Two Degree-of-Freedom Spherical Motor with Arc-Shaped Poles
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Solution Overview
Problem
Current spherical motors for applications like UAVs and robotics face limitations in torque, thermal handling, and complexity due to large air gaps and heavy stator designs, leading to inefficient performance and complicated winding patterns.
Innovation Solution
A two-degree-of-freedom brushless DC motor design featuring a stator with arc-shaped poles and distributed windings, along with a rotor configured to rotate about perpendicular axes, which reduces air gap and weight, enhancing torque and thermal management through a simpler winding configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a large air gap is used between magnets and inner spherical stator, then the spherical motor can accommodate windings, but the generated torque is reduced
Solution Approach 1:
The patent transitions from a conventional cylindrical motor structure to a spherical structure, fundamentally changing the spatial dimension and geometry. This spherical configuration allows windings to be arranged in a three-dimensional space around the rotor, maximizing winding density and magnetic interaction while maintaining a compact design that generates high torque without requiring a large air gap
2Strength
If a heavy spherical stator is used, then the motor structure is more robust, but the generated torque is reduced
Solution Approach 1:
The patent applies local quality by strategically placing magnets only in specific regions of the spherical rotor where they are most effective for generating torque. This localized magnet arrangement, combined with optimized winding distributions in different spherical zones, maximizes the magnetic interaction efficiency and torque generation while minimizing the overall mass of the stator structure
Solution Approach 2:
The patent employs composite material strategies by using magnetically soft materials for the stator structure combined with magnetically hard materials for the rotor magnets. This material selection optimizes both the structural integrity and magnetic field generation, achieving high torque output without requiring excessive stator mass
3Power
If complex winding patterns are used, then the motor can achieve desired performance, but the winding process becomes complicated and time-consuming
Solution Approach 1:
The patent segments the winding system into distinct modular components arranged in specific spherical zones. By dividing the windings into separate modules that can be independently manufactured and assembled, the complex three-dimensional winding pattern becomes manageable through systematic segmentation, reducing manufacturing complexity while maintaining optimal magnetic field distribution for high performance
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 design achieves improved torque output, better thermal handling, and a more compact, reliable structure with higher power density, addressing the limitations of existing spherical motors.
Implementation Method 1
A two degree-of-freedom brushless DC motor includes a stator, a rotor, a plurality of distributed stator windings, and a stator voice coil winding
Implementation Method 2
The rotor includes a plurality of magnets and is configured to rotate about a plurality of perpendicular axes
Data Source
AI summary
A two degree-of-freedom brushless DC motor includes a stator, a rotor, a plurality of distributed stator windings, and a stator voice coil winding. The stator includes an inner stator structure and a plurality of arc-shaped stator poles. The inner stator structure includes a main body and a plurality of spokes that are spaced apart from each other to define a plurality of stator slots. Each arc-shaped stator pole is connected to a different one of the spokes. The rotor is spaced apart from the stator, includes a plurality of magnets, and is configured to rotate about a plurality of perpendicular axes. The distributed stator windings are wound around the plurality of spokes and extend through the stator slots. The stator voice coil winding is wound around the outer surfaces of the arc-shaped stator poles. The arc-shape and spacing of the stator poles define the stator as being spherically shaped.