Magnetic Ball Drive Coupling for Spherical Wheel Traction

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Solution Overview

Problem

Spherical wheel-based mobile robots face challenges with slip and traction issues due to external support structures, which lead to motion errors and contamination, and existing magnetic induction and traction-based systems have low actuation efficiency and require frequent maintenance.

Innovation Solution

A magnetically coupled ball drive system with an internal support structure and controllable magnetic force, using permanent magnets and ferromagnetic materials, eliminates the need for external support structures, allowing for adjustable traction forces and reduced slip by shielding the internal components from debris and enabling omnidirectional actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external support structures are used to connect spherical wheels to chassis, then the spherical wheels can be mounted and supported, but slip and contamination occur leading to motion errors and degradation of performance

Engineering Contradiction:

Improveactuation performanceVSAvoidslip and contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the external support structure (frame) that connected the spherical wheel to the chassis and replaces it with a magnetic coupling system. The magnetic coupler attaches the spherical wheel directly to the chassis through magnetic attraction, eliminating the mechanical contact points that caused slip and contamination. This extraction of the harmful external support structure resolves the contradiction by maintaining structural connection while eliminating slip and debris contamination.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical support structure with a magnetic field-based coupling system. Instead of using physical contact between the frame and spherical wheel, the magnetic coupler uses magnetic attraction forces to maintain the connection. This substitution eliminates mechanical slip and contamination while maintaining the necessary structural support, thereby improving reliability without the harmful effects of external mechanical supports.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If magnetic induction is used for actuation, then actuation is achieved, but actuation efficiency is very low

Engineering Contradiction:

Improveactuation efficiencyVSAvoidactuation efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent replaces magnetic induction (electromagnetic actuation) with direct magnetic coupling using permanent magnets. Instead of using electromagnetic induction which has low efficiency, the system uses permanent magnets in the magnetic coupler to create a strong, direct magnetic attraction between the spherical wheel and chassis. This mechanical-like magnetic coupling provides high actuation efficiency with minimal energy loss, resolving the contradiction between achieving actuation and maintaining efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Force

If traction forces are increased to maximize traction, then traction force is improved, but slip occurs when the limit is exceeded

Engineering Contradiction:

Improvetraction forceVSAvoidmotion accuracy

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent changes the magnetic coupling strength parameter to optimize the balance between traction force and slip prevention. By adjusting the magnetic attraction force in the magnetic coupler, the system maintains optimal normal force between the spherical wheel and chassis, ensuring sufficient traction while preventing slip. This parameter optimization resolves the contradiction by allowing high traction forces without exceeding the slip threshold, maintaining motion accuracy.

Inventive Principle:

Principle #35Parameter changes

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 minimizes slip and maximizes traction force, reducing maintenance needs and improving the reliability and efficiency of spherical wheel actuation across various terrains and conditions, while maintaining low rolling resistance and preventing contamination.

Implementation Method 1

a magnetic coupler coupling the internal support structure of the spherical wheel to the first pair of drive wheels via a controllable magnetic force

Methodology Applied

Scientific EffectMagnetic attraction force: Magnetism

Implementation Method 2

A repulsive magnetic force is applied from the outer surface of the spherical wheel to prevent contact with the external yoke

Methodology Applied

Scientific EffectRepulsive magnetic force: Ion Repulsion/Attraction

Data Source

PatentUS12051958B2Magnetically coupled ball drive for actuation of spherical surfaces

Publication Date: 2024.07.30 STEVENS INSTITUTE OF TECHNOLOGY

AI summary

A magnetically coupled ball drive system for actuation of spherical surfaces and wheels is disclosed. An internal support structure interacts with exterior drive wheels magnetically to produce rotational motion. A related improvement involving reduction of slip due to insufficient traction is also presented to establish a design for a more robust and versatile device that can be used in robotics or for producing vehicle locomotion.