scholarly journals Improving Wheelset Stability of Railway Vehicles by Using an H∞/LPV Active Wheelset System

2021 ◽  
Author(s):  
Van Tan Vu ◽  
Van Da Tran ◽  
Manh Hung Truong ◽  
Oliver Sename ◽  
Peter Gaspar
Keyword(s):  
Lateral Displacement ◽  
Evolutionary Process ◽  
Contact Forces ◽  
Railway Vehicle ◽  
Railway Vehicles ◽  
Highly Nonlinear ◽  
Lpv Control ◽  
Lateral Creep ◽  
Railway Engineering ◽  
Yaw Angle

The complexity of railway vehicle structures has been part of an evolutionary process for almost two hundred years. Challenges such as increased weight, increased maintenance, higher costs and energy consumption have become common. The vision for future railway vehicles is to reduce complexity, hence enable simpler structures and reduce maintenance and cost, and of course various research challenges arise from this. In fact, a number of papers in the railway engineering literature have presented practical ways to control steering of railway vehicles to improve performance. The model of the railway wheelset is highly nonlinear, mainly due to the nature of the wheelset structure and the related wheel-rail contact forces involved during operation. In this paper, the simplest design in terms of retrofitting, the actuated solid-axle wheelset is considered, we investigate actively controlled wheelsets from a Linear Parameter Varying (LPV) control aspect. We use the grid-based LPV approach to synthesize the H∞ / LPV controller, which is self-scheduled by the forward velocity, as well as the longitudinal and lateral creep coefficients. The aim of the controller is to reduce the lateral displacement and yaw angle of the wheelset. Simulation results show that the proposed controller ensures the achievement of the above targets in the considered frequency domain up to 100 rad/s.

Spectral Distribution of Derailment Coefficient in Non-Linear Model of Railway Vehicle–Track System With Random Track Irregularities

2013 ◽  
Vol 8 (3) ◽  
Author(s):  
Ewa Kardas-Cinal
Keyword(s):  
Spatial Frequency ◽  
Second Harmonic ◽  
Lateral Displacement ◽  
Strong Dependence ◽  
Contact Forces ◽  
Railway Vehicle ◽  
Characteristic Structure ◽  
Window Width ◽  
Derailment Coefficient ◽  
Hunting Frequency

Improving the running safety and reducing the risk of derailments are the key objectives in the assessment of the running characteristics of railway vehicles. The present study of the safety against derailment is focused on the effect of wheelset hunting on the derailment coefficient Y/Q and, especially, how it is reflected in the power spectral density (PSD) of Y/Q. The lateral Y and vertical Q forces at the wheel/rail contact are obtained in numerical simulations for a four-axle railway vehicle moving at a constant velocity along a tangent track with random geometrical irregularities. The PSD of Y/Q, calculated as a function of spatial frequency, is found to have a characteristic structure with three peaks for the leading wheelsets and one peak for the trailing wheelsets of the front and rear bogies. The positions of the PSD maxima remain unchanged with increasing ride velocity, while their magnitudes and shapes evolve. One of the PSD peaks occurs for all wheelsets at the same spatial frequency corresponding to the wheelset hunting, while an additional peak at the double hunting frequency is found for the leading wheelsets. Such a peak structure is also found in the PSD of Y/Q determined in simulations with modified parameters of the vehicle primary suspension and for different track sections. The peak at the double hunting frequency is shown, by a detailed analysis of the contact forces, the flange angles and their PSDs, to result from the nonlinear geometry of the wheel/rail contact leading to the second-harmonic term in Y/Q. The emergence of this peak is also closely related to the phase difference between the hunting oscillations of the wheelset lateral displacement and the oscillations of its yaw angle, for which the difference is significantly smaller for the leading wheelset than for the trailing one. Finally, the effect of wheelset hunting is also shown to manifest itself in the strong dependence of the running average of Y/Q, which is used in the railway technical safety standards for the assessment of the safety against derailment (with the Nadal criterion), on the applied window width.

