Functional Safety Requirements Research Articles

Redundant series cell voltage measurement circuit design of battery management system for functional safety

In most battery management system (BMS) circuit designs, the analog front end (AFE) chip is used to get the series cell voltage of the battery pack. However, it can lead to incorrect calculations by the BMS, causing errors in battery information, failures in protection control, and triggering a battery system fire accident if the AFE chip is abnormal. Unfortunately, the BMS will never know the correct of measured results if it is measured by a single AFE chip. This paper proposes a redundant series voltage measurement system (RSVMS) for the series cell voltage of the battery pack. The original AFE is referred to as the main AFE (m-AFE). The RSVMS can be regarded as redundant AFE (r-AFE). In this paper, the r-AFE consists of a series cell selector and an analog-to-digital (ADC) converter with an isolated communication function to transmit measurement results to the microcontroller unit (MCU) of the BMS. Due to the hardware requirements of functional safety, it does not allow using two identically designed hardware as redundant systems. To satisfy the hardware level of functional safety and to minimize the hardware cost and size, the series cell selector of r-AFE shares the same hardware circuit as the Active Hybrid Equalizer Circuit (A-HEC). The cell selector of A-HEC is composed of the back-to-back MOSFET switch array with a simple ON/OFF function. The MCU of BMS will identify the abnormal of voltage measurement results when the difference of m-AFE and r-AFE is over the threshold. In summary, r-AFE can ensure the accuracy of cell voltage measurement for m-AFE to avoid significant errors when estimating battery information and avoid disaster caused by failure or malfunction of protection functions. In addition, the m-AFE and r-AFE are two independent designs to avoid similar errors caused by identical circuit configurations.

Automating Fault Test Cases Generation and Execution for Automotive Safety Validation via NLP and HIL Simulation

The complexity and the criticality of automotive electronic implanted systems are steadily advancing and that is especially the case for automotive software development. ISO 26262 describes requirements for the development process to confirm the safety of such complex systems. Among these requirements, fault injection is a reliable technique to assess the effectiveness of safety mechanisms and verify the correct implementation of the safety requirements. However, the method of injecting the fault in the system under test in many cases is still manual and depends on an expert, requiring a high level of knowledge of the system. In complex systems, it consumes time, is difficult to execute, and takes effort, because the testers limit the fault injection experiments and inject the minimum number of possible test cases. Fault injection enables testers to identify and address potential issues with a system under test before they become actual problems. In the automotive industry, failures can have serious hazards. In these systems, it is essential to ensure that the system can operate safely even in the presence of faults. We propose an approach using natural language processing (NLP) technologies to automatically derive the fault test cases from the functional safety requirements (FSRs) and execute them automatically by hardware-in-the-loop (HIL) in real time according to the black-box concept and the ISO 26262 standard. The approach demonstrates effectiveness in automatically identifying fault injection locations and conditions, simplifying the testing process, and providing a scalable solution for various safety-critical systems.

Використання методу верифікації FMEDA/FIT для оцінювання кібербезпеки програмованого логічного контролера: нова інтерпретація принципу SIS

The object of this study is a programmable logic controller (safety PLC), which is part of an information and control system designed for safe management of important technological processes. The subject of this study is the substantiation of the legality of reusing the results obtained during the development of the safety PLC in accordance with the requirements of functional safety to assess the level of its cyber security. The purpose of this work is to investigate the possibility of "cross" evaluation of the safety characteristics of the safety PLC, namely, the possibility of evaluating the level of cyber security of the programmable logic controller based on known data regarding its level of functional safety, in order to optimize the use of available resources in the project. The study tasks are following: to provide a theoretical basis for the relationship between safety PLC characteristics such as functional safety and cybersecurity. Determine the metrics by which it will be possible to assess the degree of reuse of existing results. Perform an analysis of potential cyberattacks depending on the architecture of the information and control system, which performs security functions, as well as on the possible modes of its use. Determine and evaluate the degree of "cross" influence of critical characteristics of the research object. To perform a calculation analysis of the potential financial and time gain from the reuse of already known results for the minimum configuration of the safety PLC. Conclusions. The study demonstrated the relevance of the question of assessing the cybersecurity of a programmable logic controller based on the use of existing data, regarding its level of functional security (SIL). The proposed approach provides opportunities to significantly optimize the use of resources in safety PLC certification projects. However, the main methodological conclusion is that the well-known principle of Security Informed Safety can be developed and used in practice in the opposite direction, as Security supported/assessed by Safety. That is, to the principle of "assessment of functional safety taking into account/on information (cyber) security" the principle of "assessment of information (cyber) security with the support of/taking into account the results of the assessment of functional security" is added.

