Encoded Diagnostics for Functional Safety Fault Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current functional safety systems face challenges in effectively detecting and responding to faults and errors in complex systems, particularly in environments prone to interference, where bit flips or software overwrites can occur due to bugs, memory issues, or malicious attacks, leading to potential unsafe operational states.
Innovation Solution
A method involving a safety module that stores and encodes state information as unique codewords with minimum hamming distances, allowing for the detection of mismatches and outputting safety messages based on matches or mismatches between stored and valid codewords, thereby triggering fault recovery processes and maintaining functional safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional functional safety systems are used without encoded diagnostics, then the system structure is simpler, but the system cannot reliably detect bit flips or software overwrites caused by interference, bugs, or malicious attacks
Solution Approach 1:
The system pre-calculates and stores valid codewords in a codeword table before operation. These codewords are generated using encoding functions that incorporate subsystem identifiers and state information, establishing a reference framework in advance that enables rapid fault detection without complex real-time calculations
Solution Approach 2:
The patent introduces codewords as an intermediary layer between the subsystem state and the safety diagnosis function. Instead of directly monitoring subsystem states, the system encodes states into codewords and compares them against valid codewords, allowing indirect but reliable fault detection that isolates the complexity of encoding algorithms from the core safety logic
2Measurement precision
If the system monitors all subsystem states in detail, then the measurement precision improves, but the processing time and system complexity increase
Solution Approach 1:
The patent segments the state monitoring function by creating separate encoding paths for different subsystems, each with its own identifier and state parameters. The codeword table is organized by subsystem, allowing the system to validate only relevant subsystem states rather than processing all system information uniformly, thus reducing overall processing time while maintaining precision
Solution Approach 2:
The system performs partial validation by comparing only the essential codeword components against the codeword table. The encoding function generates codewords with sufficient redundancy for fault detection, but does not compute all possible state variations, achieving adequate measurement precision with reduced processing effort
Data Source
AI summary
A method includes, storing a set of valid codewords including: a first valid functional codeword representing a functional state of a controller subsystem; a first valid fault codeword representing a fault state of the controller subsystem and characterized by a minimum hamming distance from the first valid functional codeword; a second valid functional codeword representing a functional state of a controller; and a second valid fault codeword representing a fault state of the controller; in response to detecting functional operation of the controller subsystem, storing the first valid functional codeword in a first memory; in response to detecting a match between contents of the first memory and the first valid functional codeword, outputting the second valid functional codeword; in response to detecting a mismatch between contents of the first memory and every codeword in the first set of valid codewords, outputting the second valid fault codeword.