Hydraulic Boom Control with Counter-Balance Valves for Bounce Reduction
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Solution Overview
Problem
Existing boom systems, particularly in vehicles like concrete pump trucks, experience undesirable dynamic behavior due to their length and mass, leading to vibrations and oscillations induced by external loads and pumping actions, which conventional counter-balance valves struggle to mitigate effectively without impacting efficiency.
Innovation Solution
The implementation of a hydraulic system with independent metering control valves that manage dynamic pressure and flow rates to stabilize the boom, while maintaining counter-balance valve protection, by using a pair of counter-balance valves and control valves to open and close them dynamically, and employing sensors to monitor and respond to disturbances and faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional counter-balance valves are used to prevent uncommanded movement, then safety is improved, but boom vibrations and oscillations worsen
Solution Approach 1:
The hydraulic control system is divided into separate functional components: counter-balance valves for safety (preventing uncommanded movement) and independent metering control valves for vibration control. This segmentation allows each component to perform its specialized function without interfering with the other, resolving the contradiction between safety and vibration reduction.
Solution Approach 2:
Independent metering control valves act as intermediaries between the operator's commands and the hydraulic actuator. These valves dynamically regulate flow and pressure to counteract vibrations while the counter-balance valves maintain safety by preventing uncommanded movement, thus mediating between conflicting requirements.
2Productivity
If the boom is made long and slender to facilitate pumping concrete a substantial distance, then productivity is improved, but dynamic stability worsens
Solution Approach 1:
The control system continuously monitors boom position and hydraulic parameters, using this feedback to dynamically adjust metering valve openings. This real-time feedback allows the system to maintain stability of the extended boom structure while achieving substantial pumping distances.
Solution Approach 2:
The system transitions from static valve positioning to dynamic control where metering valves continuously adjust their opening based on real-time conditions. This dynamic adaptation allows the long, slender boom to maintain stability throughout its range of motion while achieving extended pumping distances.
3Object-affected harmful factors
If independent metering control valves are added to control dynamic pressure and flow rates, then vibration reduction is improved, but device complexity worsens
Solution Approach 1:
The independent metering control valves perform multiple functions: they control vibration by regulating flow dynamics, maintain system pressure, and enable precise positioning. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in overall system complexity while achieving vibration reduction.
4Ease of manufacture
If counter-balance valves are mounted directly to the hydraulic cylinder, then ease of installation is improved, but ability to sense and respond to pressure oscillations worsens
Solution Approach 1:
The control function for detecting and responding to pressure oscillations is extracted from the counter-balance valves and assigned to independent metering control valves. This separation allows the counter-balance valves to remain simply mounted to the cylinder for ease of installation, while the metering valves handle the complex sensing and response to pressure variations.
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 reduces boom vibrations and oscillations while ensuring safety and preventing single-point faults from causing uncommanded movement, enhancing the stability and reliability of boom systems with reduced mass and simplified hydraulic line routing.
Implementation Method 1
By actuating the hydraulic cylinder, the boom may be deployed and retracted
Implementation Method 2
a hydraulic cylinder may be used to actuate the boom. By actuating the hydraulic cylinder, the boom may be deployed and retracted
Implementation Method 3
The hydraulic pressure applied to one of the counter-balance valves is delivered to a corresponding one of the ports of the hydraulic cylinder thereby urging a piston of the hydraulic cylinder to move
Implementation Method 4
The counter-balance valves are typically mounted directly to the hydraulic cylinder... The counter-balance valves provide safety protection to the system
Implementation Method 5
This approach reduces boom vibrations and oscillations while ensuring safety and preventing single-point faults from causing uncommanded movement
Data Source
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AI summary
A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second independent control valves (700, 800), and first and second blocking valves (350, 450). The actuator includes first and second corresponding chambers. In a first mode, the second counter-balance valve is opened by the first control valve, and the first counter-balance valve is opened by the second control valve. In a second mode, at least one of the counter-balance valves is closed. A meter-out control valve (800, 700) may be operated in a flow control mode, and/or a meter-in control valve (700, 800) may be operated in a pressure control mode. Boom dynamics reduction may occur while the boom is in motion (e.g., about a worksite). By opening the counter-balance valves, sensors at the control valves may be used to characterize external loads. The control valves may respond to the external loads and at least partially cancel unwanted boom dynamics. The system may further detecting faults in actuators with counter-balance valves and prevent any single point fault from causing a boom falling event and/or mitigate such faults.