Spherical Motor for Multiaxis Control
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Solution Overview
Problem
Existing motor devices for rotating elements about two intersecting axes are complex, bulky, and heavy, often requiring complex electronic compensation for inertia and lacking independent axis control without additional components like constant velocity joints.
Innovation Solution
An electric motor device with a spherical rotor and stator, utilizing electromagnetic or piezoelectric elements for rotation and levitation, allowing independent orientations with reduced inertia and weight, and incorporating magnetic or piezoelectric means for position detection and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional multiaxis motor devices use cradle structures with rotary motors mounted on perpendicular axes, then the element can be moved in pivoting about both axes, but the structure becomes relatively complex, bulky, and heavy
Solution Approach 1:
The patent replaces the traditional mechanical cradle and rotary motor assembly with a spherical motor system where electromagnetic forces directly actuate the spherical element. The stator contains electromagnetic coils that generate magnetic fields to rotate the spherical rotor about any axis passing through its center, eliminating the need for mechanical gimbals and perpendicular motor mounts.
Solution Approach 2:
The patent employs spherical geometry for both the rotor and stator components. The spherical rotor can rotate freely about any axis passing through its center, and the spherical stator contains the electromagnetic coils that generate the rotating magnetic field. This spherical configuration inherently provides multiaxis rotation capability without complex mechanical linkages.
2Adaptability or versatility
If traditional motor devices use gimbal-like structures to enable independent axis rotation, then the element can pivot about both axes independently, but the overall size and weight increase
Solution Approach 1:
The patent eliminates mechanical gimbals and replaces them with an electromagnetic field-based system. The stator coils generate a rotating magnetic field that can independently control the orientation of the spherical rotor about any two axes, achieving independent axis control without additional mechanical components that would increase weight.
Solution Approach 2:
The spherical motor system serves multiple functions with a single integrated structure. The same electromagnetic coils in the stator that generate rotational force also enable independent control about multiple axes, eliminating the need for separate gimbal mechanisms and reducing overall device weight.
3Device complexity
If the first axis carries the second axis directly with associated motors and elements, then the structure is simplified, but unbalance and inertia are difficult to compensate
Solution Approach 1:
The patent replaces the mechanical axis-carrying structure with a spherical motor system where the spherical rotor is suspended within the spherical stator. This eliminates the mechanical hierarchy of axes carrying each other, and the electromagnetic suspension provides inherent balance, eliminating unbalance and inertia compensation issues.
Solution Approach 2:
The electromagnetic field generated by the stator coils acts as an active counterbalance system. By precisely controlling the magnetic field distribution, the system can compensate for any unbalance or inertial effects, maintaining stable operation without requiring passive counterweights or complex compensation mechanisms.
4Device complexity
If electromagnetic elements with magnets and coils are used for rotor levitation and movement, then friction is limited and structure is simplified, but precise position control requires sophisticated electrical means
Solution Approach 1:
The patent uses electromagnetic fields for both actuation and sensing. The same stator coils that generate the magnetic field for rotor movement can detect the rotor's position by measuring changes in magnetic field characteristics, eliminating the need for separate mechanical sensors and simplifying the overall system while maintaining precision.
Solution Approach 2:
The electromagnetic system serves dual functions: the stator coils generate the magnetic field for rotor actuation and simultaneously detect rotor position through magnetic field sensing. This self-service capability eliminates the need for separate sensing mechanisms and reduces system complexity while maintaining precise position control.
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 solution results in a compact, lightweight motor device with simplified mechanical complexity, reduced friction, and effective position control, suitable for applications like aircraft control surfaces with improved force return to the pilot.
Implementation Method 1
the rotor is fitted with at least two magnets with alternating polarization and the stator is fitted with at least one coil that is preferably controlled to move the rotor and to provide levitation for the rotor in the stator
Implementation Method 2
the electrical means comprise piezoelectric elements arranged in pairs and controlled to give rise to creeping movement of said elements so as to move the rotor
Data Source
AI summary
An electric motor device includes a rotor, a stator, and electrical means for driving rotation of the rotor relative to the stator, the device being characterized in that the stator includes a substantially spherical cavity receiving the rotor, which is itself substantially spherical, and in that the electrical means are arranged to drive the rotor in rotation about at least two axes.