Vehicle Relay Control for Safe Non-Critical Actuator Fallback
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Solution Overview
Problem
The increasing complexity and cost of vehicle control systems due to the need for all actuator drive controllers to have failure detection and calculation functions, especially in systems controlling fundamental vehicle actions like driving, braking, and steering, lead to higher development costs and power consumption.
Innovation Solution
A vehicle control system with a central control device and relay devices that diagnose and manage actuator states, where specific relay devices do not require abnormality diagnosis functions, allowing for reduced manufacturing costs while maintaining high fail-operational capability by setting non-fundamental actuators to safe states during central control device abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all actuator drive controllers have failure detection function and calculation function, then fail-operational capability is improved, but development cost and manufacturing cost increase
Solution Approach 1:
The patent applies local quality by differentiating the functional requirements of relay devices based on the type of actuator they control. Zone ECUs controlling fundamental actuators (driving, braking, steering) are equipped with both failure detection function and calculation function, while zone ECUs controlling non-fundamental actuators are equipped with only failure detection function. This localized differentiation reduces overall system complexity and development cost while maintaining adequate fail-operational capability for critical functions.
2Reliability
If all actuator drive controllers have failure detection function and calculation function, then fail-operational capability is improved, but power consumption increases
Solution Approach 1:
The patent implements local quality by assigning different functional configurations to relay devices based on actuator criticality. Zone ECUs for non-fundamental actuators operate with only failure detection function, consuming less power, while zone ECUs for fundamental actuators maintain both failure detection and calculation functions. This localized functional differentiation reduces overall system power consumption while preserving fail-operational capability for safety-critical systems.
3Reliability
If central control device abnormality is detected, then safety is improved by setting actuators to safe states, but system complexity increases due to diagnosis functions
Solution Approach 1:
The patent applies segmentation by dividing the control system into a central control device and multiple zone ECUs with differentiated functions. The central control device performs abnormality diagnosis and determines safe states, while zone ECUs execute the actual actuator control based on their specific functional capabilities. This segmentation allows the diagnosis function to be centralized, reducing overall system complexity while maintaining safety through distributed execution.
Solution Approach 2:
The patent implements local quality by assigning different levels of diagnostic and control capabilities to different zone ECUs based on the criticality of the actuators they control. This localized functional differentiation reduces the overall diagnostic complexity in the system while ensuring that safety-critical actuators receive appropriate monitoring and control, thereby improving safety without uniformly increasing system complexity across all components.
Data Source
AI summary
A vehicle control system includes a central ECU configured to calculate target outputs of actuators, and relay devices each disposed in a communication path between the central ECU and a corresponding actuator among the actuators. The plurality of relay devices includes a specific relay device configured transfer a control signal from the central ECU only to a fixed actuator that is an actuator not related to driving control, braking control, and steering control of a vehicle. The specific relay device is configured to output, to the fixed actuator coupled to the specific relay device, one of a signal for setting the fixed actuator in an operating state or a signal for setting the fixed actuator in a non-operating state, in response to detection of an abnormality in the central ECU. The specific relay device does not have a function of diagnosing an abnormality in the specific relay device.