Magnetically Levitated Spherical Magnet for 3D Attitude Control
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Solution Overview
Problem
Existing attitude control systems for spacecraft rely on mechanical rotors and propulsive thrusters, which are bulky, power-intensive, and have finite lifetimes, leading to potential failures and propellant expenditure.
Innovation Solution
A system utilizing rotatable magnetic masses within sets of coils, enabling three-dimensional attitude control through magnetic torques and levitation, eliminating mechanical bearings and propellant reliance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical reaction wheels are used for attitude control, then three-axis control capability is achieved, but mechanical wear and finite lifetime occur
Solution Approach 1:
The patent replaces mechanical reaction wheels with magnetic field-based control. A magnetically levitated spherical dipole magnet is suspended within coils, and attitude control is achieved through magnetic torques rather than mechanical rotation. This eliminates mechanical bearings, lubrication, and physical wear, thereby extending system lifetime and improving reliability.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the control system and the satellite body. Electromagnetic coils generate magnetic fields that interact with the magnetized sphere to produce torques for attitude control, serving as a non-contact intermediary that replaces direct mechanical actuation.
2Reliability
If mechanical reaction wheels are used for attitude control, then three-axis control capability is achieved, but size, weight, and power are increased
Solution Approach 1:
The patent replaces heavy mechanical reaction wheels with a lightweight magnetic levitation system. The spherical magnet suspended in electromagnetic fields requires no mechanical structure, bearings, or lubrication systems, dramatically reducing the weight of the attitude control system while maintaining three-axis control capability.
Solution Approach 2:
The magnetically levitated sphere serves multiple functions simultaneously: it acts as both the control moment gyroscope and the reaction mass, while the same electromagnetic coils provide both levitation and torque generation. This multi-functionality reduces the overall system weight compared to traditional separate components.
3Duration of action of moving object
If reaction control thrusters are used to expend momentum, then wheel rotation rate is reduced, but propellant is consumed
Solution Approach 1:
The patent replaces mechanical reaction wheels that require propellant-based momentum dumping with a magnetic field system. The magnetically levitated sphere can be decelerated and reversed using electromagnetic torques without any propellant consumption, eliminating the trade-off between wheel lifetime and propellant usage.
4Reliability
If magnetic levitation is used for attitude control, then mechanical wear is eliminated, but active control power is required
Solution Approach 1:
The patent employs continuous electromagnetic fields to maintain magnetic levitation and control the magnetized sphere. The coils continuously generate magnetic fields to provide both levitation force and control torque, ensuring uninterrupted attitude control without mechanical contact or wear, thereby extending system lifetime despite continuous power consumption.
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
Provides reduced size, weight, and power consumption, extended operational lifetime, and failsafe operation by avoiding mechanical wear and propellant use, while offering redundant three-dimensional control.
Implementation Method 1
A non-propulsive, three-dimensional attitude control system can include a set of coils operable to exert torques onto a spherical dipole magnet in three dimensions
Implementation Method 2
The set of coils may include diamagnetic material to passively stabilize a location of the magnet within the set of coils
Data Source
AI summary
Embodiments provided herein include rotatable magnets (e.g., spherical dipole magnets) disposed within sets of coils that can be used to operate the magnets as reaction/momentum “spheres” and/or as control moment gyroscopes. The coils are able to exert three-dimensional torques onto the magnet in order to effect attitude control of a satellite or other system. The coils can also optionally exert translational forces onto the magnet in order to maintain the magnet in position and avoid contact with static components. Diamagnetic materials can also be included to provide stabilizing repulsive magnetic forces to maintain the magnet in position and/or to reduce the necessary performance of the coils with respect to applying stabilizing translational forces.