Autonomous Vehicle Software Message Testing for Non-Determinism

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Solution Overview

Problem

Autonomous vehicle software exhibits non-deterministic behavior under the same circumstances, leading to unpredictable driving decisions, which is critical to address for reliable operation.

Innovation Solution

Run multiple simulations of the software and compare output messages from decision-making modules to identify and flag differences indicative of non-determinism, filtering out irrelevant messages and setting tolerances to focus on significant deviations, aggregating data to detect anomalies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple simulations are run and compared to detect non-determinism, then software reliability is improved, but processing time and computational resources increase

Engineering Contradiction:
Improvesoftware reliabilityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the simulation output into discrete messages with specific fields that can be independently compared. By dividing the output comparison into field-level operations (timestamp fields, decision fields, control fields), the system efficiently identifies non-determinism without requiring complete re-analysis of entire simulation datasets, thus reducing processing time while maintaining reliability detection capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by pre-defining tolerance thresholds for acceptable differences between simulation runs and pre-identifying critical fields that indicate non-determinism. This preliminary configuration allows the comparison process to focus only on relevant differences within acceptable bounds, significantly reducing the computational burden of multiple simulation comparisons while maintaining reliable detection of actual non-deterministic behavior

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If detailed comparison of all output fields is performed, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvedifference detection precisionVSAvoidcomparison system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating the comparison depth applied to different fields based on their importance. Critical fields (such as decision-making outputs and control commands) undergo precise field-level comparison, while less critical fields use coarser comparison methods or are excluded entirely. This selective approach maintains high measurement precision for safety-critical parameters while reducing overall system complexity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes parameters by introducing tolerance thresholds that dynamically adjust the stringency of field comparisons. For numerical fields, tolerance ranges define acceptable variation without indicating non-determinism. This parameter-based approach enables precise detection of meaningful differences while filtering out negligible variations, thereby maintaining measurement precision without requiring overly complex comparison logic

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12387017B1Non-determinism testing for software for controlling autonomous vehicles
Publication Date: 2025.08.12 WAYMO LLC
  • US12387017B1 patent drawing
  • US12387017B1 patent drawing
  • US12387017B1 patent drawing

AI summary

The disclosure relate to detecting differences indicative of non-determinism in software used to control autonomous vehicles. For instance, a simulation may be run using the software at least two times. The output of the simulations may be tracked. The output of the simulations includes messages may be generated by a decision making module of the software that affect vehicle behavior. A pair of messages generated from each of the at least two times the simulation is run may be compared. Based on the comparison, a difference indicative of non-determinism in the software may be detected.