scholarly journals Considerations on longitudinal dynamics of passenger trains with blocked wheelsets during braking

Author(s):  
C Cruceanu ◽  
C Crăciun
2013 ◽  
Vol 378 ◽  
pp. 74-81 ◽  
Author(s):  
Cătălin Cruceanu ◽  
Camil Ion Crăciun

There are presented and analyzed specific aspects regarding the main mechanic and pneumatic issues determining the in-train dynamic forces developed during braking actions. Particularities in case of passenger trains are highlighted, with the aim of proving that even in the case of short trains, fitted with UIC type P braking system, longitudinal dynamics can cause significant reactions whose effect cannot be neglected, both in terms of traffic safety and comfort. Numerical examples presented stand for this.


1972 ◽  
Vol 51 (11) ◽  
pp. 392
Author(s):  
Sydney Jones
Keyword(s):  

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 88
Author(s):  
Riccardo Mandriota ◽  
Stefano Fabbri ◽  
Matthias Nienhaus ◽  
Emanuele Grasso

The need for reducing the cost of and space in Electrically Assisted Bicycles (EABs) has led the research to the development of solutions able to sense the applied pedalling torque and to provide a suitable electrical assistance avoiding the installation of torque sensors. Among these approaches, this paper proposes a novel method for the estimation of the pedalling torque starting from an estimation of the motor load torque given by a Load Torque Observer (LTO) and evaluating the environmental disturbances that act on the vehicle longitudinal dynamics. Moreover, this work shows the robustness of this approach to rotor position estimation errors introduced when sensorless techniques are used to control the motor. Therefore, this method allows removing also position sensors leading to an additional cost and space reduction. After a mathematical description of the vehicle longitudinal dynamics, this work proposes a state observer capable of estimating the applied pedalling torque. The theory is validated by means of experimental results performed on a bicycle under different conditions and exploiting the Direct Flux Control (DFC) sensorless technique to obtain the rotor position information. Afterwards, the identification of the system parameters together with the tuning of the control system and of the LTO required for the validation of the proposed theory are thoroughly described. Finally, the capabilities of the state observer of estimating an applied pedalling torque and of recognizing the application of external disturbance torques to the motor is verified.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Guo Lie ◽  
Ren Zejian ◽  
Ge Pingshu ◽  
Chang Jing

Automotive collision avoidance system, which aims to enhance the active safety of the vehicle, has become a hot research topic in recent years. However, most of the current systems ignore the active protection of pedestrian and other vulnerable groups in the transportation system. An advanced emergency braking control system is studied by taking into account the pedestrians and the vehicles. Three typical braking scenarios are defined and the safety situations are assessed by comparing the current distance between the host vehicle and the obstacle with the critical braking distance. To reflect the nonlinear time-varying characteristics and control effect of the longitudinal dynamics, the vehicle longitudinal dynamics model is established in CarSim. Then the braking controller with the structure of upper and lower layers is designed based on sliding mode control and the single neuron PID control when confronting deceleration or emergency braking conditions. Cosimulations utilizing CarSim and Simulink are finally carried out on a CarSim intelligent vehicle model to explore the effectiveness of the proposed controller. Results display that the designed controller has a good response in preventing colliding with the front vehicle or pedestrian.


Author(s):  
A Elia

The objective in introducing tilting systems for passenger trains is to optimize the service, shortening travel time and improving comfort, while making minimum alterations to existing track layouts and service conditions. The development of the Pendolino system is described in this paper, starting from early tests on bogies and on tilting systems. The author then describes the extensive service experience of Fiat, with more than 50 million train-km produced and 100 trainsets in service or under construction for service in European countries. An outline is presented of current developments and the product strategy, together with a description of available R&D prediction/measuring tools.


Author(s):  
Stuart O. Parsons

Approximately ten cases have been documented of people falling out of the side exit doors of moving passenger trains throughout the US. Most of these individuals were elderly passengers and the events usually happened late at night. Amtrak has classified most of these accidents as individuals with mental disorders or suicidal tendencies. Legal actions at the present time have been dismissed by the courts due primarily to the lack of any witnesses to the events. An investigation was conducted of a passenger car allegedly involved in one of these accidents. A number of recommendations were made including: 1) a systems engineering study of the problem, 2) an interlock system which would prevent the side exit door locking handle from being activated while the train is in motion, 3) an “All Green Board” at the engineer's station to indicate that all doors on the train are locked before starting the train, 4) a protective translucent cover installed over the regular door handle to indicate the criticality of opening this door, 5) a new warning sign on the exit doors which follows the ANSI standard, and 6) a training program, related to this dangerous situation, for all Amtrak operational personnel.


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