Vehicle Control Interface Box for CAN Congestion Prioritization
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Solution Overview
Problem
When CAN communication between a vehicle and an autonomous driving system becomes congested, the transmission of control instructions and signals may fail, leading to inappropriate execution of autonomous driving.
Innovation Solution
A vehicle control interface box is configured with a first reception unit, a calculation unit, a transmission unit, and a setting unit. The calculation unit calculates an index value showing the degree of CAN communication congestion, and the setting unit sets a transmission plan for control instructions based on the index value and the priority of the control instructions, ensuring that high-priority instructions are transmitted promptly while reducing congestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If CAN communication is used for interface between autonomous driving system and vehicle, then communication simplicity is improved, but communication reliability deteriorates when congestion occurs
Solution Approach 1:
The transmission cycle of control instructions is made dynamic rather than fixed. The determination unit adjusts the transmission cycle based on the priority of control instructions and the current state of CAN communication (congestion level). High-priority instructions receive shorter transmission cycles for prompt transmission, while low-priority instructions receive longer cycles when congestion is detected, thereby resolving the contradiction between communication simplicity and reliability.
2Reliability
If control instructions are transmitted with high frequency, then autonomous driving execution accuracy is improved, but CAN communication congestion worsens
Solution Approach 1:
Different transmission cycles are assigned to different control instructions based on their priority and the current CAN communication state. Instead of using a uniform transmission cycle for all instructions, the system applies local quality by tailoring the transmission frequency to each instruction's specific needs and the current communication conditions, thereby maintaining execution accuracy while avoiding overall congestion.
Solution Approach 2:
The transmission cycle parameter is dynamically changed based on the priority of control instructions and the congestion state of CAN communication. The determination unit adjusts this parameter in real-time, changing it from a fixed value to a variable that adapts to system conditions, thus resolving the contradiction between transmission frequency and communication throughput.
3Productivity
If transmission cycle is extended for low-priority instructions, then CAN communication congestion is reduced, but transmission delay for important instructions increases
Solution Approach 1:
Control instructions are segmented into different priority levels (high-priority and low-priority). The determination unit segments the transmission strategy accordingly, applying different transmission cycles to different segments. This segmentation ensures that high-priority instructions are transmitted promptly with shorter cycles, while low-priority instructions use longer cycles to reduce congestion, thereby resolving the time loss contradiction.
Data Source
AI summary
A VP includes a base vehicle and a VCIB. The VCIB includes a reception unit, an index value calculation unit, a transmission unit, and a transmission plan setting unit. The reception unit receives a control request for the base vehicle from an ADS. The index value calculation unit calculates an index value showing a degree of congestion of CAN communication. The transmission unit transmits a control instruction for the base vehicle generated based on the control request to the base vehicle. The transmission plan setting unit sets a transmission plan of the control instruction to the base vehicle. The transmission plan setting unit sets the transmission plan according to a degree of priority of the control instruction in CAN communication and the index value.