The analytical relationship between the friction torque and the lateral displacement of wheelsets was deduced in this study based on motion characteristics

ABSTRACT As vehicles become increasingly electrified, electrical machines for propulsion can be divided into many sources making the vehicle highly over-actuated. For over-actuated vehicles, the allocation of a propulsive force is an underdetermined process with respect to both the number of wheels and electrical machines. Hence, the allocation can be made to favour particular attributes such as energy

Shear pads are devices used to improve vehicle dynamics performance on heavy haul railways wagons. In this work, we present a method to determine the elastic properties of such components using experimental/numerical approach. The final goal is to provide adequate input to multi-body analysis software commonly applied to study and design railroad vehicles. We also considered the effect of side frame

ABSTRACT The modelling, simulation and analysis methods in automotive development are in the process of transformation. Increasing system complexity, variant diversity and efforts to improve efficiency lead to more complex simulations and depend on virtual vehicle development, testing and approval across a large application area. Consequently, the new key requirements of modern validation involve more

In this paper, we discuss three improved brush models. The first one deals with the coupling between the slip and spin parameters and is valid for relatively high steering speed and small camber angles; the second one is more complex and considers the presence of a two-dimensional velocity field inside the contact patch due to large camber angles; the third one is more general and combines both the

Based on the traditional automatic transmission, Dedicated Hybrid Transmission (DHT) with P2 configuration is developed by replacing hydraulic torque converter with a wet electronically controlled clutch and a driving motor. The paper proposed a coordinated control strategy of the upshift process for the P2 configuration parallel hybrid vehicle equipped with DHT to ensure the shift quality. Firstly

Large variations load-to-curb weight ratios are linked to significant changes in parameters critical to control design for vehicle stability control system. Unique and highly customised vehicles, such as the lightweight solar car in this paper, are more susceptible to the impact of such variations when developing control methods. The purpose of this study is to study the influence of variation in loading

ABSTRACT A new semi-analytical boundary element method is proposed for determining the wheel–rail contact zone and the normal stress distribution within it. The potential contact area is discretised using strip elements, employing an iterative algorithm to satisfy the contact constraints. At each iteration, the length of the contact strips is updated using an analytical expression based on Hertz's

The high-speed freight trains are increasingly using containers for efficient cargo handling and improved transportation economy. The dynamic interactions of the containers with the vehicle can cause greater vehicle vibration, especially at speeds as high as 350 km/h. This study investigates the vibration response of a high-speed freight car (electric motor unit, EMU) through development and analysis

Using a 3-degree-of-freedom lateral dynamic vehicle-trailer system model with the LuGre tyre model, this paper proposes a constrained unscented transformation based scheme for estimating the lateral velocity of a vehicle trailer. It is shown that the proposed lateral velocity estimation scheme is robust to the road condition. An affine quadratic stability approach is used to analyze the stability of

The vibration performance of a tram vehicle running on the curved track is influenced by the speed of the running vehicle, the geometry of the track, the roughness of the wheel and rail, and environmental characteristics. This paper investigates the random vibration analysis of tram-track interaction on a curved track due to the polygonal wheel and track irregularity by the pseudo excitation method

The use of detailed wheel/rail contact models has long been frustrated by the complicated preparations needed, to analyse the profiles for the local geometry and creep situation for the planar contact approach. A new software module is presented for this that automates the calculations in a generic way. Building on many components developed by others, this greatly simplifies the running of CONTACT

ABSTRACT This paper presents a novel, non-iterative, general formulation for the transient analysis of interacting elastodynamic systems in contact that may exhibit relative motion with respect to each other. The overall system consists of a collection of individual structures (subsystems). Each of the structure is solved at first independently of the others assuming no interactive contact forces exist

ABSTRACT In this paper, modelling methods are developed to achieve dynamics exploration for the vehicle–track system and its substructures. First, a coupled model, with the satisfaction of wheel–rail displacement compatibility and force equilibrium within each time step, is constructed for the characterisation of vehicle–track interaction, where the vehicle is modelled as a multi-rigid-body system

Using dynamic load identification technology to identify the wheel-rail force of rail vehicles is an economical and convenient method for indirect measurement. In this paper an analytical load identification method is proposed. Firstly, based on the theory of structural dynamics, the Duhamel integral is applied, combined with the characteristics of the rail vehicle system, to derive the analytical

ABSTRACT Proper maintenance of railway tracks is essential to ensure railway safety. A track condition monitoring system was developed for the preventive maintenance of the track by installing the on-board sensing device in the in-service vehicles and monitoring the track condition by measuring the car-body acceleration. This paper describes the application of time–frequency analysis for the condition

Turnouts are among the weakest links of railway lines, but the derailment risk of vehicles passing the through route of a turnout is seldom considered. The potential factors affecting derailment are screened according to field investigations of a train derailment case at the through route of a turnout. A detailed wagon-turnout interaction model considering the non-uniform cross-sections of turnout

