vector india conference 2019€¦ · it provides asil-dependent requirements for the whole...

V0.1 | 2019-05-10

Conforming to Safety Standard

Vector India Conference 2019

https://www.vector.com/in/en-in/events/vh-vector-india/2019/vh-vtts19/

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▪ Introduction to ISO 26262

▪ Parts of ISO 26262

▪ ASIL Levels

▪ Part 4 : Product Development – System Level

▪ Part 6 : Product Development – Software Level

▪ Fitting software tools into ISO 26262 process

▪ Demo

▪ Q&A

Agenda

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Introduction of ISO26262

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Present cars and Electronics:

Background

Introduction of ISO 26262

• Increasing Functional complexity and Software based cars

• Increasing risk from systematic faults and random hardware Failures

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How safety is important ?


▪ Safety is most important of course

▪ Due to technology, environment, cost etc 100% safety is not possible

▪ There is always remains a risk about danger!

▪ So we have to think about acceptable Risk

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What is Functional Safety?


Assessment of safety measures ( Safety Functions) and its numerous evaluation is the basis of Functional Safety

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What is ISO26262?


▪ ISO 26262 is IEC 61508 adapted to the needs of the Automotive Industry

▪ Adopts a similar approach to software testing and code coverage requirements to other, longer-lived standards (such as DO-178B)

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What is ISO26262?


▪ It applies to safety-related road vehicle E/E systems, and addresses hazards due to malfunctions, excluding nominal performances of active and passive safety systems.

▪ Risk is determined based on customer risk by identifying the so-called Automotive Safety Integrity Level (ASIL) associated with each undesired effects.

▪ It provides ASIL-dependent requirements for the whole lifecycle of the E/E system (including Hardware and Software components)

- Series production passenger cars

Maximum gross weight up to 3500 kg

- Does not apply to E/E systems in special purpose vehicles

e.g., vehicles designed for drivers with disabilities

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Origins of ISO26262 (Automotive IEC 61508)


IEC 61508

Initial work of individual companies

Initiative within national

standardization bodies

First draft of requirement specification

ISO

TC22

SC3

WG16

MISRA

BNA

FAKRAOEM suppliers

Technical services

20029.20052003 1.2004

11.2005

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ISO 26262 Parts

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ISO 26262 Parts

▪ Part 1 : Vocabulary

▪ Part 2 : Management of Functional Safety

▪ Part 3 : Concept phase

▪ Part 4 : Product Development: System Level

▪ Part 5 : Product Development: Hardware Level

▪ Part 6 : Product Development: Software Level

▪ Part 7 : Production and Operation

▪ Part 8 : Supporting Processes

▪ Part 9 : ASIL-oriented and Safety-oriented Analyses

▪ Part 10 : Guidelines on ISO 26262

▪ Part 11 : Guidelines on application of ISO 26262 to semiconductors

▪ Part 12 : Adaption of ISO26262 for motorcycles

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ISO26262 Process

ISO26262 Parts

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ASIL

ISO26262 Parts

▪ ISO/DIS 26262 replaces SILs with ASILs (Automotive Safety Integrity Levels)

▪ ASILs designed to specify the measures required to avoid unreasonable residual risk

▪ ASIL levels A-D, with D being the most demanding

▪ Risk of each hazardous event is evaluated on the basis of:

– Frequency of the situation (or “exposure”)

– Impact of possible damage (or “severity”)

– Controllability

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ASIL Ranking Table

ASIL

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Part 4 : Product Development – System Level

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Overview


▪ Identify and plan the functional safety activities for each sub-phase of system development

- Includes supporting processes activities

- Includes methods to be used Tailoring of the

lifecycle

▪ Applies to both systems and subsystems

Safety plan

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Example Product Development at the System Level


After the initiation of the product

development of the technical safety

requirements, the system design is

performed

Depending on the complexity of the architecture, the

requirements can be derived iteratively, and

integrated after the Hardware &Software

implementation.

Integrate software & hardware, validation is performed to comply

with each safety requirement in

accordance with its specification and ASIL

classification

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4.6 - Specification of the Technical Safety Requirements


▪ Develop the technical safety requirements

▪ Refinement of the functional safety requirements

considering the preliminary architectural assumptions

▪ Verify the technical safety requirements comply with the

functional safety requirements

Describe how to implement the Functional Safety Concept

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4.6 - Specification of the Technical Safety Requirements


Requirements Engineering of this nature requires additional initial effort but benefits will be obtained whenever changes are required.

Cost of a project WITHOUTRequirements Engineering

Cost of a project WITHRequirements Engineering

Deliver

Deliver (less delay)Project Start

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4.7 - System Design


▪ To develop the system design and the technical safety concept that comply with the functional requirements and the technical safety requirements specification.

▪ Verify the System design and technical safety concept comply with Technical safety requirements specification.

▪ Need to have bidirectional traceability between System design and Technical safety requirements specification.

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4.8 - Item integration and testing


▪ Integrate the elements of an item

- If applicable, systems or elements of other

technologies and external measures or systems

- Test the integrated item for compliance with each

safety requirement

▪ Verify that the system design is correctly implemented by the entire item

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Each functional and technical safety requirements shall be tested at least once in the complete integration phase.

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4.9 - Safety Validation


▪ To provide evidence of due compliance with the functional safety goals and that the safety concepts are appropriate for the functional safety of the item.

▪ To provide evidence that the safety goals are correct, complete and fully achieved at vehicle level.

▪ The validation plan shall include:

1. The configuration of the item

2. The specification of test cases and acceptance criteria

3. The required environmental conditions

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4.10 - Functional safety assessment


▪ Assess the functional safety achieved by the item

▪ Initiated by the entity with responsibility for functional safety e.g., the vehicle manufacturer

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4.11 – Release for Production


▪ To specify the criteria for the release for production at the completion of the item development.

