Hydraulic Excavator Bucket Control Near a Variable Target Surface

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Solution Overview

Problem

Existing hydraulic excavator systems face challenges in operating the front work implement at a speed that aligns with operator lever operations while maintaining work accuracy, as the accuracy priority mode restricts speed and the speed priority mode allows faster operation but with potential increased penetration outside the set area.

Innovation Solution

A work machine with a controller that sets a speed correction region above the target surface, varying its width based on the operation device's input, ensuring the work tool does not penetrate into this region, allowing for speed-adjusted operation while maintaining accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If accuracy priority mode is selected to suppress penetration of bucket tip outside set area, then manufacturing precision is improved, but speed of front work implement is reduced

Engineering Contradiction:
Improvework accuracyVSAvoidimplement speed
Core Design Contradiction:
Manufacturing precisionVSSpeed

Solution Approach 1:

The control system dynamically adjusts the width of the speed correction region based on the operation amount of the operation device. When the operation amount is large (operator requests high speed), the speed correction region width is increased, allowing faster movement while still preventing penetration. When operation amount is small, the region width is reduced, enabling higher precision work. This dynamic adjustment resolves the contradiction by making the system adaptable to different operational requirements.

Inventive Principle:
Principle #15Dynamics

2Productivity

If speed priority mode is selected to operate front work implement at high speed, then productivity is improved, but penetration of bucket tip outside set area is enlarged

Engineering Contradiction:
Improvework speedVSAvoidwork accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system changes the parameter of speed correction region width based on the operation amount. By varying this parameter, the system allows high-speed operation when needed while maintaining precision boundaries. The width parameter is specifically adjusted to balance speed and accuracy requirements, enabling productivity improvement without sacrificing work accuracy.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If fixed width speed correction region is used, then device complexity is reduced, but adaptability to different operation amounts is reduced

Engineering Contradiction:
Improvecontrol system complexityVSAvoidadaptability to operation amount
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The speed correction region width is made dynamic rather than fixed, adjusting automatically according to the operation amount detected from the operation device. This dynamic characteristic provides high adaptability to different operational scenarios without requiring complex manual intervention or multiple fixed configurations, achieving a balance between complexity and versatility.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3683365B1Work machinery
Publication Date: 2023.07.19 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3683365B1 patent drawingFigure 1
  • EP3683365B1 patent drawingFigure 2
  • EP3683365B1 patent drawingFigure 3

AI summary

Provided is a work machine that can operate a front work implement at a speed according to an operator's lever operation while securing the accuracy of work by machine control. A hydraulic excavator 1 includes a controller 20 that sets a target surface for a bucket 10 and controls the operation of a front work implement 1B in such a manner that the bucket does not penetrate to below the target surface. The controller sets a speed correction region on an upper side of the target surface, varies a width R of the speed correction region in accordance with an operation amount of an operation device 15A or 15C, and controls the operation of the front work implement in such a manner that the work tool does not penetrate into the speed correction region.