The calculation of the wheel–rail contact forces is one of the most difficult yet time-consuming processes in multibody system (MBS) simulations for a vehicle-track interaction system. The classical combination of the Hertzian model with the FASTSIM algorithm is the most widely used model in MBS code for railway application and the ‘exact’ solver CONTACT is seldom used due to its high computational

Braking energy recovery is one of the main technologies affecting the economic performance of an electric vehicle. To improve economy from as much recovered braking energy as possible on the premise of ensuring vehicle security is the goal of regenerative braking control strategy. However, due to the non-linear and multi-objective characteristics of hybrid braking system, finding the optimal regenerative

A direct yaw moment control (DYC) for energy-efficiency and a DYC for stability of electric vehicles (EVs) are proposed. The DYC for energy-efficiency is active during non-safety-critical cornering manoeuvres to improve the energy-efficiency of EVs. The DYC for stability is active during safety-critical manoeuvres to keep the vehicle stable. A combination of the DYC for energy-efficiency and the DYC

As the energy storage device of an electric vehicle (EV), in order to meet the mileage requirements, a battery pack always has large volume and mass and is responsible for a considerable portion of the yaw rotational inertia of the entire vehicle. As the yaw rotational inertia has a negative impact on the vehicle cornering response, a new type of EV chassis structure is proposed herein, which is equipped

This paper uses vehicle system dynamics simulations to investigate curving resistance generated from the wheel-rail interface. More than 600 simulations were conducted using a freight wagon model to investigate the implications of curve radii, vehicle speeds and track superelevation for curving resistance, as well as the changes of curving resistance with wheelset Angle of Attack (AoA) and track cant

Due to trends such as automation and new drives in commercial vehicle engineering, research is being carried out on drive concepts with individual wheel drives. In the off-road sector, these concepts offer the potential to exceed the manoeuvrability and traction performance of conventional drive trains. Mechanical drive trains are limited in this respect due to their nature (differential gears, etc

ABSTRACT This work addresses the lateral stabilisation problem of four-wheels ground vehicles. The objective is to estimate the largest state-space region such that the closed-loop vehicle lateral stability can be guaranteed. Sum-of-squares (SOS) programming technique is applied to find these maximum invariant sets while accounting for steering and yaw moment input saturations. The algorithm allows

The suspension system of maglev train has intrinsic nonlinear characteristics. The identification processing ability of nonlinear terms and the control accuracy of control algorithm have an important influence on the suspension stability of the train. Especially when the track stiffness is weak, it is easier to affect the suspension stability under the action of small deformation, resulting in the

ABSTRACT Active suspension system can drastically improve dynamic behaviours of the railway vehicle but will also introduce safety-critical issues. The fault-tolerant analysis, therefore, is essential for the design and implementation of active suspension. However, this issue did not receive enough attention so far and only few papers can be found related to the fault tolerance of active steering for

Aiming at the problem of improving driving comfort under the condition of ensuring driving safety and limited suspension travel, this paper proposes a sliding mode adaptive controller suitable for strong disturbance action. Considering the nonlinear characteristics of the hydraulic actuator, a one-half vehicle suspension model with uncertain parameters and external disturbances is established. In the

ABSTRACT Active wheelset steering promises an attractive cost–benefit ratio and is highly likely to be implemented in the future. Previous studies investigated the steering effect simply through a wear index like wear number. However, a wear index cannot predict how much the material removal on wheels can be reduced, and it is unable to reveal the wear pattern. This paper builds an iterative wear model

ABSTRACT The development of new technologies in public passenger transport in urban agglomerations has forced the institutions responsible for organising such transport to engage in unconventional initiatives in order to improve it and make more available, especially for elderly and disabled people. One of such initiatives consists in striving for putting into operation an increasing number of tram

The air spring is the main part of the secondary suspension of passenger railway vehicles. The aim of this paper is to review existing modelling techniques for air springs in order to check if challenges set in the past decade for available models have been met. The advantages and disadvantages of different air spring models (phenomenological/mechanical, thermodynamic, analytic, FEM) are summarised

The levitation bogie of the TR-series maglev vehicle is redesigned by adding an intermediate buffer layer between the levitationbogie and the levitation module to improve the curve negotiation capacity of the high-speed maglev vehicle and reduce the vertical coupleddynamic effect of the vehicle and the track beam. As the existing TR08 maglev vehicle dynamic model has been verified by experiments, anew

The roll centre (RC) is a core parameter for vehicle lateral dynamics and control, which can be obtained via suspension geometry configuration or suspension kinematics and compliance (K&C) test. However, these methodologies are used for laboratory tests and are suitable at low lateral acceleration. In other words, the RC is hard to measure directly while the vehicle is running on the road. In this

In passenger cars active suspensions have been traditionally used to enhance comfort through body control, and handling through the reduction of the tyre load variations induced by road irregularities. However, active suspensions can also be designed to track a desired yaw rate profile through the control of the anti-roll moment distribution between the front and rear axles. The effect of the anti-roll