Excavator Bucket Posture Control for Target-Surface Tracking
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Solution Overview
Problem
Existing hydraulic excavators face challenges in maintaining the intended work state of the bucket, leading to deviations from the excavation target surface, which affects work performance due to incorrect automatic bucket control.
Innovation Solution
A work machine equipped with a controller that determines the work state of the bucket based on operator input and posture sensors, adjusting actuator commands to maintain the bucket's position relative to the target surface, ensuring the bucket follows the intended excavation or rubbing state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bucket action is controlled to cause the claw tip of the bucket to always come close to the excavation target surface, then the distance between the bucket and the target surface is reduced, but the work state of the bucket deviates from the operator's intention
Solution Approach 1:
The control system dynamically adjusts the bucket control based on the determined work state. When excavation is intended, the system allows the bucket to follow the target surface closely; when rubbing is intended, the system maintains a different posture relationship. This dynamic adaptation resolves the contradiction by making the control strategy flexible rather than fixed.
Solution Approach 2:
The system changes the control parameters (target posture values) based on the work state. Different work states (excavation vs. rubbing) have different target posture relationships between the bucket bottom surface and the target surface. This parameter change allows the system to optimize for either distance reduction or work state conformity depending on the current operational context.
2Extent of automation
If automatic control of the bucket angle is executed, then the bucket can follow the excavation target surface, but the work performance lowers when the control contradicts the operator's intention
Solution Approach 1:
The control system incorporates feedback about the operator's intentions through operation input detection. By monitoring the operation input device and determining the intended work state, the system provides feedback-adjusted automatic control that aligns with operator intentions. This prevents the automation from contradicting the operator's intent and maintains high work performance.
Solution Approach 2:
The degree of automation is dynamically adjusted based on the work state. The system executes automatic control when it aligns with operator intentions (detected through operation inputs), and adjusts or suspends automatic control when it would contradict operator intentions. This dynamic control strategy maintains both high automation benefit and high work performance.
3Measurement precision
If the bucket posture is adjusted to make the distance shorter, then the excavation target surface is followed more accurately, but the bucket may contact the ground surface incorrectly
Solution Approach 1:
The system changes the target posture parameters based on the work state. For excavation work, the target posture allows the claw tip to follow the surface closely. For rubbing work, the target posture maintains a different relationship to prevent incorrect ground contact. This parameter adaptation resolves the contradiction by optimizing the posture for the current work type.
Solution Approach 2:
The control system applies different posture control strategies to different parts of the bucket depending on the work state. When excavating, the claw tip is positioned to follow the surface closely. When rubbing, the rear end side of the bucket bottom surface is positioned to contact the ground properly. This localized quality control prevents harmful incorrect contact while maintaining following accuracy where needed.
Data Source
AI summary
The invention of the present application intends to provide a work machine that can improve the work performance by keeping the work state of work equipment conforming to the intention of an operator in machine control for causing the work equipment to follow an excavation target surface. For this purpose, a controller determines the work state of the work equipment on the basis of an operation input amount inputted from an operation input device and the posture of the work equipment with respect to the target surface, computes a range of an action command value of actuators in which the work state determined is kept, and corrects, within the range, the action command value of the actuators to make the distance between the work equipment and the target surface small.