scholarly journals Reconstruction of an informative railway wheel defect signal from wheel–rail contact signals measured by multiple wayside sensors

2018 ◽  
Vol 233 (1) ◽  
pp. 49-62 ◽  
Author(s):  
Alireza Alemi ◽  
Francesco Corman ◽  
Yusong Pang ◽  
Gabriel Lodewijks
Keyword(s):  
Contact Force ◽  
Ad Hoc ◽  
Impact Load ◽  
Fusion Model ◽  
Informative Signal ◽  
Railway Systems ◽  
Multiple Sensors ◽  
Reconstructed Signal ◽  
Force Signal ◽  
Defect Signal

Wheel impact load detectors are widespread railway systems used for measuring the wheel–rail contact force. They usually measure the rail strain and convert it to force in order to detect high impact forces and corresponding detrimental wheels. The measured strain signal can also be used to identify the defect type and its severity. The strain sensors have a limited effective zone that leads to partial observation from the wheels. Therefore, wheel impact load detectors exploit multiple sensors to collect samples from different portions of the wheels. The discrete measurement by multiple sensors provides the magnitude of the force; however, it does not provide the much richer variation pattern of the contact force signal. Therefore, this paper proposes a fusion method to associate the collected samples to their positions over the wheel circumferential coordinate. This process reconstructs an informative signal from the discrete samples collected by multiple sensors. To validate the proposed method, the multiple sensors have been simulated by an ad hoc multibody dynamic software (VI-Rail), and the outputs have been fed to the fusion model. The reconstructed signal represents the contact force and consequently the wheel defect. The obtained results demonstrate considerable similarity between the contact force and the reconstructed defect signal that can be used for further defect identification.

scholarly journals Evaluation of the influential parameters contributing to the reconstruction of railway wheel defect signals

2019 ◽  
Vol 234 (9) ◽  
pp. 1005-1016
Author(s):  
Alireza Alemi ◽  
Francesco Corman ◽  
Yusong Pang ◽  
Gabriel Lodewijks
Keyword(s):  
Impact Load ◽  
Simulated Data ◽  
Dynamic Force ◽  
Fusion Method ◽  
Railway Wheel ◽  
Multiple Sensors ◽  
Main Indicator ◽  
The Impact ◽  
Influential Parameters ◽  
Defect Signal

A wheel impact load detector is used to assess the condition of a railway wheel by measuring the dynamic forces generated by defects. This system normally measures the impact force at multiple points by exploiting multiple sensors to collect samples from different portions of the wheel circumference. The outputs of the sensors are used to estimate the dynamic force as the main indicator for detecting the presence of the defect. This method fails to identify the defect type and its severity. Recently, a data fusion method has been developed to reconstruct the wheel defect signal from the wheel–rail contact signals measured by multiple wayside sensors. The reconstructed defect signal can be influenced by different parameters such as train velocity, axle load, number of sensors, and wheel diameter. This paper aims to carry out a parametric study to investigate the influence of these parameters. For this purpose, VI-Rail is used to simulate the wheel–rail interaction and provide the required data. Then, the developed fusion method is exploited to reconstruct the defect signal from the simulated data. This study provides a detailed insight into the effects of the influential parameters by investigating the variation of the reconstructed defect signals.

Design and experiment of a modular multisensory hand for prosthetic applications

2017 ◽  
Vol 44 (1) ◽  
pp. 104-113 ◽  
Author(s):  
Bo Zeng ◽  
Shaowei Fan ◽  
Li Jiang ◽  
Hong Liu
Keyword(s):  
Contact Force ◽  
Upper Limb ◽  
Impedance Control ◽  
Transmission Mechanism ◽  
Human Hand ◽  
Prosthetic Hand ◽  
Control Performance ◽  
Content Type ◽  
Multiple Sensors ◽  
Modular Unit

