Hydraulic Actuator Speed Limiting via Flow Rate Signal Attenuation
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Solution Overview
Problem
Existing dynamic testing systems face inefficiencies due to pressure drops caused by safety valves, which reduce energy efficiency and provide only a single safety layer, limiting the speed of hydraulic actuators.
Innovation Solution
A method and test station configuration that utilize a flow rate control circuit to adjust the flow rate of hydraulic fluid to the actuators, allowing for controlled reduction of actuator speed without additional pressure drops, by switching between a differential signal and an attenuated differential signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an input safety valve is used to limit hydraulic fluid flow rate for worker safety, then actuator speed is reduced to safe levels, but pressure drops occur and energy efficiency is reduced
Solution Approach 1:
The patent replaces the mechanical input safety valve with an electronic control system that uses a sensor to detect actuator position and a controller to modulate the control valve, thereby substituting a mechanical flow limitation approach with an electronic feedback control approach that avoids unnecessary pressure drops
Solution Approach 2:
The patent implements a feedback control system where a sensor detects the actuator position and feeds this information back to the controller, which then adjusts the control valve to maintain safe actuator speeds without requiring constant pressure drop-based flow limitation
2Reliability
If an input safety valve is used to control hydraulic fluid flow, then actuator speed is limited, but the system provides only a single safety layer
Solution Approach 1:
The patent implements a feedback control system where a sensor detects the actuator position and feeds this information back to the controller, which then adjusts the control valve to maintain safe actuator speeds without requiring constant pressure drop-based flow limitation
Solution Approach 2:
The controller serves multiple functions: it manages normal actuator operation, enforces safety speed limits, and can respond to emergency stop signals, thereby providing multiple safety layers through a single integrated control system rather than requiring separate safety valves
3Productivity
If higher pressurization is used to overcome pressure drops from safety valves, then normal operation can be maintained, but energy consumption increases
Solution Approach 1:
The patent replaces the mechanical input safety valve with an electronic control system that uses a sensor to detect actuator position and a controller to modulate the control valve, thereby substituting a mechanical flow limitation approach with an electronic feedback control approach that avoids unnecessary pressure drops
Solution Approach 2:
The patent uses dynamic feedback control to adjust the control valve in real-time based on actual actuator position and velocity, allowing the system to maintain safe operation with minimal energy loss rather than using static high pressurization to overcome fixed pressure drops
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 effectively limits the speed of hydraulic actuators while maintaining energy efficiency by avoiding additional pressure drops, providing a safer working environment without redundant safety valves.
Implementation Method 1
The actuators of the test stations are driven by hydraulic fluid flows
Implementation Method 2
The actuations performed by each actuator are controlled using a control valve (e.g., proportional control valve) that regulates the flow rate and direction of the hydraulic fluid flow through the actuator
Implementation Method 3
Such input safety valves inherently impose pressure drops in the system
Data Source
Figure 1
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AI summary
In a method of controlling a hydraulic actuator of a test station, a differential signal is generated based on a difference between a reference signal and a feedback signal using an actuator controller. A flow rate control circuit is set in one of a first state and a second state based on a flow rate attenuation signal. The differential signal is delivered to the control valve as an actuator command signal when the flow rate control circuit is in the first state. An attenuated differential signal is delivered to the control valve as the actuator command signal when the flow rate control circuit is in the second state. A flow rate and a direction of the hydraulic fluid flow is controlled based on the actuator command signal. The flow rate corresponding to the attenuated differential signal is less than the flow rate corresponding to the differential signal.