Mechatronic aspects of an innovative two-axle railway vehicle

Within the Shift2Rail research program the goals for a sustainable growth of the railway sector are set. Among these are substantial reduction of Life Cycle Costs, improved reliability and energy efficiency, the reductionof noise emissions, and the achievement of full interoperability of the rolling stock. Therefore, a new generation of running gear is envisioned. An innovative two-axle vehicle that can reduce weight, initial investmentand maintenance cost, and emissions is proposed for a metro line system. The vehicle proposed will have only one suspension step. To further reducethe weight and incorporate the otherwise missing anti-roll bar, a compositematerial connection frame is introduced. The two-axle configuration suffers from poor ride comfort, due to the lack of a second suspension step acting as filter, and from poor steering capability, due to the long distance between wheelsets. Active suspensions are therefore introduced to improve both ride comfort and steering capability. This Ph.D. thesis showcases the key activities undertaken during the developmentof the innovative vehicle, building a simulation framework where the vehicle can be virtually tested. Several modelling environments are used such as: SIMPACK for vehicle dynamics, Abaqus for finite elements modelling, Simscape for hydraulic physics simulations, and Simulink for control logic development. During the Ph.D. time two elements of the mechatronic vehicle have been designed and manufactured, i.e. the carbon fiber connection frame and the steering active suspension. The two components models have been experimentally validated and introduced into the simulation environment. A ride comfort and a wheelset steering control strategy have been designed to overcome the limitations introduced by the two-axle configuration. The proposed solutions aim at being applicable in the whole operational scenario of the innovative vehicle. The present work emphasises the possibility of introducing innovative mechatronic solutions as an alternative to standard bogie solutions aiming at reducing costs and emissions, blurring the boundaries between academic view and possible industrial applications.Inom forskningsprogrammet Shift2Rail sattes målen för en hållbar tillväxt av järnvägssektorn. Dessa mål innefattar en avsevärd minskning av livscykelkostnader, en ökad tillförlitlighet och energieffektivitet, minskning av bullerutsläpp och full driftskompatibilitet för den rullande materielen. För att uppnå målen föreslås här en ny generation av löpverk. Ett innovativt tvåaxligt fordon som kan minska vikten, den initiala investerings- och underhållskostnaden samt utsläppen föreslås därför här för ett tunnelbanesystem. Det föreslagna fordonet kommer bara att ha ett fjädringssteg. För att ytterligare minska vikten och inkludera den annars saknade krängningshämmaren, introduceras en sammankopplande ram av kompositmaterial. Den tvåaxliga konfigurationen lider av dålig åkkomfort, eftersom det saknas ett andra fjädringssteg som fungerar som filter. På grund av det långa hjulaxelavståndet lider konfigurationen även av dålig styrförmåga. För att förbättra både åkkomfort och styrförmåga introduceras därför aktiva fjädringar. Denna doktorsavhandling beskriver de viktigaste aktiviteterna som genomfördes under utvecklingen av det innovativa fordonet, uppbyggnaden av ett simuleringsramverk där fordonet kan testas virtuellt. Flera modelleringsmiljöer används, såsom SIMPACK för fordonsdynamik, Abaqus för modellering i finita element, Simscape för hydrauliska simuleringar och Simulink för utveckling av styrlogiken. Under doktorsarbetets gång har två delar av det mekatroniska fordonet designats och tillverkats, det är kolfiberkopplingsramen och den aktiva fjädringen i styrningen. Modellerna för dessa två komponenter har experimentellt validerats och introducerats i simuleringsmiljön. Kontrollstrategier för åkkomfort och styrningen av hjulaxlarna har utformats för att övervinna de begränsningar som den tvåaxliga konfigurationen innebär. De föreslagna lösningarna syftar till att vara tillämpliga i hela driftscenariot för det innovativa fordonet. Detta arbete betonar möjligheten att introducera innovativa mekatroniska lösningar som ett alternativ till vanliga boggilösningar som syftar till att minska kostnader och utsläpp, och sudda ut gränserna mellan den akademiska synen och möjliga industriella tillämpningar.QC 230510</p

