Yaw Rate Sensor Normality Detection Using Lateral G Cross-Check
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Solution Overview
Problem
Existing vehicle behavior control systems face challenges in accurately determining whether a yaw rate sensor is in a normal state, particularly due to temporary noise leading to erroneous determinations, which can result in improper vehicle control, especially on low friction coefficient roads.
Innovation Solution
A vehicle behavior control apparatus that includes a steering angle detector, lateral acceleration detector, and yaw rate detector, with a controller featuring an abnormality detector and a normality detector. The normality detector calculates differences between estimated and actual yaw rates from these sensors to determine if the yaw rate sensor is in a normal state, ensuring accurate determination by considering both differences within predetermined values and a predetermined time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a failure determination comparing estimated yaw rate with detected yaw rate is used to determine sensor normal state, then the determination process is simple, but erroneous determination occurs on low friction coefficient roads where steering angles may cause false normal state indication
Solution Approach 1:
The determination process is segmented into multiple independent checks: first checking the difference between estimated and detected yaw rates, then separately checking the difference between detected and lateral G yaw rates. Both checks must pass for normal state determination, dividing the single complex determination into simpler, more reliable segments that reduce false positives on low friction roads
Solution Approach 2:
The lateral G yaw rate serves as an intermediary reference value to verify the detected yaw rate's validity. By introducing this intermediate calculation based on lateral acceleration and steering angle, the system gains an additional verification layer that acts as a mediator to confirm whether the detected yaw rate is reliable before determining sensor normal state
2Speed
If the system determines yaw rate sensor abnormality immediately upon detecting noise, then response speed is fast, but temporary noise may lead to erroneous abnormal state determination and improper vehicle control
Solution Approach 1:
The system performs preliminary verification by calculating the lateral G yaw rate and comparing it with the detected yaw rate before finalizing the abnormal state determination. This preliminary action of cross-checking with an independently calculated value helps filter out temporary noise that would otherwise trigger false abnormality alarms, ensuring more reliable determination
Solution Approach 2:
The system uses feedback from multiple sources (steering angle, lateral acceleration, and detected yaw rate) to continuously verify sensor status. The lateral G yaw rate calculation provides feedback that contradicts false abnormality signals caused by temporary noise, creating a feedback mechanism that corrects erroneous determinations before they affect vehicle control
Data Source
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AI summary
A normality detector includes a steering angle yaw rate calculator, a first difference calculator, a lateral G yaw rate calculator, a second difference calculator, and a normality determination section. The steering angle yaw rate calculator calculates a steering angle yaw rate. The first difference calculator calculates a first difference which is a difference between the steering angle yaw rate and an actual yaw rate. The lateral G yaw rate calculator calculates a lateral G yaw rate. The second difference calculator calculates a second difference which is a difference between the lateral G yaw rate and the actual yaw rate. The normality determination section determines that the yaw rate detector is in a normal state when the first difference falls within a first predetermined value and the second difference falls within a second predetermined value.