Hydraulic Valve Current Ramping for Smooth Attachment Actuation
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Solution Overview
Problem
Existing hydraulic systems in working machines experience sudden fluid flow changes, leading to impacts and reduced responsiveness when activating or stopping attachments, which can cause vibrations and delay in activation or stopping times.
Innovation Solution
A hydraulic system with a controller that gradually changes the input current value to the control valve in a ramp manner, combined with step changes, to manage fluid flow to attachments, reducing impacts and maintaining responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the control valve opening is controlled to gradually increase the hydraulic fluid flow, then the impact on the attachment is reduced, but the activation time is delayed and responsiveness is deteriorated
Solution Approach 1:
The current range is segmented into multiple regions (first current range for gradual change and second current range for step change). The controller applies different control strategies in different current ranges: gradual ramp increase in the first range to reduce impact, and quick step increase in the second range to improve responsiveness. This segmentation resolves the contradiction by applying appropriate control intensity to different phases of activation.
Solution Approach 2:
The control strategy dynamically adjusts the rate of current increase based on the current value. The controller transitions from a gradual ramp increase mode to a quick step increase mode as the current value progresses through different ranges. This dynamic adjustment allows the system to balance impact reduction and responsiveness activation depending on the current phase of operation.
2Speed
If the hydraulic fluid flow is suddenly increased to the hydraulic actuator, then the activation responsiveness is improved, but a large impact is applied to the attachment
Solution Approach 1:
The control process is divided into distinct phases with different control characteristics. The first current range uses gradual ramp increase to minimize impact, while the second current range uses quick step increase to achieve fast response. This segmentation allows the system to avoid sudden full-power activation while still achieving rapid overall response.
Solution Approach 2:
The controller performs preliminary gradual increase of the input current value in the first current range before transitioning to the quick step increase in the second current range. This preliminary action prepares the hydraulic system for the upcoming rapid flow change, reducing the shock and impact on the attachment while maintaining overall responsiveness.
3Speed
If the control valve opening is quickly increased to activate the attachment, then the responsiveness is improved, but the hydraulic fluid flow changes suddenly causing vibrations
Solution Approach 1:
The input current value change is segmented into gradual ramp increase in the first current range and quick step increase in the second current range. This segmentation allows the system to achieve fast overall response while minimizing sudden flow changes that cause vibrations and instability.
Solution Approach 2:
The control strategy dynamically adapts the rate of current change based on the current value's position in the control range. By transitioning from gradual to quick increase as the current progresses, the system maintains stability during the initial phase and achieves rapid response in the final phase, reducing vibrations throughout the activation process.
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
The solution effectively minimizes vibrations and maintains responsiveness by controlling fluid flow transitions smoothly, ensuring timely activation and deactivation of attachments.
Implementation Method 1
a control valve that adjusts the flow rate and the pressure of a hydraulic fluid that is supplied to a hydraulic actuator... including, for example, a solenoid proportional valve
Implementation Method 2
a hydraulic actuator that causes the attachment to operate... when the control valve is opened and the hydraulic fluid is supplied to the hydraulic actuator
Data Source
AI summary
A hydraulic system includes a control valve to adjust a flow rate and a pressure of hydraulic fluid supplied to a hydraulic actuator to actuate an attachment attached to a working machine, and a controller configured or programmed to control an opening of the control valve by changing an input current value input to the control valve. The controller is configured or programmed to, in activating or stopping the attachment by changing the input current value to a target current value corresponding to a target opening of the control valve, gradually change the input current value in a ramp manner while the input current value is within a first current range in which the attachment is actuated.