Active Front Steering Actuator Locking via CAN Parameter Validation
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Solution Overview
Problem
Active Front Steering (AFS) systems face challenges in timely error detection and actuator locking due to communication delays in Controller Area Network (CAN) message traffic, leading to potential false failure detection and delayed actuator locking, which compromises safety and reliability.
Innovation Solution
The system monitors AFS messages for errors, determines invalid parameters, and takes remedial actions by setting predetermined values for valid parameters to quickly lock the AFS actuator and reduce false failure detection, utilizing a CAN-based communication network to interconnect modules like the Hand Wheel Sensor (HWS) module, AFS module, and Supervisory Control Module (SCM).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the AFS system uses CAN-based communication network to interconnect modules, then the system can achieve standardized data transmission and module interconnection, but communication delays occur that prevent timely error detection and actuator locking
Solution Approach 1:
The system performs preliminary error checking by monitoring the validity of received messages and parameters before using them for control decisions. The control module continuously validates incoming CAN messages from HWS and AFS modules, detecting errors in advance before they affect actuator operation, thus reducing the effective error detection time despite CAN communication delays.
Solution Approach 2:
The system implements feedback mechanisms where the control module continuously monitors the validity of parameters received through CAN communication. When invalid parameters are detected, the system provides feedback by setting affected parameters to default values and locking the actuator, creating a closed-loop error detection and response system that compensates for communication delays.
2Reliability
If the system locks the actuator within a designated period upon error detection, then safety metrics are met, but communication delays cause the system to miss the locking deadline
Solution Approach 1:
The system performs preliminary validation of message validity continuously during operation. By checking parameter validity in advance and maintaining a rolling count of consecutive invalid messages, the system prepares for potential failure conditions before they require actuator locking, enabling faster response when actual failures occur.
Solution Approach 2:
The system implements a rolling count mechanism that accumulates evidence of communication failures over multiple consecutive messages. This cushioning approach allows the system to tolerate occasional communication glitches while preparing for sustained failure conditions, balancing false failure detection avoidance with timely actuator locking when genuine failures occur.
3Measurement precision
If the system monitors message traffic continuously for error detection, then actual failures can be detected accurately, but the probability of false failure detection increases due to communication delays
Solution Approach 1:
The system performs preliminary validation by checking parameter validity bits and maintaining a rolling count of consecutive invalid messages. This preliminary action filters out transient communication errors while capturing sustained failure conditions, improving the accuracy of failure detection while reducing false positives caused by occasional communication delays.
Solution Approach 2:
The system uses a threshold-based approach with a rolling count of consecutive invalid messages (e.g., requiring multiple consecutive invalid messages before triggering failure detection). This partial action approach balances sensitivity to actual failures against resistance to false detection, using excessive monitoring (multiple message checks) to confirm genuine failures while filtering out transient errors.
Data Source
AI summary
A vehicle parametric active front steering (AFS) system remedial action is described herein. AFS system modules inter-communicate via messages containing parameters. The AFS system detects a message error, determines an invalid parameter, and takes appropriate remedial action. An error is detected if an error condition is satisfied or if occurrence of incorrect messages reaches or exceeds a certain predetermined frequency. The AFS system takes the remedial action by setting default values of valid parameters corresponding to the invalid parameter.