Excavator Bucket Control at Slope Boundaries Using Expansion Surfaces
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Solution Overview
Problem
Existing control systems for work machines struggle to construct excavation objects with desired shapes when dealing with multiple design surfaces having different gradients, leading to potential deviations and incomplete formation of features like the top of slope due to control delays and overlapping control surfaces.
Innovation Solution
A control system that includes an expansion surface creation unit to generate surfaces with matching gradients in the top-of-slope and toe-of-slope directions, and a working equipment control unit to guide the bucket along these surfaces without using the toe-of-slope expansion surface in certain scenarios, ensuring precise alignment with the target construction surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If expansion surfaces are created in both top-of-slope direction and toe-of-slope direction, then the bucket can continuously follow the design surfaces, but the bucket may dig into the third design surface and the excavation object is not constructed in desired shape
Solution Approach 1:
The patent applies local quality by creating expansion surfaces with the same gradient as the first design surface in specific directions (top-of-slope direction toward the second design surface, but not in the toe-of-slope direction toward the third design surface). This directional differentiation allows the bucket to continuously follow the design surfaces at the top of slope boundary while preventing unwanted digging into the third design surface at the toe of slope boundary, thereby achieving the desired excavation shape with controlled precision.
2Shape
If the bucket is controlled to continuously move along both the second design surface and the first design surface, then the top of slope can be formed, but control delay causes the bucket to not completely follow the design surfaces
Solution Approach 1:
The patent applies preliminary action by pre-defining expansion surfaces that extend from the first design surface in the top-of-slope direction with the same gradient. This allows the control system to prepare the target path in advance, enabling the bucket to continuously follow the combined path of the expansion surface and first design surface without interruption or delay at the boundary between the second and first design surfaces, ensuring accurate top of slope formation.
3Manufacturing precision
If separate control processes are used for top-of-slope and toe-of-slope directions, then the top of slope can be constructed in desired shape, but the system complexity increases
Solution Approach 1:
The patent applies asymmetry by creating expansion surfaces only in the top-of-slope direction where continuous following is beneficial, while intentionally not creating expansion surfaces in the toe-of-slope direction where such expansion would cause harmful digging. This asymmetric approach simplifies the control system compared to creating expansion surfaces in all directions, while still achieving the desired top of slope shape accuracy through targeted application of the expansion surface technique.
Data Source
AI summary
Disclosed is a control system of a work machine, the control system including: a construction data storage unit that stores a plurality of design surfaces set as an excavation object of the work machine; an expansion surface creation unit that creates, in each of a top-of-slope direction and a toe-of-slope direction, an expansion surface obtained by expanding a target construction surface indicating a target shape of a slope of the excavation object designated from among the plurality of design surfaces; and a working equipment control unit that controls, when the expansion surface is created in each of the top-of-slope direction and the toe-of-slope direction, the working equipment provided in the work machine based on the expansion surface in the top-of-slope direction and the target construction surface, without using the expansion surface in the toe-of-slope direction.