Cloud-Fog Automation: Vision, Enabling Technologies, and Future Research Directions

The Industry 4.0 digital transformation envisages future industrial systems to be fully automated, including the control, upgrade, and configuration processes of a large number of heterogeneous wired/wireless interconnected devices in Industrial Internet of Things (IIoT) environments. Most of the industrial automation systems today are based on the traditional International Society of Automation (ISA)-95 model, with some recently transitioned to Cloud Automation systems. Latest developments in network connectivity technologies, Artificial Intelligence (AI), and Cloud/Fog computing technologies have motivated us to rethink the ISA-95 model. In this paper, we propose a vision that aims to migrate most of the computational and automation tasks closer to the ground, which we term the collaborative “Cloud-Fog Automation” paradigm. We perform a comprehensive survey of the state-of-the-art and formulate the three pillars of this vision: Deterministic Connectivity, Deterministic Connected Intelligence, and Deterministic Networked Computing. In each of these pillars, we review their latency and reliability, security, and functional safety requirements and challenges. Finally, we articulate and highlight key future research directions to realize this vision.

Energy-Efficient Functional Safety Design Methodology Using ASIL Decomposition for Automotive Cyber-Physical Systems

Automotive cyber-physical systems (ACPS) are typical cyber-physical systems because of the joint interaction between the cyber part and physical part. Functional safety requirement (including response time and reliability requirements) for an ACPS function must be assured for safe driving. Auto industry is cost-sensitive, power-sensitive, and environment-friendly. Energy consumption affects the development efficiency of the ACPS and the living environment of people. This paper solves the problem of optimizing the energy consumption for an ACPS function while assuring its functional safety requirement (i.e., energy-efficient functional safety for ACPS). However, implementing minimum response time, maximum reliability, and minimum energy consumption is a conflicting problem. Consequently, solving the problem is a challenge. In this paper, we propose a three-stage design process toward energy-efficient functional safety for ACPS. The topic problem is divided into three sub-problems, namely, response time requirement verification (first stage), functional safety requirement verification (second stage), and functional safety-critical energy consumption optimization (third stage). The proposed energy-efficient functional safety design methodology is implemented by using automotive safety integrity level decomposition, which is defined in the ACPS functional safety standard ISO 26262. Experiments with real-life and synthetic ACPS functions reveal the advantages of the proposed design methodology toward energy-efficient functional safety for ACPS compared with state-of-the-art algorithms.

Vehicle fault diagnosis using FTA and FMEA method

In recent years, users requirements for the richness of car functions have gradually increased. The application of a large number of electronic components in the automobile makes the degree of complexity of the automobile higher, so the user has a higher demand for the stability of the automobile system. Especially once a key functional component fails, driving safety will be seriously affected. Because in the design process, we find and analyze the possible causes of failure, so as to avoid the impact of failure in the design as much as possible. We use FMEA (Failure Mode and Effect Analysis) Analysis method and FTA (Fault Tree Analysis) analysis method to analyze the car headlight fault. These two analysis methods can efficiently and accurately analyze faults and determine the most basic events leading to failure. Based on the above analysis results, the proposed solution to improve the system can be given, so that the system can meet the functional safety requirements.

