Excavator Controller Adaptive Target Surface for Volume Consistency
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Solution Overview
Problem
Existing excavation methods, such as the bench cut method, often result in inconsistent excavation amounts due to variations in excavation distance, leading to reduced work efficiency and potential over or under excavation.
Innovation Solution
A hydraulic excavator system with a controller that calculates and adjusts the target surface to maintain a consistent excavation volume by generating a second target surface superior to the initial target surface when the estimated excavation volume exceeds a predetermined limit, ensuring the operating range of the work implement is limited to this adjusted surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the excavation area is established based on a predetermined bench height and the work position is calculated using a fixed excavation amount setting distance, then the calculation is simple, but the excavation amount becomes inconsistent when the actual excavation distance varies from the predetermined bench height
Solution Approach 1:
The patent applies dynamics by making the excavation area calculation adaptive rather than fixed. The controller dynamically adjusts the excavation area based on the actual distance between the work implement and the target surface, allowing the system to respond to varying excavation conditions. This resolves the contradiction by enabling accurate excavation amount control (improving precision) while maintaining reasonable computational complexity through efficient distance-based adjustments.
Solution Approach 2:
The patent changes the parameter of excavation area calculation from a fixed predetermined value to a dynamic value based on actual distance measurements. By modifying how the excavation area is determined (from fixed bench height to variable distance-based calculation), the system achieves consistent excavation amounts across different excavation scenarios without excessive computational complexity.
2Ease of manufacture
If the target surface is set at a predetermined depth from the current landform to achieve a target excavation amount, then the initial excavation setup is simple, but the excavation amount becomes inaccurate when the excavation distance changes
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual distance between the work implement and the target surface during excavation operations. The controller uses this distance information to adjust the excavation area calculation in real-time, ensuring that the excavation amount remains accurate even when excavation distances vary. This feedback mechanism resolves the contradiction by maintaining reliability without significantly complicating the initial setup process.
Solution Approach 2:
The patent applies preliminary action by pre-establishing the relationship between excavation distance and excavation area in the control algorithm. Rather than requiring complex real-time adjustments during excavation, the system pre-calculates appropriate excavation areas based on measured distances, enabling accurate excavation amounts while keeping the operational process simple and reliable.
3Productivity
If machine control limits the work implement operating range to hold the front work implement on or above the target surface, then work efficiency for finishing excavation surfaces is improved, but the excavation amount per operation becomes difficult to control precisely
Solution Approach 1:
The patent applies dynamics by making the excavation area boundary adaptive based on actual excavation distance. The controller dynamically adjusts where the excavation area limit is positioned, allowing the machine control to maintain both high productivity and precise excavation amount control. This resolves the contradiction by enabling the system to respond to varying distances while maintaining consistent excavation volumes.
Solution Approach 2:
The patent applies local quality by adjusting the excavation area parameters specifically based on local distance conditions rather than using a uniform approach throughout the excavation site. The controller tailors the excavation area calculation to the specific distance between the work implement and target surface at each location, enabling precise excavation amount control while maintaining efficient operation across diverse terrain conditions.
Data Source
AI summary
An hydraulic excavator calculates an estimated excavation volume Va defined by a bucket claw tip position (first position) at an excavation start, a bucket claw tip position (second position) at an excavation end set in advance, a current landform, a first target surface, and a bucket width w. A second target surface is generated at a position superior to the first target surface when the estimated excavation volume Va exceeds a limit volume Vb; and the second target surface is generated at a position at which the excavation volume defined by the first position, the second position, the current landform, the second target surface, and the bucket width is closer to the limit volume Vb. The hydraulic actuators are controlled such that an operating range of a work implement is limited on the second target surface and to an area superior to the second target surface.