Excavator Arm Position Detection Using Fisheye Image Correction

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Solution Overview

Problem

Conventional construction machines struggle to accurately detect the position of the coupling between the second and third working units due to factors such as the coupling moving out of the image capturing region or being obscured, leading to coarse image data.

Innovation Solution

A working machine equipped with an image capturing unit using a fisheye lens to capture images of a protruding end of the second working unit, combined with a position detecting unit that performs projective transformation and distortion correction to estimate angles and positions, allowing precise detection of the coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional camera captures images of the third working unit (bucket), then the position detection is attempted, but the coupling position cannot be accurately detected when the bucket moves away from the working machine body

Engineering Contradiction:

Improveposition detection accuracyVSAvoiddetection coverage range

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

Instead of capturing images of the third working unit (bucket) to detect its position, the invention inverts the approach by capturing images of the second working unit (arm) to detect the position of the coupling between the second and third working units. This inversion allows the image capturing unit to reliably detect the coupling position even when the bucket moves away from the working machine body, as the arm remains within the image capturing region.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If the image capturing unit tries to capture the coupling between second and third working units, then position detection is attempted, but the coupling moves out of the image capturing region

Engineering Contradiction:

Improvecoupling position detection accuracyVSAvoidimage capturing region

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The invention uses the second working unit (arm) as an intermediary object to detect the position of the coupling between the second and third working units. By capturing images of the arm, which remains within the image capturing region, the system can indirectly but accurately determine the coupling position through image processing, avoiding the problem of the coupling moving out of the capture region.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the third working unit moves away or gets obscured, then conventional detection fails, but the invention maintains detection capability

Engineering Contradiction:

Improvedetection reliabilityVSAvoidobscuration and distance effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention performs preliminary detection by capturing images of the second working unit (arm) before the third working unit (bucket) moves away or gets obscured. By detecting the coupling position based on the arm's position and orientation, the system proactively maintains detection reliability even when the bucket subsequently moves out of range or becomes obscured by terrain or other objects.

Inventive Principle:

Principle #10Preliminary action

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

Accurate detection of the coupling position is achieved even when the third working unit moves away or is obscured, using a fisheye lens and projective transformation to enhance image clarity and precision.

Implementation Method 1

an image capturing unit using a fisheye lens to capture images of a protruding end of the second working unit

Methodology Applied

Scientific EffectFisheye lens wide-angle capture: Lens

Implementation Method 2

a position detecting unit that performs projective transformation and distortion correction to estimate angles and positions

Methodology Applied

Scientific EffectProjective transformation:

Data Source

PatentUS12559917B2Working machine and position detecting device

Publication Date: 2026.02.24 COMTESCO CORP

AI summary

A working machine includes: a working machine body; a first working unit (boom) having one end connected to the working machine body, and configured to be displaced relative to the working machine body; a second working unit (arm) connected to another end of the first working unit via a link; a third working unit (bucket) connected to the second working unit via a link; an image capturing unit provided on the working machine body, and configured to capture an image of one end of the second working unit that is located near the first working unit; and a position detecting unit configured to detect a position of another end of the second working unit that is located near the third working unit based on the image captured by the image capturing unit.