Hydraulic Actuator Meter-Out Pressure Control for Stable Deceleration
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Solution Overview
Problem
Existing hydraulic drive systems struggle to improve the operability of hydraulic actuators, primarily relying on meter-in flow rate control for actuator movement.
Innovation Solution
A hydraulic drive system that includes a hydraulic pump capable of changing discharge flow rates, separate meter-in and meter-out control valves, an operation device, pressure sensors, and a control device that sets target meter-out flow rates and controls the meter-out control valve based on drainage pressure and target flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If meter-in flow rate control is used to control hydraulic actuator movement, then the actuator can be driven, but the operability and deceleration performance are insufficient
Solution Approach 1:
The hydraulic control system is segmented into two independent control paths: meter-in control for actuator extension and meter-out control for actuator retraction. This segmentation allows independent optimization of each control function, enabling precise deceleration control during retraction without compromising extension performance
Solution Approach 2:
Instead of controlling actuator speed only through meter-in flow restriction, the invention inverts the control approach by controlling speed through meter-out flow restriction. This inversion enables effective deceleration control by regulating the exhaust flow from the actuator, which directly impacts the actuator's deceleration performance
2Ease of operation
If separate meter-in and meter-out control valves are provided, then deceleration control is improved, but system complexity increases
Solution Approach 1:
The control device is designed with multi-functionality, integrating both meter-in control and meter-out control functions into a single electronic control unit. This universal controller manages multiple control valves through a unified control algorithm, reducing overall system complexity despite the presence of separate control valves
Solution Approach 2:
The invention replaces complex mechanical linkage systems with an electronic control system that uses sensors and electronic actuators to control valve openings. This substitution simplifies the mechanical structure while maintaining precise control capabilities for both meter-in and meter-out functions
3Speed
If meter-out flow rate control is implemented, then actuator deceleration performance is enhanced, but control system complexity increases
Solution Approach 1:
The control system incorporates feedback mechanisms where sensors detect actual actuator position and flow rates, and the control device adjusts valve openings based on this feedback to achieve target deceleration rates. This closed-loop control simplifies the overall system architecture by using intelligent control algorithms rather than complex mechanical linkages
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 configuration allows for precise control of the hydraulic actuator's speed, particularly deceleration, enhancing the operability and stability of the actuator in response to operation commands.
Implementation Method 1
a first pressure sensor that detects a drainage pressure of the hydraulic actuator
Implementation Method 2
a meter-out control valve that is provided separately from the meter-in control valve and controls a meter-out flow rate of the working fluid being drained from the hydraulic actuator into a tank
Data Source
AI summary
This hydraulic drive system includes: a hydraulic pump capable of changing a discharge flow rate of a working fluid; a meter-in control valve that controls a meter-in flow rate of the working fluid flowing from the hydraulic pump to a hydraulic actuator; a meter-out control valve that is provided separately from the meter-in control valve and controls a meter-out flow rate of the working fluid being drained from the hydraulic actuator into a tank; an operation device that outputs an operation command; a first pressure sensor that detects a drainage pressure of the hydraulic actuator; and a control device that sets a target meter-out flow rate according to the operation command from the operation device and controls an opening degree of the meter-out control valve on the basis of the drainage pressure detected by the first pressure sensor and the target meter-out flow rate.