Wheel Loader Bucket Control for Multi-Pattern Excavation

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Solution Overview

Problem

Conventional automatic control systems for work vehicles like wheel loaders are limited to a single excavation pattern, failing to efficiently excavate with various patterns and appropriate fuel efficiency regardless of the operator's skill level.

Innovation Solution

A work vehicle equipped with sensors to detect acceleration, lift, and tilt amounts, controlled by a controller that adjusts the lift and tilt operations based on specific conditions to execute multiple excavation patterns efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If conventional automatic control ends tilt and lift operations based on predetermined lift force increase, then single excavation pattern can be executed automatically, but various excavation patterns cannot be executed automatically

Engineering Contradiction:
Improveautomatic execution of excavation patternsVSAvoidvariety of excavation patterns
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The control system dynamically switches between different excavation patterns (deep penetration, medium penetration, shallow penetration) based on real-time detection of acceleration, lift amount, and tilt amount. The controller adjusts control parameters and operation sequences adaptively during the excavation process, transforming the static single-pattern control into a dynamic multi-pattern system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes control parameters (acceleration thresholds, lift amount thresholds, tilt amount thresholds) to execute different excavation patterns. By modifying these parameters, the same control system can adapt to various excavation requirements without hardware changes, resolving the contradiction between automation and versatility.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If fixed single excavation pattern is used, then control system is simple, but fuel efficiency and excavation effectiveness vary for different objects

Engineering Contradiction:
Improvecontrol system complexityVSAvoidexcavation efficiency and fuel efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The excavation process is segmented into distinct phases (insertion period with negative acceleration, lift period with positive acceleration, deceleration period) with specific control strategies for each phase. This segmentation allows the system to optimize control for each phase while maintaining overall system manageability, improving productivity without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system continuously monitors acceleration, lift amount, and tilt amount, using this feedback to adjust operations in real-time. This feedback mechanism enables automatic adaptation to different excavation conditions and patterns, significantly improving excavation efficiency and fuel efficiency compared to fixed-pattern control.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4187020B1Work vehicle
Publication Date: 2026.04.01 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP4187020B1 patent drawingFigure 1
  • EP4187020B1 patent drawingFigure 2
  • EP4187020B1 patent drawingFigure 3

AI summary

Provided is a work vehicle capable of excavating an excavation object efficiently and in various excavation patterns with appropriate fuel efficiency, regardless of the operator's skill level. The work vehicle includes a controller. The controller executes control including insertion control, acceleration control, and deceleration control. The insertion control keeps the tilt amount (stroke amount S2) of the bucket and increases the lift amount (stroke amount S1) of the lift arm in the insertion period Ph1 from the timing when the work vehicle meets an entry condition for object, where the acceleration α of the vehicle becomes negative, to the timing when the acceleration α first becomes positive. The acceleration control keeps the tilt amount and increases the lift amount if the acceleration condition that the acceleration α becomes positive is met in the lift period Ph2 from the timing when the work vehicle first meets the insertion condition to the timing when the end condition is met, where the lift amount and the tilt amount reach their specified values. The deceleration control keeps the lift amount and increases the tilt amount when the deceleration condition that the acceleration α becomes negative is met in the lift period Ph2.