Motor Vehicle Slip Angle Estimation on Banked Roads
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Solution Overview
Problem
Current motor vehicle slip angle estimation techniques fail to accurately account for banked road surfaces, leading to inaccuracies due to sensor bias and noise.
Innovation Solution
A method to determine the slip angle of a motor vehicle by calculating multiple lateral velocities with and without consideration of the bank angle, using integrals of their derivatives, and adjusting these calculations based on thresholds for yaw rate, yaw acceleration, and steering angle to mitigate sensor errors and account for banked roads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current slip angle estimation techniques are used, then the estimation process is simple, but the accuracy deteriorates due to sensor bias and noise on banked roads
Solution Approach 1:
The estimation technique is segmented into multiple components: a first estimator that provides a baseline slip angle estimation, a bank angle detector that identifies road banking conditions, and a second estimator that provides corrections when banking is detected. This segmentation allows the system to maintain simplicity under normal conditions while improving accuracy when needed.
Solution Approach 2:
The system dynamically switches between estimation modes based on detected bank angle thresholds. When the bank angle exceeds a predetermined threshold, the system transitions from using only the first estimator to incorporating the second estimator, thereby adapting the complexity of the estimation process to the actual road conditions.
2Measurement precision
If multiple lateral velocities with bank angle consideration are calculated, then the slip angle estimation accuracy improves, but the computational complexity increases
Solution Approach 1:
The system performs partial correction by calculating multiple lateral velocities only when bank angle exceeds a threshold. Instead of continuously computing all correction terms, the system applies corrections selectively, reducing computational power consumption while maintaining accuracy when it matters most.
Solution Approach 2:
The system uses feedback from bank angle detection to control the computational process. When the detected bank angle exceeds a predetermined threshold, the feedback triggers the calculation of corrected lateral velocities using the second estimator, thereby optimizing computational resources based on actual road conditions.
3Ease of operation
If sensor data is used without bank angle compensation, then the processing is straightforward, but the slip angle estimation becomes inaccurate on banked roads
Solution Approach 1:
The system extracts the bank angle component from the overall vehicle dynamics and handles it separately through a dedicated bank angle detector and correction estimator. This extraction allows the main processing to remain straightforward while isolating the complex bank angle compensation to a specific module that activates only when needed.
Data Source
AI summary
A technique for determining a slip angle of a motor vehicle, while compensating for bank angle of the motor vehicle, includes a number of steps. Initially, a first lateral velocity of a motor vehicle is determined, without consideration of a bank angle and is derived from an integral of a first lateral velocity derivative (vy dot). A second lateral velocity of the motor vehicle is also determined, with consideration of the bank angle and is derived from an integral of a second lateral velocity derivative. A third lateral velocity of the motor vehicle is also determined, with consideration of the bank angle and the first and second lateral velocities and is derived from an integral of a third lateral velocity derivative. A longitudinal velocity of the motor vehicle is also determined. A slip angle of the motor vehicle is then determined, based upon the third lateral velocity and the longitudinal velocity or the first lateral velocity and the longitudinal velocity.