Functional, thermal and EMC analysis for a safety critical analogue design applied to a transportation systems

Safety-critical equipment depends on the study of functional, thermal, EMC (Electromagnetic Compatibility) and RAMS (Reliability, Availability, Maintainability and Safety) fields. The variation of one area characteristic could result in a failure to fulfil safety requirements. Traditionally, thermal, EMC or RAMS issues were only considered once the design was done. This paper proposes a novel analogue equipment design methodology by studying these areas dependently from the beginning of the design process. Each area requirements and design parameters and the relation among them are defined qualitatively and quantitatively. Based on these dependences among all the areas, the cross-influence of each parameter variation in other areas requirements is demonstrated. The obtained results are intended to aid the fulfilment of requirements of the design of any safety critical analogue circuit, and to help designers to know beforehand the consequences of any change in the design, saving time and money. The application of this methodology in a SIL 2 RF transmitter is shown and the improvement and worsening of requirements depending on the parameters variation is exposed

Low power RF circuit design in standard CMOS technology

Low Power Consumption is one of the critical issues in the performance of small battery-powered handheld devices. Mobile terminals feature an ever increasing number of wireless communication alternatives including GPS, Bluetooth, GSM, 3G, WiFi or DVB-H. Considering that the total power available for each terminal is limited by the relatively slow increase in battery performance expected in the near future, the need for efficient circuits is now critical. This book presents the basic techniques available to design low power RF CMOS analogue circuits. It gives circuit designers a complete guide of alternatives to optimize power consumption and explains the application of these rules in the most common RF building blocks: LNA, mixers and PLLs. It is set out using practical examples and offers a unique perspective as it targets designers working within the standard CMOS process and all the limitations inherent in these technologies

A Maturity Model Proposal for Industrial Maintenance and Its Application to the Railway Sector

Maintenance is one of the major concerns of the industrial sector. Acquiring better levels of maintenance maturity is one of the objectives to be achieved. Therefore, prescriptive maintenance is one of the areas of recent research. Current works in literature are focused on specifics of maintenance strategies (from preventive to prescriptive), usually related to a fixed asset. No previous work has been identified regarding the methodology and guidelines to be followed to be able to evolve within the different strategies from a generic perspective. To address the lack of a methodology that shows a more evolutionary path between maintenance strategies, this paper presents Maintenance Maturity Model M3: a maturity model that identifies three areas of action, four levels of maturity, and the activities to be carried out in each of them to make progress in the maturity level of maintenance strategies. The implementation of prescriptive maintenance should be done in a gradual way, starting at the lowest levels. M3 approaches the problem from a broader perspective, analyzing the 18 different domains and the different levels of prior maturity to be considered for prescriptive maintenance. A study has also been carried out on the different maintenance actions and the applicability of the proposed M3 maturity model to the railway infrastructure maintenance is discussed. In addition, this paper also highlights future research lines and open issues

Prediction of Rolling Contact Fatigue Behavior in Rails Using Crack Initiation and Growth Models along with Multibody Simulations

Rolling contact fatigue (RCF) is a common cause of rail failure due to repeated stresses at the wheel-rail contact. This phenomenon is a real problem that greatly affects the safety of train operation. Preventive and corrective maintenance tasks have a big impact on the Life Cycle Cost (LCC) of railway assets, and therefore cutting-edge strategies based on predictive functionalities are needed to reduce it. A methodology based on physical models is proposed to predict the degradation of railway tracks due to RCF. This work merges a crack initiation and a crack growth model along with a fully nonlinear multibody model. From a multibody assessment of the vehicle-track interaction, an energy dissipation method is used to identify points where cracks are expected to appear. At these points, crack propagation is calculated considering the contact conditions as a function of crack depth. The proposed methodology has been validated with field measurements, conducted using Eddy Currents provided by the infrastructure manager Network Rail. Validation results show that RCF behavior can be predicted for track sections with different characteristics without the necessity of previous on-track measurements

A maturity model proposal for industrial maintenance and its application to the railway sector

Maintenance is one of the major concerns of the industrial sector. Acquiring better levels of maintenance maturity is one of the objectives to be achieved. Therefore, prescriptive maintenance is one of the areas of recent research. Current works in literature are focused on specifics of maintenance strategies (from preventive to prescriptive), usually related to a fixed asset. No previous work has been identified regarding the methodology and guidelines to be followed to be able to evolve within the different strategies from a generic perspective. To address the lack of a methodology that shows a more evolutionary path between maintenance strategies, this paper presents Maintenance Maturity Model M3: a maturity model that identifies three areas of action, four levels of maturity, and the activities to be carried out in each of them to make progress in the maturity level of maintenance strategies. The implementation of prescriptive maintenance should be done in a gradual way, starting at the lowest levels. M3 approaches the problem from a broader perspective, analyzing the 18 different domains and the different levels of prior maturity to be considered for prescriptive maintenance. A study has also been carried out on the different maintenance actions and the applicability of the proposed M3 maturity model to the railway infrastructure maintenance is discussed. In addition, this paper also highlights future research lines and open issues

