Ph. D. Project
Title:
Modeling for Safety Assessment in the Context of Decarbonized Rail Transport: Application to an Electrotechnical Battery Charging System of a Very Light Train.
Dates:
2024/10/01 - 2027/09/30
Supervisor(s):
Description:
Introduction:
The implementation of the very light train as a decarbonization solution for rail transport represents a promising prospect for the future of transport systems in fine-grained territorial service lines (LDFT). These lines currently suffer from a lack of decarbonized transport offerings. The success of deploying such a solution lies both in the technical prowess of the system design and in the optimization of its operation and ensuring its viability throughout its life cycle. In this context, this thesis aims to develop safety and security assessment methods specifically adapted to the onboard battery charging system, thereby contributing to the safe design and operation of the railway system. This innovative charging system, which allows the onboard batteries to be recharged, is based on the use of a third rail. When the vehicle is above this rail, a shoe descends from the vehicle to make contact with the rail. An approach to safety and security analysis of the onboard battery charging system is necessary, taking into account stochastic and functional aspects, in accordance with the increasing requirements for system availability and safety.
Problem Statement and Objectives:
This research focuses on developing methods for evaluating the health status of components, considering the performance and availability constraints of the Safety Instrumented System (SIS) components. SIS are used to ensure the functional safety of installations, which means reducing risks to a level equal to or below the tolerable risk. To design an SIS, several safety standards are used: the main standard [IEC 61508], for process safety [IEC 61511], and for railway safety [IEC 50126]. The objectives include the development of model-based estimation methods to analyze system structures decomposed into layers: sensors, logic units (decision), and actuators. The problem also includes the automatic detection of faults and/or degradations, the prediction of the degradation state of components leading to decision-making based on multidisciplinary criteria. Finally, mission reconfiguration based on required performance and the remaining useful life (RUL) necessary to ensure the safety of humans and property is considered.
Literature Review:
Initially, an analysis of the state of the art in the field of Safety Instrumented Systems (SIS) will be necessary. The specific issues of multi-technical systems in the railway field will need to be identified. We will particularly focus on the evaluation of test strategy on SIS performance [Mechri et al. 2022], the issue of their modeling [Mechri et al. 2023], and the optimal construction of SIS as well as the modeling and evaluation of their performance considering various parameters (common cause factor, time between tests, test effect on component health, etc.) [Simon et al. 2016], [Mechri et al. 2015]. Secondly, to take into account the impact of component aging on the safety function, a literature review of current Health Management Systems (HMS) and Prognostics and Health Management (PHM) methods will be conducted, considering their integration into SIS evaluation. Solutions to be implemented in the case of constraints related to the limited availability of experimental data will also be considered.
Methodology and Planning:
The work is organized over three years. The first year will be dedicated to the literature review and structural analysis of the multi-component architecture of the battery charging system. Training in modeling tools and knowledge of safety standards will also be addressed. An initial risk analysis and evaluation of the necessary reduction level to assess the architecture of the SIS to be implemented will be carried out.
The second year will focus on developing SIS modeling tools to ensure safety and security during the operation of the railway vehicle's battery charging system. Work will continue on implementing solutions based on experimental data and use cases, and their application to the battery charging demonstrator, thus achieving the first proof of safety level of the proposed solution. The bibliographic analyses of the field and the proposed modeling structures can be valorized to confront the solutions with the scientific community (LambdaMu Conference, presentation at GDRMACS Actions meetings, for example, Health Aware Control Design in Dynamic Systems).
The third year will be focused on exploiting the models and searching for structures adapted to the objectives and safety levels. Proposals for improving and optimizing the solution concerning safety objectives will then be made. Consideration of operational constraints and projection on mission selection strategies to ensure the safety of the installation and users will also be implemented. Finally, this third year will be concentrated on applying the system by integrating the results on a prototype, as well as the scientific valorization of the thesis results in a journal, and the writing and defense of the thesis.
W. Mechri. et al. Alternating test strategy for multi-state safety system performance analysis. 9th International Conference on Control, Decision and Information Technologies, CoDIT 2023, Jul 2023, Rome, Italy. (Best Paper Award)
W. Mechri, et al. Study of testing strategy for performance analysis of actuator layer in safety instrumented system, 1-th European Workshop on Advanced Control and Diagnosis, ACD 2022, Nancy, France.
C. Simon, et al. A Kaufmann reliability network approach based on components off-the-shelf to design Safety Instrumented Systems. Journal Européen des Systèmes Automatisés (JESA), 2016, 49 (4-5), pp.449-469.
W. Mechri et al. Switching Markov chains for a holistic modeling of SIS unavailability. Reliability Engineering and System Safety, 2015, 133, pp.212-222.
