Tow Ball Position Detection Using Movable Rear Camera Triangulation

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Solution Overview

Problem

Existing systems lack an accurate method for estimating the position of a tow ball, which is crucial for automated trailer assist functions due to varying sizes and adjustable heights of tow balls on vehicles.

Innovation Solution

A method and system using a rear camera mounted on a movable vehicle component, such as a tailgate or trunk, capture multiple images from different positions to determine the tow ball's position by correlating changes in camera and pixel positions, enabling precise estimation through triangulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single camera position is used to detect tow ball position, then the system is simple, but the measurement precision is insufficient due to varying tow ball sizes and heights

Engineering Contradiction:
Improvetow ball position estimation accuracyVSAvoidcamera positioning system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from a single 2D camera view to a multi-view 3D spatial arrangement by mounting cameras at different positions (e.g., rear bumper and tailgate). This dimensional change enables triangulation of the tow ball position, resolving the ambiguity caused by varying tow ball sizes and heights that cannot be distinguished from distance changes in a single view.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The detection system is segmented into multiple independent camera units positioned at different locations on the vehicle. Each camera captures images from its specific viewpoint, and the system processes these segmented views separately before integrating them through triangulation algorithms to achieve precise 3D position estimation.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If multiple camera positions are used to improve measurement precision, then tow ball position detection accuracy improves, but the device complexity increases

Engineering Contradiction:
Improvetow ball position detection accuracyVSAvoidmulti-camera system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the rear camera multi-functional by enabling it to operate in different positions (rear bumper and tailgate) that serve dual purposes: standard rearview monitoring and specialized tow ball position detection. This eliminates the need for dedicated separate cameras, reducing overall system complexity while maintaining measurement precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically adjusts camera mounting positions based on operational needs. The rear camera can be relocated between the rear bumper and tailgate depending on whether the vehicle is in towing mode or normal operation, allowing the system to adapt its complexity to actual requirements rather than maintaining fixed high complexity continuously.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Automates the calibration process, reducing human error and providing accurate tow ball position data for enhanced trailer assist operations.

Implementation Method 1

The controller estimates the position of the tow ball using the two images and the two pixel positions

Methodology Applied
Scientific EffectTriangulation: Parallax

Data Source

PatentEP4210973B1Tow ball position detection system and method
Publication Date: 2025.11.05 AUMOVIO AUTONOMOUS MOBILITY US LLC
  • EP4210973B1 patent drawingFigure 1
  • EP4210973B1 patent drawingFigure 2
  • EP4210973B1 patent drawingFigure 3

AI summary

A method and system are disclosed for performing a trailer operation for a vehicle having a tow ball. The method includes receiving a first image from a rear camera disposed along a rear portion of the vehicle in a first position; and detecting a pixel position of a representation of the tow ball in the first image. Following the rear camera being moved from the first position to a second position along the rear portion of the vehicle, the method includes receiving a second image from the rear camera. The method also includes detecting a second pixel position of a representation of the tow ball in the second image; and estimating a position of the tow ball relative to the vehicle based on the first and second positions of the rear camera and the detected pixel positions of the representations of the tow ball in the first and second images.