Hydraulic Control Arrangement for Precise Actuator Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing hydraulic control arrangements have limited volume flow resolution, which restricts the speed resolution, positioning accuracy, and pressure control accuracy of downstream hydraulic actuators.
Innovation Solution
A method and hydraulic control arrangement using two pressure chambers, where a predetermined pressure medium volume is metered into or discharged from one chamber to achieve precise control, leveraging the compressibility of the pressure medium for fine positioning, with switching valves controlled via pulse width modulation for ballistic control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If switching valves are used with pulse width modulation control, then the device complexity is reduced compared to proportional control valves, but the volume flow resolution and positioning accuracy are limited
Solution Approach 1:
The system divides the control task into two independent pressure chambers, each controlled by switching valves. One chamber handles coarse positioning while the other enables fine positioning through compressibility effects, segmenting the control functions to achieve high resolution without complex proportional valves
Solution Approach 2:
The invention changes the control parameter from direct flow rate control to volume control utilizing pressure medium compressibility. By controlling the volume of pressure medium supplied to or discharged from one chamber, the system achieves fine positioning through the compressibility parameter of the pressure medium
2Measurement precision
If volume control based on compressibility is implemented, then the positioning accuracy is improved, but the control mechanism becomes more complex
Solution Approach 1:
The system uses the inherent compressibility of the pressure medium itself as the control mechanism, without requiring external compression devices or complex actuators. The pressure medium serves itself as the compliant element, simplifying the control mechanism while achieving fine positioning
3Measurement precision
If switching valves operate in ballistic mode with short pulses, then the response time is reduced and control precision is improved, but the energy efficiency decreases
Solution Approach 1:
The system pre-pressurizes one chamber to a level above the other chamber's pressure before actuation. This preliminary pressure differential preparation enables the switching valve to achieve the desired volume transfer with shorter, more efficient pulses, improving both response time and energy efficiency
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 approach enhances the positioning accuracy and fine control of hydraulic actuators by regulating pressure medium volume rather than flow, allowing for precise movement of hydraulic consumers through controlled compression and decompression.
Implementation Method 1
leveraging the compressibility of the pressure medium for fine positioning
Implementation Method 2
The switching position is achieved by energizing an actuating solenoid
Data Source
Figure 1
Figure 2~3
AI summary
The method involves determining a pressure fluid volume supplied or discharged to a pressure chamber (6,8), to set a predetermined reference chamber pressure or a predetermined desired consumer location, such as a piston position of a hydraulic cylinder (2). The switching valve arrangement is controlled, such that the pressure chamber is removed or supplied with the predetermined hydraulic fluid volume. The actual pressure or the actual loading position are checked. The opening duration of the switching valve arrangement is modified to provide a desired hydraulic fluid volume. An independent claim is included for a digital hydraulic controlling arrangement for controlling of a consumer.