Vehicle Energy Supply Monitoring With Cyclic Failure-Rate Modeling
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Solution Overview
Problem
Existing methods for monitoring power supply to motor vehicles with self-driving functions do not adequately account for cyclic diagnostic measures, which are crucial for safety but violate continuous/static safety criteria, leading to incomplete safety validation and increased failure probability.
Innovation Solution
A method is introduced to model failure probability using piecewise- and time-dependent failure rates, incorporating cyclic diagnostics by defining controllable and uncontrollable fault periods, and applying a weighted average to determine a metric for failure probability, allowing cyclic safety measures to be included in safety assessments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cyclic diagnostic measures are implemented for safety monitoring, then reliability of safety validation is improved, but they violate continuous/static safety criteria and cannot be included in PMHF calculation
Solution Approach 1:
The patent segments the diagnostic coverage into continuous/static portions and cyclic portions. The continuous diagnostic coverage (DC_cont) is separated from the cyclic diagnostic coverage (DC_cyc), allowing each to be evaluated according to its own temporal characteristics. This segmentation enables cyclic diagnostics to be included in PMHF calculation while maintaining compliance with continuous safety criteria for the continuous portion.
Solution Approach 2:
The patent introduces dynamic, time-dependent failure rates that vary based on the diagnostic cycle. The failure rate λ(t) is modeled as a piecewise function that accounts for periods when cyclic diagnostics are active versus when they are not. This dynamic approach allows the system to reflect the actual temporal behavior of cyclic diagnostics while integrating them into the static PMHF framework.
2Measurement precision
If hourly cyclic diagnoses are performed before travel, then detection of faults is improved, but the system cannot be considered continuous/static and is excluded from safety case
Solution Approach 1:
The patent segments the overall diagnostic coverage into continuous/static components and cyclic components. By separating DC_cont from DC_cyc, the patent allows the continuous portion to satisfy safety case requirements while the cyclic portion contributes additional fault detection capability. This segmentation resolves the contradiction by allowing both types of diagnostics to coexist in the safety analysis.
Solution Approach 2:
The patent creates a unified PMHF calculation framework that can accommodate both continuous/static diagnostics and cyclic diagnostics. The generalized formula integrates multiple diagnostic types with different temporal characteristics, making the safety evaluation method universal and applicable to various diagnostic strategies without requiring separate analysis methodologies.
3Reliability
If piecewise time-dependent failure rate is used to model cyclic diagnostics, then accurate inclusion in PMHF calculation is achieved, but calculation complexity increases
Solution Approach 1:
The patent performs preliminary segmentation of the diagnostic coverage and failure rate into continuous and cyclic components before conducting the PMHF calculation. By pre-defining DC_cont, DC_cyc, and the piecewise failure rate model, the patent simplifies the subsequent integration process. This preliminary action reduces calculation complexity by organizing the complex time-dependent parameters into manageable segments that can be systematically processed.
Data Source
AI summary
A method for monitoring a safety-relevant electrical component of a motor vehicle, in particular for a self-driving function. A safety-relevant component is provided for a motor vehicle. A cyclic diagnosis of the safety-relevant component is carried out. A metric for failure probability is determined for the safety-relevant component by using a piecewise- and thus time-dependently defined failure rate of the component.