Cryocooler Vibration Control Using FPGA-Based Harmonic Processing
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Solution Overview
Problem
Cryocoolers used in satellites to cool imaging payloads generate vibrations that degrade image quality, and existing digital signal processor (DSP) based vibration cancellation systems are costly and power-intensive, making them unsuitable for deep space missions.
Innovation Solution
A vibration control system utilizing a field programmable gate array (FPGA) with discrete Fourier transforms (DFT) to process the harmonics of the cryocooler motor drive, minimizing resource usage and costs while effectively mitigating vibrations, and includes a vibration sensor and cryocooler drive electronics to adjust the drive waveform and reduce vibration impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DSP-based vibration cancellation processing is used, then vibration mitigation performance is improved, but cost and power consumption increase
Solution Approach 1:
The patent replaces the traditional DSP-based vibration cancellation system with an FPGA-based system that uses discrete Fourier transforms (DFT) to process cryocooler motor drive harmonics. This substitution reduces power consumption and cost while maintaining effective vibration mitigation through harmonic processing and drive waveform adjustment.
2Reliability
If DSP-based vibration cancellation processing is used, then vibration mitigation performance is improved, but device complexity and cost increase
Solution Approach 1:
The patent substitutes a simpler FPGA-based DFT processing system for the complex DSP-based system. The FPGA implementation with DFT algorithms provides equivalent vibration cancellation performance with reduced device complexity and lower cost, making it suitable for space-based imaging platforms.
3Ease of manufacture
If FPGA-based design is used, then cost and radiation tolerance are improved, but digital signal processing resources are limited
Solution Approach 1:
The patent changes the signal processing approach from full-spectrum DSP processing to targeted DFT processing at specific harmonic frequencies of the cryocooler motor drive. This parameter change allows the FPGA to achieve effective vibration mitigation using its limited digital signal processing resources, while maintaining cost-effectiveness and radiation tolerance for space missions.
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 system provides effective vibration mitigation with reduced resource consumption and costs, enabling its use in deep space missions while maintaining image quality, by using DFT to process the cryocooler's harmonic content and adjust the drive waveform based on vibration signals.
Implementation Method 1
a vibration sensor that is physically affixed to the cryocooler. The vibration sensor senses a physical vibration of the cryocooler and to generates a vibration signal therefrom
Implementation Method 2
The harmonic content of the cryocooler drive waveform is controlled by the cryocooler drive electronics based on the vibration signal
Data Source
AI summary
A system for vibration control of a cryocooler that cools an imager. The system includes a vibration sensor that is physically affixed to the cryocooler. The vibration sensor senses a physical vibration of the cryocooler and to generates a vibration signal therefrom. The system also includes cryocooler drive electronics operatively coupled to the vibration sensor and the cryocooler. The cryocooler drive electronics output a drive waveform that drives the cryocooler so as to reduce the vibration impact of the cryocooler. The harmonic content of the cryocooler drive waveform is controlled by the cryocooler drive electronics based on the vibration signal.