Hydraulic Spool Valve Vibration Sensing for Dead Band Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic spool valves exhibit variability in dead bands due to system parameters, making it difficult for operators to control fluid flow initiation and cessation smoothly, as the current required for opening differs from that required for closing, leading to inconsistent operator feedback.
Innovation Solution
Incorporating an accelerometer in the controller to detect characteristic vibrations during fluid flow initiation and cessation, allowing for the identification of distinct electrical current values for opening and closing, which are then programmed into the operator interface for consistent command control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single electrical current threshold is used for valve opening and closing control, then the control system is simple, but the dead band variability and hysteresis cause inconsistent operator feedback and difficulty in smooth flow control
Solution Approach 1:
The system dynamically adapts the electrical current threshold based on the valve's operational state. During opening, the threshold is set to the opening dead band value; during closing, it is set to the closing dead band value. This dynamic adjustment allows the system to maintain consistent operator feedback without requiring a complex multi-threshold control architecture, as the adaptation is automatically performed based on flow detection
Solution Approach 2:
The system implements feedback by detecting the characteristic vibration signal that occurs during valve opening and closing transitions. This feedback mechanism allows the controller to identify when the valve has reached its target state (open or closed) and adjust the electrical current threshold accordingly, ensuring consistent operator feedback while maintaining relatively simple control logic
2Reliability
If the valve is designed with a characteristic dead band, then the valve provides stable flow control, but the variability in dead bands between different valves and systems makes it difficult for operators to know the required command threshold
Solution Approach 1:
The system performs self-characterization by automatically detecting the opening and closing dead bands during initial operation or calibration. The controller monitors the electrical current and flow sensor signals to identify the characteristic vibration patterns that occur at valve transitions, automatically storing these values for future use. This eliminates the need for manual dead band measurement and ensures each valve system is automatically adapted to its specific characteristics
Solution Approach 2:
The system replaces manual mechanical adjustment and operator trial-and-error with an automated electronic detection system. The flow sensor and controller work together to electronically identify the dead band thresholds through vibration detection, substituting the need for mechanical calibration procedures and providing consistent, repeatable threshold values without requiring operator expertise in valve characterization
3Reliability
If different electrical current values are used for opening and closing, then hysteresis effects are addressed, but the control system requires separate threshold values that increase system complexity
Solution Approach 1:
The system dynamically selects between opening and closing threshold values based on the current operational state. The controller continuously monitors flow conditions and automatically switches between the appropriate threshold, eliminating the need for complex manual threshold management. This dynamic approach ensures accurate valve positioning while keeping the control system relatively simple through automated state-based selection
Solution Approach 2:
The system uses feedback from flow sensors and vibration detection to determine whether the valve is in an opening or closing transition. This feedback mechanism allows the controller to automatically select the appropriate dead band threshold value without requiring complex threshold management, as the selection is driven by real-time operational conditions rather than manual configuration
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 repeatability in controlling the opening and closing of hydraulic spool valves by using different electrical current profiles for opening and closing, ensuring gentle and predictable fluid flow management, thereby improving operator control and system consistency.
Implementation Method 1
a characteristic vibration is generated by turbulent hydraulic fluid flow within the valve when hydraulic fluid flow is first initiated between the first and second ports
Implementation Method 2
a characteristic vibration is generated by turbulent hydraulic fluid flow within the valve
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present disclosure relates to a valve assembly (100) including a valve moveable between an open positon where hydraulic fluid flow is permitted between first (105) and second (104) ports of the valve and a closed position where hydraulic fluid flow is blocked between the first and second ports. A characteristic vibration is generated by turbulent hydraulic fluid flow within the valve when hydraulic fluid flow is first initiated between the first and second ports as the valve moves from the closed position toward the open position. The valve assembly also includes a controller (200) for providing electrical current to control movement of the valve via a solenoid (130). The controller includes an accelerometer (204) for sensing the characteristic vibration. The controller identifies an electrical current value of the electrical current at a time when the characteristic vibration is detected.