In-Vehicle Road Plane Estimation for Pitch and Roll Correction
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Solution Overview
Problem
Existing vehicle position estimation techniques fail to accurately account for pitch and roll angles when traveling on slopes or roads with cross slopes, leading to incorrect feature association and increased calculation load, and often suffer from sensitivity errors in Inertial Measurement Units (IMUs).
Innovation Solution
An information processing device that calculates a normal vector of an approximate road plane from map data and uses this to determine the pitch and roll angles of the vehicle, allowing for accurate position estimation by transforming measurement data accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pitch angle and roll angle are added as estimation parameters to cope with slopes and cross slopes, then the accuracy of vehicle posture estimation is improved, but the calculation load increases and the estimation may not stably terminate within the required time cycle
Solution Approach 1:
The patent extracts the pitch and roll angle calculations from the main self-position estimation process. By calculating these angles separately using the normal vector method from map data and measurement data, rather than including them as full estimation parameters in the optimization loop, the calculation load of the main estimation algorithm is reduced while still achieving accurate posture estimation.
Solution Approach 2:
The patent performs preliminary calculation of pitch and roll angles using the normal vector method before executing the main self-position estimation. This preliminary action provides accurate initial values for the estimation process, enabling faster convergence and stable termination within the required time cycle while maintaining high accuracy.
2Productivity
If pitch angle and roll angle are determined from IMU data, then the calculation speed is improved, but the accuracy of angle calculation deteriorates due to sensitivity error and offset in common IMUs
Solution Approach 1:
The patent introduces the normal vector calculated from map data and measurement data as an intermediary to determine pitch and roll angles. Instead of directly using IMU data which contains errors, the normal vector serves as a mediator that provides accurate reference information for angle calculation, combining the benefits of both IMU speed and map-based accuracy.
Solution Approach 2:
The patent replaces the mechanical sensor-based angle measurement (IMU) with a geometric calculation method based on normal vectors derived from map data and measurement data. This substitution eliminates sensitivity errors and offset issues inherent in mechanical sensors while maintaining calculation efficiency.
Data Source
AI summary
A control unit 15 of an in-vehicle device 1 configured to acquire, from landmark data LD that is map data including position information of one or more features, plural pieces of position information of a feature which is drawn on a road surface and which exists at or around a vehicle. Then, the control unit 15 is configured to calculate a normal vector of an approximate plane calculated based on the acquired plural pieces of the position information. Then, the control unit 15 is configured to calculate at least one of a pitch angle or a roll angle of the vehicle based on the orientation of the vehicle and the normal vector.