ISO 26262 Vehicle Development: V-Model Guidelines Overview
1. Concept Phase (Left Side of the V)
The cycle begins with defining system concepts and assessing risks.
Hazard Analysis and Risk Assessment (HARA)
• Objective: Identify hazards and assess risks based on severity, exposure, and controllability.
• Output: Safety goals categorized using Automotive Safety Integrity Levels (ASIL), which dictate the rigor required in the development process.
Functional Safety Concept
• Objective: Establish high-level safety requirements to mitigate hazards.
• Output: Functional safety requirements (e.g., fault tolerance and safe states) that guide system design.
2. System Development (Design & Specification)
System Architecture Design
• Objective: Develop a vehicle architecture with safety mechanisms.
• Guideline: Incorporate redundancy, fault tolerance, and diagnostic coverage.
• Output: Technical safety requirements derived from the functional requirements.
System Requirements Specification
• Objective: Convert safety goals into technical specifications.
• Guideline: Ensure traceability of system components to safety goals.
3. Hardware and Software Development (Implementation)
Hardware Development
• Objective: Design hardware that meets safety requirements.
• Guideline: Perform Failure Mode and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) to identify failure risks.
• Key Metrics: Diagnostic coverage, failure rates, and random hardware failure mitigation.
Software Development
• Objective: Develop safety-critical software.
• Guideline: Follow ASIL-based development processes, with traceability and modularity.
• Key Processes: Unit testing, integration testing, and error-handling mechanisms.
4. Integration and Testing (Right Side of the V)
System Integration
• Objective: Combine hardware and software components, ensuring they meet safety requirements.
• Guideline: Perform integration testing, ensuring interactions between components are safe.
Verification and Validation (V&V)
• Objective: Ensure that each phase meets safety goals.
• Guideline:
• Verification: Test each component against safety requirements.
• Validation: Ensure the overall system performs safely under real-world conditions.
5. Production, Operation, and Decommissioning
Production
• Objective: Maintain safety integrity during manufacturing.
• Guideline: Establish quality controls to ensure safety mechanisms are not compromised.
Operation and Maintenance
• Objective: Ensure vehicle safety during its lifecycle.
• Guideline: Implement safety assessments, updates, and monitoring to detect potential safety issues.
Decommissioning
• Objective: Safely decommission systems at the end of life.
• Guideline: Ensure safe handling of safety-critical components, especially in electric vehicles.
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