Understanding ISO 26262 for Automotive Electronics
- ISO 26262 is a functional safety standard specifically for automotive electronic and electrical systems. It's essential to ensure that these systems function correctly even in the event of failures.
- The standard is structured around the V-model of system development, emphasizing the importance of systematic design validation and verification to ensure the safety integrity levels (ASIL).
Establish Safety Goals
- Identify and analyze potential risks associated with automotive electronics using the Hazard Analysis and Risk Assessment (HARA) process.
- Derive safety goals from the HARA, ensuring these are attainable within your technical and operational contexts.
System and Component Level Requirements
- Translate safety goals into specific system-level requirements. Ensure traceability from top-level system requirements to individual component specifications.
- Use a requirement management tool that supports ISO 26262 traceability, like DOORS or Polarion.
Hardware Design and Implementation
- Incorporate safety mechanisms in hardware designs, such as watchdog timers, fault-tolerant circuits, and safety-redundant components.
- Perform Failure Mode and Effects Analysis (FMEA) on the hardware to evaluate potential failure modes and impacts and address these with appropriate design modifications.
Example: Redundant Circuit Design
void main_system_function() {
if(system_safety_check()) {
execute_main_task();
} else {
switch_to_redundant_system();
}
}
Verification and Validation
- Use formal verification methods to validate the design against safety requirements. This process helps identify safety-critical issues early.
- Conduct hardware-in-the-loop (HIL) testing to simulate real-time operation environments and validate the system behavior under dynamic conditions.
Safety Analysis and Testing
- Perform safety audits and reviews periodically to ensure ongoing compliance, looking for any areas of improvement or potential non-conformance.
- Use simulation and fault injection testing to evaluate the robustness of safety mechanisms under a variety of failure scenarios.
- Example: Inject faults in a controlled environment to assess system behavior.
Documentation and Compliance Evidence
- Maintain comprehensive documentation of safety requirements, design details, verification results, and compliance evidence, as ISO 26262 requires documented proof of compliance.
- Organize documentation effectively to streamline both internal reviews and external audits, ensuring that all safety-related decisions and changes are justified and well-documented.