Sliced Secure Boot an Accelerated Secure Boot Concept Compatible with Automotive Safety Controllers

<div>The secure boot has successfully protected systems from executing untrusted software (SW), but low-power controllers lack sufficient time to check every memory cell while satisfying real-time functional safety requirements. Automotive controllers need to maintain security through multiple cycles of remote, unsupervised operation and safely reach a secure state when an anomaly is detected. To accelerate the boot time, we propose Sliced Secure Boot: build fingerprints by slicing orthogonally through memory blocks, protect each cell with a reusable fingerprint using a reproducible pattern with sufficient entropy, and randomly check one fingerprint pattern during boot. We do not claim that sampling offers equivalent protection to exhaustive checks but demonstrate that careful sampling can provide a sufficient level of detection while maintaining compatibility with both startup time and functional safety requirements.</div>

On Neural Networks Redundancy and Diversity for Their Use in Safety-Critical Systems

An increasing number of critical functionalities integrated in embedded critical systems rely on deep learning (DL) technology. This article summarizes certain key aspects of DL’s intrinsic stochastic and training-data-dependent nature that are at odds with current domain-specific functional safety standards. We exemplify how redundancy and diversity of neural networks can help to reconcile DL technology and functional safety requirements.

New Approaches of Side-Channel Attacks Based on Chip Testing Methods

The state-of-the-art test infrastructure security is based on the assumption of preventing access to the sensitive information and the (publicly) accessible outputs or test infrastructure subset are supposed to not leak any secret information. In addition, for achieving functional safety requirements, the on-chip test infrastructure is re-used in-field and cannot be completely disabled after manufacturing test phase. Therefore, the access to the scan chains or similar test access ports which can lead to sensitive information needs to be restricted or encrypted to guarantee the security of the test infrastructure. However, in this work we show that having access to (small delay) test results on insensitive (public) outputs can in fact reveal secret data. Using real hardware, we have performed template attacks using the results of delay testing on the output of cryptographic circuits and were able to retrieve the key with very few test inputs. This template attack requires only a few random patterns on the victim device, which could be different from the device used for template building. In addition, the attack is also resilient against runtime variation and noise, as well as inaccuracies and down-sampling of delay testing measurements.

Film dance creation practice supported by Cyber Physical System.

The traditional eight arts include film and dance. Dance is often included in the creation of films. With the progress of the times, dance has shown unprecedented vitality in film. This also puts forward higher requirements for shooting technology in film creation. To solve the contradiction between high performance of equipment and energy sensing, a new energy aware scheduling framework is proposed based on Cyber Physical System, which utilizes the balance between performance and energy consumption optimization, and uses allocation technology and list scheduling to ensure energy constraints. Besides, a highly energy-efficient and stable scheduling algorithm for film creation is constructed. The algorithm problems are mainly divided into functional safety requirements, verification problems, and energy consumption optimization problems under functional safety. The experimental results show that the system can obtain better schedulability at a lower time complexity and reasonably reflect the dynamic and static energy constraints ratio. The basic framework system based on dynamic step size also achieves better time performance than other step sizes. According to the experiment's findings, the energy consumption of all scheduling components is relatively low and can be maintained within a specific range. The research and analysis of this study can provide a theoretical reference for the equipment algorithm of film dance creation practice, promote interaction with technical practice, and assist in promoting the development process of film dance creation.

Design and verification of VCU system based on ISO26262

According to ISO26262 standard, the functional safety analysis of the pure electric vehicle’s concept stage of Vehicle Control Unit (VCU) was carried out. From this, the safety goals and ASIL levels of the VCU are determined. According to the safety analysis method, the functional safety requirements of the VCU at the vehicle level are obtained. At the hardware architecture level, the functional safety design of the VCU’s microcontroller module, storage module, and power supply module is carried out to meet the functional safety development requirements. Carefully consideration of software failures that may occur during VCU software development. These include software architecture design, safety-critical code/program flow monitoring, change management, and safety-critical variables. The fault injection test of the VCU demonstrates the feasibility of this technology.

