Steering Control Device Abnormality Detection via Integrated Rotation Angle
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Solution Overview
Problem
In vehicle steering systems with a dynamically cut-off power transmission path, the stopper mechanism's inability to restrict the steering shaft's rotation range leads to uncontrolled continuous rotation, necessitating early detection of mechanical restriction failures.
Innovation Solution
A steering control device with a processor that acquires integrated rotation angles from an angle sensor and determines abnormality conditions, using different thresholds based on the steering wheel's state to detect stopper mechanism failures, enabling early detection and prevention of unlimited rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper mechanism is used to mechanically restrict the rotation range of the steering shaft, then the rotation range can be regulated within a regulatory rotation amount, but the stopper mechanism may become incapable of mechanically restricting the rotation range, leading to unlimited rotation
Solution Approach 1:
The patent replaces the purely mechanical stopper mechanism with a hybrid system that incorporates electronic detection (angle sensor) and software control (processor-based abnormality determination). The processor monitors the integrated rotation angle and detects abnormalities when the steering shaft rotation exceeds the regulatory rotation amount, providing a non-mechanical backup to the mechanical stopper mechanism.
Solution Approach 2:
The patent implements a feedback system where the angle sensor continuously detects the steering shaft rotation angle, the processor integrates these angles over time, and the system provides feedback when the integrated rotation angle indicates an abnormality. This feedback loop enables real-time monitoring and early detection of stopper mechanism failures.
2Manufacturing precision
If the stopper mechanism is designed with high mechanical precision, then the rotation range can be accurately restricted, but the complexity of the mechanical structure increases
Solution Approach 1:
The patent reduces mechanical complexity by replacing precise mechanical restriction with a combination of a simple mechanical stopper and an electronic monitoring system. The angle sensor and processor provide the precision previously requiring complex mechanical design, while the mechanical stopper itself remains a simple component.
Solution Approach 2:
The angle sensor serves multiple functions: it detects the steering shaft rotation angle for normal operation, integrates angles to determine abnormality conditions, and provides data for both the reaction force motor control and the stopper mechanism monitoring. This multi-functionality reduces the need for separate specialized components.
3Reliability
If software-based abnormality determination is implemented, then early detection of stopper mechanism failure is possible, but the system complexity increases
Solution Approach 1:
The processor performs multiple functions using the same hardware: it controls the reaction force motor, integrates angle sensor data, determines abnormality conditions, and manages overall steering control. This multi-functionality enables early detection capability without adding dedicated hardware for each function.
Solution Approach 2:
The system uses its own existing components (angle sensor and processor) to monitor and detect abnormalities in the stopper mechanism, rather than requiring separate dedicated detection hardware. The integrated rotation angle calculation and abnormality determination are performed using the same processing resources already allocated for normal steering control.
Data Source
AI summary
A steering control device includes a processor that controls a steering unit that uses a reaction force motor as a drive source. The processor is configured to execute an integrated rotation angle acquisition process of acquiring an integrated rotation angle that is an integrated value of the rotation angle of a steering shaft, based on a detection result of an angle sensor. The processor is configured to execute an abnormality determination process of determining whether an abnormality condition for detecting an abnormality of a stopper mechanism is satisfied, based on the integrated rotation angle. The abnormality determination process includes a process of determining that the abnormality condition is satisfied, when the processor is capable of determining that the integrated rotation angle is out of a regulatory rotation amount.