Vehicle Slip Angle Estimation via Camera Vanishing Point
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Solution Overview
Problem
Existing slip angle estimation devices for vehicles fail to accurately calculate the slip angle when traveling on lateral inclination roads due to lateral forces affecting lateral acceleration detection.
Innovation Solution
A slip angle estimation device using an imaging device to capture images of the vehicle's front or rear, determining tracking points, optical flows, and a vanishing point to calculate the slip angle based on horizontal distances, which is not affected by lateral road inclinations, along with a control unit to manage reference frames and calculate slip angles using motion state quantities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lateral acceleration sensor is used to detect lateral acceleration for slip angle calculation, then the slip angle can be estimated under normal road conditions, but the detection accuracy deteriorates when the vehicle travels on a lateral inclination road due to lateral forces acting on the inertia weight
Solution Approach 1:
The patent extracts the harmful lateral force component from the acceleration sensor output by detecting road inclination angle with a separate inclination sensor, and removes this extracted component from the lateral acceleration signal to obtain corrected acceleration data that is not affected by road inclination
Solution Approach 2:
The patent introduces an inclination sensor as an intermediary device to detect road inclination angle, which then serves as a correction parameter to compensate the lateral acceleration sensor output, thereby eliminating the harmful effect of road inclination on slip angle calculation
2Measurement precision
If an imaging device is used to calculate slip angle based on vanishing point detection, then accurate slip angle estimation is achieved on lateral inclination roads, but the device complexity increases due to additional imaging components and image processing requirements
Solution Approach 1:
The patent uses the vanishing point in the captured image as an intermediary geometric feature that indirectly indicates the vehicle's slip angle, allowing accurate measurement without directly measuring the slip angle itself
Solution Approach 2:
The patent replaces the traditional mechanical/inertial measurement approach with an optical imaging approach, using camera-based vanishing point detection to determine slip angle, thereby avoiding the harmful effects of lateral forces on inertial sensors
Data Source
AI summary
A slip angle estimation device for a vehicle comprises an imaging device for capturing an image of at least one of the front and the rear of the vehicle and a control unit. The imaging device is a CCD camera including a lens and an imaging sensor. The control unit is configured to determine a plurality of tracking points for a plurality of captured objects, determine an optical flow for the plurality of tracking points based on two images captured at predetermined elapsed time intervals, determine a vanishing point based on intersections of the plurality of optical flows, and calculate a slip angle of the vehicle based on a ratio of a horizontal distance between an image center and the vanishing point to a distance between a lens center of the CCD camera and an imaging sensor.