Derailment Analysis of High-Speed Railway Vehicle Bogies

2011 ◽  
Vol 110-116 ◽  
pp. 186-195 ◽  
Author(s):  
Yung Chang Cheng ◽  
Chern Hwa Chen ◽  
Che Jung Yang
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Vertical Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Bogie Frame ◽  
Suspension Parameters ◽  
Yaw Angle

Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a 12 degree-of-freedom (12-DOF) bogie system which takes account of the lateral displacement, vertical displacement, the roll angle and the yaw angle of the each wheelset and the bogie frame, moving on curved tracks are derived. The nonlinear creep forces and moments are constructed via the saturation constant of the nonlinear creep model in completeness. The effect of the suspension parameters of a bogie system on the derailment quotient is investigated. Results obtained in this study show that the derailment quotient of a bogie system increases as the vehicle speed increases. In addition, the derailment quotient of a bogie system is generally decreased with the increasing values of suspension parameters.

Dynamic Analysis for Derailment Safety of High-Speed Railway Vehicle Bogies

2011 ◽  
Vol 199-200 ◽  
pp. 239-242
Author(s):  
Chern Hwa Chen ◽  
Yung Chang Cheng ◽  
Shun Chin Yang ◽  
Yuh Yi Lin ◽  
Cheng Hsin Chang ◽  
...  
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Vertical Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Suspension Parameters ◽  
Derailment Safety ◽  
Yaw Angle

Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a 12 degree-of-freedom (12-DOF) bogie system which takes account of the lateral displacement, vertical displacement, the roll angle and the yaw angle of the each wheelset and the bogie frame, moving on curved tracks are derived. The nonlinear creep forces and moments are constructed via the saturation constant of the nonlinear creep model in completeness. The effect of the suspension parameters of a bogie system on the derailment quotient is investigated. Results obtained in this study show that the derailment quotient of a bogie system increases as the vehicle speed increases. In addition, the derailment quotient of a bogie system is generally decreased with the increasing values of suspension parameters.

Parametric Analysis of Ride Comfort for Tilting Railway Vehicles Running on Irregular Curved Tracks

2016 ◽  
Vol 16 (09) ◽  
pp. 1550056 ◽  
Author(s):  
Yung-Chang Cheng ◽  
Chin-Te Hsu
Keyword(s):  
Ride Comfort ◽  
Lateral Displacement ◽  
Equations Of Motion ◽  
Roll Angle ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
Nonlinear Creep ◽  
Rail Irregularities ◽  
Yaw Angle

The ride comfort of a tilting railway vehicle moving on curved tracks with rail irregularities is studied. Using the nonlinear creep model and Kalker's linear theory, the governing differential equations of motion for a tilting railway vehicle running on irregular tracks are first derived. The tilting railway vehicle is modeled by a 27 degree-of-freedom (DOF) car system, considering the lateral displacement, vertical displacement, roll angle and yaw angle of both the wheelsets and bogie frames, as well as the lateral displacement, roll angle and yaw angle of the car body. Based on the international standard ISO 2631-1, the effect of vehicle speed on the ride comfort index of the tilting vehicle is investigated for various tilting angles, using both linear and nonlinear creep models, and various radii of curved tracks, as well as for various suspension parameters. Finally, the ride comfort indices computed with rail irregularities are found to be higher than those with no rail irregularities, indicating that the effect of rail irregularities on the ride comfort of a tilting vehicle cannot be disregarded in practice.

Hunting stability and derailment analysis of a car model of a railway vehicle system

2011 ◽  
Vol 226 (2) ◽  
pp. 187-202 ◽  
Author(s):  
Y-C Cheng ◽  
C-T Hsu
Keyword(s):  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Vehicle Speed ◽  
System Parameters ◽  
Suspension Parameters ◽  
Linear Creep ◽  
Non Linear ◽  
Creep Models ◽  
Yaw Angle

