Excavator Work Device Ground-Contact Detection for Accurate Terrain Shape Data
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Solution Overview
Problem
Existing methods for generating terrain profile data based on construction history do not accurately determine whether the work device is performing an excavating operation, leading to potential discrepancies between recorded and actual shapes.
Innovation Solution
A work machine equipped with sensors and controllers to compute the position and posture of the work device, determine ground contact state, and generate present-condition shape data by analyzing the movement locus of monitoring points during ground contact, ensuring accurate shape data generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If terrain profile data is generated from monitoring point position information during arm crowding operation, then construction history data can be recorded for completed amount management, but the accuracy of terrain profile data deteriorates when the work device is not actually performing excavating operation
Solution Approach 1:
The system continuously monitors multiple parameters (pilot pressure, arm cylinder pressure, bucket cylinder pressure, boom angle, arm angle, bucket angle) and uses this feedback to determine the ground contact state. This feedback mechanism allows the system to distinguish between actual excavating operations and aerial movements, ensuring terrain profile data is only generated when the bucket is actually contacting the ground, thus maintaining data accuracy while enabling comprehensive construction history recording
Solution Approach 2:
The control unit acts as an intermediary that processes multiple sensor inputs and determines the ground contact state before generating terrain profile data. This intermediary function filters out invalid data from aerial operations while preserving valid excavation data, resolving the contradiction between comprehensive data recording and data accuracy
2Measurement precision
If the system uses multiple sensors and complex ground contact state determination, then terrain profile data accuracy is improved, but device complexity increases
Solution Approach 1:
The control unit performs multiple functions: it monitors pilot pressure, arm cylinder pressure, bucket cylinder pressure, boom angle, arm angle, and bucket angle simultaneously; determines ground contact state; and generates terrain profile data only when appropriate. This multi-functional approach consolidates complex sensing and processing into a single control unit, improving measurement precision without proportionally increasing overall system complexity
Solution Approach 2:
The system merges multiple sensing functions (pressure sensing, angle sensing) and processing functions into an integrated control unit that handles all aspects of ground contact state determination. This consolidation reduces the number of separate components needed, achieving high measurement precision while managing device complexity through integration
Data Source
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AI summary
A controller determines whether or not a work device is in a ground contact state, by using detection data of a pressure sensor and at least one balance relation between forces or moments acting on the work device, and generate partial shape data of a work object formed by the work device, on the basis of a movement locus of a monitoring point set to the work device and an external shape of the work device in a ground contact period in which the work device is determined to be in the ground contact state, and update the present-condition shape data of the work object on the basis of the partial shape data.