Purpose This paper aims to present the design and experiment of a modular multisensory prosthetic hand for applications. Design and experiment of a modular multisensory hand for prosthetic applications. Design/methodology/approach This paper reveals more details focusing on the appearance, mechanism design, electrical design and control of the prosthetic hand considering anthropomorphism, dexterity, sensing and controllability. The finger is internally integrated with the actuator, the transmission mechanism, the sensors and the controller as a modular unit. Integrated with multiple sensors, the prosthetic hand can not only perceive the position, the contact force and the temperature of the environment like a human hand but also provide the foundation for the practical control. Findings The experiments show that the prosthetic hand can accurately control the contact force to achieve stable grasps based on the sensors feedback and a simple and effective force-tracking impedance control algorithm. In addition, the experiments based on the cosmesis validate not only the cosmesis functionality but also the control performance for a prosthesis–cosmesis system. Practical implications Because of the small size, low weight, high integration, modularity and controllability, the prosthetic hand is easily applied to upper-limb amputees. Meanwhile, the finger as a modular unit is easy to be fixed, maintained and applied to a partial upper-limb amputee. Originality/value Each modular finger of the prosthetic hand integrated with the actuator, the transmission mechanism, the sensors and the controller as a whole can independently control the position and the force. The cosmetic glove design can provide pretty appearance without compromising the control performance.

An Extensible Software Design Applied to Rapid Thermal Processing

1993 ◽  
Vol 303 ◽  
Author(s):  
Paul Dankoski ◽  
Paul Gyugyi ◽  
Gene Franklin
Keyword(s):  
Ad Hoc ◽  
Computer Integrated Manufacturing ◽  
Sensors And Actuators ◽  
Multiple Sensors ◽  
Complex Interactions ◽  
Physical Sensors ◽  
Reliable Communications ◽  
Uniform Manner ◽  
Extensible Software ◽  
And Control

ABSTRACTThe next five to ten years will show a dramatic increase in the number of sensors and actuators in use. Several advances in technology, namely integrated sensors, fast reliable communications, and powerful computers, are making such changes possible. Coordinating the complex interactions of multiple sensors and control settings can be too confusing for an ad-hoc approach. Applying modern model-based control theory to multi-input/multi-output systems has the potential of improving the yield and throughput in a computer integrated manufacturing environment.Our expectation is that as more sensors and actuators become available, it will be important to handle internal communications between processing subsystems in a uniform manner to allow for incremental expansions to the processing equipment. Because of the wide assortment of physical sensors available for control equipment, an architecture is presented which attempts to unify the communications and control in a multiprocessor environment. The focus of this paper will be to explain one method of controlling a Rapid Thermal Multiprocessing chamber and how it is designed to handle future growth.The implementation and experimentation are being performed on the Rapid Thermal Multiprocessor (RTM) at the Center for Integrated Systems (CIS) at Stanford University.

Experimental Study of Normal Contact Force Between a Rolling Pneumatic Tyre and a Single Asperity

2017 ◽  
Vol 09 (06) ◽  
pp. 1750081 ◽  
Author(s):  
Yuan-Fang Zhang ◽  
Julien Cesbron ◽  
Hai-Ping Yin ◽  
Michel Bérengier
Keyword(s):  
Contact Force ◽  
Numerical Models ◽  
Force Transducer ◽  
Contact Forces ◽  
Exterior Surface ◽  
Normal Contact ◽  
Single Asperity ◽  
Direct Measurements ◽  
Time Signals ◽  
Force Signal

This paper proposes a novel experimental test apparatus that permits direct measurements of tyre/asperity normal contact forces under rolling conditions without interfacial layer. A reduced-sized pneumatic tyre is set rolling on the exterior surface of a cylindrical test rig simulating a smooth road surface except a single asperity of simple geometric shape connected to an embedded force transducer. Distinct asperity geometries lead to similar shapes of force signal but different magnitudes whose relationships with the indentation have exponents close to those in classical analytical solutions. By analyzing the time signals of the contact force and their frequency contents for different rolling speeds, the quasi-static nature of the contact, commonly assumed in numerical models, is verified.

