Guardian Scrubbing Slots for Time-Triggered Protocol Testing
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Solution Overview
Problem
Existing distributed time-triggered protocol systems face challenges in testing local guardians without interrupting the system's normal operation and risk inadvertently injecting faults during testing, particularly in FlexRay networks.
Innovation Solution
Implementing a special node, referred to as an autocratic node, that sources timing-related frames and uses protocol functionality to establish a time base, allowing for in situ testing of local guardians without interrupting the system, and includes a scrubbing time slot to monitor for latent faults, thereby preventing transmission of timing-related frames from end nodes and ensuring compliance with the communication schedule.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional guardian testing methods are used, then testing can be performed, but the system operation is interrupted and faults may be inadvertently injected
Solution Approach 1:
The patent implements a preliminary action by establishing a dedicated scrubbing slot in the TDMA schedule before normal operation begins. This slot is pre-configured for guardian testing purposes, allowing testing to occur without disrupting the established communication schedule. The autocratic node prepares the testing framework in advance, enabling seamless integration of testing into the operational flow.
Solution Approach 2:
The patent segments the TDMA schedule by creating a dedicated scrubbing slot separate from normal data transmission slots. This segmentation isolates testing activities to a specific time window, allowing guardians to be tested independently without affecting other nodes' normal operations. The scrubbing slot is further segmented by assigning different nodes to specific slots within it.
2Reliability
If local guardians prevent transmission of timing-related frames, then timing synchronization is maintained, but testing of guardian functionality becomes difficult
Solution Approach 1:
The patent introduces an intermediary mechanism by using the autocratic node as a mediator between testing requirements and the guardians' frame blocking function. The autocratic node generates special test frames during scrubbing slots that are designed to bypass or challenge the guardians' blocking behavior, allowing testing without compromising the guardians' normal timing synchronization function.
Solution Approach 2:
The patent implements periodic action by scheduling regular scrubbing slots at predetermined intervals in the TDMA schedule. During these periodic windows, guardians are temporarily overridden or challenged with test frames, while at all other times they maintain their normal blocking behavior to ensure timing synchronization. This periodic testing approach balances testing needs with operational reliability.
Data Source
AI summary
A cluster comprises a plurality of end nodes that communicate with one another over at least one communication channel. Each end node is assigned a time slot for transmission of frames; wherein each node comprises a local guardian configured to prevent transmission of timing-related frames sourced from the respective end node. The cluster also comprises a special node that communicates with the plurality of end nodes, wherein the special node establishes a time base and sources timing-related frames to the plurality of end nodes. The transmission schedule includes at least one common scrubbing time slot during which each of the plurality of end nodes is configured to generate a timing-related frame. The special node is configured to determine if the local guardian in any of the plurality of nodes failed to prevent transmission of the respective generated timing-related frame during the common scrubbing time slot.