Vehicle Control Timing Adjustment for Jitter-Tolerant Scheduling
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Solution Overview
Problem
In vehicle control systems, software from various suppliers and OEMs coexist, leading to potential instability due to unintended high-priority processing-induced jitter in execution timing, which complicates design and increases overhead, especially when trying to comply with safety standards like ASIL_D.
Innovation Solution
A vehicle control device with an execution management unit that adjusts processing timing based on a jitter tolerance, using an execution state recording unit and setting information management unit to manage and record execution states and settings, allowing for jitter suppression by temporarily or permanently changing execution timing or replacing it with another processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-division scheduling is used to guarantee execution timing for each company, then execution timing is guaranteed and system stability is improved, but time slot granularity becomes fine, making design complicated and overhead large
Solution Approach 1:
The patent merges multiple fine-grained time slots into a coarser time slot, allowing multiple tasks from different companies to share the same time slot. This reduces the number of time slots needed, simplifying design and reducing overhead while still guaranteeing execution timing through the shared time slot mechanism
Solution Approach 2:
The patent creates a universal time slot that can accommodate multiple tasks from different companies simultaneously, making the time slot multi-functional. This universal time slot approach eliminates the need for dedicated time slots for each company, reducing design complexity while maintaining execution timing guarantees
2Reliability
If dedicated time slots are allocated for each company's tasks, then execution timing is guaranteed, but the number of time slots increases, increasing system overhead
Solution Approach 1:
The patent combines multiple dedicated time slots into a single shared time slot that serves multiple companies. By merging the time slots, the total number of time slots is reduced, decreasing system overhead while maintaining execution timing guarantees through proper task scheduling within the shared slot
3Manufacturing precision
If fine-grained time slot allocation is used to prevent jitter, then execution timing precision is improved, but design becomes complicated and overhead increases
Solution Approach 1:
The patent merges fine-grained time slots into coarser time slots while maintaining execution timing precision through intelligent task scheduling. The merging reduces the number of time slots and simplifies design, while the scheduling mechanism ensures that tasks still execute with the required precision within the coarser time slot framework
Data Source
AI summary
There are provided a vehicle control device and a control method thereof capable of improving safety and reliability with a simple configuration. A vehicle control device 1 that controls a vehicle includes an execution management unit P3 that manages execution of predetermined processing, an execution state recording unit P5 that records a history of execution states of the predetermined processing, and a setting information management unit P4 that manages setting information related to the execution of the predetermined processing. The setting information includes a jitter tolerance which is a tolerance of a jitter. The execution management unit P3 adjusts an execution timing of processing to be adjusted, which is included in the predetermined processing and in which the jitter is generated, based on the jitter tolerance of the processing to be adjusted.