Excavator Bucket Weight Sensing for Ground Hardness Estimation
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Solution Overview
Problem
Existing construction machines face challenges in accurately estimating ground hardness due to complex arithmetic processing and increased risk of erroneous determination, especially when finely classifying sensor waveform features, leading to decreased estimation accuracy.
Innovation Solution
A construction machine equipped with a work attachment, a weight detection unit, and a hardness estimation unit that estimates ground hardness based on the weight of earth held by the bucket during a predetermined excavation operation, ensuring a target speed condition is met, thereby simplifying the estimation process and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the hardness estimation unit determines the feature of the waveform of the detection value by the sensor, then the hardness estimation can be performed, but the arithmetic processing becomes complicated and the risk of erroneous determination increases
Solution Approach 1:
The patent extracts only the essential information needed for hardness estimation - specifically the maximum value and minimum value of the detection signal during excavation. By taking out only these critical parameters rather than analyzing the complete waveform features, the system achieves accurate hardness estimation while significantly simplifying the arithmetic processing and reducing the risk of erroneous determination.
2Measurement precision
If the features of the waveform are finely classified according to the hardness of the ground, then high resolution hardness estimation can be achieved, but the accuracy of determination of the waveform is deteriorated
Solution Approach 1:
The patent changes the parameters used for hardness estimation from complex waveform features to simple numerical values (maximum value and minimum value of the detection signal). This parameter transformation maintains high resolution hardness estimation capability while improving waveform determination accuracy, as the system no longer relies on fine classification of complex waveform features.
3Measurement precision
If the work attachment executes excavation operation changing posture from excavation start posture to excavation completion posture, then the weight of earth can be detected, but the control complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the excavation operation parameters including the start posture, completion posture, and speed conditions. The control unit is configured in advance to execute the excavation operation with these predetermined parameters, which simplifies the real-time control complexity while ensuring accurate earth weight detection through consistent operational conditions.
Data Source
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AI summary
A construction machine (1) includes a machine body (1S), a work attachment (20) that includes a bucket (23) for excavating and holding earth constituting ground, and is capable of executing an excavation operation of the ground via the bucket (23) in a state of being attached to the machine body (1S), a weight detection unit capable of detecting a weight of the earth (E) held by the bucket (23), and a hardness estimation unit for estimating hardness of the ground. When estimating the hardness of the ground, the hardness estimation unit executes estimation processing of estimating the hardness of the ground based on the weight of the earth (E) detected by the weight detection unit and first hardness correspondence data defining a change in the weight of the earth (E) due to a difference in the hardness of the ground after execution of a predetermined excavation operation in which the work attachment (20) changes its posture while satisfying a target speed condition from an excavation start posture to an excavation completion posture capable of holding the earth (E) after excavation.