Dynamic Yaw Rate and Steering Angle Weighting for Turning Radius Estimation
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Solution Overview
Problem
Existing techniques for estimating a vehicle's travel trajectory using odometry information, such as yaw rate and steering angle sensors, face errors due to the sensors' responsiveness and accuracy issues, particularly during abrupt yaw rate changes caused by steering operations, sudden braking, or uneven road surfaces.
Innovation Solution
An estimating apparatus comprising an odometry acquiring unit, an estimate calculating unit, a change rate calculating unit, and a contribution adjusting unit, which adjusts the contribution of yaw rate and steering angle based on yaw rate changes to minimize errors, using the yaw rate for accurate detection at low speeds and the steering angle for responsive detection at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the yaw rate sensor is used for turning radius calculation, then detection accuracy is improved, but responsiveness deteriorates during abrupt yaw rate changes
Solution Approach 1:
The patent dynamically adjusts the contribution ratio between yaw rate sensor output and steering angle sensor output based on the absolute value of yaw rate. When yaw rate is high (abrupt changes), the steering angle sensor contribution is increased to improve responsiveness. When yaw rate is low (steady state), the yaw rate sensor contribution is increased to improve accuracy. This dynamic adjustment resolves the contradiction between accuracy and responsiveness.
2Speed
If the steering angle sensor is used for turning radius calculation, then responsiveness is improved, but measurement accuracy deteriorates due to tire skid errors
Solution Approach 1:
The patent dynamically adjusts the contribution ratio between yaw rate sensor output and steering angle sensor output based on the absolute value of yaw rate. When yaw rate is high (abrupt changes), the steering angle sensor contribution is increased to improve responsiveness. When yaw rate is low (steady state), the yaw rate sensor contribution is increased to improve accuracy. This dynamic adjustment resolves the contradiction between accuracy and responsiveness.
3Reliability
If switching between yaw rate sensor and steering angle sensor is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the outputs of both yaw rate sensor and steering angle sensor through a contribution ratio adjustment mechanism. Instead of simple switching, it combines both sensor signals with dynamically adjusted weights based on yaw rate magnitude. This approach maintains reliability by utilizing both sensors while managing complexity through a unified calculation framework.
Data Source
AI summary
An odometry acquiring unit acquires odometry information including a yaw rate applied to a vehicle and a steering angle of the vehicle. An estimate calculating unit calculates an estimate of a turning radius based on the steering angle and the yaw rate acquired by the odometry acquiring unit. A change rate calculating unit calculates a yaw change rate representing a degree of change in the yaw rate acquired by the odometry acquiring unit. A contribution adjusting unit makes an adjustment of decreasing a contribution of the yaw rate and increasing a contribution of the steering angle, to calculation of an estimate performed by the estimate calculating unit, as the yaw change rate increases.