▪ The release for production confirms that the item complies with the requirements for functional safety at vehicle level.

▪ The documentation shall include

a) the name and signature of the person in charge of release

b) the version/s of the released item

c) the configuration of the released item

d) references to associated documents

e) the release date

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Part 6 : Product Development – Software Level

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Software Level


ISO 26262 (Part 6) refers more specifically to the development of software, particularly:

– Initiation of product development at the software level

– Derivation of software safety requirements from the system level

(following from part 4) and their subsequent verification

– Software architectural design

– Software unit design and implementation

– Software unit testing, and

– Software integration and testing

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6.5 Initiation of Product Development at Software Level


To plan and initiate the functional safety activities for the sub phases of the software development

Evaluate work products to ensure they meet previously established requirements

Ensure that the item developed, or parts of it,

comply with the requirements

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6.5 Modeling and Coding Guidelines


To support the correctness of the design and implementation, the design and coding guidelines for the modeling, or programming languages, shall address following topics:

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6.6 Specification of Software Safety Requirements


▪ Specify the SW safety requirements from the technical

safety requirements (including their ASIL) and the

system design specification

▪ Detail the hardware-software interface requirements

▪ Verify that the SW safety requirements are consistent

with the technical safety requirements and the system

design specification

Compliant with technical safety requirements and system design, and consistent with relevant hardware safety requirements

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6.6 Verification of Software Safety Requirements


A verification activity shall be performed to demonstrate that the software safety requirements are traceable with he technical safety requirements, the system design and consistent with the relevant parts of the hardware safety requirements achieving complete traceability.

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6.7 Software Design (1\2)


▪ To develop a software architectural design that realizes the software safety

requirements and verify the software architectural design achieving bi-directional

traceability.

▪ The software architectural design represents all software components and their

interactions with one another in a hierarchical structure.

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6.7 Software Design (2\2)


The software architectural design shall exhibit

– Modularity

– Encapsulation

– Minimum complexity

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6.8 Software Unit design & implementation


▪ To specify the software units in accordance with the SW architectural design and the associated SW safety requirements, to implement the software units as specified and to verify the design of the SW units and implementation.

▪ The specification of the software units shall describe the functional behavior and the internal design.

▪ The design and implementation of software unit shall achieve

– Avoidance of unnecessary complexity

– Testability

– Maintainability

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6.8 Verification of software unit design and implementation


The software unit design and implementation shall be verified to demonstrate

▪ Compliance with the hardware-software interface

▪ Completeness regarding the software safety requirements and the software architecture through traceability

▪ Compliance of the source code with its specification

▪ Compliance of the source code with the coding guidelines

▪ Compatibility of the software unit implementations with target hardware.

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6.8 Verification of software unit design and implementation


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6.9 Software Unit Testing


▪ Demonstrate that the software units satisfy their specification and do not contain undesired functionality.

▪ The following testing methods can be used for proving compliance with specification and Hardware Software interface, correct implementation, absence of unintended functionality, robustness, and sufficiency of the resources.

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6.9 Test case specification and structural coverage metrics


To evaluate:

▪ The completeness of test cases

▪ To demonstrate that there is no unintended functionality

▪ The coverage of requirements at the software unit level shall be determined and

▪ The structural coverage shall be measured in accordance with the metrics listed.

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6.10 SW integration & Testing


▪ To integrate the software components and demonstrate that the software architectural design is correctly realized by the embedded software.

▪ Integrated software tested against architectural design and interfaces between the software units and the software component.

▪ Software integration test shall demonstrate

– Compliance with the software architectural design

– Compliance with the specification of the hardware-software interface

– Correct implementation of the functionality

– Robustness

– Sufficiency of the resources to support the functionality.

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6.11 Verification of SW safety requirements


▪ To demonstrate that the embedded software fulfils the software safety requirements and embedded software satisfies its requirements in the target environment.

▪ The results of the verification of the software safety requirements shall be evaluated in accordance with:

– Compliance with the expected results

– Coverage of the software safety requirements

– A pass or fail criteria

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Fitting software tools into ISO 26262 process

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VectorCAST Compliance with ISO 26262


▪ ISO/DIS 26262 is a new standard for the Automotive sector

- But it is based on principles which have been long established elsewhere

▪ The concept of adopting Aerospace development principles sounds expensive.

But tools to handle these issues are:

• Designed to apply these principles cost effectively, and

• Sophisticated and proven

▪ Similarly, the VectorCAST have long been established to provide the support for IEC 61508 based principles

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V Model Process


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Coding Standard Enforcement


MISRA C/C++

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Software Unit Testing


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Unit Test Case Execution


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Coverage Analysis


ISO 26262-8:2018 Table 12: Structural coverage at the software architectural level

Methods VectorCAST Support ASIL

A B C D

1a Function coverage ✓ + + ++ ++

1b Call coverage ✓ + + ++ ++

ISO 26262-8:2018 Table 9: Structural coverage metrics at the software unit level

Methods VectorCAST Support ASIL

A B C D1a Statement coverage ✓ ++ ++ + +

1b Branch coverage ✓ + ++ ++ ++

1c MC/DC (Modified Condition/Decision Coverage) ✓ + + + ++

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Coverage Analysis


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Traceability Matrix


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Demo

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Conclusion

▪ IEC 26262 ensures the safety of the electrical / electronic / programmable electronic devices in Road vehicles.

▪ Using tools with a proven track record and pedigree to automate the software development process:

– Will help in producing safe product

– Provides confidence to the manufacturers

– Save time and money

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Q&A

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Author:

Yadav, Sunil

Vector India

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