SSI Interlocking Safety Validation via Automated Path Execution
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Solution Overview
Problem
Existing methods for checking safety requirements of SSI-based data in interlocking control systems are inefficient, requiring expert skills and general-purpose model checking software, and fail to validate all possible scenarios, particularly for communicating interlockings.
Innovation Solution
A method that uses a computer-implemented software module to validate SSI-based data by generating constraint violation files, selecting relevant data, initializing variables, and executing paths to detect unsafe states, allowing for exhaustive search and user-friendly operation without requiring expert informatics skills.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If general-purpose model checking software is used to validate SSI-based data, then validation coverage can be improved, but the complexity of operation increases and expert skills are required
Solution Approach 1:
The patent introduces an intermediary validation system that sits between the SSI-based data and the general-purpose model checking software. This intermediary automatically translates and prepares the data, eliminating the need for experts to manually configure complex model checkers while maintaining comprehensive validation coverage.
Solution Approach 2:
The validation system performs self-service by automatically executing the validation process without requiring expert intervention. The system autonomously generates test cases, executes them against the SSI data, and produces validation results, making the process accessible to non-experts.
2Reliability
If exhaustive path execution is performed to validate all scenarios, then validation completeness is improved, but processing time increases
Solution Approach 1:
The system performs preliminary actions by pre-generating and organizing test paths before execution. It identifies and prioritizes critical paths that are most likely to reveal safety issues, allowing exhaustive validation of essential scenarios while reducing unnecessary processing of less critical paths.
Solution Approach 2:
The validation process is segmented into multiple independent phases: path generation, path selection, execution, and analysis. This segmentation allows the system to process validation in manageable chunks, improving efficiency while maintaining completeness through systematic coverage of all necessary paths.
3Ease of manufacture
If manual verification procedures are used to check application data, then ease of implementation is improved, but validation thoroughness deteriorates
Solution Approach 1:
The patent replaces manual mechanical verification procedures with an automated electronic validation system. The system automatically executes predefined paths against the SSI data and checks for safety violations, providing thorough validation without requiring manual intervention while remaining easy to implement through configuration files.
Data Source
Figure 1
AI summary
Method for checking safety requirements of SSI-based data used in an interlocking control system for controlling an interlocking equipment, the method comprising the steps of: a) obtaining (2) application data representative of interlocking logic operations of the interlocking equipment; b) preparing (4) a constraint violation file containing data representative of a plurality of constraint violation conditions, said data describing a plurality of unsafe scenarios of the interlocking equipment; for each constraint violation condition of the plurality of constraint violation conditions: c) selecting (6) data of the application data according to the constraint violation condition, said selected data corresponding to a predetermined unsafe scenario of the plurality of unsafe scenarios defined in the constraint violation file; d) determining (7) at least one predetermined context associated to said unsafe scenario, said context comprising a plurality of paths through the application data; e) initializing (8) variables that define all possible states of said scenario, thus obtaining a predetermined initial state, said variable being representative of the scenario from the point of view of settings of the interlocking equipment; f) executing (10), starting from said initial state, all possible paths of the context in the application data, thus obtaining respective resulting states; g) at an end of each path, determining (12) if an unsafe state has been reached by comparing a respective resulting state with the data of the constraint violation file; h) if no unsafe state has been detected, determining (12) if the resulting state has not been reached; -i) repeating steps f), g) and h), starting, for each path, from the respective resulting state, until unsafe states or no new states are reached.