Turning Unit Abnormality Detection Under High-Torque Deformation
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Solution Overview
Problem
Existing abnormality detection systems in steering systems, such as steer-by-wire and electric power steering, face challenges in accurately detecting abnormalities due to elastic deformations in power transmission mechanisms, leading to potential false positives when high torque is applied.
Innovation Solution
An abnormality detection device that includes sensors to detect motor rotation angle, conjunction state quantity, and actual current value, with a processing circuit performing a series of processes to calculate differences and determine abnormalities only when the actual current value is within a certain threshold, thereby reducing false positives from elastic deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor outputs large torque, then the power transmission capability is improved, but elastic deformation of power transmission components occurs causing false abnormality detection
Solution Approach 1:
The system changes the operational parameters by introducing a current threshold value to distinguish between normal high-torque operation and actual abnormalities. When the motor current exceeds the threshold, the system recognizes elastic deformation as normal and suppresses false abnormality detections, thereby maintaining detection accuracy across varying torque conditions.
Solution Approach 2:
The abnormality detection mechanism dynamically adjusts its sensitivity based on real-time motor current conditions. The determination process is activated or deactivated depending on whether the current threshold is exceeded, making the detection system adaptive to changing operational states and preventing false positives during high-torque operation.
2Reliability
If the determination process is always performed, then abnormality detection coverage is maximized, but false positives increase under high torque conditions
Solution Approach 1:
The determination process is made dynamic by conditionally activating it based on motor current levels. The processing circuit performs the determination process only when the absolute value of actual current is below the threshold, creating a dynamic detection regime that adapts to operational conditions and eliminates false positives during high-torque operation.
Solution Approach 2:
The system uses the motor current value as a parameter to control the execution of the determination process. By comparing actual current against a threshold parameter, the system intelligently enables or disables abnormality detection, optimizing both coverage and precision across different operating conditions.
Data Source
AI summary
An abnormality detection device includes a processing circuit configured to perform an abnormality detecting process. The abnormality detecting process includes a first state quantity acquiring process, a second state quantity acquiring process, a difference calculating process of calculating a difference between a first state quantity and a second state quantity, and a determination process of comparing an absolute value of the difference with a difference threshold value. The abnormality detecting process is a process of detecting an abnormality of a turning unit when the absolute value of the difference is greater than the difference threshold value, and the processing circuit is configured not to perform the determination process when an absolute value of an actual current value is greater than a current threshold value.