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ISO 26262 is a functional safety standard under development at the time of this thesis. It is an adaptation of the functional safety standard IEC 61508, aimed at development of automotive electrical/electronic systems. The version of ISO-26262 that was used and discussed in this thesis is the final draft released in January 2011. In this thesis, a subset of ISO-26262 is applied in the development of a safety critical driver assistance system for a Scania vehicle. The parts of ISO-26262 that are treated are Part 3: Concept phase, Part 4: Product development at the system level and Part 5: Product development at the hardware level. Throughout the thesis we evaluate ISO-26262 and report our experience of working with it. The driver assistance system under development, which ISO-26262 is applied to, is Collision Avoidance by Steering, a system that aims to avoid or mitigate rear-end collisions with vehicles in front by automatic steering of the vehicle.

Safety is considered as one of the most important areas in future research and development within the automotive industry. New functionality, such as driver support and active/passive safety systems are examples where development mainly focuses on safety. At the same time, the trend is towards more complex systems, increased software dependence and an increasing amount of sensors and actuators, resulting in a higher risk associated with software and hardware failures. In the area of functional safety, standards such as ISO 26262 assess safety mainly focusing on qualitative assessment techniques, whereas usage of quantitative techniques is a growing area in academic research. This thesis considers the field functional safety, with the emphasis on how hardware and software failure probabilities can be used to quantitatively assess safety of a system/function. More specifically, this thesis presents a method for quantitative safety assessment using Bayesian networks for probabilistic modeling. Since the safety standard ISO 26262 is becoming common in the automotive industry, the developed method is adjusted to use information gathered when implementing this standard. Continuing the discussion about safety, a method for modeling faults and failures using Markov models is presented. These models connect to the previous developed Bayesian network and complete the quantitative safety assessment. Furthermore, the potential for implementing the discussed models in the Modelica language is investigated, aiming to find out if models such as these could be useful in practice to simplify design work, in order to meet future safety goals.

Autonomous vehicles (AVs) are a class of safety-critical systems that are capable of decision-making and operate with little or no human intervention. For such complex systems designed to function in diverse operational domains such as rain, snow, freeway, urban roads, etc., system safety is paramount. Management of the system's safety throughout its life-cycle, from the conceptualization stage to the end of the lifecycle, is of primary importance. We describe a revision of functional safety standard ISO 26262 to support autonomous vehicles and the underlying electronic/electrical control architecture. There is a need to modify the Automotive Safety Integrity Levels (ASILs) defined in the ISO 26262 as "Controllability", a factor in determining an ASIL, is no longer applicable; the driver is no longer in a position to control the vehicle. The vehicle has taken over the responsibility of evaluating the environment and determines its next course of action to complete its current mission. These decisions have a tremendous impact on the overall safety of the system during a hazardous event and can be the difference between a successful journey and a traffic incident. To better enable the designers of such systems, we introduce a new method to assess the functional safety and derive safety goals, which are the top level safety requirement. We present a new metric-Risk Mitigation Factor to assess the decision making capability of the vehicle and to replace controllability in the ASIL definition. The case study presented highlights the advantages of using the introduced metric in defining safety goals for the autonomous vehicle. / Master of Science / Autonomous vehicles (AVs) are changing the way we perceive mobility and transportation. AVs are soon to be a part of everyday life, from giving you a ride to the office to taking children to the dentist. All the possible benefits of AVs are attainable if the systems designed are safe for use. Safety in AVs is the primary challenge in design and development. It is crucial to incorporate the principles of safety in system design from the beginning of the inception phase to the end of the lifecycle of the vehicle. The challenges for ensuring safety in AVs are enormous, from implementing the correct operation for a system to assuring that system behavior is safe in the presence of a malfunction; the scale and complexity of the systems drive the safety requirements. In the work presented, we focus on the functional safety of the underlying electrical/ electronic architecture of the vehicle, describing a revision of the automotive functional safety standard ISO 26262 for AV development. We propose to leverage the decision-making capabilities of the vehicle to assure safety in a hazardous situation.

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Hydrostatic steering systems are used in construction and agricultural machines alike. Because of their high power density, hydraulic drives are qualified for the use in vehicles with high steering loads. Conventional hydrostatic steering systems are limited in terms of steering comfort and driver assistance. For realisation of appropriate steering functions, electro-hydraulic solutions are necessary. This paper provides an overview on existing implementations and introduces a novel steering system. The presented active steering system with independent meter-in and meter-out valves fills the gap between existing active steering systems and steer-by-wire solutions. An appropriate control and safety concept provides advanced steering functions for on-road usage without the fully redundant structure of steer-by-wire systems.

With advances in technology, modern integrated circuits have higher complexities and reduced transistor sizing. In deep sub-micron, the parameter variation-control is difficult and component delays vary from one manufactured chip to another. Therefore, the delays are not discrete values but are a statistical quantity, and statistical evaluation methods have gained traction. Furthermore, fault injection based gate-level fault coverage is non-scalable and statistical estimation methods are preferred. This dissertation focuses on scalable statistical methods to select critical paths in the presence of process variations, and to improve the defect coverage for complex integrated circuits. In particular, we investigate the sensitization probability of a path by a test pattern under statistical delays. Next, we investigate test pattern generation for improving the sensitization probability of a path, selecting critical paths that yield high defect coverage, and scalable method to estimate fault coverage of complex designs using machine learning techniques.

In 2011 a new functional safety standard for electronic and electrical systems in vehicles waspublished, called ISO 26262. This standard concerns the whole lifecycle of the safety criticalelements used in cars, including the development process of such elements. As the correctnessof the tools used when developing such an element is critical to the safety of the element,the standard includes requirements concerning the software tools used in the development,including verification tools. These requirements mainly specify that a developer of a safetycritical element should provide proof of their confidence in the software tools they are using.One recommended way to gain this confidence is to use tools developed in accordance to a“relevant subset of [ISO 26262]”.This project aims to develop a verification system in accordance to ISO 26262, exploringhow and what specifications should be included in this “relevant subset” of ISO 26262 andto which extent these can be included in their current form. The work concludes with thedevelopment of a single safety element of the verification system, to give an demonstrationof the viability of such a system.

The topic of this diploma thesis is the safety of a gas burner control. The aim is to fully automate the system by using a gas burner safety control system (Fail-Safe PLC) so as to reduce to minimum the risks. Because great emphasis is placed on safety, so Czech standards and what is connected with safety control systems are discussed. This project is implemented in cooperation with industrial automation company ElektroMAR a. s.

Hydrostatic steering systems are used in construction and agricultural machines alike. Because of their high power density, hydraulic drives are qualified for the use in vehicles with high steering loads. Conventional hydrostatic steering systems are limited in terms of steering comfort and driver assistance. For realisation of appropriate steering functions, electro-hydraulic solutions are necessary. This paper provides an overview on existing implementations and introduces a novel steering system. The presented active steering system with independent meter-in and meter-out valves fills the gap between existing active steering systems and steer-by-wire solutions. An appropriate control and safety concept provides advanced steering functions for on-road usage without the fully redundant structure of steer-by-wire systems.