Using a heuristic linear creep model, this article derives the governing differential equations of motion for a vehicle travelling on curved tracks. The vehicle is modelled by a 27-degrees-of-freedom (27-DOF) car system, with lateral and vertical displacement, roll and yaw angle of each wheelset and the bogie frames, as well as lateral displacement, and roll and yaw angle of the car body taken into consideration. To analyse the respective effects of major system parameters on vehicle dynamics, the 27-DOF system is reduced to a 14-DOF system by excluding designated subsets of the system parameters. The effects of suspension parameters of a vehicle on the critical hunting speeds were evaluated by the 14- and 27-DOF systems. The results obtained in this study, show that the critical hunting speeds derived using the 14-DOF system are generally higher than those obtained using the 27-DOF system. Additionally, the critical hunting speeds derived using the heuristic non-linear creep model are lower than those achieved using the linear creep model. The effects on derailment quotients of vehicle speeds are evaluated using both linear and non-linear creep models with various suspension parameters. Finally, the effects of vehicle speed on the derailment quotient for sharp curves and low vehicle speed are investigated and compared with both linear and non-linear creep models.

Multiobjective Optimization of a Railway Vehicle Dampers Using Genetic Algorithm

2013 ◽  
Author(s):  
Seyed Milad Mousavi Bideleh ◽  
Viktor Berbyuk
Keyword(s):  
Genetic Algorithm ◽  
Multiobjective Optimization ◽  
Dynamic Response ◽  
Ride Comfort ◽  
Lateral Displacement ◽  
Contact Forces ◽  
Design Parameters ◽  
Railway Vehicle ◽  
Level Shift ◽  
Vehicle Speed

Ride comfort, safety, wear and vehicle speed are the most important factors in evaluating the efficiency of railway transportation. In order to decrease the track access charges it is often desirable to run the vehicle at maximum allowed speed, while keeping an admissible amount of wear in system. This usually deteriorates the ride comfort and safety level during the operation. Therefore, an optimization problem to find a tradeoff value for vehicle speed and design parameters is inevitable. Since, ride comfort, safety and wear values are sensitive to primary and secondary suspensions’ damping parameters it is desirable to find the optimum values of such design variables. In this regard, the multiobjective optimization of railway vehicle dampers is considered to increase the cost-efficiency of railway operation. One car vehicle model with 26 degrees of freedom (DOF) along with a set of initial states, design parameters and operational conditions is explored here. All bodies are assumed to be rigid. Vehicle carbody and bogie frames supposed to have the full set of DOF in space. While, only lateral and yaw motions are considered for each wheelset. It is also assumed that wheelset roll angle is a function of the lateral displacement. Primary and secondary suspensions compromised of parallel linear springs and dampers in longitudinal, vertical and lateral directions which connect wheelsets to bogie frames, and bogie frames to carbody, respectively. Lagrange formalism is employed to obtain the system’s equations of motion. The nonlinear heuristic theory is chosen to relate creepages and the corresponding creep contact forces. The dynamic response of the system is obtained for different operational scenarios including ideal and imperfect tangent and curved tracks. Series-based functions are chosen to approximate the harmonic lateral track irregularities. Accelerations at carbody level, shift forces and wear number are used to evaluate the ride comfort, safety and wear, respectively. MATLAB genetic algorithm optimization routine is applied to perform the optimization. The Pareto sets and Pareto fronts obtained from this study provide the vectors of optimal design parameters corresponding to maximum admissible vehicle speed and guarantee the best tradeoff values for safety and comfort with threshold on wear for each operational scenario. Analysis of the obtained results gives insight into multiobjective optimized dynamic response of a railway vehicle and useful hints for designing adaptive bogie systems with the possibility to switch between optimal damping parameters value and provide the best operational efficiency.

Nonlinear Analysis on Hunting Stability for High-Speed Railway Vehicle Trucks on Curved Tracks

2004 ◽  
Vol 127 (4) ◽  
pp. 324-332 ◽  
Author(s):  
Sen-Yung Lee ◽  
Yung-Chang Cheng
Keyword(s):  
High Speed ◽  
Lateral Displacement ◽  
Vertical Displacement ◽  
Degree Of Freedom ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Hunting Stability ◽  
Six Degree Of Freedom ◽  
Yaw Angle

Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of a ten-degree-of-freedom truck system, considering the lateral displacement, the vertical displacement, the roll and yaw angles of the each wheelset, and the lateral displacement and yaw angle of the truck frame, moving on curved tracks, are derived in completeness. To illustrate the accuracy of the analysis, the limiting cases are examined. The influences of the suspension parameters, including those losing in the six-degree-of-freedom system, on the critical hunting speeds evaluated via the linear and nonlinear creep models, respectively, are studied and compared.

