Excavator Attachment Control for Stable Ground Pressing Force
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Solution Overview
Problem
Existing construction machines, such as hydraulic excavators, face challenges in maintaining a steady pressing force during flat ground preparation due to fluctuations in ground surface conditions and soil quality, making it difficult for unskilled operators to achieve consistent compaction.
Innovation Solution
A controller for construction machines that calculates and maintains a target gravity center velocity for the working attachment, using a control part to adjust the manipulation signals based on posture information and kinetic energy, ensuring a steady compaction force by focusing on the composite gravity center of the boom, arm, and bucket.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic cylinder pressure is used to estimate pressing force, then pressing force control is achieved, but pressure fluctuation occurs due to ground surface variations and soil quality
Solution Approach 1:
The patent replaces the conventional hydraulic pressure-based force estimation system with a gravity center velocity-based control system. Instead of using hydraulic cylinder pressure sensors and control, the invention uses posture detection means to detect the gravity center position and velocity detection means to detect the gravity center velocity of the working attachment, substituting the mechanical hydraulic control system with a sensor-based velocity control system that is less sensitive to ground surface variations and soil quality fluctuations.
Solution Approach 2:
The patent implements feedback control by continuously detecting the gravity center velocity of the working attachment and comparing it with a target gravity center velocity. The control unit adjusts the drive forces of the hydraulic cylinders based on the deviation between actual and target velocities, creating a closed-loop feedback system that maintains steady pressing force despite external disturbances from ground surface variations and soil quality changes.
2Ease of operation
If hydraulic cylinder extension and contraction is used for pressing force control, then flat ground preparation is achieved, but operator skill is required to maintain steady pressing force
Solution Approach 1:
The patent enables the working attachment to self-regulate its pressing force by automatically detecting its own gravity center velocity and adjusting its drive forces accordingly. The control system performs self-service control without requiring operator intervention to maintain steady pressing force, allowing unskilled operators to achieve consistent flat ground preparation results by simply operating the hydraulic excavator as usual while the system autonomously compensates for variations in ground conditions and soil quality.
3Reliability
If gravity center velocity control is implemented, then steady pressing force is achieved, but control system complexity increases
Solution Approach 1:
The patent achieves multi-functionality by using the gravity center velocity control system for multiple purposes: it simultaneously controls pressing force stability, enables flat ground preparation, and provides adaptive compensation for various ground conditions and soil qualities. The control unit integrates multiple functions including posture detection, velocity calculation, target velocity determination based on grounding work requirements, and coordinated control of multiple hydraulic cylinders, making the system universally applicable to different working conditions without requiring separate control mechanisms for each function.
Data Source
AI summary
A controller includes a drive part, a posture information acquisition part, and a control part, the control part calculates a gravity center velocity of a working device on the basis of posture information about the working device detected by the posture information acquisition part and calculates a target gravity center velocity being a target value of the gravity center velocity on the basis of a difference between a grounding work to be exerted to the ground by the working device and a target grounding work, and provides a feedback correction to an instruction signal to make the gravity center velocity approach the target gravity center velocity and inputs the corrected instruction signal into the drive part.