Adjustable Superconducting Magnetic Spring Oscillator
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Solution Overview
Problem
Existing vertical superconducting magnetic mass-spring oscillators face challenges with hollow niobium balls due to processing difficulties and severe cross-coupling effects, while non-spherical proof masses result in high stiffness, high natural frequency, and increased instrument noise, particularly affecting low-frequency signal measurements.
Innovation Solution
A vertical superconducting magnetic mass-spring oscillator with an adjustable natural frequency is designed, utilizing a semi-closed barrel proof mass and a combination of negative-stiffness and positive-stiffness superconducting coils to balance gravity and adjust stiffness through magnetic repulsive forces, reducing cross-coupling and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer tightly wound disc type superconducting coil is used to levitate the proof mass, then the proof mass can be fully levitated without mechanical connection, but the magnetic field gradient becomes large, resulting in high stiffness and high natural frequency
Solution Approach 1:
The single superconducting coil is divided into two separate coils: a first superconducting coil and a second superconducting coil. This segmentation allows independent control of magnetic field gradients, enabling reduction of the overall magnetic field gradient while maintaining levitation capability. The first coil generates a magnetic field gradient in a first direction, while the second coil generates a magnetic field gradient in a second direction, and their combined effect reduces the total gradient acting on the proof mass.
Solution Approach 2:
Different regions of the magnetic field are given different properties through the two-coil configuration. The first coil provides magnetic field support in one direction while the second coil provides support in another direction, allowing local optimization of magnetic field distribution. This enables reduction of magnetic field gradient in critical regions while maintaining adequate levitation force.
2Stability of the object's composition
If a hollow niobium ball is used as proof mass, then spherical geometry provides uniform magnetic field distribution, but processing difficulty increases and cross-coupling effects become severe
Solution Approach 1:
The invention transitions from a spherical proof mass to a cylindrical proof mass with asymmetric coil positioning. The two superconducting coils are positioned at different locations relative to the cylindrical proof mass, creating an asymmetric magnetic field configuration that reduces cross-coupling effects between vertical and horizontal motions while maintaining ease of manufacturing for both the cylindrical mass and coil structures.
Solution Approach 2:
The system introduces dynamic control capabilities through independent current control of the two superconducting coils. By dynamically adjusting the currents in each coil, the magnetic field distribution can be optimized in real-time to reduce cross-coupling effects and improve manufacturing feasibility without sacrificing field uniformity where needed.
3Stability of the object's composition
If high stiffness is achieved through strong magnetic field gradient, then levitation stability improves, but the transfer function from acceleration to displacement decreases and instrument noise increases
Solution Approach 1:
The system enables dynamic adjustment of stiffness characteristics through independent control of currents in the two superconducting coils. By optimizing the current distribution, the magnetic field gradient can be tuned to achieve adequate levitation stability while maintaining a softer overall spring constant, thereby improving the transfer function from acceleration to displacement and reducing instrument noise.
Solution Approach 2:
The invention changes the magnetic field configuration parameters by using two coils with different orientations and positions instead of a single coil. This parameter change allows decoupling of levitation stability requirements from overall stiffness requirements, enabling stable levitation with lower effective stiffness and improved measurement sensitivity.
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 adjustable natural frequency and reduced stiffness enable low-frequency signal measurement capabilities with reduced cross-coupling, enhancing the performance of superconducting gravity measuring instruments and inertial sensors.
Implementation Method 1
uses several sets of superconducting solenoid coils to generate a small gradient magnetic field so as to enable levitation of the proof mass
Implementation Method 2
by using the Meissner-state superconductor as a proof mass, a mass-spring oscillator a superconducting magnetic mass-spring oscillator can be constructed by the magnetic interaction between the superconducting current-carrying coil and the Meissner-state superconductor
Implementation Method 3
the single-layer tightly wound disc type superconducting coil in the barrel generates a large magnetic field gradient, and the mass-spring oscillator has a large stiffness
Implementation Method 4
The mass-spring oscillator works at a low temperature of 4.2 K; the full levitation of the proof mass can be achieved without mechanical connection, so that the mass-spring oscillator has only residual gas damping, and the quality factor (Q value) is high; and the superconducting coil constructing the oscillator is in a zero resistance state
Data Source
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AI summary
The present invention discloses a vertical superconducting magnetic mass-spring oscillator with an adjustable natural frequency, comprising: a proof mass, a negative-stiffness superconducting coil and a positive-stiffness superconducting coil; the negative-stiffness superconducting coil is mounted at an opening of a semi-closed space of the proof mass, so that a part of magnetic lines of the negative-stiffness superconducting coil are in a compressed state in a closed space of the proof mass, and the other part of the magnetic lines of the negative-stiffness superconducting coil are in an expanded state outside the closed space of the proof mass; a vertical magnetic repulsive force applied to the proof mass by the negative-stiffness superconducting coil varies with a displacement of the proof mass from an equilibrium position, with the variation magnitude proportional to the displacement and the variation direction the same as the displacement direction; and the positive-stiffness superconducting coil is mounted in the semi-closed space of the proof mass, and a vertical magnetic repulsive force applied to the proof mass by the positive-stiffness superconducting coil varies proportionally to the displacement of the proof mass from the equilibrium position, with the variation direction opposite to the displacement direction. The present invention realizes that the natural frequency of the superconducting mass-spring oscillator is adjustable, and meanwhile, the cross-coupling effect of horizontal and vertical degrees of freedom of the proof mass can be reduced.