Hardware-in-the-loop simulation experiment for semi-active vibration control of lateral vibrations of railway vehicle by magneto-rheological fluid damper

The active lateral suspension (ALS) of a train consists of either active or semi-active technologies. However, such an active system on a real railway vehicle is not easy to test because of cost and time. In this study, a hardware-in-the-loop simulation (HILS) system is developed to test the ALS. To this end, the dynamic model of a railway vehicle is equipped with the actuator, two bogies and four-wheel sets, and the ALS is used. The proposed HILS system consists of an alternating current servo motor connected to a ball-screw mechanism and a digital control system. The digital control system implements the dynamic model and the control algorithm. The design and manufacture of the HILS system are explained in detail. Both the passive damper and the magneto-rheological (MR) fluid damper are tested using the HILS system, where the sky-hook control algorithm was applied for the MR fluid damper. Experimental results show that the proposed HILS system can be effectively used for the performance estimation of the ALS.     

Semi-active H∞ control of high-speed railway vehicle suspension with magnetorheological dampers

In this paper, semi-active H∞ control with magnetorheological (MR) dampers for railway vehicle suspension systems to improve the lateral ride quality is investigated. The proposed semi-active controller is composed of a H∞ controller as the system controller and an adaptive neuro-fuzzy inference system (ANFIS) inverse MR damper model as the damper controller. First, a 17-degree-of-freedom model for a full-scale railway vehicle is developed and the random track irregularities are modelled. Then a modified Bouc–Wen model is built to characterise the forward dynamic characteristics of the MR damper and an inverse MR damper model is built with the ANFIS technique. Furthermore, a H∞ controller composed of a yaw motion controller and a rolling pendulum motion (lateral motion+roll motion) controller is established. By integrating the H∞ controller with the ANFIS inverse model, a semi-active H∞ controller for the railway vehicle is finally proposed. Simulation results indicate that the proposed semi-active suspension system possesses better attenuation ability for the vibrations of the car body than the passive suspension system.     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part I: system integration and modelling

In this paper, it is aimed to investigate semi-active suspension systems using magnetorheological (MR) fluid dampers for improving the ride quality of railway vehicles. A 17-degree-of-freedom (DOF) model of a full-scale railway vehicle integrated with the semi-active controlled MR fluid dampers in its secondary suspension system is proposed to cope with the lateral, yaw, and roll motions of the car body, trucks, and wheelsets. The governing equations combining the dynamics of the railway vehicle integrated with MR dampers in the suspension system and the dynamics of the rail track irregularities are developed and a linear quadratic Gaussian (LQG) control law using the acceleration feedback is adopted, in which the state variables are estimated from the measurable accelerations with a Kalman estimator. In order to evaluate the performances of the semi-active suspension systems based on MR dampers for railway vehicles, the random and periodical track irregularities are modelled with a uniform state-space formulation according to the testing data and incorporated into the governing equation of the railway vehicle integrated with the semi-active suspension system. Utilising the governing equations and the semi-active controller developed in this paper, the simulation and analysis are presented in Part II of this paper.     

Fault detection and isolation for a nonlinear railway vehicle suspension with a Hybrid Extended Kalman filter

Fault detection is considered to be one way to improve system reliability and dependability for railway vehicles. The secondary lateral and anti-yaw dampers are the most critical parts in railway suspension systems. So far, the dampers have been modelled as linear components in the fault detection and isolation observer design. In this work, a Hybrid Extended Kalman filter is used to capture the nonlinear characteristics of the dampers. In order to detect and isolate faults, a nonlinear residual generator is developed, which can distinguish clearly between different types of faults. A lateral half train model serves as an example for the proposed technique. The results show that failures in the nonlinear suspension system can be detected and isolated accurately.     

Semi-active suspension systems for railway vehicles using magnetorheological dampers. Part II: simulation and analysis

In this paper, the semi-active suspension system for railway vehicles based on the controlled (MR) fluid dampers is investigated, and compared with the passive on and passive off suspension systems. The lateral, yaw, and roll accelerations of the car body, trucks, and wheelsets of a full-scale railway vehicle integrated with four MR dampers in the secondary suspension systems, which are in the closed and open loops respectively, are simulated under the random and periodical track irregularities using the established governing equations of the railway vehicle and the modelled track irregularities in Part I of this paper. The simulation results indicate that (1) the semi-active controlled MR damper-based suspension system for railway vehicles is effective and beneficial as compared with the passive on and passive off modes, and (2) while the car body accelerations of the railway vehicle integrated with semi-active controlled MR dampers can be significantly reduced relative to the passive on and passive off ones, the accelerations of the trucks and wheelsets could be increased to some extent. However, the increase in the accelerations of the trucks and wheelsets is insignificant.     

