Excavator Controller Managing Deviation and Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing machine control technologies for hydraulic excavators face challenges in maintaining excavation along a target surface when both a design surface and a dangerous area are present, as the excavation assistance control and deviation prevention control interfere with each other, leading to potential bucket tip deviation or penetration into the design surface.
Innovation Solution
A work machine with a controller that integrates excavation assistance control and deviation prevention control, ensuring the operation direction of the work tool approximates to that generated by excavation assistance control alone, even when proximate to a work area boundary, by adjusting the velocities of front implement members to prevent deviation and maintain surface alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If deviation prevention control is activated to decelerate the work implement before a dangerous area, then the work implement velocity is reduced to prevent entry into the prohibited area, but the excavation assistance control becomes ineffective and the bucket tip floats above the design surface
Solution Approach 1:
The controller dynamically changes the velocity parameters of front implement members based on their respective roles. When the work implement approaches a dangerous area, the controller decelerates the deceleration target front implement member (e.g., boom) while maintaining or adjusting the velocity of the excavation target front implement member (e.g., arm) to preserve the velocity vector direction needed for precise excavation along the design surface.
Solution Approach 2:
The control system segments the front implement members into different functional groups: deceleration target members that are controlled to prevent dangerous area entry, and excavation target members that are controlled to maintain excavation precision. This segmentation allows independent velocity control of different members to resolve the contradiction between safety and precision.
2Manufacturing precision
If excavation assistance control is used to move the bucket tip along the design surface, then the velocity vector of the bucket tip is directed along the design surface, but when the work implement enters a deceleration area, the arm crowding operation is decelerated more than expected and the boom raising operation becomes excessive
Solution Approach 1:
The control system dynamically adjusts the velocity commands for different front implement members based on real-time conditions. When approaching a dangerous area, the controller applies different velocity adjustment strategies: decelerating members that would cause dangerous area entry while maintaining or minimally adjusting members critical for excavation precision, thereby adapting the overall system behavior to satisfy both safety and precision requirements.
Solution Approach 2:
The controller changes the velocity parameters of individual front implement members selectively. By identifying which members are deceleration targets and which are excavation targets, the controller applies parameter changes (velocity adjustments) differently to each group, preventing excessive boom raising while maintaining arm crowding effectiveness for precise excavation.
3Reliability
If both excavation assistance control and deviation prevention control are activated simultaneously, then the controller must manage conflicting control objectives, but the controls interfere with each other causing bucket tip deviation from the design surface
Solution Approach 1:
The control system segments the control objectives into distinct control streams: excavation assistance control for precision and deviation prevention control for safety. By segmenting the front implement members into excavation targets and deceleration targets, the controller can manage each control objective independently without interference, reducing the effective complexity of managing conflicting goals.
Solution Approach 2:
The controller acts as an intermediary that reconciles the conflicting control objectives. It receives input from both excavation assistance control and deviation prevention control, processes them through the segmentation framework, and outputs coordinated velocity commands to the actuators, thereby mediating between the two control systems to prevent interference.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A hydraulic excavator includes: a work implement having a plurality of front implement members including a bucket; and a controller that is capable of controlling the work implement by using: excavation assistance control of controlling the work implement such that the bucket moves along a predetermined target excavation surface; and deviation prevention control of preventing deviation of the work implement from a predetermined work area by decelerating or stopping operation of a subject front implement member that is included in the plurality of front implement members and that can deviate the work implement from the work area. The controller- controls the work implement such that when the controller controls the work implement by using both the excavation assistance control and the deviation prevention control, an operation direction of the bucket approximates to an operation direction of the bucket that is to be generated when the work implement is controlled by using only the excavation assistance control.