Yaw Rate Sensor Zero-Point Correction on Straight Roads
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Solution Overview
Problem
Existing sensor output correction methods, such as those described in Japanese Patent First Publication No. 2010-107244, have limited opportunities to sample and update correction values, leading to a risk that the correction value for zero-point deviation differs from the actual deviation, especially due to ambient temperature variations and limited operational conditions like vehicle ignition states.
Innovation Solution
A sensor output correction apparatus that includes a detected value acquisition portion, a curvature determining portion, and a zero-point determination portion to determine a zero-point equivalent value based on sensor data when the vehicle is moving on a straight road, allowing for continuous correction value updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the correction value is calculated using sensor detected values only during door opening/closing intervals, then the correction value can be obtained, but the sampling opportunities are limited and the correction value may not reflect the actual zero-point deviation under varying temperature conditions
Solution Approach 1:
The patent changes the sampling condition from a static, limited window (door opening/closing) to a dynamic, continuous sampling process during vehicle operation. The system now updates correction values whenever the vehicle is moving, allowing frequent updates that adapt to changing temperature conditions while maintaining correction accuracy.
Solution Approach 2:
The patent performs preliminary filtering of sensor data by identifying straight road sections before calculating correction values. This preliminary action ensures that only reliable data from straight road conditions is used, improving the accuracy of the correction value while enabling more frequent updates compared to the previous door-based sampling method.
2Reliability
If the correction value is updated frequently during vehicle operation, then the correction value reflects current temperature conditions, but additional sampling conditions and processing are required
Solution Approach 1:
The patent makes the existing sensor system multi-functional by using it for both original detection purposes and correction value calculation. The same sensors that detect vehicle motion and position are also used to identify straight road sections and trigger correction updates, eliminating the need for separate sampling hardware and reducing system complexity.
Solution Approach 2:
The system uses its own operational data (vehicle motion, position changes) to automatically determine when to update correction values. The vehicle's own movement patterns during straight road sections trigger the correction process, making the system self-regulating without requiring external control inputs or additional monitoring complexity.
Data Source
AI summary
A sensor output correction system is provided which is capable of minimizing a risk that a correction value for use in zero-point correction differs from an actual deviation of a zero-point. An ECU includes a travel road information acquisition portion which obtains a curvature of a travel road on which a system-mounted vehicle is traveling and a vehicle information acquisition portion which obtains a detected value of a yaw rate sensor. The ECU determines whether the system-mounted vehicle is traveling on a straight path or not based on the curvature derived by the travel road information acquisition portion. The ECU determines a value (i.e., a zero-point equivalent value) which corresponds to a deviation of a current zero point of the yaw rate sensor based on detected values of the yaw rate sensor sampled while the system-mounted vehicle is moving on the straight path. The ECU determines a correction value which is subtracted from the detected value using the zero-point equivalent value.