Linear Actuator Force Control for Piston Buckling Limits
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Solution Overview
Problem
Linear actuators in oil and gas exploration face the issue of piston buckling due to exceeding a critical threshold force, limiting their operational capacity, as traditional methods calculate and enforce a single maximum force regardless of piston extension length.
Innovation Solution
Dynamically calculate the maximum allowable force based on piston material strength, measured force, and extension length to prevent buckling, allowing higher forces when the piston is partially extended.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single maximum force limit is enforced based on full extension buckling calculations, then piston buckling is prevented, but the actuator cannot exert higher forces when partially extended
Solution Approach 1:
The patent implements dynamic control of the piston extension length based on real-time calculation of buckling thresholds. The system adjusts the maximum allowable force according to the current extension length, allowing higher forces when partially extended and lower forces when fully extended. This dynamic adaptation resolves the contradiction by making the force capability variable rather than fixed.
Solution Approach 2:
The system changes the operational parameters (extension length and force) dynamically based on calculated buckling thresholds. By continuously monitoring extension length and adjusting the maximum allowable force accordingly, the system optimizes performance across different operating conditions while preventing buckling.
2Length of moving object
If the piston is allowed to extend fully for maximum stroke capability, then the actuator achieves full range of motion, but the buckling threshold is reduced
Solution Approach 1:
The system dynamically adjusts the maximum allowable force based on the current extension length. When the piston is fully extended, the system reduces the maximum force threshold to prevent buckling. When retracted, the system allows higher forces. This dynamic parameter adjustment resolves the contradiction between achieving full stroke and maintaining high force capability.
Solution Approach 2:
The system performs preliminary calculation of buckling thresholds at different extension lengths and uses this information to control operation. By knowing the buckling threshold before applying force, the system can safely operate at maximum extension with appropriate force limits.
3Reliability
If a conservative maximum force limit is applied in all configurations, then safety against buckling is ensured, but the actuator utilization is reduced
Solution Approach 1:
The system changes the force parameter dynamically based on extension length rather than applying a conservative fixed limit. This allows the actuator to operate at higher utilization levels when partially extended while maintaining safety through real-time parameter adjustment based on buckling calculations.
Solution Approach 2:
The system uses feedback from extension length measurements to adjust the maximum allowable force in real-time. This feedback mechanism ensures reliability by preventing buckling while maximizing productivity by allowing higher forces when the piston is retracted.
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
Enables the actuator to exert higher forces without buckling by adjusting to varying extension lengths, optimizing performance and preventing structural failure.
Implementation Method 1
Traditionally, the buckling load of a piston is calculated via Euler's critical load formula (or Johnson's parabolic formula) using some combination of (i) the Young's modulus of the piston's material, (ii) the length of the piston when fully extended, and (iii) the distal constraints of the piston
Data Source
AI summary
A method for controlling a stroker actuator, that includes measuring a piston extension length, calculating a piston buckling threshold based on the piston extension length, measuring a piston force, making a determination that the piston force exceeds the piston buckling threshold, and based on the determination, shortening the piston extension length.