Vehicle Dynamic Analysis and Evaluation of Continuously Controlled Semi-Active Suspensions Using Hardware-in-the-loop Simulation

A semi-active suspension system with continuously variable damper is greatly expected to be used mainly in the future as a high-performance suspension system due to its cost-effectiveness, light weight, and low energy consumption. In this paper, to develop a suitable control logic for the semi-active suspension system, the hardware-in-the-loop simulation is performed for the experimental continuously variable damper combined with a quarter-car model, and the simulation results are compared for passive, on/off controlled, and continuously controlled dampers in the aspects of ride comfort and driving safety, assuming each damper to be installed on the vehicle.     

H8 Control Performance of a Full-Vehicle Suspension Featuring Magnetorheological Dampers

Summary This paper presents an investigation of the feedback control performance of a full-vehicle suspension system featuring magnetorheological (MR) dampers. A cylindrical MR damper is designed and manufactured by incorporating a Bingham model of aMR fluid which is commercially available. After evaluating the field-dependent damping characteristics of the MR damper, a full-vehicle suspension system installed with 4 independent MR dampers is constructed and its governing equations of motion which include vertical, pitch and roll motions are derived. A H 8 controller which has inherent robustness against system uncertainties is formulated by treating the sprung mass of the vehicle as uncertain parameter. This is accomplished by adopting the loop shaping design procedure. For the demonstration of a practical feasibility, control performance characteristics for vibration suppression of the proposed MR suspension system are evaluated under various road conditions through the hardware-in-the-loop simulation (HILS) methodology.     

H8 Control Performance of a Full-Vehicle Suspension Featuring Magnetorheological Dampers

Summary This paper presents an investigation of the feedback control performance of a full-vehicle suspension system featuring magnetorheological (MR) dampers. A cylindrical MR damper is designed and manufactured by incorporating a Bingham model of aMR fluid which is commercially available. After evaluating the field-dependent damping characteristics of the MR damper, a full-vehicle suspension system installed with 4 independent MR dampers is constructed and its governing equations of motion which include vertical, pitch and roll motions are derived. A H 8 controller which has inherent robustness against system uncertainties is formulated by treating the sprung mass of the vehicle as uncertain parameter. This is accomplished by adopting the loop shaping design procedure. For the demonstration of a practical feasibility, control performance characteristics for vibration suppression of the proposed MR suspension system are evaluated under various road conditions through the hardware-in-the-loop simulation (HILS) methodology.     

Sloshing effects and running safety in railway freight vehicles

This paper deals with the study of running dynamic effects for a partially filled railway tank vehicle. A computational fluid dynamics model in 2D is established and used to define the motion of the sloshing fluid and the forces generated on the tank, for curving conditions typical of railway freight transport. From these results, an equivalent mechanical model is identified which is able to correctly reproduce the forces generated on the tank. Finally, a mathematical model is defined for the entire freight car, including the bogies with primary suspensions, the tank and a discrete number of equivalent models positioned at different places along the longitudinal axis of the tank. This model is used to simulate the dynamics of the tank for a variety of curve geometries, train speeds and fill levels. By these simulations, derailment and rollover risks are evaluated and the most critical conditions for running safety are defined. Results show that sloshing can increase significantly the risk of tank rollover whereas its influence on the risk of derailment is minor.     

An efficient recursive least square-based condition monitoring approach for a rail vehicle suspension system

A model-based condition monitoring strategy for the railway vehicle suspension is proposed in this paper. This approach is based on recursive least square (RLS) algorithm focusing on the deterministic ‘input–output’ model. RLS has Kalman filtering feature and is able to identify the unknown parameters from a noisy dynamic system by memorising the correlation properties of variables. The identification of suspension parameter is achieved by machine learning of the relationship between excitation and response in a vehicle dynamic system. A fault detection method for the vertical primary suspension is illustrated as an instance of this condition monitoring scheme. Simulation results from the rail vehicle dynamics software ‘ADTreS’ are utilised as ‘virtual measurements’ considering a trailer car of Italian ETR500 high-speed train. The field test data from an E464 locomotive are also employed to validate the feasibility of this strategy for the real application. Results of the parameter identification performed indicate that estimated suspension parameters are consistent or approximate with the reference values. These results provide the supporting evidence that this fault diagnosis technique is capable of paving the way for the future vehicle condition monitoring system.     

