Excavator Control Using Soil-Nature Mapping for Precise Digging
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Solution Overview
Problem
Semi-automatic excavators fail to maintain construction precision due to variations in soil nature and excavation depths, leading to difficulties in forming designed surfaces when soil nature is not uniform.
Innovation Solution
A work machine equipped with a controller that corrects operation commands based on soil-nature information, bucket-claw-tip position, and drive load, generating a soil-nature map to adjust excavation force according to soil conditions, ensuring consistent construction precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If semi-automatic control is implemented without considering soil nature, then automation level increases, but construction precision deteriorates due to soil nature variations
Solution Approach 1:
The system implements feedback by measuring the actual drive load during excavation operations and using this information to update the soil-nature map. The controller continuously monitors the relationship between operation commands and actual excavation resistance, adjusting future operation commands based on accumulated soil nature data. This closed-loop feedback mechanism enables the semi-automatic control system to adapt to varying soil conditions while maintaining construction precision.
Solution Approach 2:
The system changes operational parameters dynamically by adjusting operation commands based on the estimated load derived from soil-nature information. Instead of using fixed control parameters, the controller modifies excavation force, speed, and other operational parameters according to the measured soil characteristics at different locations, enabling precise construction across heterogeneous soil conditions.
2Manufacturing precision
If operation commands are adjusted according to soil nature and excavation depth, then construction precision is maintained, but device complexity increases due to additional sensing and control systems
Solution Approach 1:
The system employs self-service by utilizing the excavator's own operational data to characterize soil nature. The drive load sensor, which is already part of the standard excavator system, is used to automatically build the soil-nature map without requiring external soil testing equipment or manual soil classification. The system serves itself by converting routine operational data into valuable soil information that improves future excavation precision.
Solution Approach 2:
The drive load sensor serves multiple functions: it monitors hydraulic system health, provides feedback for semi-automatic control, and characterizes soil nature for constructing the soil-nature map. By making the sensor multi-functional, the system avoids adding dedicated soil measurement equipment, thereby reducing overall device complexity while achieving precise construction control.
3Adaptability or versatility
If soil-nature map is generated and used for operation correction, then adaptability to different soil conditions improves, but loss of time increases due to data processing and map generation
Solution Approach 1:
The system performs preliminary action by continuously building and updating the soil-nature map during the excavation process itself. Rather than requiring time-consuming soil surveys before construction begins, the system accumulates soil nature data as excavation progresses, making the information available for correcting subsequent operation commands. This approach converts what would be preparatory time into productive excavation time.
Solution Approach 2:
The soil-nature map generation and operation correction occur continuously throughout the excavation process without interrupting work flow. The controller real-time processes drive load data and adjusts operation commands on the fly, maintaining continuous excavation activity. This eliminates downtime associated with batch processing or periodic soil testing, ensuring uninterrupted productive action.
Data Source
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AI summary
To provide a work machine that can maintain the construction precision of semi-automatic control irrespective of excavation depths and differences in soil nature. A controller acquires soil-nature information on the basis of an operation command given to a work implement, a bucket-claw-tip position outputted from a bucket-position measuring device, and a drive load of the work implement outputted from a load measuring device; generates a soil-nature map on the basis of the bucket-claw-tip position, and the soil-nature information; calculates an estimated load that is an estimate of an excavation load on the basis of the soil-nature map and a bucket-claw-tip target position; and corrects the operation command in accordance with the estimated load.