Mechatronic aspects of an innovativetwo-axle railway vehicle

Within the Shift2Rail research program the goals for a sustainable growth of the railway sector are set. Among these are substantial reduction of Life Cycle Costs, improved reliability and energy efficiency, the reductionof noise emissions, and the achievement of full interoperability of the rolling stock. Therefore, a new generation of running gear is envisioned. An innovative two-axle vehicle that can reduce weight, initial investmentand maintenance cost, and emissions is proposed for a metro line system. The vehicle proposed will have only one suspension step. To further reducethe weight and incorporate the otherwise missing anti-roll bar, a compositematerial connection frame is introduced. The two-axle configuration suffers from poor ride comfort, due to the lack of a second suspension step acting as filter, and from poor steering capability, due to the long distance between wheelsets. Active suspensions are therefore introduced to improve both ride comfort and steering capability. This Ph.D. thesis showcases the key activities undertaken during the developmentof the innovative vehicle, building a simulation framework where the vehicle can be virtually tested. Several modelling environments are used such as: SIMPACK for vehicle dynamics, Abaqus for finite elements modelling, Simscape for hydraulic physics simulations, and Simulink for control logic development. During the Ph.D. time two elements of the mechatronic vehicle have been designed and manufactured, i.e. the carbon fiber connection frame and the steering active suspension. The two components models have been experimentally validated and introduced into the simulation environment. A ride comfort and a wheelset steering control strategy have been designed to overcome the limitations introduced by the two-axle configuration. The proposed solutions aim at being applicable in the whole operational scenario of the innovative vehicle. The present work emphasises the possibility of introducing innovative mechatronic solutions as an alternative to standard bogie solutions aiming at reducing costs and emissions, blurring the boundaries between academic view and possible industrial applications.Inom forskningsprogrammet Shift2Rail sattes målen för en hållbar tillväxt av järnvägssektorn. Dessa mål innefattar en avsevärd minskning av livscykelkostnader, en ökad tillförlitlighet och energieffektivitet, minskning av bullerutsläpp och full driftskompatibilitet för den rullande materielen. För att uppnå målen föreslås här en ny generation av löpverk. Ett innovativt tvåaxligt fordon som kan minska vikten, den initiala investerings- och underhållskostnaden samt utsläppen föreslås därför här för ett tunnelbanesystem. Det föreslagna fordonet kommer bara att ha ett fjädringssteg. För att ytterligare minska vikten och inkludera den annars saknade krängningshämmaren, introduceras en sammankopplande ram av kompositmaterial. Den tvåaxliga konfigurationen lider av dålig åkkomfort, eftersom det saknas ett andra fjädringssteg som fungerar som filter. På grund av det långa hjulaxelavståndet lider konfigurationen även av dålig styrförmåga. För att förbättra både åkkomfort och styrförmåga introduceras därför aktiva fjädringar. Denna doktorsavhandling beskriver de viktigaste aktiviteterna som genomfördes under utvecklingen av det innovativa fordonet, uppbyggnaden av ett simuleringsramverk där fordonet kan testas virtuellt. Flera modelleringsmiljöer används, såsom SIMPACK för fordonsdynamik, Abaqus för modellering i finita element, Simscape för hydrauliska simuleringar och Simulink för utveckling av styrlogiken. Under doktorsarbetets gång har två delar av det mekatroniska fordonet designats och tillverkats, det är kolfiberkopplingsramen och den aktiva fjädringen i styrningen. Modellerna för dessa två komponenter har experimentellt validerats och introducerats i simuleringsmiljön. Kontrollstrategier för åkkomfort och styrningen av hjulaxlarna har utformats för att övervinna de begränsningar som den tvåaxliga konfigurationen innebär. De föreslagna lösningarna syftar till att vara tillämpliga i hela driftscenariot för det innovativa fordonet. Detta arbete betonar möjligheten att introducera innovativa mekatroniska lösningar som ett alternativ till vanliga boggilösningar som syftar till att minska kostnader och utsläpp, och sudda ut gränserna mellan den akademiska synen och möjliga industriella tillämpningar.QC 230510</p

Improved curving performance of an innovative two-axle vehicle: a reasonable feedforward active steering approach

A mechatronic rail vehicle with reduced tare weight, two axles and only one level of suspension is proposed with the objective of reducing investment and maintenance costs. A wheelset to carbody connection frame in composite material will be used both as structural and as suspension element. Active control is introduced to steer the wheelsets and improve the curving performance. A feedforward control approach for active curve steering based on non-compensated lateral acceleration and curvature is proposed to overcome stability issues of a feedback approach. The feedforward approach is synthesised starting from the best achievable results of selected feedback approaches in terms of wheel energy dissipation and required actuation force. A set of 357 running cases (embracing 7 curves, 17 speeds per curve and 3 conicities) is used to design the controller. The controller is shown to perform well for conicity and track geometry variations and under the presence of track irregularities.QC 20201007</p

iVRIDA: intelligent Vehicle Running Instability Detection Algorithm for high-speed rail vehicles using Temporal Convolution Network : – A pilot study

Intelligent fault identification of rail vehicles from onboard measurements is of utmost importance to reduce the operating and maintenance cost of high-speed vehicles. Early identification of vehicle faults responsible for an unsafe situation, such as the instable running of highspeed vehicles, is very important to ensure the safety of operating rail vehicles. However, this task is challenging because of the nonlinear dynamics associated with multiple subsystems of the rail vehicle. The task becomes more challenging with only accelerations recorded in the carbody where, nevertheless, sensor maintenance is significantly lower compared to axlebox accelerometers. This paper proposes a Temporal Convolution Network (TCN)-based intelligent fault detection algorithm to detect rail vehicle faults. In this investigation, the classifiers are trained and tested with the results of numerical simulations of a high-speed vehicle (200 km/h). The TCN based fault classification algorithm identifies the rail vehicle faults with 98.7% accuracy. The proposed method contributes towards digitalization of rail vehicle maintenance through condition-based and predictive maintenance.QC 20220726part of proceedings ISBN 9781936263363</p

Active suspension in railway vehicles:a literature survey

Since the concept of active suspensions appeared, its large possible benefits has attracted continuous exploration in the field of railway engineering. With new demands of higher speed, better ride comfort and lower maintenance cost for railway vehicles, active suspensions are very promising technologies. Being the starting point of commercial application of active suspensions in rail vehicles, tilting trains have become a great success in some countries. With increased technical maturity of sensors and actuators, active suspension has unprecedented development opportunities. In this work, the basic concepts are summarized with new theories and solutions that have appeared over the last decade. Experimental studies and the implementation status of different active suspension technologies are described as well. Firstly, tilting trains are briefly described. Thereafter, an in-depth study for active secondary and primary suspensions is performed. For both topics, after an introductory section an explanation of possible solutions existing in the literature is given. The implementation status is reported. Active secondary suspensions are categorized into active and semi-active suspensions. Primary suspensions are instead divided between acting on solid-axle wheelsets and independently rotating wheels. Lastly, a brief summary and outlook is presented in terms of benefits, research status and challenges. The potential for active suspensions in railway applications is outlined