Browsing by Author "Bensaci Chaima"

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    A Comparative Study of STPA Hierarchical Structures in Risk Analysis: The case of a Complex Multi-Robot Mobile System
    (Hal open science journal.Volume 18, 2019.pp 163-174, 2019-01-01) Zennir Youcef; Bensaci Chaima
    Autonomous multi-robot systems are among the most complex systems to control, especially when those robots navigate in fully hazardous and dynamic environments such as chemical analysis laboratories which include dangerous and harmful products (poisonous, flammable, explosive...). This paper presents an approach for systems-complex and theoretic safety assessment, also it considers their coordinating, cooperating and collaborating using different control architectures (centralized, hierarchical and modified hierarchical). We classified at first those control architectures according to their properties using Bowtie analysis method, and then we used a systems-theoretic hazard analysis technique (STPA) to identify the potential safety hazard scenarios and their causal factors .
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    A New Approach to System Safety of humanmulti-robot mobile system control with STPA and FTA
    (ALGERIAN JOURNAL OF SIGNALS AND SYSTEMS (AJSS). Vol. 5, Issue 1.pp79-85, 2020-03-01) Bensaci Chaima; Zennir Youcef
    Autonomous Mobile multi-robots are among the most complex systems in their control. Especially when those robots navigate in hazardous and dynamic environments such as chemical analysis laboratories which include dangerous and harmful products (poisonous, flammable, explosive ...). This study deals the safety problem in a robotic analysis laboratory and investigates the possibility to use those autonomous multirobots in such environments with the presence of human workers without serious hazards. We used a systems-theoretic hazard analysis technique (STPA) in addition to fault tree analysis to identify the potential safety hazard scenarios, their causal factors and we conclude by a set of recommendations.
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    Distributed vs. Hybrid Control Architecture Using STPA and AHP - Application to an Autonomous Mobile Multi-robot System
    (International Journal of Safety and Security Engineering.Vol. 11, No. 1.pp 1-12, 2021-02-17) Bensaci Chaima; Zennir Youcef; Innal Fares
    Systems composed of a fleet of autonomous mobile robots are among the most complex control systems. This control complexity is at a high level especially when those robots navigate in hazardous and dynamic environments such as chemical analysis laboratories. These systems include different dangerous and harmful products (toxic, flammable, explosive...) with different quantity. In order to perform its mission on a regular basis, this multi-robot system can be controlled according to multiple architectures. We propose, firstly, to apply the System Theoretic Process Analysis (STPA) on two selected control architectures, namely distributed and hybrid architectures in order to obtain a set of loss scenarios for each kind of architecture. For further assessment, the Analytic Hierarchy Process (AHP) is used to choose the best architecture. The proposed approach provides a risk analysis and a more practical comparison between the two control architectures of a mobile multi-robot system and facilitates decision-making, even in complex situations.
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    Evaluation du niveau d'intégrité de sécurité d'un système industriel
    (Université du 20 Août 1955-SKIKDA . Institut des Sciences et Techniques Appliquées (ISTA-Skikda), 2024-07-04) Bouzekar Marouane; Laouar Haitem; Bensaci Chaima
    La principale vocation de la sécurité est d’éliminer les risques inacceptables qui pourraient être responsable de blessures physiques, d’atteinte à la santé des personnes, dégrader l’environnement et causer des pertes de production à coût élevé. La sécurité, ce n’est évidemment pas que de l’organisation. C’est aussi des méthodologies à suivre, des moyens techniques à déployer. Et pour cela, une norme s’est imposée à l’échelle internationale : l’IEC 61508. Il s’agit d’une norme orientée “performances”, c’est-à-dire qu’elle laisse à l’utilisateur le soin de réaliser son analyse de risque et elle lui propose des moyens pour le réduire. Elle porte plus particulièrement sur le système E/E/PE (Electrical/ Electronic/Programmable Electronic Safety- related systems), c’est-à-dire les systèmes électroniques et électriques de sécurité. La norme CEI 61511 décrit différentes méthodes pour déterminer le niveau d’intégrité de sécurité d’une fonction instrumentée de sécurité SIL « Sfety Integrity Level ». Cette étude est accomplie sur le site du complexe GLN1K Skikda. Ayant pour objectif maîtrise du risque au niveau de la colonne d’épuration présenté au niveau d’unité de liquéfaction afin d’évaluer le niveau SIL ainsi d’apporter une amélioration du fonctionnement et des performances de ses installations, ainsi que leur sécurisation. Dans cette étude, on a utilisé la méthode HAZOP pour identifier tous les scénarios et décortiquer leurs enchainements. Ainsi, une sélection des scénarios à la base d’une cotation. Ensuite déterminer le niveau d’intégrité de sécurité par la méthode LOPA « SIL requis ».
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    Risk Identification of Robotic Systems through the Application of System-Theoretic Process Analysis
    (ALGERIAN JOURNAL OF SIGNALS AND SYSTEMS (AJSS).Vol. 9, Issue 2.pp 107-112, 2024-06-01) Bensaci Chaima; Zennir Youcef
    Autonomous multi-mobile robots are becoming increasingly prevalent in various applications, ranging from industrial automation to healthcare and logistics. While these robots offer enhanced efficiency and productivity, their operation introduces many safety challenges. In this paper, the application of SystemTheoretic Process Analysis (STPA) is proposed as a systematic approach to identify and mitigate risks associated with the main features of autonomous multi-mobile robots. This approach is illustrated using a case study concerning a transportation task of hazardous products within a robotic analysis laboratory. Through a structured analysis process, STPA enables the identification of unsafe control actions, the establishment of safety constraints also the generation of safety requirements. The ultimate goal is to improve the autonomous attribute of mobile robots, so on ensuring their operational safety in high-risk environments.
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    STPA and Bowtie risk analysis study for centralized and hierarchical control architectures comparison
    (Alexandria Engineering Journal.Alexandria University.Volume 59, Issue 5. pp 1-18., 2020-06-21) Bensaci Chaima; Zennir Youcef; Innal Fares
    The industrial zones are increasingly invaded by groups of mobile robots that are the most capable to perform complex tasks by collaborating and cooperating together. The operation of a mobile robot within a dynamic and high-risk environment with strong interaction between robot-robot and human-robot is of a certain complexity of control and safety. Such type of systems requires a safety and hazard investigation to verify if it is able to operate under certain operating conditions, while still ensuring the control and collaboration between mobile robots and human. This paper presents an approach that combines aspects of System-Theoretic Process Analysis (STPA) and Bowtie for safety assessment purposes. The approach we propose is used for a case related to multi-robot systems considering the coordinating, cooperating and collaborating aspects. At first, a risk identification study is done using STPA to extract a set of risk scenarios related to different types of hierarchical coordination architectures in addition to their factors. Afterward, an evaluation of the obtained scenarios is performed by the Bowtie method. The aim of our study is to better compare different control approaches of a multi-agent system. The combination offers detailed hazard identification. It further provides a classification of risks which helps to improve STPA outcomes thus facilitate decision-making over the suitable approach.