수소충전소 설비운영 안전관리 상용화를 위한 CBM+활용 방안 연구

Purpose: This study aims to meet the functional safety requirements using condition-based maintenance plus (CBM+) to ensure the safe operation of equipment, such as chillers, compressors, and dispensers, used in hydrogen refueling facilities. BRMethods: For the commercialization of the safety management of hydrogen refueling stations, we demonstrate an approach for detecting equipment abnormalities during operation by measuring sound, vibration, and current. CBM+ is used for fault diagnosis; the results are compared with those of the traditional fault diagnosis methods.BRResults: At hydrogen refueling stations in South Korea, 90.48% of accidents occurred due to hydrogen leakage from 2005 to 2014. During the same period, 7 (31.82%) out of 22 such accidents were caused by human errors in the United States. Through structural analysis of vertical axis, lateral sides, and height of the hydrogen charging stations, we propose a method that uses sensor nodes, sensor systems, and communication systems for CBM+.BRConclusion: Only a few empirical studies have reported the use of CBM+ for hydrogen refueling stations in South Korea. Effective strategies for CBM+ have also not been presented. Through technical research and institutional improvement, including this study, it is necessary to secure functional safety and PHM technology for CBM for the safe operation of hydrogen refueling stations in South Korea. In addition, data based on several factors, including the equipment component type, failure, and safety risk level, must be acquired in a standard format. However, to eliminate the safety risks of hydrogen refueling stations, hydrogen leakage accidents must be primarily avoided.

수소충전소 압축기의 CBM+ 데이터수집을 위한 기술개발

Purpose: This paper demonstrates Functional Safety Requirements by collecting and analyzing the condition-based maintenance (CBM+) data of the compressors such as chillers, compressors, and dispensers of a hydrogen refueling station (HRS) installation as well as HRS operation using power quality monitoring (PQM) instrumentation at the HRS input stage.BRMethods: Demonstrate fault measurement items and fault diagnosis such as sound, vibration, and current with CBM+. The feature extraction of the collected data in this process was analyzed using an LSTM AutoEncoder to demonstrate the occurrence of failures.BRResults: There were a total of 21 HRS accidents from 2005 to 2014 in Japan and 22 accidents in the US from 2004 to 2012. In particular, approximately 90% of the hydrogen gas leakage accidents in Japan and approximately 91% in the US were due to human error. The CBM+ of a hydrogen compressor was demonstrated by connecting a PQM instrument to the HRS input. BRConclusion: A technically developed PQM measuring device was installed at the Gwangju HRS input power source and data was collected for approximately 3 months. After analyzing and evaluating the collected data through the LSTM AutoEncorder, it was demonstrated that HRS failure occurred after approximately 7 days. Therefore, we propose a failure detection and failure diagnosis model through the CBM+ of domestic HRSs.

HAZARD AND RISK ANALYSIS OF RAILWAY VEHICLE CONTROL SYSTEMS ACCORDING TO SAFETY INTEGRITY LEVELS

This article presents an approach to the verification of the safety integrity level (SIL) of rail vehicle subassemblies in accordance with the applicable railway standards PN-EN ISO 50126-1, PN-EN ISO 50126:2, and PN-EN ISO 50129. Particular attention has been given to the calculation procedure related to the determination of the tolerable hazard rate and tolerable functional failure rate indicators in a situation where various reliability indicators have been declared for components of rail vehicles, such as MTTFD or B10D. In this case, the verification of the safety integrity level using the above-mentioned railway standards may be difficult, and it becomes necessary to use additional standards for safety systems based on electronic components. An example is the PN-EN ISO 13849-1:2006-01 standard, which contains a calculation method based on the transformation of the exponential model, which is useful for hazard and risk analyses of electronic systems containing components with different reliability indices. Another supplementary standard is the PN-EN 61025:2007 standard, which concerns fault tree analysis. Based on the above-mentioned standards, an algorithm was developed to verify the safety integrity level of the frequency converter control system. The obtained results allowed us to confirm the fulfillment of the functional safety requirements of the considered system.

