Simulation-Based Tolerance Zones for Steer-By-Wire Samples
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Solution Overview
Problem
Current methods lack a systematic procedure to ascertain meaningful parameter tolerances for product samples, leading to potential deviations in system behavior between prototypes and manufactured products, especially in steer-by-wire and highly automated driving steering systems, which are subject to stricter normative requirements.
Innovation Solution
A computer-implemented method using dissimilarity metrics (gap, ν-gap, and L2 metrics) to calculate a tolerance zone around a target parameter sample, ensuring that product specimens maintain a tolerable system behavior similarity by determining individual parameter tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If parameter tolerances are defined based on expert knowledge, then the selection process is simple and quick, but the system behavior dissimilarity between product samples and specimens may be significant
Solution Approach 1:
The patent transforms the tolerance definition process from expert-based qualitative judgment to a systematic quantitative approach by calculating dissimilarity metrics (gap metric, ν-gap metric, L2 metric) between product samples and specimens. This enables objective determination of parameter tolerances that guarantee acceptable system behavior similarity while reducing time loss through automated computation.
2Reliability
If parameter tolerances are made strict, then system behavior similarity between product samples and specimens is improved, but production costs increase unnecessarily
Solution Approach 1:
The patent applies partial action by determining tolerances only for parameters that have significant influence on system behavior, identified through sensitivity analysis. Parameters with low influence can have looser tolerances, avoiding unnecessary production costs while maintaining adequate system behavior similarity for critical parameters.
3Ease of manufacture
If parameter tolerances are made lax, then production costs are reduced, but significant deviations in system behavior between product samples and specimens occur
Solution Approach 1:
The patent systematically determines optimal parameter tolerances by calculating dissimilarity metrics and identifying the boundary where system behavior similarity becomes unacceptable. This enables cost-effective tolerance selection that avoids both excessive strictness and insufficient control, achieving the optimal balance between production cost and system behavior similarity.
4Reliability
If a systematic procedure for tolerance ascertainment is implemented, then the system behavior dissimilarity is controlled, but the complexity of the process increases
Solution Approach 1:
The patent replaces complex manual expert evaluation processes with automated computational methods using dissimilarity metrics (gap metric, ν-gap metric, L2 metric). This substitution transforms a potentially complex expert-based process into a systematic computational procedure that provides objective, repeatable results while actually reducing overall process complexity through automation.
Data Source
AI summary
A computer-implemented method for ascertaining a tolerance zone in an operational design domain (ODD) around a target parameter sample of a parameterizable simulation model for a product, in particular a steer-by-wire steering system and/or a steering system for highly automated driving. The method includes: calculating a dissimilarity metric based on each pair of a plurality of pairs, wherein each pair comprises a parameterized simulation model associated with the target parameter sample and a parameterized simulation model of a plurality of parameterized simulation models, wherein each pair yields a distance, thereby resulting in a plurality of distances; optionally wherein the dissimilarity metric is based on a gap metric, a ν-gap metric and/or an L2 metric; and determining the tolerance zone in the ODD around the target parameter sample based on the plurality of distances and on a maximum tolerable distance.