Positioning for Train-infrastructure Asset Health Status Monitoring within the SIA-project

Railway infrastructure and vehicle maintenance expenditures are estimated to cost over 20,000M€ per year at European level. This indicates the demand for developing a low-cost system capable of providing prognostic information about the health status of the railway at the points of the interaction between the vehicle and the infrastructure (wheelset, pantograph, rail and catenary). To achieve these capabilities, SIA (System for vehicle-infrastructure Interaction Assets health status monitoring) is being developed by a consortium from five different European countries. Within the SIA system, events are captured by a network of sensors, which are time stamped and then accurately geo-referenced by the positioning sub-system of SIA. The positioning sub-system is based on EGNSS positioning algorithms tailored for the railway environment and comprises onboard as well as back-office processing. GNSS-based positioning in the railway environment is very challenging. Hence, Galileo with its advanced signal structure is utilized in SIA (in addition to GPS) to improve availability as well as accuracy. The onboard positioning algorithm has been developed based on a novel GNSS-IMU hybridized approach. The new approach can overcome frequent measurement gaps within the GNSS observations and maintain the accuracy level required by SIA system. An overview of the back-office positioning in SIA complements the presentation of the onboard processing

A maturity model proposal for industrial maintenance and its application to the railway sector

Maintenance is one of the major concerns of the industrial sector. Acquiring better levels of maintenance maturity is one of the objectives to be achieved. Therefore, prescriptive maintenance is one of the areas of recent research. Current works in literature are focused on specifics of maintenance strategies (from preventive to prescriptive), usually related to a fixed asset. No previous work has been identified regarding the methodology and guidelines to be followed to be able to evolve within the different strategies from a generic perspective. To address the lack of a methodology that shows a more evolutionary path between maintenance strategies, this paper presents Maintenance Maturity Model M3: a maturity model that identifies three areas of action, four levels of maturity, and the activities to be carried out in each of them to make progress in the maturity level of maintenance strategies. The implementation of prescriptive maintenance should be done in a gradual way, starting at the lowest levels. M3 approaches the problem from a broader perspective, analyzing the 18 different domains and the different levels of prior maturity to be considered for prescriptive maintenance. A study has also been carried out on the different maintenance actions and the applicability of the proposed M3 maturity model to the railway infrastructure maintenance is discussed. In addition, this paper also highlights future research lines and open issues

Panhead accelerations-based methodology for monitoring the stagger in overhead contact line systems

The monitoring of overhead contact lines (OCL) is a key part of railway infrastructure maintenance. This paper proposes a methodology to assess the lateral geometry of contact wire, the so-called stagger, by using the dynamic response of a pantograph. The methodology is tested in a validated virtual environment that resembles the behaviour of the pantograph when it interacts with the OCL. A signal processing is developed to define features relating the lateral position of the contact wire with the vertical acceleration of the contact strip. It is demonstrated that these features have a clear and close connection with the lateral position of the contact wire. Subsequently, model-driven machine learning algorithms are defined using these features to address the OCL stagger prediction and the detection of out-of-range lateral displacement due to a faulty steady-arm. The methodology shows a good prediction performance in the estimation of the stagger amplitude/central position and the steady-arms diagnosis. The prediction of the stagger amplitude is performed with a root-mean-square error of 4.7(10) mm. In addition, the area under the Precision-Recall curve is 0.952 CI95 [0.940, 0.962] for the steady-arms diagnosis

Edge intelligence-based proposal for onboard catenary stagger amplitude diagnosis

In recent years, the integration of Digital Twins (DT) for the adoption of smarter maintenance strategies has grown exponentially in different industrial sectors. New IoT and edge computing systems are being developed for this purpose, however, there are still some open issues and challenges to be solved. Firstly, this paper presents new approaches to the initial dependencies of the studied solution and make a new proposal to improve the interoperability of the presented system. Secondly, this paper provides a methodology applicable to similar developments of edge-based AI (Artificial Intelligence) solution, which comprises of four phases: the presentation of the multi-objective problem and the pre-selection of AI-based models, the description of the evaluation architecture, the profiling of the different models for the selection of the most suitable one and explainable AI strategies for getting insights of the selected model. Finally, it presents a use case of an edge-solution for the railway catenary geometry diagnostic (stagger amplitude of the overhead wire), saving the interoperability of the message exchange with other systems is provided