Wheel Loader Excavation Intent Detection for Bucket Detent Control

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Solution Overview

Problem

Existing wheel loaders with autonomous excavation systems mistakenly initiate excavation during leveling due to increased lift arm cylinder pressure, and require dedicated buckets with inclined portions, limiting the use of standard buckets.

Innovation Solution

A wheel loader with a lift arm and bucket system that includes load detection devices and a controller for bucket detent control, executing autonomous excavation only when the detected load exceeds predetermined thresholds, ensuring accurate determination of excavation intent.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an inclined portion is provided in the bottom plate portion of the bucket to increase bottom pressure during excavation, then the bottom pressure easily increases during excavation, but the bottom pressure also easily increases during leveling work, causing erroneous determination of excavation start

Engineering Contradiction:
Improvedetermination accuracy of excavation startVSAvoidoperational reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The determination of excavation start is segmented into multiple independent criteria: vehicle speed decrease, bottom pressure increase, and working device posture change. By dividing the determination into separate detectable parameters, the system can accurately identify true excavation events while filtering out false positives from leveling operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A controller acts as an intermediary that receives and processes signals from multiple detection sources (speed sensor, pressure sensor, posture detector). The controller integrates these intermediate measurements to make the final determination, preventing erroneous activation by any single parameter change.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Extent of automation

If a dedicated bucket with an inclined portion is prepared to enable autonomous excavation, then autonomous excavation can be achieved, but a typical bucket cannot be used, increasing device complexity

Engineering Contradiction:
Improveautonomous excavation capabilityVSAvoidbucket structure complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The control system is designed to work with typical buckets that already exist in the market. By using universal detection methods (speed, pressure, posture) rather than requiring specialized bucket modifications, the system maintains compatibility with standard equipment while achieving autonomous functionality.

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

Solution Approach 2:

The patent replaces mechanical modifications to the bucket (such as adding inclined portions) with electronic sensing and control systems. Sensors and controllers detect operational parameters and automatically adjust hydraulic control, substituting mechanical design changes with intelligent control mechanisms.

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

3Ease of operation

If autonomous excavation control is implemented using only bottom pressure detection, then the system is simple to operate, but erroneous determination occurs during leveling work, reducing measurement precision

Engineering Contradiction:
Improveoperational simplicityVSAvoidexcavation start detection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

Multiple detection methods are merged into a unified control system: vehicle speed monitoring, bottom pressure detection, and working device posture detection are combined. The controller processes all three signals together to determine excavation start, maintaining operational simplicity while improving detection accuracy through multi-parameter analysis.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4640955A1Wheel loader
Publication Date: 2025.10.29 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP4640955A1 patent drawingFigure 1
  • EP4640955A1 patent drawingFigure 2
  • EP4640955A1 patent drawingFigure 3A~3C

AI summary

A wheel loader capable of suppressing the execution of autonomous excavation which is not intended by an operator is provided. In a wheel loader 1 capable of carrying out bucket detent control for holding a bucket 23 in a posture in which a bottom surface of the bucket 23 is parallel to a ground surface that a vehicle body is touching and autonomous excavation control for autonomously excavating a working target object, a controller 5, 5A is configured to execute processing relating to the bucket detent control, and, in a case where a lift arm force F is more than a predetermined working device load Fth, determine that the excavation of the working target object will start and execute processing relating to the autonomous excavation control.