The implementation of the very light train as a decarbonization solution for rail transport represents a promising prospect for the future of transport systems in fine-grained territorial service lines (LDFT). These lines currently suffer from a lack of decarbonized transport offerings. The success of deploying such a solution lies both in the technical prowess of the system design and in the optimization of its operation and ensuring its viability throughout its life cycle. In this context, this thesis aims to develop safety and security assessment methods specifically adapted to the onboard battery charging system, thereby contributing to the safe design and operation of the railway system. This innovative charging system, which allows the onboard batteries to be recharged, is based on the use of a third rail. When the vehicle is above this rail, a shoe descends from the vehicle to make contact with the rail. An approach to safety and security analysis of the onboard battery charging system is necessary, taking into account stochastic and functional aspects, in accordance with the increasing requirements for system availability and safety.
Problem Statement and Objectives:
This research focuses on developing methods for evaluating the health status of components, considering the performance and availability constraints of the Safety Instrumented System (SIS) components. SIS are used to ensure the functional safety of installations, which means reducing risks to a level equal to or below the tolerable risk. To design an SIS, several safety standards are used: the main standard [IEC 61508], for process safety [IEC 61511], and for railway safety [IEC 50126]. The objectives include the development of model-based estimation methods to analyze system structures decomposed into layers: sensors, logic units (decision), and actuators. The problem also includes the automatic detection of faults and/or degradations, the prediction of the degradation state of components leading to decision-making based on multidisciplinary criteria. Finally, mission reconfiguration based on required performance and the remaining useful life (RUL) necessary to ensure the safety of humans and property is considered.
Literature Review:
Initially, an analysis of the state of the art in the field of Safety Instrumented Systems (SIS) will be necessary. The specific issues of multi-technical systems in the railway field will need to be identified. We will particularly focus on the evaluation of test strategy on SIS performance [Mechri et al. 2022], the issue of their modeling [Mechri et al. 2023], and the optimal construction of SIS as well as the modeling and evaluation of their performance considering various parameters (common cause factor, time between tests, test effect on component health, etc.) [Simon et al. 2016], [Mechri et al. 2015]. Secondly, to take into account the impact of component aging on the safety function, a literature review of current Health Management Systems (HMS) and Prognostics and Health Management (PHM) methods will be conducted, considering their integration into SIS evaluation. Solutions to be implemented in the case of constraints related to the limited availability of experimental data will also be considered.
Methodology and Planning:
The work is organized over three years. The first year will be dedicated to the literature review and structural analysis of the multi-component architecture of the battery charging system. Training in modeling tools and knowledge of safety standards will also be addressed. An initial risk analysis and evaluation of the necessary reduction level to assess the architecture of the SIS to be implemented will be carried out.
The second year will focus on developing SIS modeling tools to ensure safety and security during the operation of the railway vehicle's battery charging system. Work will continue on implementing solutions based on experimental data and use cases, and their application to the battery charging demonstrator, thus achieving the first proof of safety level of the proposed solution. The bibliographic analyses of the field and the proposed modeling structures can be valorized to confront the solutions with the scientific community (LambdaMu Conference, presentation at GDRMACS Actions meetings, for example, Health Aware Control Design in Dynamic Systems).
The third year will be focused on exploiting the models and searching for structures adapted to the objectives and safety levels. Proposals for improving and optimizing the solution concerning safety objectives will then be made. Consideration of operational constraints and projection on mission selection strategies to ensure the safety of the installation and users will also be implemented. Finally, this third year will be concentrated on applying the system by integrating the results on a prototype, as well as the scientific valorization of the thesis results in a journal, and the writing and defense of the thesis.
W. Mechri. et al. Alternating test strategy for multi-state safety system performance analysis. 9th International Conference on Control, Decision and Information Technologies, CoDIT 2023, Jul 2023, Rome, Italy. (Best Paper Award)
W. Mechri, et al. Study of testing strategy for performance analysis of actuator layer in safety instrumented system, 1-th European Workshop on Advanced Control and Diagnosis, ACD 2022, Nancy, France.
C. Simon, et al. A Kaufmann reliability network approach based on components off-the-shelf to design Safety Instrumented Systems. Journal Européen des Systèmes Automatisés (JESA), 2016, 49 (4-5), pp.449-469.
W. Mechri et al. Switching Markov chains for a holistic modeling of SIS unavailability. Reliability Engineering and System Safety, 2015, 133, pp.212-222.
Keywords:
Safety Instrumented Systems (SIS), Health Management Systems, PHM, Rail Transport
Conditions:
Duration: 36 months
Thesis funded as part of Collaborative Projects / I-Démo Regionalized, in the GRAND EST REGION
Project name: CESAM 'Charging Electric Train with Safe Autonomous Mobility'
(LOHR Industrie ; FUTURAIL ; UL / CRAN ; SATT Connectus pour UHA / IRIMAS)
Thesis funded as part of Collaborative Projects / I-Démo Regionalized, in the GRAND EST REGION
Project name: CESAM 'Charging Electric Train with Safe Autonomous Mobility'
(LOHR Industrie ; FUTURAIL ; UL / CRAN ; SATT Connectus pour UHA / IRIMAS)
Department(s):
| Modeling and Control of Industrial Systems |
Funds:
BPI, Collaborative Projects / I-Démo Regionalized, in the GRAND EST REGION
Publications: