Aircraft Hydraulic Actuator Damping Test via Velocity Correction
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Solution Overview
Problem
Existing damping test methods for hydraulically operated actuators in aircraft without pressure sensors are unreliable due to variations from manufacturing tolerances, effective working pressure, and measurement errors, which complicates the determination of damping force and can lead to inaccurate results.
Innovation Solution
A damping test method that acquires and corrects the ideal velocity characteristic of the control surface using temperature and operating speed data, sets upper and lower limits based on predicted fluctuations, and determines if the measured operating speed falls within these limits, thereby minimizing the impact of manufacturing and measurement variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are used to measure damping force, then measurement precision is improved, but device complexity and system weight increase
Solution Approach 1:
The patent replaces the mechanical/physical pressure sensors with a control-based measurement system. The control apparatus calculates damping force by analyzing operational parameters (operating speed, temperature) and comparing them against ideal characteristics, substituting physical measurement devices with computational analysis to reduce system complexity while maintaining measurement capability
Solution Approach 2:
The patent introduces operational parameters (operating speed, temperature) as intermediary measurements that indirectly reflect damping force characteristics. Instead of directly measuring pressure/damping force with sensors, the system uses these intermediary parameters as proxies to assess actuator performance, thereby avoiding the need for complex pressure sensing hardware
2Measurement precision
If pressure sensors are installed in hydraulic lines, then measurement precision is improved, but weight of stationary object increases
Solution Approach 1:
The patent extracts the measurement function from physical pressure sensors and relocates it to the control apparatus through computational algorithms. By removing the pressure sensors from the hydraulic system, the system achieves the desired measurement capability without the weight penalty of sensor hardware, effectively extracting the measurement function from the physical domain to the computational domain
3Device complexity
If damping test is performed without pressure sensors, then device complexity is reduced, but measurement precision deteriorates due to manufacturing tolerances and variations
Solution Approach 1:
The patent implements feedback by continuously comparing actual operational parameters (operating speed, temperature) against ideal characteristics and using this comparison to assess damping force. The control apparatus monitors operational deviations and uses feedback loops to calculate damping characteristics, compensating for manufacturing variations through real-time comparative analysis
Solution Approach 2:
The patent changes the measurement approach by shifting from direct physical pressure measurement to indirect parameter-based assessment. The system measures and analyzes operational parameters (speed, temperature) that correlate with damping characteristics, transforming the measurement problem from direct physical quantity measurement to relational parameter analysis that accounts for manufacturing variations
4Reliability
If safety margin is increased in actuator and hydraulic line design, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent performs preliminary characterization of ideal actuator characteristics during the design phase, establishing baseline performance parameters. By pre-defining these ideal characteristics, the system can later assess actual performance deviations without requiring excessive safety margins in the physical design, as the assessment framework already accounts for expected variations
Data Source
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AI summary
The control apparatus acquires an ideal velocity characteristic of a control surface(104,105), and the temperature of pressure oil of the actuator (11,12) to be tested and the operating speed of the control surface (104,105) when the actuator is attached to the control surface. The control apparatus corrects the ideal velocity characteristic of the control surface by using the pressure oil temperature and the control surface operating speed. The control apparatus sets an upper limit and a lower limit by using a predicted value for a fluctuation range for a fluctuation factor that causes a fluctuation of the control surface operating speed, with reference to the corrected ideal velocity characteristic, measures the pressure oil temperature and the operating speed by actuating the control surface (104,105), with the actuator to be tested placed in a damping mode, and determines whether the measured value falls within the range between the upper limit and the lower limit.