Excavator Implement Trajectory Control for Variable Soil Hardness
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Solution Overview
Problem
Existing automatic excavation control technologies fail to account for variations in excavation surface gradients and object hardness, leading to inefficient soil excavation and potential operational failures in hydraulic excavators.
Innovation Solution
A work machine equipped with a controller that calculates and adjusts target loci and postures for the work implement based on real-time information about the excavation surface gradient and object hardness, ensuring appropriate excavation trajectories and postures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed target locus is used for excavation, then the control system is simple, but the excavation efficiency decreases when surface gradient or object hardness varies
Solution Approach 1:
The patent implements dynamic adjustment of the target locus based on real-time detection of surface gradient and object hardness. The controller modifies excavation depth, bucket position, and movement trajectory according to detected environmental conditions, transforming a static control system into a dynamic one that adapts to varying excavation conditions.
Solution Approach 2:
The system changes operational parameters (excavation depth, bucket angle, movement speed) based on detected conditions. When object hardness increases or surface gradient changes, the controller adjusts these parameters to optimize excavation efficiency while preventing operational failures.
2Productivity
If excavation depth is increased to improve productivity, then more soil is excavated per cycle, but the risk of bucket failure increases in hard objects
Solution Approach 1:
The system uses sensors to detect object hardness and surface gradient in real-time, providing feedback to the controller. Based on this feedback, the controller dynamically adjusts the target locus and excavation parameters, increasing depth when conditions permit and reducing depth when hardness increases, thereby maintaining both productivity and reliability.
Solution Approach 2:
The excavation depth is not fixed but dynamically adjusted based on detected object hardness. The system transitions from a static deep excavation approach to a dynamic approach that modifies depth in real-time according to encountered resistance, preventing bucket failure while maintaining efficient excavation.
3Device complexity
If the target locus does not account for surface gradient, then the control algorithm is simpler, but excavation performance deteriorates on sloped surfaces
Solution Approach 1:
The system performs preliminary detection of surface gradient before excavation begins and uses this information to pre-calculate an adjusted target locus that accounts for the slope. This preliminary action allows the control algorithm to compensate for gradient effects without requiring complex real-time adjustments during excavation.
Data Source
AI summary
A work machine is capable of appropriately setting a target locus and target postures for a work implement depending on an excavation environment and an excavation object under automatic excavation control. To accomplish this, a controller calculates a target locus passing through an excavation starting position where a control point is positioned when an excavation is started, an excavation-in-progress position where the control point is positioned when the excavation is in progress, and an excavation finishing position where the control point is positioned when the excavation is finished, and a target posture for the work implement at the time the control point moves on the target locus. The controller controls a control valve such that the control point moves on the target locus and such that a posture of the work implement at the time where the control point moves on the target locus matches the target posture.