Hydraulic Pump Control for Excavator Finish Accuracy
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Solution Overview
Problem
Existing hydraulic construction machine control systems face challenges in maintaining finish accuracy during excavating operations, particularly when excavating load increases, as they reduce delivery flow rate to manage pressure, leading to speed imbalances and reduced operation speed, which can result in compromised finish accuracy.
Innovation Solution
A control system that adjusts pump horsepower and flow rate based on the target surface distance between the work device and the construction target surface, increasing horsepower as the distance decreases to maintain accurate operation even under increased load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pump horsepower control is applied to reduce delivery flow rate when delivery pressure increases, then efficiency deterioration is suppressed, but drive speed of hydraulic actuator is reduced
Solution Approach 1:
The control system dynamically changes the delivery flow rate parameter of the hydraulic pump based on the detected excavating load. When load pressure exceeds a predetermined threshold, the system reduces the delivery flow rate to suppress efficiency deterioration, while when load pressure is within the threshold, it maintains higher flow rate to ensure adequate drive speed.
2Stress or pressure
If delivery flow rate is reduced to manage pressure when excavating load increases, then pressure control is achieved, but speed balance between hydraulic actuators is deviated and operation speed is reduced
Solution Approach 1:
The control system continuously detects the actual excavating load through load detection means and compares it with the predetermined threshold value. Based on this feedback comparison, the control means adjusts the delivery flow rate in real-time, ensuring pressure control when load increases while maintaining operation speed when load is within acceptable limits.
3Power
If pump horsepower control is applied to lower horsepower when delivery pressure increases, then excessive load on engine is reduced, but delivery flow rate and operation efficiency are compromised
Solution Approach 1:
The system dynamically adjusts the horsepower of the hydraulic pump based on actual operating conditions. When the excavating load exceeds the threshold, the control means reduces horsepower to prevent excessive engine load. When the load is within the threshold, the system maintains higher horsepower to ensure adequate delivery flow rate and operation efficiency, creating a dynamic adaptation to workload conditions.
Data Source
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AI summary
There is provided a control system for a hydraulic construction machine that helps to attain predetermined finish accuracy even if the excavating load increases during a horizontally leveling operation or a slope face forming operation. The control system for the hydraulic construction machine includes: a hydraulic actuator; a work device driven by the hydraulic actuator; a hydraulic pump supplying a hydraulic fluid to the hydraulic actuator; a pump flow rate control section controlling the delivery flow rate of the hydraulic pump; a pump horsepower control section controlling the horsepower of the hydraulic pump; and a target surface distance acquiring section measuring or computing a target surface distance that is the distance between a construction target surface on which the work device works and the work device. The pump flow rate control section is configured to perform control such that as the target surface distance decreases, the delivery flow rate decreases, and the pump horsepower control section is configured to perform control such that as the target surface distance decreases, the horsepower of the hydraulic pump increases.