Cryocooler Phase Control for Adaptive Vibration Cancellation
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Solution Overview
Problem
Stirling cycle cryogenic coolers generate vibrations due to moving components, which can limit sensor performance, and existing vibration cancellation methods are inefficient in adapting to changing transfer functions and temperatures.
Innovation Solution
Adaptive phase control is implemented in the active vibration cancellation process to adjust the phase angle of cancellation signals, using mechanical phase delay offset values to optimize vibration cancellation across multiple harmonics, thereby improving the efficiency and stability of the cryogenic cooler's vibration suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adaptive feed-forward vibration control is used to suppress vibrations at fundamental frequency and harmonics, then vibration reduction is achieved, but the system becomes inefficient in adapting to changing transfer functions and temperatures
Solution Approach 1:
The system dynamically adjusts the phase angle of cancellation signals based on real-time measurements of vibration forces. The phase angle is modified according to the measured magnitude and phase angle of vibration forces from previous cancellation signals, enabling the system to adapt to changing transfer functions and temperatures while maintaining effective vibration suppression.
2Stability of the object's composition
If mechanical phase delay offset values are used to optimize vibration cancellation across multiple harmonics, then vibration suppression stability is improved, but the system requires complex phase control calculations
Solution Approach 1:
The system uses feedback from measured vibration forces to continuously adjust the phase angle of cancellation signals. The measured magnitude and phase angle of vibration forces are fed back into the control algorithm, which calculates the optimal phase angle adjustment to maintain stable vibration suppression across multiple harmonics despite the increased computational complexity.
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
The adaptive phase control significantly reduces vibrations across a range of frequencies, enhancing the performance and stability of cryogenic coolers by autonomously adjusting to changing conditions, such as temperature and orientation, without the need for extensive empirical tuning.
Implementation Method 1
piezoelectric force transducers that sense physical vibrations that the cryocooler creates and that generate electrical output signals corresponding to the sensed vibrations
Implementation Method 2
Each of these moving components is driven by a linear motor, which is part of the moving component assembly. For example, a piston assembly includes a wire coil wound around a bobbin that annularly surrounds the shaft portion of the piston; the piston assembly sits in a magnetic field, and upon receiving current through the coil, an electromagnetic force drives the piston in a linear motion
Data Source
Figure 1A~1B
Figure 2~4
Figure 5~7
AI summary
A method includes identifying (1105) a magnitude and phase angle of vibration forces resulting from a previous cancellation signal, where a first measured force vector is defined by this magnitude and phase angle. The method also includes identifying (1110) a magnitude and phase angle of a first cancellation force and transmitting (1120) a first AFF cancellation signal configured to generate the first cancellation force, where a first cancellation force vector is defined by this magnitude and phase angle. The method further includes identifying (1125) a magnitude and phase angle of vibration forces resulting from the first AFF cancellation signal, where a first resultant force vector is defined by this magnitude and phase angle. Moreover, the method includes determining (1130) whether a phase angle difference between the phase angles of the first resultant force vector and the first measured force vector is substantially equal to zero. If so, the method includes continuing (1150) to transmit the first AFF cancellation signal.