Cryocooler Frequency Scaling to Match CMG Operation and Reduce Jitter
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Solution Overview
Problem
Existing cryogenic coolers for space-borne systems, particularly those with electro-optic/infrared sensor systems, face challenges due to vibration disturbances and high costs associated with cryoradiators, as they often operate at frequencies (30-70 Hz) that are not compatible with control moment gyroscopes (CMGs) operating at 100 Hz, leading to line-of-sight jitter and increased vibration.
Innovation Solution
A cryocooler system is designed to operate at the CMG frequency of 100 Hz, featuring a compressor with piston assemblies coupled to flexures and an advanced regenerator, along with an inertance channel and surge volume, to match the exported disturbances of CMGs, resulting in reduced size, weight, and improved cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If cryocooler operates at 30-70 Hz, then cooling function is provided, but vibration disturbance increases and causes line-of-sight jitter
Solution Approach 1:
The patent changes the operating frequency parameter of the cryocooler from conventional 30-70 Hz to match the CMG operating frequency of 100 Hz. This parameter change resolves the technical contradiction by operating in a frequency range that avoids resonance with optical systems while maintaining effective cooling performance through optimized component design for high-frequency operation.
2Object-affected harmful factors
If cryocooler operates at 100 Hz matching CMG frequency, then vibration disturbance is reduced, but device complexity increases due to component scaling
Solution Approach 1:
The patent applies parameter changes by scaling component dimensions and optimizing design parameters specifically for 100 Hz operation. The piston assemblies, flexures, and regenerator are designed with modified geometries and material properties to achieve effective cooling at the higher frequency, managing the complexity through targeted parameter optimization rather than fundamental design changes.
Solution Approach 2:
The patent incorporates dynamic elements including piston assemblies coupled to flexures that provide compliant mounting and vibration isolation. The dynamic design of the regenerator and pulse tube system is optimized for high-frequency operation, allowing the system to adapt to 100 Hz oscillations while maintaining cooling effectiveness and reducing transmitted vibrations.
3Weight of stationary object
If component sizes are reduced for higher frequency operation, then weight and size decrease, but manufacturing precision requirements increase
Solution Approach 1:
The patent reduces component sizes and weights by optimizing dimensions for 100 Hz operation, where smaller masses can achieve the required cooling capacity at higher frequencies. The manufacturing precision challenges are managed through careful selection of materials with appropriate mechanical properties and optimization of geometric parameters to maintain structural integrity and thermal performance with reduced dimensions.
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 achieves reduced size and weight by up to 20% and enhanced cooling efficiency, simplifying integration and eliminating the need for complex isolation systems, while maintaining structural robustness and low system complexity.
Implementation Method 1
a compressor configured to operate at a selected frequency matching an operating frequency of the one or more control moment gyroscopes
Implementation Method 2
one or more piston assemblies coupled to flexures configured to communicate a spring force to one or more pistons within the one or more piston assemblies
Implementation Method 3
a regenerator assembly, the cold tip configured to provide cooling to a structure external to the cryocooler
Implementation Method 4
a cold tip in fluid communication with a surge volume via an inertance channel
Data Source
Figure 1
Figure 1A~1C
Figure 2A~2B
AI summary
Components (101-102) within a cryocooler (100) are scaled and/or configured for operation at a CMG operating frequency (e.g., 100 Hz) rather than at 30 to 70 Hz, matching the exported disturbances of control moment gyroscopes on the same platform and reducing line-of- sight jitter for electro-optic infrared focal plane array sensors. The smaller piston working volume and other reduced component sizes allow the cryocooler to be smaller and lighter than designs operating at lower frequencies. Combined with an advanced regenerator (124) suitable for the higher frequency operation, the cryocooler has improved cooling efficiency over such lower frequency designs.