Work Machine Control System Velocity Limiting for Excavation Precision
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Solution Overview
Problem
Existing work machine control systems often result in unintended excavation of the target ground shape, causing operator discomfort due to sudden movements, as they fail to accurately control the work unit's velocity and operation in accordance with the operator's intention.
Innovation Solution
A work machine control system that includes a position detection unit, a generation unit for creating target excavation ground shape information, and a control unit that limits the work unit's velocity to a predetermined limitation velocity based on this information, ensuring precise operation and minimizing operator discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the work unit is controlled to precisely follow the target ground shape, then the target ground shape is not eroded, but unnecessary target ground shapes appear and the work unit moves suddenly upward causing operator discomfort
Solution Approach 1:
The control system dynamically adjusts the velocity limitation based on the distance to the target excavation ground shape. When the work unit is far from the target, higher velocities are permitted. When approaching the target, the velocity limitation is automatically reduced, preventing sudden movements and unnecessary corrections that would cause operator discomfort while still achieving precise final positioning.
Solution Approach 2:
The system changes the velocity parameter dynamically during operation. The work unit control unit calculates a velocity limitation value based on the distance between the work unit and the target excavation ground shape, and adjusts the velocity command accordingly. This parameter change allows the system to balance precision and operator comfort at different stages of the excavation process.
2Manufacturing precision
If the velocity limitation is applied to prevent target ground shape erosion, then the target ground shape integrity is maintained, but the excavation process becomes slower
Solution Approach 1:
The velocity limitation is not applied uniformly throughout the excavation process but is dynamically adjusted based on proximity to the target. When the work unit is far from the target excavation ground shape, the velocity limitation is relaxed or not applied, allowing high-speed excavation. Only when approaching the target does the velocity limitation become active, minimizing its impact on overall productivity while ensuring precision at the critical final stage.
Solution Approach 2:
The velocity limitation is applied partially - only in the region close to the target excavation ground shape where precision is critical. The control system identifies a specific distance threshold and applies velocity limitation only within this zone, allowing unrestricted or higher velocities outside this zone. This partial application of the constraint maintains productivity while achieving the necessary precision.
Data Source
AI summary
A work machine control method of controlling a work machine including a work unit with a working tool, the work machine control method includes: detecting a position of the work unit; obtaining the position of the work unit based on the detected position information item and generating a first target excavation ground shape information item as an information item of an intersection portion of at least one target construction face indicating a target shape with respect to a first cut face which intersects a work unit operation plane as an operation plane for the work unit and is parallel to a vertical direction; and controlling a velocity in a direction in which the work unit approaches an excavation target so that the velocity becomes equal to or less than a limitation velocity based on the first target excavation ground shape information item.