ECU Clock Synchronization Diagnosis With Periodic and Offset Deviation
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Solution Overview
Problem
In vehicle control systems with multiple electronic control units (ECUs) connected via a network, determining synchronization abnormalities between time information without increasing processing load is challenging due to the need for parallel execution with vehicle control processes.
Innovation Solution
A vehicle control system and method that utilizes a master ECU to transmit and receive signals with slave ECUs to calculate delay times and determine periodic and offset deviations in clock periods, allowing separate determination of synchronization abnormalities without considering periodic deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the process for determining synchronization abnormality is repeatedly executed in parallel with vehicle control process, then synchronization monitoring is achieved, but processing load increases
Solution Approach 1:
The patent extracts the determination of periodic deviation from the overall synchronization abnormality determination process. By separately determining periodic deviation based on processing periods (difference between clock periods and transmission delay), the system can then determine offset deviation without considering periodic deviation influence. This extraction reduces the computational complexity of the main determination process, thereby reducing processing load while maintaining reliable synchronization monitoring.
2Device complexity
If offset deviation is determined without considering periodic deviation, then calculation is simplified, but measurement precision may be affected
Solution Approach 1:
The patent segments the synchronization abnormality determination into two distinct parts: (1) periodic deviation determination based on processing periods, and (2) offset deviation determination excluding periodic deviation influence. This segmentation allows each part to be calculated independently with appropriate precision, simplifying the overall calculation while maintaining measurement accuracy through structured analysis.
Solution Approach 2:
The patent performs preliminary determination of periodic deviation before determining offset deviation. By first calculating the periodic deviation based on processing periods and then using this information to adjust the offset deviation determination, the system preliminarily separates the two types of deviations. This preliminary action ensures that offset deviation measurement is not contaminated by periodic deviation, maintaining precision while simplifying the calculation process.
Data Source
AI summary
The vehicle control system includes an abnormality diagnosis unit for determining whether a synchronization abnormality between a master ECU and a slave ECU has occurred. The abnormality diagnosis unit transmits and receives a signal between the master ECU and the slave ECU and acquires time information. The slave ECU calculates a delay time of transmission based on the acquired time information. Then, the abnormality diagnosis unit first determines whether or not there is a periodic shift. When determining that there is no periodic deviation, the abnormality diagnosis unit determines whether or not there is an offset deviation based on the difference obtained by subtracting the delay time from the second time and the first time. The abnormality diagnosis unit determines that a synchronization abnormality has occurred when it is determined that there is a periodic deviation or when it is determined that there is the offset deviation.