Work Machine Sensor Segmentation for Obstacle Detection

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Solution Overview

Problem

Existing work machine detection systems struggle to recognize non-retroreflective materials and obstacles below the upper swing structure, limiting their detection range and ability to restrict operations effectively.

Innovation Solution

A work machine equipped with sensors that distinguish retroreflective materials from other objects, with a detection range extending above the lower track structure, allowing the controller to restrict actuator operations based on the type and location of detected objects, ensuring safe operation without reducing the detection range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the detection range is extended to include areas below the upper swing structure, then the detection capability for workers and obstacles is improved, but the lower track structure may be falsely detected as an object

Engineering Contradiction:
Improvedetection capabilityVSAvoidfalse detection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The detection range is segmented into a first detection region (below the upper swing structure) and a second detection region (above the lower track structure). The controller applies different detection logic to each region: in the first region, only retroreflective materials trigger operation restriction, while in the second region, all objects trigger restriction. This segmentation resolves the contradiction by allowing extended detection without false positives from the track structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different detection characteristics are applied to different spatial zones. The first detection region uses selective detection (only retroreflective materials), while the second detection region uses comprehensive detection (all objects). This local differentiation allows the system to maintain high detection precision across the extended range while avoiding false detections of the lower track structure.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If laser light is applied in a scanning manner to detect reflected light, then retroreflective materials can be detected, but other materials and obstacles without retroreflective material cannot be recognized

Engineering Contradiction:
Improveretroreflective material detectionVSAvoiddetection coverage
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system adds a spatial dimension to detection by creating two vertically separated detection regions. The laser scanning method maintains its effectiveness for retroreflective materials in the first region, while the second region above the track structure provides additional coverage for other objects. This dimensional approach allows the system to maintain specialized detection precision while expanding overall detection versatility.

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

3Reliability

If the detection range is restricted by the gap between upper swing structure and lower track structure, then the lower track structure can be excluded from detection, but workers or obstacles below the lower surface cannot be detected

Engineering Contradiction:
Improvestructure exclusionVSAvoiddetection range
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The detection space is segmented into two regions with the lower track structure located between them. The first detection region extends below the upper swing structure to detect workers and obstacles, while the second detection region extends above the lower track structure. This segmentation allows the system to detect objects in both zones while the controller distinguishes the track structure from actual targets based on its known position between the two regions.

Inventive Principle:
Principle #1Segmentation

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

The system effectively prevents contact with obstacles while maintaining a comprehensive detection range, enabling suitable operation restriction and enhancing safety by accurately identifying retroreflective materials and other objects.

Implementation Method 1

a surrounding monitor device that applies laser light in a scanning manner from the work vehicle toward the monitor region, receives laser light reflected by the regressive reflection material, and detects the presence of the worker based on a light reception level. The regressive reflection material includes a cube corner reflector in which a multiplicity of cube corner prisms are arranged.

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 2

receives laser light reflected by the regressive reflection material

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3922777B1Work machine
Publication Date: 2025.03.26 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3922777B1 patent drawingFigure 1~2
  • EP3922777B1 patent drawingFigure 3
  • EP3922777B1 patent drawingFigure 4

AI summary

A work machine includes a sensor capable of detecting a retroreflective material and other objects in a distinguishable manner, a solenoid valve that restricts an operation signal outputted from an operation device, and a controller configured to control the solenoid valve based on a detection result of the sensor. The controller is configured to control the solenoid valve based on information concerning whether or not the object detected by the sensor is a retroreflective material and information concerning whether a position of the object detected by the sensor is in a first detection region at least partially including an operation range of a machine body or a second detection region located adjacent to and above the first detection region. This makes it possible to restrain a contact between the work machine and an obstacle while restraining a reduction in a detection range due to exclusion of a structure of the work machine from an object of detection.