Excavator Actuator Control for Design Surface Following
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Solution Overview
Problem
Conventional hydraulic excavators struggle to assist operators in moving a work tool along a design surface regardless of the surface angle and work implement posture, leading to inefficient excavation and alignment tasks.
Innovation Solution
A work machine equipped with a multijoint work implement, actuators, an operation device, a controller, and a work implement posture/position measurement device, which determines and adjusts the target velocities of actuators to ensure the work tool follows the design surface, distinguishing between excavation and alignment actions based on the surface angle and implement posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the work machine uses conventional semiautomatic control that determines work type based only on arm operation signals, then the control system is simple, but it cannot assist operators when excavating vertical design surfaces where boom operation is required
Solution Approach 1:
The system changes the determination parameters from only arm operation signals to include both arm and boom operation signals. By detecting the presence or absence of operation signals from multiple sources (arm operation device and boom operation device), the system can accurately distinguish between shaping work and cutting edge alignment work across different excavation scenarios, including vertical surfaces
Solution Approach 2:
The control system is designed to handle multiple work types (shaping work and cutting edge alignment work) using a unified determination mechanism. The same control apparatus determines work type based on operation signal patterns, making the system universally applicable to both horizontal and vertical design surfaces without requiring separate control systems
2Manufacturing precision
If the work machine does not distinguish between shaping work and cutting edge alignment work, then the control system is simple, but the work tool cannot move accurately along the design surface
Solution Approach 1:
The system continuously monitors operation signals from both arm and boom operation devices, feeds this information back to the work type determination section, and adjusts the target velocity of actuators accordingly. This closed-loop feedback mechanism ensures accurate work tool positioning by dynamically correcting actuator velocities based on the detected work type and current operation state
Solution Approach 2:
The control system dynamically adjusts the target velocity of actuators based on the determined work type. For shaping work, the system corrects velocities to maintain constant distance from the design surface, while for cutting edge alignment work, it allows free movement. This dynamic velocity adjustment enables precise positioning adaptability across different excavation modes
3Productivity
If the work machine requires manual operation for both arm and boom to excavate vertical surfaces, then operator control is flexible, but excavation efficiency decreases due to increased operational complexity
Solution Approach 1:
The control system automatically determines the work type and adjusts actuator velocities without requiring explicit operator input for mode switching. The system serves itself by monitoring operation signals and autonomously selecting the appropriate control mode (shaping work or cutting edge alignment work), thereby improving excavation efficiency while maintaining operator control flexibility
Solution Approach 2:
The system performs preliminary determination of work type based on operation signal patterns before executing the excavation action. By pre-identifying whether the operation is shaping work or cutting edge alignment work, the system can proactively adjust velocity corrections and actuator control strategies, enabling smoother and more efficient excavation operations
Data Source
AI summary
A work machine capable of assisting in an operator's operation to allow a work tool move along a design surface indicating a target shape of an object to be worked irrespectively of an angle of the design surface and a posture of a work implement is provided. A controller determines an excavation actuator in charge of an excavation action and determines an alignment actuator in charge of an alignment action for a work tool out of a plurality of actuators on the basis of the design surface set by a work execution target setting device and the posture of the work implement measured by a work implement posture/position measurement device, determines a target velocity of the excavation actuator on the basis of operation signals outputted from an operation device, and limits a target velocity of the alignment actuator in a direction in which the work tool approaches the design surface.