Aerial Work Platform Hydraulic Flow Split for Precise Dual Motion
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Solution Overview
Problem
Existing lifting nacelles with hydraulic systems face challenges in precisely controlling the simultaneous displacement of multiple parts of their lifting structure, leading to imprecise and difficult-to-control movements due to complex and expensive proportional solenoid valves, which are not always desirable, especially for smaller nacelles.
Innovation Solution
The hydraulic actuators are divided into two groups, with a control unit determining target flows for each group, and a regulated proportion of the fluid is distributed to both groups to ensure precise and controlled activation, eliminating the need for complex proportional solenoid valves and using a simple, inexpensive flow regulation and distribution system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If proportional solenoid valves are used to control fluid flow to each hydraulic actuator, then precise control of simultaneous actuator movement is achieved, but the hydraulic circuit becomes complex and expensive
Solution Approach 1:
The hydraulic actuators are divided into two groups (first group and second group). A regulated proportion of fluid is sent jointly to both groups, then distributed to each group with precise flow rates. This segmentation allows centralized flow regulation instead of individual valve control for each actuator, reducing system complexity while maintaining precision.
Solution Approach 2:
A flow distribution device acts as an intermediary between the pump and the two groups of hydraulic actuators. This device receives fluid from the pump and automatically distributes it to the first and second groups based on their respective flow requirements, eliminating the need for complex proportional solenoid valves at each actuator while ensuring precise flow control.
2Measurement precision
If proportional solenoid valves are installed for each hydraulic actuator, then precise fluid flow control is achieved, but the cost of the hydraulic system increases
Solution Approach 1:
The flow control function is merged into a single flow distribution device that serves both groups of actuators. Instead of having separate proportional solenoid valves for each actuator, one flow distribution device performs the control function for all actuators, significantly reducing component count and system cost while maintaining precise flow control capability.
Solution Approach 2:
The flow distribution device performs multiple functions: it regulates the total fluid flow from the pump, distributes fluid to two different groups of actuators, and controls the flow rate to each group based on their requirements. This multi-functional device replaces multiple specialized proportional solenoid valves, reducing overall system cost.
3Productivity
If multiple hydraulic actuators are actuated simultaneously without flow regulation, then productivity increases, but the movements become imprecise and difficult to control
Solution Approach 1:
The flow distribution device provides automatic feedback control by monitoring the flow requirements of the first and second groups of actuators and adjusting the distribution accordingly. This ensures that when multiple actuators operate simultaneously, each receives the precise flow rate it needs, maintaining movement precision while enabling high productivity through parallel operation.
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 allows for simultaneous, precise, and controlled movement of different parts of the lifting structure, increasing productivity and reliability while reducing the complexity and cost of the hydraulic system, making it suitable for self-propelled nacelles with moderate lifting heights and power requirements.
Implementation Method 1
hydraulic actuators that the user actuates by means of a fluid, typically oil, which circulates in a hydraulic circuit under the effect of an electrically driven pump
Implementation Method 2
each hydraulic actuator of the nacelle can be associated with a proportional solenoid valve which takes from the flow of fluid delivered by the motor pump a flow of fluid which is sent to the actuator
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an aerial work platform which comprises a chassis, a platform, a lifting structure moved by hydraulic actuators (41, 42) and a hydraulic system (S), controlled by a control unit (50) and including a circulation circuit (60), an electric motor pump (80) and flow control means (90). In order to operate in a simple and economical way the controlled simultaneous movement of two different portions of the lifting structure, the actuators are divided between first and second groups (G1, G2) and the control unit determines a first target flow rate (Q1) according to the actuation of one of the actuators of the first group by the operator and a second target flow rate (Q2) according to the actuation of one of the actuators of the second group by the operator, as well as to control the motor pump with a delivery rate (QR) greater than or equal to the sum of the first and second target flow rates. In addition, the flow control means are controlled by the control unit in order to send jointly to the first and second groups a regulated proportion of the fluid delivered by the motor pump, having a controlled flow rate (Q0) equal to the sum of the first and second target flow rates, and then to divide this regulated proportion into two adjusted shares, respectively having the first and second target flow rates and respectively sent to the first and second groups. The flow control means comprise a flow control device (91) as well as a flow distribution device (92) arranged downstream of the flow control device in relation to the flow delivered by the motor pump.