Hydraulic Flow Control for Combined Construction Machine Actuation
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Solution Overview
Problem
Existing construction machine control systems face challenges in accurately controlling the flow rate of hydraulic fluid to multiple actuators during combined operations, leading to interference between delivery flow rate control and meter-in valve opening, resulting in inaccurate flow distribution and reduced performance.
Innovation Solution
A construction machine equipped with a hydraulic pump, regulator, directional control valves, and a controller that adjusts the delivery flow rate and valve openings based on sensed operation velocities and flow rates, ensuring the delivery flow rate exceeds the total target flow rate during combined operations, and precisely controls valve openings to minimize flow rate differences between actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the delivery flow rate of the hydraulic pump is corrected on the basis of the estimated inflow flow rate, then the flow rate control accuracy is improved, but flow rate errors remain for each actuator section due to leakage, compression, and meter-in valve characteristics
Solution Approach 1:
The patent applies local quality by individually correcting the opening amount of meter-in valves for each hydraulic actuator based on their specific characteristics (leakage, compression, valve properties). Instead of uniform correction at the pump level, each actuator receives customized flow rate correction through its dedicated meter-in valve, ensuring accurate flow distribution despite varying actuator section characteristics.
Solution Approach 2:
The patent introduces meter-in valves as intermediary components between the hydraulic pump and each actuator. These meter-in valves serve as mediators that individually regulate and correct the flow rate to each actuator based on estimated inflow requirements, enabling precise flow distribution while isolating the pump from direct control of multiple actuators.
2Measurement precision
If both the opening amount of the meter-in valve and the delivery flow rate of the hydraulic pump are corrected on the basis of the estimated inflow flow rate, then the flow rate control accuracy is improved, but interference occurs and hunting happens in the inflow flow rate
Solution Approach 1:
The patent segments the flow rate control function by separating the correction of meter-in valve opening amounts from the correction of pump delivery flow rate. The controller independently adjusts meter-in valve openings based on estimated inflow flow rates without simultaneously correcting pump delivery flow rate, thereby avoiding control interference and hunting while maintaining accurate flow distribution to each actuator.
3Measurement precision
If the opening amount of the meter-in valve is directly corrected on the basis of the estimated inflow flow rate, then the flow rate control accuracy is improved, but if the delivery flow rate from the hydraulic pump is insufficient, an error is generated between the target inflow flow rate and the actual inflow flow rate
Solution Approach 1:
The patent applies preliminary action by first determining the total target flow rate required by all actuators before individual meter-in valve corrections are made. The controller calculates the sum of target flow rates for all actuators, ensures the pump can deliver sufficient flow rate, and then distributes this flow rate to individual actuators through corrected meter-in valve openings, preventing flow rate deficiency errors.
4Measurement precision
If the delivery flow rate of the hydraulic pump is controlled regarding a high-load-side hydraulic actuator with a high load, then the flow rate control accuracy is improved, but the inflow flow rate control becomes complex with multiple control elements
Solution Approach 1:
The patent applies universality by using a single meter-in valve control mechanism that serves all hydraulic actuators regardless of load level. The controller calculates target flow rates for all actuators, sums them to determine total pump delivery requirements, and then individually corrects meter-in valve openings based on this total, providing a unified control approach that works for both high-load and low-load actuators without requiring separate control systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables accurate operation of multiple hydraulic actuators by preventing interference between delivery flow rate control and valve opening control, ensuring sufficient delivery flow rate and precise flow distribution, thereby enhancing operational accuracy and efficiency.
Implementation Method 1
a hydraulic pump 7, a regulator 7a that adjusts the delivery flow rate of the hydraulic pump 7, plural hydraulic actuators 4a to 6a, plural directional control valves 8a1 to 8a5 that adjust the flow rate of a hydraulic fluid that is delivered from the hydraulic pump 7 and is distributed to the plural hydraulic actuators 4a to 6a
Implementation Method 2
This construction machine includes velocity sensors 12 to 14 that sense the respective operation velocities of the plural hydraulic actuators 4a to 6a
Data Source
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AI summary
A construction machine is provided that can cause each hydraulic actuator to accurately operate according to operation by an operator in combined operation in which a hydraulic fluid of a hydraulic pump is subjected to flow dividing and is supplied to plural hydraulic actuators. A controller 10, in a case of determining that combined operation is being carried out, controls a regulator 7a in such a manner that the delivery flow rate of a hydraulic pump 7 becomes larger than the total target flow rate of plural hydraulic actuators 4a, 5a, and 6a, and controls the respective opening amounts of plural directional control valves 8a1, 8a3, and 8a5 in such a manner that the difference between the respective target flow rates of the plural hydraulic actuators and the respective inflow flow rates of the plural hydraulic actuators sensed by velocity sensors 12 to 14 becomes small.