DYNAMICS ANALYSIS OF HIGH-SPEED RAILWAY VEHICLES EXCITED BY WIND LOADS

2011 ◽  
Vol 11 (06) ◽  
pp. 1103-1118 ◽  
Author(s):  
YUNG-CHANG CHENG ◽  
CHERN-HWA CHEN ◽  
CHE-JUNG YANG
Keyword(s):  
Wind Speed ◽  
Lateral Displacement ◽  
Oscillation Amplitude ◽  
Dynamic Responses ◽  
Wind Loads ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Car Body ◽  
Yaw Angle

Based on Kalker's linear theory and the heuristic nonlinear creep model, the nonlinear coupled differential equations of motion are derived for a vehicle model with 20 degrees of freedom, considering the lateral displacement and yaw angle of each wheelset, the lateral displacement, vertical displacement, roll angle and yaw angle of the bogie frame, and the car body moving on a curved track. The dynamic responses of a railway vehicle with wind loads acting laterally and vertically, and wind moments acting about the longitudinal axis of the car body are investigated. The analysis results indicate that the oscillation amplitude of the car body increases as the wind speed increases. Furthermore, the average amplitude of oscillation of the wheelset increases with the wind speed as well. It is concluded that the influence of wind loads on the dynamic stability of a vehicle cannot be ignored.

A New Dynamic Model of High-Speed Railway Vehicle Moving on Curved Tracks

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
Sen-Yung Lee ◽  
Yung-Chang Cheng
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Lateral Displacement ◽  
Creep Model ◽  
Railway Vehicle ◽  
Nonlinear Creep ◽  
Six Degrees Of Freedom ◽  
Car Body ◽  
Yaw Angle

A new dynamic model of railway vehicle moving on curved tracks is proposed. In the new model, the motion of the car body is considered and the motion of the truck frame is not restricted by a virtual boundary. Based on the heuristic nonlinear creep model, the nonlinear coupled differential equations of the motion of an eight degrees of freedom car system—considering the lateral displacement and the yaw angle of each wheelset, the truck frame, and the half car body—moving on curved tracks are derived completely. To illustrate the accuracy of the analysis, the limiting cases are examined. It is shown that the influence of the gyroscopic moment of the wheelsets on the critical hunting speed is negligible. In addition, the influences of the suspension parameters, including those losing in the six degrees of freedom system, on the critical hunting speeds evaluated via the linear and the nonlinear creep models are studied and compared.

scholarly journals Simulation of Energy Absorption Performance of the Couplers in Urban Railway Vehicles during a Heavy Collision

Machines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 91
Author(s):  
Sunghyun Lim ◽  
Yong-hyeon Ji ◽  
Yeong-il Park
Keyword(s):  
Reaction Force ◽  
Crash Test ◽  
Railway Vehicle ◽  
Buffer System ◽  
Railway Vehicles ◽  
Hydraulic Shock Absorber ◽  
Coupling Buffer ◽  
Absorption Performance ◽  
Different Characteristics ◽  
The Impact

Railway vehicles are generally operated by connecting several vehicles in a row. Mechanisms connecting railway vehicles must also absorb front and rear shock loads that occur during a train’s operation. To minimize damage, rail car couplers are equipped with a buffer system that absorbs the impact of energy. It is difficult to perform a crash test and evaluate performance by applying a buffer to an actual railway vehicle. In this study, a simulation technique using a mathematical buffer model was introduced to overcome these difficulties. For this, a model of each element of the buffer was built based on the experimental data for each element of the coupling buffer system and a collision simulation program was developed. The buffering characteristics of a 10-car train colliding at 25 km/h were analyzed using a developed simulator. The results of the heavy collision simulation showed that the rubber buffer was directly connected to the hydraulic shock absorber in a solid contact state, and displacement of the hydraulic buffer hardly occurred despite the increase in reaction force due to the high impact speed. Since the impact force is concentrated on the vehicle to which the collision is applied, it may be appropriate to apply a deformation tube with different characteristics depending on the vehicle location.

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