КРИТЕРІЇ ISO 21434 ДЛЯ ФОРМУВАННЯ СИСТЕМНИХ СПЕЦИФІКАЦІЙ У ПРОЦЕСАХ A-SPICE ДЛЯ АВТОМОБІЛІВ

With the increasing presence of electronics and autonomous systems in modern automobiles, cybersecurity has become a critical concern. Automotive manufacturers and other stakeholders are actively seeking ways to ensure reliable protection against cyber attacks. One approach involves the utilization of ISO 21434, a standard designed to enhance cybersecurity in the automotive industry. This research article investigates the ISO 21434 standard and its application in the field of automotive production, specifically in software development under the A-SPICE standard. The publication describes the methods and concepts used to enhance cybersecurity in the automotive industry and establishes the role of ISO 21434 within the A-SPICE model. The study's findings are valuable for companies and professionals involved in the development and implementation of cybersecurity measures in the automotive sector. Implementing the ISO 21434 standard can mitigate the risk of cyber attacks and improve the quality and reliability of automobiles, thus making the automotive industry safer and more trustworthy for consumers. The article provides an overview of key cybersecurity standards in the automotive industry. ISO 26262 sets out processes and requirements for functional safety in automotive systems, including cybersecurity considerations. SAE J3061 focuses on cybersecurity management in electronic systems of vehicles and is widely used in the industry. ISO/SAE 21434, introduced in 2020, replaces the previous ISO 26262 standard and specifies cybersecurity requirements in the automotive industry. These standards are closely related as they aim to ensure the safety and security of automotive products. Furthermore, the Automotive SPICE (Software Process Improvement and Capability Determination) framework is widely employed for evaluating and enhancing software development processes in the automotive sector. A-SPICE, a specific variant of Automotive SPICE, provides a framework for improving software development processes in automotive organizations. ISO 21434 guides cybersecurity activities within the A-SPICE framework, emphasizing the importance of a systematic and standardized approach to cybersecurity. To effectively implement cybersecurity in automotive products developed under A-SPICE, compliance with the ISO 21434 standard is crucial. However, mere adherence to the standard may be insufficient for achieving a high level of cybersecurity. Additional tools such as risk analysis methodologies and cybersecurity management can be employed to ensure robust cybersecurity measures. Risk analysis results can help identify vulnerabilities in the security system, enabling the development of effective mitigation measures. Cybersecurity management ensures compliance with the standard throughout the product development lifecycle. ISO 21434 can be applied at various stages of the V-model software development process, including requirements definition, design, and testing. During requirements definition, cybersecurity requirements are identified and incorporated into the system or software specifications. In the design phase, architectures are developed considering the cybersecurity requirements outlined in the standard. The testing phase addresses the fulfillment of cybersecurity requirements and evaluates the effectiveness of cybersecurity measures. In conclusion, the inclusion of ISO 21434 criteria in the development process of automotive software significantly impacts the quality and safety of products. The research demonstrates that applying ISO 21434 criteria allows for a systematic and structured approach to software development, ensuring the reliability, safety, and compliance of software products with regulatory requirements in the automotive industry. The article presents an analysis of standards, methods, and approaches used in the automotive industry and highlights the influence of ISO 21434 on the A-SPICE framework, defining its position within the model. Ultimately, this publication contributes to the advancement of knowledge in automotive cybersecurity.

Constrained Control Allocation Improving Fault Tolerance of a Four Wheel Independently Driven Articulated Vehicle

In articulated vehicles steering is accomplished by adjusting the articulation angle. Commonly a steering actuator is used to pivot the two vehicle sections. This actuator can be dispensed with if the pivoting is controlled by selective distribution of the drive torques to the individually driven wheels instead. Since steering is a safety-critical function, it must be ensured even if one of the drive motors fails. For this purpose, we propose a control method for a fault-tolerant four wheel independently driven articulated vehicle. The control method was developed and tested in a simulation environment and validated on a 1:5 scale demonstrator vehicle. The proposed method with constrained control allocation maintains the desired velocity and articulation angle by distributing the driving torques to the four wheels considering the current actuator limits. Both the simulation and the vehicle tests show that the control method meets the control objectives even when a sudden actuator limit occurs during critical driving scenarios like cornering. Thus, the vehicle can keep its maneuverability in the event of a detected failure of a drive motor. Together with reliable failure detection, the proposed approach provides a basis for further development towards innovative fault-tolerant electric articulated vehicles that meet the requirements of functional safety.

