Vehicle Road Bank Angle Detection via Slip Angle Difference
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Solution Overview
Problem
Existing systems fail to accurately detect road bank angle and lateral acceleration, leading to false positives and negatives in vehicle control systems, especially on icy or snowy roads, due to accelerometer measurements being affected by road bank.
Innovation Solution
A vehicle control system incorporating a mapping sensor for course angle, yaw rate sensor, accelerometer, speedometer, and a processor to determine road bank angle by calculating slip angle differences, correcting for the impact of road bank on lateral acceleration measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If accelerometer measurements are used to determine lateral acceleration, then vehicle control can be implemented, but measurement precision deteriorates due to road bank effects causing false positives and false negatives
Solution Approach 1:
The patent introduces mapping sensors (GPS/GLONASS) and yaw rate sensors as intermediary devices to measure course angle and yaw rate independently of the accelerometer. These sensors serve as mediators to detect road bank angle through slip angle difference calculations, bypassing the inaccurate accelerometer measurements on banked roads. The intermediary sensors provide clean reference data that is not corrupted by road bank effects.
Solution Approach 2:
The patent replaces the mechanical accelerometer-based lateral acceleration measurement system with an alternative approach using mapping sensors and yaw rate sensors combined with computational algorithms. Instead of relying on the physical accelerometer that is directly affected by road bank gravity components, the system uses positional data from mapping sensors and rotational data from yaw rate sensors to compute slip angle differences, thereby substituting the flawed mechanical measurement system with a computational one that is immune to road bank effects.
2Measurement precision
If traditional road bank detection methods are used, then system complexity is reduced, but measurement precision deteriorates due to inability to accurately distinguish road bank from lateral acceleration
Solution Approach 1:
The patent makes existing sensors multi-functional by using mapping sensors not only for navigation and positioning but also for road bank detection through course angle measurement. Yaw rate sensors are used both for vehicle stability control and for road bank angle detection. This multi-functionality allows the system to achieve accurate road bank detection without adding dedicated specialized sensors, thereby limiting the increase in system complexity while improving measurement precision.
Solution Approach 2:
The patent uses mapping sensors and yaw rate sensors as intermediary devices to indirectly measure road bank angle through slip angle difference calculations, rather than using direct but inaccurate accelerometer-based methods. These intermediary sensors provide reference data that, when processed through specific algorithms, yield accurate road bank angle measurements without requiring complex additional hardware.
3Reliability
If accelerometer data is used without correction, then system complexity is minimized, but reliability deteriorates due to false positives and false negatives in road bank identification
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously compares the slip angle difference (derived from mapping sensor course angle and yaw rate sensor data) with the expected behavior on flat ground. When a discrepancy is detected, the system calculates and applies a correction to the lateral acceleration measurement. This feedback loop ensures that road bank effects are systematically compensated for, improving reliability without requiring overly complex processing.
Solution Approach 2:
The patent performs preliminary calculations of slip angle difference using mapping sensor and yaw rate sensor data before final road bank identification and lateral acceleration correction. By pre-computing the slip angle difference and comparing it against thresholds, the system prepares correction factors in advance, which are then applied to improve the accuracy of road bank detection and lateral acceleration measurement, reducing false positives and negatives.
Data Source
AI summary
Systems and methods for detecting road bank and determining road bank angle include determining a road bank angle as a function of difference in slip angle where the difference in slip angle is a function of difference in course angle and difference in yaw angle.