Camera-Based Hitch Angle Detection for Varied Drawbar Shapes
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Solution Overview
Problem
Existing techniques for detecting a trailer hitch angle are limited by their reliance on specific equipment and calibration, and are not versatile enough to handle various drawbar shapes, making them complex and impractical for widespread use.
Innovation Solution
A hitch angle detection system utilizing a camera on the tractor to capture images of the trailer, with a left-right direction calculator and hitch angle calculator to determine the hitch angle relative to the tractor's direction, allowing for detection without special equipment and adaptable to different drawbar shapes by using a marker on the trailer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a technique for detecting a hitch angle based on a straight line recognized from an image of a coupled portion is used, then the detection can be performed without special equipment, but it cannot detect the hitch angle correctly when the drawbar has various shapes such as a straight line shape or a Y-letter shape
Solution Approach 1:
The patent introduces a marker as an intermediary element attached to the drawbar. This marker serves as a mediator between the camera system and the drawbar structure, providing a standardized visual reference that can be reliably detected regardless of the drawbar's shape. The marker translates the complex problem of recognizing various drawbar geometries into a simpler problem of detecting a known marker pattern.
Solution Approach 2:
The patent changes the detection parameter from recognizing drawbar geometric features (which vary by shape) to detecting marker characteristics (which remain constant). By transforming the detection target from the drawbar itself to a standardized marker attached to it, the system achieves consistent detection accuracy across different drawbar configurations.
2Measurement precision
If a technique for detecting a hitch angle using a laser range finder is used, then the hitch angle can be detected with high precision, but it requires special equipment such as a marker, a laser range finder, and separate calibration for each
Solution Approach 1:
The patent replaces the active laser range finder system with a passive optical camera system. Instead of using laser beams to actively measure distances, the system uses a camera to capture images and computationally determine the hitch angle from the captured visual information. This substitution eliminates the need for laser equipment and complex calibration procedures while maintaining detection capability.
Solution Approach 2:
The patent uses a camera to create a visual copy or image of the drawbar and marker configuration. By capturing the spatial relationship in an image and analyzing it computationally, the system determines the hitch angle without requiring physical laser measurement equipment. The image serves as a digital replica that contains all necessary geometric information.
3Device complexity
If a technique for detecting a hitch angle using a marker pasted on the upper surface of a drawbar is used, then the detection can be performed with a simple camera system, but it is not applicable when the shape of the drawbar or the upper surface of the drawbar is not suitable for a marker to be pasted
Solution Approach 1:
The patent enhances the universality of the detection system by making the marker placement flexible rather than restrictive. The system can detect hitch angles regardless of drawbar shape by accommodating different marker placement scenarios, making the solution applicable to a wide variety of drawbar configurations including straight line shapes, Y-letter shapes, and other geometries.
Data Source
AI summary
A hitch angle detection system to detect a trailer hitch angle with a simple, versatile configuration is provided. Edge detection is performed in a portion including an image of a rear bumper of a tractor and an image of a front bumper of a trailer, the portion being included in an image captured by a rear camera, to extract an edge of the tractor rear bumper image and an edge of the trailer front bumper image. A straight line with which the edge of the rear bumper image is best approximated is calculated as a straight line parallel with the tractor left-right direction. A straight line with which the edge of the trailer front bumper image is best approximated is calculated as a straight line parallel with the trailer left-right direction. The relative angle of the straight line to the straight line is calculated as the trailer hitch angle.