Slewing Axis Position Identification Using Reflector Tracking

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Solution Overview

Problem

Existing position measurement systems for work machines, such as those using GNSS and total stations, suffer from accuracy issues and limited versatility due to environmental interference and high costs, restricting their use in various scenarios.

Innovation Solution

A position identification system that utilizes a position information detector, such as a three-dimensional camera or LiDAR, to track the slewing axis of a work machine's upper slewing body, identifying its position by analyzing the movement of a specific part, like a reflector or the arm, to determine the slewing axis accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GNSS is used for position measurement, then position information can be obtained, but measurement accuracy decreases in certain environments such as inside tunnels, near high-voltage wires, or in mountain valleys

Engineering Contradiction:
Improveposition measurement accuracyVSAvoiduse scene limitation
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The position identification system divides the measurement task into two independent parts: (1) detecting the position of a specific part on the work machine using a position information detector, and (2) calculating the slewing axis position based on detected position information and slewing angle information. This segmentation allows the system to use simple detectors without requiring complex infrastructure like GNSS satellites or total stations, thereby improving both measurement accuracy and environmental adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system introduces a reflector as an intermediary object attached to the work machine. The reflector serves as a visible target for the position information detector, enabling accurate position detection without direct detection of the work machine itself. This intermediary approach allows the use of simple optical detectors instead of complex measurement systems, resolving the contradiction between measurement accuracy and environmental versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a total station with automatic tracking function is used for position detection, then position identification can be achieved, but the facility cost becomes expensive

Engineering Contradiction:
Improveposition detection accuracyVSAvoidfacility cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system replaces expensive total station equipment with inexpensive components: a simple position information detector (such as a camera or optical sensor), a reflector, and a work machine equipped with sensors. The detector captures position information of the reflector, and the controller calculates the slewing axis position through coordinate transformation. This substitution of expensive infrastructure with cheap components directly addresses the cost issue while maintaining measurement accuracy.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system replaces the mechanical/optical total station system with an electronic computing system. Instead of using a total station to directly measure the work machine position, the system uses a position information detector to capture images or data, then uses a controller to perform coordinate transformation calculations based on detected position information and slewing angle information. This substitution of mechanical measurement systems with electronic computation reduces facility costs while maintaining or improving measurement accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If simple position detectors are used, then cost is reduced, but position measurement accuracy may be insufficient

Engineering Contradiction:
Improvedetector costVSAvoidposition measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the measurement approach by using the work machine's slewing motion itself as part of the measurement process. The controller detects position information of a specific part at multiple different slewing angles, then uses the change in position information across these dynamic states to calculate the slewing axis position. This dynamic measurement approach allows simple detectors to achieve high accuracy by leveraging the work machine's own motion rather than requiring the detector to maintain extremely high precision at a single static position.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback mechanism where the controller uses detected position information combined with sleving angle information to iteratively calculate and refine the slewing axis position. The process involves detecting position at multiple angles, performing coordinate transformations, and using the relationship between position changes and angle changes to determine the axis location. This feedback-based calculation approach compensates for the limited precision of simple detectors by using multiple measurements and mathematical processing to achieve high overall accuracy.

Inventive Principle:
Principle #23Feedback

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

Enhances the versatility and accuracy of position identification for work machines by using simple, cost-effective detectors, enabling precise positioning even in challenging environments.

Implementation Method 1

a position information detector 53 and a controller 52. The controller 52 identifies a position of a slewing axis AX by using slewing information that is information acquired by the position information detector 53 when the upper slewing body 2 is slewing

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4692475A1Position identification system, position identification device, and position identification method
Publication Date: 2026.02.11 KOBELCO CONSTR MASCH CO LTD
  • EP4692475A1 patent drawingFigure 1
  • EP4692475A1 patent drawingFigure 2
  • EP4692475A1 patent drawingFigure 3

AI summary

A position identification system (50) includes a position information detector (53), and a controller (52) that identifies the position of a slewing axis (AX) of an upper slewing body (2) of a work machine (100) by using slewing information that is information acquired by the position information detector (53) when the upper slewing body (2) is slewing. The slewing information includes specific part position information that is information regarding the position of a specific part (5, 60) of the work machine (100), the specific part rotating about the slewing axis (AX) along with the slewing of the upper slewing body (2).