Invalidity Detection ECU for CAN Bus Error Handling

Solution Overview

Problem

The transmission of error frames to invalidate unauthorized frames in CAN networks can inadvertently restrict authorized ECUs, leading to passive mode operation and reduced data transmission capabilities due to incremented reception error counters.

Innovation Solution

An invalidity detection electronic control unit (ECU) that receives frames and transmits an error frame only if a predetermined condition is met, followed by a normal frame conforming to the CAN protocol, thereby reducing the adverse effects on authorized ECUs by decrementing their reception error counters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an error frame is transmitted to invalidate an unauthorized frame, then the unauthorized frame is blocked, but the reception error counter of authorized ECUs is incremented causing them to enter passive mode

Engineering Contradiction:

Improveunauthorized frame blockingVSAvoiddata transmission capability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invalidity detection ECU transmits a normal frame before transmitting an error frame to invalidate an unauthorized frame. This preliminary action of sending a normal frame ensures that authorized ECUs receive at least one valid frame, which prevents their reception error counters from being incremented and avoids forcing them into passive mode, while the subsequent error frame still successfully blocks the unauthorized frame.

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If an error frame is transmitted to invalidate an unauthorized frame, then the unauthorized frame is blocked, but authorized ECUs are restricted from transmitting data

Engineering Contradiction:

Improveunauthorized frame blockingVSAvoidauthorized ECU operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The invalidity detection ECU transmits a normal frame before transmitting an error frame to invalidate an unauthorized frame. This preliminary action of sending a normal frame ensures that authorized ECUs receive at least one valid frame, which prevents their reception error counters from being incremented and avoids forcing them into passive mode, while the subsequent error frame still successfully blocks the unauthorized frame.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS10693905B2Invalidity detection electronic control unit, in-vehicle network system, and communication method

Publication Date: 2020.06.23 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

An invalidity detection electronic control unit connected to a bus used by a plurality of electronic control units (ECUs) to communicate with one another in accordance with controller area network (CAN) protocol includes a receiving unit that receives a frame for which transmission is started and a transmitting unit that transmits an error frame on the bus before a tail end of the frame is transmitted if the frame received by the receiving unit meets a predetermined condition indicating invalidity and transmits a normal frame that conforms to the CAN protocol after the error frame is transmitted. Even when a reception error counter of the ECU connected to the bus is incremented due to the impact of the error frame, the reception error counter is decremented by the normal frame.