In-field test solution for enhancing safety in automotive applications

Automotive market is evolving rapidly, while boosting and growing semiconductor industry significantly. According to the experts, we are only in the beginning of this exciting new chapter in the evolution – Autonomous Driving. Functional safety and quality requirements for Automotive are taking clearer shape while the industry is progressing for maturity. Therefore, System-on-Chip (SoC) and Intellectual Property (IP) providers must come up with a tailored and adaptive solution, to overcome various challenges. This process is enriching for all parties – SoC providers in incorporating various IPs that addresses different aspects, as well as providing the IP vendors with comprehensive guidelines to enhance their products to adhere these requirements. As a direct consequence to this process, Test and Repair IPs are influenced heavily. This paper presents a full-scale in-field test and repair solution concept for Automotive SoCs which conforms to all safety and quality requirements.

Adjustment Method of College Students' Mental Health Based on Data Analysis Under the Background of Positive Psychology.

Colleges and universities are in an important position to train builders and successors of the socialist cause whilst promoting quality education. Mental health education is an important foundation and condition for comprehensively improving students' overall quality. This research explores adjustment methods for college students' mental health based on virtual reality under the background of positive psychology. It discusses the importance of system requirements analysis in the software development process, analyzes the system's functional requirements, safety requirements, and software and hardware requirements, and uses the Apriori algorithm to explore the influencing factors of college students' mental health. Based on the system engineering method and using the data mining clustering method undertake detailed analysis and research on the mental health of college students, it then designs an anomaly mining algorithm based on clustering to quickly find anomalous data health problems. The interface design of the system is concise and the operation is simple. Users can conveniently input, query, and count information according to the various controls on the interface, which fully embodies human-oriented characteristics. Exploration of the characteristics of students' frequent Internet access ensures the efficiency, accuracy, and comprehensiveness of the evaluation and consultation work, facilitating psychological counseling for teachers and students, and saving paper. By establishing a data mining model, mining the database, and learning about different student groups and their respective characteristics, we discuss our research on student psychology and summarize the mental health status and gender, adaptation and anxiety, introversion, emotionality, and calmness of college students. We also consider the relationship between sex, negative, and courage. Using positive psychology theory, we examine the positive experiences of students and interconnected qualities, to build a mental health practice system. In the experiment, the happiness index evaluation of the virtual reality treatment system group was significant, P = 0.002 < 0.05. Mental health education plays an important role in cultivating the healthy psychology of college students, developing their psychological potential, enhancing their adaptability, and improving their personality. This analysis based on actual data provides a reliable basis for psychological educators to improve the efficiency and effectiveness of school psychological counseling and to facilitate schools in establishing new methods of early prevention and intervention for psychological disorders, enabling institutions to create a healthy atmosphere for college students.

New Rotor Position Redundancy Decoding Method Based on Resolver Decoder.

In view of the frequent safety problems of electric vehicles, the research on accurately obtaining the rotor position of the motor through the resolver is an important means to improve the functional safety of the system. The commonly used resolver decoding method involves the resolver decoding chip method and software decoding method, but few studies integrate the two decoding methods. A single method of motor rotor position acquisition cannot meet the requirements of system functional safety. To fill this gap, this paper proposes a method to simultaneously integrate hardware decoding and software decoding in the motor control system. The decoding chip and software decoding obtain the angle data at the same time, and they provide redundancy to improve the functional safety of the electronic control system. Finally, the effectiveness of the proposed simultaneous operation of hardware decoding and software decoding is verified by experiments.

Taking 2oo3 as an example to study the improvement of Markov model considering periodic function test

Abstract In order to make the safety instrumented system meet the functional safety requirements of the classification in a longer period of time, and considering the model incompleteness of the original Markov model, we propose to add the consideration of periodic functional testing to the original Markov model for modeling. The results show that the PFDavg of the safety instrumented system with periodic functional testing is lower than that of the safety instrumented system without periodic functional testing, and the Markov model with periodic functional testing is more comprehensive and more consistent with the engineering reality.