高速铁路斜交刚构连续梁桥车桥耦合振动分析

分别采用板单元、四片式、两片式和单片式梁单元模型来计算高速铁路斜交刚构连续梁桥的空间自振频率，通过比较和分析，推荐采用四片式梁单元进行车桥耦合振动分析。计算结果表明斜交刚构连续梁桥具有足够的刚度和良好的整体性，可以满足高速列车行车时的安全性和舒适性要求。     

On fault isolation for rail vehicle suspension systems

Reliability of the railway vehicle suspension system is of critical importance to the safety of the vehicle. It is very desirable to monitor the health condition and the performance degradation of the suspension system online, which offers the important information of the suspension system and is critically important for the condition-based maintenance rather than scheduled maintenance in the future. Advanced fault diagnosis method is one of the most effective means for the health monitoring of the suspension system. In this paper, taking the lateral suspension system as an examcple, the fault isolation issue for different component faults occurring in the suspension system is concerned. The sensor configuration for obtaining the vehicle state information and the mathematical model for the lateral suspension system are presented. Four fault features in the time domain and three fault features in the frequency domain are used for each sensor signal. Three different methods, Dempster–Shafer (D–S) evidence theory, Fisher discrimination analysis (FDA) and support vector machine (SVM) techniques are applied to the fault isolation problem. Simulation study is carried out by means of the professional multi-body simulation tool, SIMPACK. The simulation results show that these methods can isolate the considered component faults effectively with a high accuracy. The D–S evidence-based fault isolation approach outperforms the other two methods.     

Identification of the technical state of suspension elements in railway systems

The running safety and passenger comfort levels in a vehicle are tightly related to the technical state of the suspension elements. The technical state of the suspension depends of the service life time as its components become old and wear out. In this paper, a study on the dynamic behaviour of a railway vehicle is established in relation to the damping elements in one of its suspension stages. An experimental measurement model is developed, obtaining a set of useful signals for the identification of the dynamic parameters of the vehicle and developing a test through the application of the operational modal analysis technique, using least-squares complex exponential method as a basis to validate the numerical model of the multi-body system. Then, the study focuses on developing numerical simulations for the identification of the technical state of the dampers by the registration of dynamic variables under commercial service conditions and on estimating the state of the suspension elements.     

Adaptive Suspension Concepts for Road Vehicles

Most vehicle suspensions are composed of passive spring and damper devices, although improved suspension performance is possible if an active system is used to control forces or relative velocities. The complexity, power requirements, and cost of fully active suspensions have restricted their use. Various partially active suspensions have been proposed and suspensions with slow load levelers and variable dampers are in widespread use. Here we analyze a class of basically passive suspensions the parameters of which can be varied actively in response to various measured signals on the vehicle. These suspensions can come close to optimal performance with simpler means than many of the active or semi-active schemes previously proposed.     

Dynamics of railway freight vehicles

This paper summarises the historical development of railway freight vehicles and how vehicle designers have tackled the difficult challenges of producing running gear which can accommodate the very high tare to laden mass of typical freight wagons whilst maintaining stable running at the maximum required speed and good curving performance. The most common current freight bogies are described in detail and recent improvements in techniques used to simulate the dynamic behaviour of railway vehicles are summarised and examples of how these have been used to improve freight vehicle dynamic behaviour are included. A number of recent developments and innovative components and sub systems are outlined and finally two new developments are presented in more detail: the LEILA bogie and the SUSTRAIL bogie.     

