Hydraulic Implement System Priority Control
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Solution Overview
Problem
In hydraulic implement systems, when multiple actuators are operated simultaneously, the insufficient hydraulic fluid flow results in slower or halted movement of actuators due to unequal fluid distribution, especially in machines with varying loads, where existing solutions like table-based duty factors and multiple pumps lead to complex flow control and instability.
Innovation Solution
A hydraulic implement system with a controller that selectively limits the velocity of the implement actuator during simultaneous lifting and tilting operations, ensuring the boom lift velocity maintains at least 65% of the desired operator velocity by adjusting the fluid flow distribution using a variable displacement pump and divided operator control device ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple actuators are operated simultaneously from a common pump, then the system can perform multiple tasks, but the hydraulic fluid flow becomes insufficient causing actuators to move slower or stop
Solution Approach 1:
The patent implements dynamic priority-based flow control where the controller continuously monitors actuator requests and dynamically adjusts fluid distribution. When multiple actuators are operated simultaneously, the system dynamically assigns priority levels and adjusts flow rates in real-time, allowing critical actuators to receive sufficient flow while non-critical actuators receive reduced flow, maintaining overall system versatility without complete velocity loss
Solution Approach 2:
The system changes the parameter of hydraulic fluid flow distribution by implementing priority-based allocation. The controller modifies flow parameters dynamically based on actuator priority levels, ensuring that high-priority actuators receive adequate flow to maintain desired velocity while lower-priority actuators receive adjusted flow during periods of insufficient total flow
2Speed
If the majority of pressurized fluid flows to actuators with least resistance, then those actuators move at desired speed, but remaining actuators receive insufficient fluid and move slower or stop
Solution Approach 1:
The patent implements feedback control where the controller continuously monitors the operational state of all actuators and the positions of operator control devices. This feedback loop allows the system to detect when multiple actuators are simultaneously activated and to adjust flow distribution accordingly, preventing the unpredictable behavior where actuators with least resistance dominate flow and ensuring reliable, predictable performance across all actuators based on their priority assignments
3Speed
If table-based duty factors are used to control fluid flow during simultaneous boom lift and bucket dump, then boom lift performance improves, but the solution becomes complex and machine-type specific
Solution Approach 1:
The patent implements a universal priority-based control architecture that can be applied across different machine types and sizes. Instead of machine-specific table-based duty factors, the system uses a generalizable priority assignment mechanism where actuators are assigned priority levels based on their functional importance. This universal approach maintains boom lift performance while eliminating the complexity and lack of adaptability associated with machine-type specific control tables
4Speed
If multiple pumps are used to provide sufficient fluid flow, then actuator velocity requirements are met, but flow control becomes complex and unstable
Solution Approach 1:
The patent extracts the complexity of multiple pump systems by implementing a single pump with priority-based flow control. Instead of using multiple pumps to provide sufficient fluid flow, the system takes out the unnecessary complexity and uses one pump with a smart controller that dynamically allocates flow based on actuator priority levels. This extraction maintains actuator velocity requirements while eliminating the complex and unstable flow control issues associated with multiple pump systems
5Device complexity
If fixed displacement gear type pumps are used, then the system is simple, but modulation of pressurized fluid supply is limited
Solution Approach 1:
The patent implements dynamic flow modulation by using a variable displacement pump that can adjust its output based on real-time system requirements. The controller continuously monitors actuator demands and dynamically modulates the pump's displacement to provide the exact amount of fluid flow needed. This dynamic capability maintains system simplicity while dramatically improving adaptability and flow modulation capability compared to fixed displacement pumps
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 enhances velocity predictability and priority control by optimizing fluid flow distribution, allowing both actuators to perform effectively under varying loads, improving the system's efficiency and stability in machines with high flow requirements and lift capacities.
Implementation Method 1
a variable displacement pump and divided operator control device ranges
Data Source
AI summary
A hydraulic implement system for a machine is disclosed. The hydraulic implement system may have a boom member, a boom actuator, and a boom operator control device movable to indicate a related operator desired boom member velocity. The hydraulic implement system may also have an implement pivotally connected to the boom member, an implement actuator, and an implement operator control device movable to indicated a related operator desired implement velocity. The range of the implement operator control device may be divided into a first portion and a second portion. The hydraulic implement system may also have a controller configured to selectively limit a velocity of the implement during manipulation of the implement operator control device within the first portion such that a lift velocity of the boom member of at least 65% of the desired boom member velocity is always possible.