scholarly journals Application of Ad-hoc Network Technology to Railway Systems

2006 ◽  
Vol 47 (2) ◽  
pp. 83-88
Author(s):  
Kiyotaka SEKI ◽  
Kunihiro KAWASAKI ◽  
Kazuki NAKAMURA
Keyword(s):  
Ad Hoc Network ◽  
Ad Hoc ◽  
Network Technology ◽  
Railway Systems

Out-of-round railway wheels—wheel-rail contact forces and track response derived from field tests and numerical simulations

2003 ◽  
Vol 217 (2) ◽  
pp. 135-146 ◽  
Author(s):  
A Johansson ◽  
J C O Nielsen
Keyword(s):  
Numerical Simulations ◽  
Contact Force ◽  
Impact Load ◽  
Numerical Models ◽  
Field Tests ◽  
Fatigue Cracking ◽  
Contact Forces ◽  
Rolling Contact ◽  
Local Defect ◽  
Different Types

The influence of different types of railway wheel out-of-roundness (OOR) on the vertical dynamic wheel-rail contact force and track response is investigated through extensive field tests and numerical simulations. The response from a freight train, provided with a number of different types of severe wheel tread damage, is studied. Two different axle loads are used in combination with different train speeds in the range 30-100km/h. The wheel defects are wheelflats, local spalls due to rolling contact fatigue cracking, long local defects and polygonal wheels (periodic OOR). The vertical wheel-rail contact force was measured using a strain gauge based wheel impact load detector. Strain gauges and accelerometers were positioned on rails and sleepers to measure the track response. Most of the magnitudes of measured impact forces were found to be lower than the current impact load limit that is used in Sweden to determine when a defective wheel should be removed for repair. Only the long local defect caused larger force magnitudes than the wheel removal criterion. Measured responses are used to calibrate and validate numerical models for simulation of train-track interaction. Results from one linear and one state-dependent track model are compared.

scholarly journals Development and validation of a safe communication protocol compliant to railway standards

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Duccio Bertieri ◽  
Andrea Ceccarelli ◽  
Tommaso Zoppi ◽  
Innocenzo Mungiello ◽  
Mario Barbareschi ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Communication Protocols ◽  
Verification And Validation ◽  
Design Development ◽  
Sensors And Actuators ◽  
Railway Network ◽  
Safety Standards ◽  
Railway Systems ◽  
Safety Case ◽  
Railway System

AbstractRailway systems are composed of a multitude of subsystems, sensors, and actuators that exchange datagrams through safety-critical communication protocols. However, the vast majority of these protocols rely on ad hoc interlacing mechanisms and safety codes which raise the heterogeneity and complexity of the overarching railway system. Therefore, Rete Ferroviaria Italiana, the company who is in charge of managing the Italian railway network, coordinated the definition of the Protocollo Vitale Standard (Standard Vital Protocol). This protocol is inspired to, and compliant with, the communication protocols adopted for the European Train Control System (ETCS) (SUBSET, UNISIG, 037, Euroradio FIS, version 2.3. 0; SUBSET, UNISIG, 098, RBC-RBC safe communication interface, 2007), and it is meant to become the standard layer to enable safe communication between components of the Italian railway system. This paper reports our experience in the design, implementation, verification, and validation of the Protocollo Vitale Standard in compliance with the European safety standards for railway systems. We first defined a safety plan and a verification and validation plan, which guide the design, development, verification, and validation activities as required by safety standards. Guidelines of such plans have been followed strictly until completion of the work, which concludes with the provision of a safety case where all safety evidences are summarized. Noticeably, we (i) selected appropriate safety mechanisms, (ii) verified the software design, (iii) implemented the software in compliance with code metrics and coding rules, (iv) conducted tests to validate the protocol against its functional and performance requirements, and ultimately (v) devised all relevant documentation and a safety case which summarizes the evidences needed for certification.

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