Study of the post-derailment safety measures on low-speed derailment tests

Prevention of train from derailment is the most important issue for the railway system. Keeping derailed vehicle close to the track centreline is beneficial to minimise the severe consequences associated with derailments. In this paper, the post-derailment safety measures are studied based on low-speed derailment tests. Post-derailment devices can prevent deviation of the train from the rail by catching the rail, and they are mounted under the axle box. Considering the different structures of vehicles, both trailer and motor vehicles are equipped with the safety device and then separately used in low-speed derailment tests. In derailment tests, two kinds of track, namely the CRTS-I slab ballastless track and the CRTS-II bi-block sleeper ballastless track, are adopted to investigate the effect of the track types on the derailment. In addition, the derailment speed and the weight of the derailed vehicle are also taken into account in derailment tests. The test results indicate that the post-derailment movement of the vehicle includes running and bounce. Reducing the derailment speed and increasing the weight of the head of the train are helpful to reduce the possibility for derailments. For the CRTS-I slab ballastless track, the safety device can prevent trailer vehicles from deviating from the track centreline. The gearbox plays an important role in controlling the lateral displacement of motor vehicle after a derailment while the safety device contributes less to keep derailed motor vehicles on the track centreline. The lateral distance between the safety device and rails should be larger than 181.5?mm for protecting the fasteners system. And for the CRTS-II bi-block sleeper ballastless track, it helps to decrease the post-derailment distance due to the longitudinal impacts with sleepers. It can also restrict the lateral movement of derailed vehicle due to the high shoulders. The results suggest that, CRTS-II bi-block sleeper ballastless track should be widely used in derailment prone areas.     

A study on a dynamic model of a vehicle simulator with 6 DOF for the Korean tilting train

This article presents a dynamic model of a railway vehicle for the development of a 6-DOF (degrees of freedom) tilting-train simulator. It will be used to verify the tilting-electronics and tilting-control algorithm that are to be applied to the Korean tilting train. It is composed of 6 electrically driven actuators, a track generation system, a graphic user interface, and a visualization system with a 1600-mm-diameter dome screen. Each system shares the data by means of Ethernet network in real time. In this study, a train model of 9-DOF with a force generation system to tilt the train body has been used. Dynamic analysis for the straight track running and curve negotiation of a railway vehicle can be performed in the model. A verification study for the application of the model to the simulator has been conducted on curving tracks with different radii.     

Curving performance simulation of an EMS-type Maglev vehicle

For electromagnetic suspension (EMS) type urban Maglev vehicles using a U-shaped electromagnet, the levitation and guidance forces are generated by only one electromagnet. Although the levitation force is actively controlled by changing the voltage of the electromagnet, the guidance force is passively determined by the levitation force. In addition, the curve negotiation performance of EMS-type urban Maglev vehicles using a U-shaped electromagnet must be considered, because an urban guideway may have some curves with shorter radii. It is, therefore, necessary to predict the curving performance with the greatest accuracy possible, in order to improve electromagnetic suspension and establish guideway design specifications. The objective is to establish a new dynamic modelling technique, so as to achieve more realistic curving simulation and thus to more accurately evaluate the curving performance of an EMS-type Maglev vehicle. The use of a full vehicle multibody dynamic model is proposed, and is applied to the evaluation of curving performance. Design changes are also investigated to obtain the bogie design directions for minimising variation in the lateral air gap, which is a criterion for curving performance.     

Modelling and validation of electromechanical shock absorbers

Electromechanical vehicle suspension systems represent a promising substitute to conventional hydraulic solutions. However, the design of electromechanical devices that are able to supply high damping forces without exceeding geometric dimension and mass constraints is a difficult task. All these challenges meet in off-road vehicle suspension systems, where the power density of the dampers is a crucial parameter. In this context, the present paper outlines a particular shock absorber configuration where a suitable electric machine and a transmission mechanism are utilised to meet off-road vehicle requirements. A dynamic model is used to represent the device. Subsequently, experimental tests are performed on an actual prototype to verify the functionality of the damper and validate the proposed model.     

Adaptive Suspension Concepts for Road Vehicles

SUMMARY

Most vehicle suspensions are composed of passive spring and damper devices, although improved suspension performance is possible if an active system is used to control forces or relative velocities. The complexity, power requirements, and cost of fully active suspensions have restricted their use. Various partially active suspensions have been proposed and suspensions with slow load levelers and variable dampers are in widespread use. Here we analyze a class of basically passive suspensions the parameters of which can be varied actively in response to various measured signals on the vehicle. These suspensions can come close to optimal performance with simpler means than many of the active or semi-active schemes previously proposed.