Dynamic Response of Commuter Rail Vehicle under Lateral Track Irregularity

Lateral track irregularities normally occur when both rail lines have some displacement laterally with respect to the original track due to prolonged exposure to sun’s heat, or may also arise from specific features such as switch and crossing work of track. These track irregularities will cause unwanted body vibration of commuter rail vehicle. These vibrations have to be suppressed for the purpose of ride comfort. This paper presents two control strategies in semi-active suspension systems which are PID and disturbance rejection control to improve passenger ride comfort. A half car model of commuter rail vehicle with three-degree-of-freedom (3-DOF) was developed based on Newton's Second Law. Vibration analyses based on simulation results in time domains are compared with passive system using MATLAB-Simulink software. The results show that the semi-active controllers are able to suppress rail vehicle body responses effectively

Simulation studies of vibration isolation using electromagnetic damper

This paper presents the review of electromagnetic damper as a vibration/isolation material. A bunch of articles about vibration and suspension system was reviewed and the key factors that contribute to electromagnetic damper was identified. Electromagnetic damper has been given special attention from many researchers and thus being among the important research area in vibration system. Vibration concept of electromagnetic damper has been elucidated by referring to several paper that demonstrate the usage of electromagnetic damper. Finite element magnetic method (FEMM) software has been used in order to identify the best configuration of geometry in the system. A simulation in Matlab was done by considering a quarter car model with a theoretical value from the Faraday’s Law equation involved in electromagnetic damper. The slotted and cylindrical geometry configurations have been simulated using FEMM and the result clearly shows that the slotted configuration has a better effect on the electromagnetic damper system

Analysis Of Primary And Secondary Lateral Suspension System Of Railway Vehicle

The aim of this paper is to study the effect of primary and secondary suspensions of a railway vehicle on stability and passenger ride comfort.The possible improvement of conventional suspension without using a controllable suspension system is investigated.A linear 17 degree-of-freedom (DOF) railway vehicle model is used to study the vibration response of the railway vehicle body.The equations of motion that represent the dynamics of the railway vehicle were derived based on Newton laws to describe the lateral,yaw and roll motions of the vehicle body,bogies and also wheel-sets.The spring stiffnesses and damping coefficients of the primary and secondary suspensions were varied incrementally in order to observe the response of the railway vehicle body.The vehicle model was simulated with lateral sinusoidal track disturbance using Matlab-SIMULINK software.The simulation results showed that the railway vehicle stability is significantly affected by the values of primary suspension,and body ride quality is affected by secondary suspension elements

Analysis of primary and secondary lateral suspension system of railway vehicle / Mohd Hanif Harun … [et al.]

The aim of this paper is to study the effect of primary and secondary suspensions of a railway vehicle on stability and passenger ride comfort. The possible improvement of conventional suspension without using a controllable suspension system is investigated. A linear 17 degree-of-freedom (DOF) railway vehicle model is used to study the vibration response of the railway vehicle body. The equations of motion that represent the dynamics of the railway vehicle were derived based on Newton laws to describe the lateral, yaw and roll motions of the vehicle body, bogies and also wheel-sets. The spring stiffnesses and damping coefficients of the primary and secondary suspensions were varied incrementally in order to observe the response of the railway vehicle body. The vehicle model was simulated with lateral sinusoidal track disturbance using Matlab-SIMULINK software. The simulation results showed that the railway vehicle stability is significantly affected by the values of primary suspension

Lateral suspension control of railway vehicle using semi-active magnetorheological damper

In railway vehicle technology, there are continuously increasing requirements regarding riding comfort, running safety, and speed of railway vehicles. These requirements are opposed by the fact that the condition of the tracks is getting worse and maintenance is becoming expensive. In view of this conflict, conventional suspension concepts are quickly at their limits. This paper investigates the performance of semi-active control of lateral suspension system namely body-based skyhook and bogie-based skyhook for the purpose of attenuating the effects of track irregularities to the body lateral displacement, body roll angle and unwanted yaw responses of railway vehicle. The controller is optimized on 17 degrees of freedom (DoF) railway vehicle dynamics model and showing better dynamics performance than its counterparts

Improvement of semi-active control suspensions based on gain-scheduling control

This study presents the development of a non-linear control strategy for a semi-active suspension controller using a gain-scheduling structure controller. The aim of the study is to overcome the constraints of conventional control strategies and improve semi-active suspension to achieve performance close to that of full active control. Various control strategies have been investigated to improve the performance of semi-active vibration control systems. A wide range of semi-active control strategies have also been experimentally tested by researchers in the attempt to enhance the performance of semi-active suspension systems. However, the findings published in the literature indicate that there appears to be a ceiling to performance improvements with the control strategies that have been proposed to date, which is about the half of what could be achieved with full active control. The main constraint for semi-active devices such as Magnetorheological (MR) dampers is that they are only capable of providing active control forces by dissipating energy, in their active mode, and they switch to work as simple passive dampers, the passive mode, when energy injection is demanded by the associated control laws. The split in durations of time between the active and passive modes for the conventional semi-active control strategies is around 50:50. This study will focus on the development of a novel semi-active control strategy that aims to extend the duration of the active mode and hence reduce the duration of the passive mode for semi-active suspensions by using a gain-scheduling control structure that dynamically changes the control force demanded by the operating conditions. The proposed control method is applied to both vertical and lateral suspensions of a railway vehicle in this study and the improvements in ride quality are evaluated with several different track data. For the purpose of performance comparison, a semi-active controller based on skyhook damping control integrated with MR dampers and also a vehicle with passive suspensions are used as the benchmark, and are used as a reference case for assessment of the proposed design. Numerical simulations are carried out to assess the performance of the proposed gain-scheduling controller. The simulation results obtained illustrate the performance improvement of the proposed control strategy over conventional semi-active control approaches, where the ride quality of the new controller is shown to be significantly improved and comparable with that of full active control. Potentially, this kind of adaptive capability with variable control approaches can be used to deliver the level of the performance that is currently only possible with fully active suspension without incurring the associated high costs and power consumption

The use of novel mechanical devices for enhancing the performance of railway vehicles

Following successful implementation of inerters for passive mechanical control in racing cars, this research studies potential innovative solutions for railway vehicle suspensions by bringing the inerter concept to the design of mechatronic systems. The inerter is a kinetic energy storage device which reacts to relative accelerations; together with springs and dampers, it can implement a range of mechanical networks distinguished by their frequency characteristics. This thesis investigates advantages of inerter-based novel devices to simplify the design of active solutions. Most of the research work is devoted to the enhancement of vertical ride quality; integrated active-plus-novel-passive solutions are proposed for the secondary suspensions. These are defined by different active control strategies and passive configurations including inerters. By optimisation of the suspension parameters, a synergy between passive and active configurations is demonstrated for a range of ride quality conditions. The evidence of cooperative work is found in the reduction of the required active forces and suspension travelling. This reveals a potential for reducing the actuator size. Benefits on power requirements and actuator dynamic compensation were also identified. One of the strategies features a nonlinear control law proposed here to compensate for 'sky-hook' damping effects on suspension deflection; this, together with inerter-based devices attains up to 50% in active force reduction for a setting providing 30% of ride quality enhancement. The study is developed from both, an analytical and an engineering perspective. Validation of the results with a more sophisticated model is performed. The lateral stability problem was briefly considered towards the end of the investigation. A potential use of inerter-based devices to replace the static yaw stiffness by dynamic characteristics was identified. This leads to a synergy with 'absolute stiffness', an active stability solution for controlling the wheelset 'hunting' problem, for reducing the creep forces developed during curve negotiation