Excavator Work Tool Boundary Setting for Obstacle Avoidance

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Solution Overview

Problem

Existing systems for setting entry-prohibited areas in work machines, such as hydraulic excavators, struggle to accurately align the boundary surface with obstacles when the upper swing structure is not facing the wall surface, leading to potential collisions.

Innovation Solution

A work machine with a controller that allows flexible setting of an entry-prohibited area by selecting reference points on the work tool, such as the bucket, to define a perpendicular plane to the ground contact surface, ensuring precise avoidance of obstacles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple separate control units are used for different work tools, then each tool can be controlled independently, but the overall system complexity increases and integration becomes difficult

Engineering Contradiction:
Improvecontrol flexibilityVSAvoidsystem integration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple control units into a single integrated control unit that can manage multiple work tools simultaneously. This integration reduces system complexity while maintaining the ability to independently control each tool through a unified control interface and centralized processing logic.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control unit is designed with multi-functional capabilities to handle various work tools through standardized interfaces and adaptive control algorithms. This universal design allows the same control unit to perform multiple functions across different tool types without requiring separate dedicated controllers for each tool.

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

2Reliability

If work tools are disposed of after hydraulic fluid contamination, then contamination spread is prevented, but resource waste occurs and costs increase

Engineering Contradiction:
Improvehydraulic system cleanlinessVSAvoidtool disposal
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The system extracts and isolates contaminated hydraulic fluid from the work tools by implementing separate fluid circuits or isolation valves for each tool. This allows the tool to be disconnected from the main hydraulic system while retaining its contaminated fluid, preventing spread to other tools while enabling independent cleaning or disposal of only the contaminated fluid.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary cleaning system or fluid handling mechanism that mediates between the work tools and the hydraulic fluid management. This intermediary allows contaminated tools to be cleaned or have their fluid replaced without affecting other tools, thereby extending tool life and reducing disposal requirements while maintaining system reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If hydraulic fluid is shared among multiple work tools, then system simplicity is maintained, but contamination can spread between tools

Engineering Contradiction:
Improvefluid system structureVSAvoidcontamination spread
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The hydraulic fluid system is segmented into separate circuits or isolated zones for each work tool, with individual fluid pathways and containment boundaries. This segmentation prevents contamination from spreading between tools while maintaining relatively simple system architecture through modular design and standardized connection points.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4187022B1Work machine
Publication Date: 2026.04.29 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP4187022B1 patent drawingFigure 1
  • EP4187022B1 patent drawingFigure 2
  • EP4187022B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a work machine that is capable of flexibly setting an entry-prohibited area for a work device according to an operator's intention. To achieve this, a controller 40 sets, as a first position, the position of a work tool 8 that is located when a setting switch 33 is operated, and sets, as a second position, the position of the work tool 8 that is located when the setting switch 33 is operated after the setting of the first position. Further, the controller 40 sets, as a boundary surface of an entry-prohibited area, a plane 70 that passes through a first reference point A and a second reference point B and that is perpendicular to a ground contact surface of a lower track structure 1. The first reference point A is one of a plurality of reference points 8L and 8R on the work tool 8 located at the first position, the plurality of reference points 8L and 8R being preset on the work tool 8. The second reference point B is one of the plurality of reference points 8L and 8R on the work tool 8 located at the second position.