MR Fluid Clutch Torque Modulation for Natural Strength Training

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Solution Overview

Problem

Conventional strength training devices often fail to provide optimal force modulation, leading to uneven resistance throughout a range of motion, resulting in 'sticking points' and inefficiencies in muscle training, particularly when multiple degrees of freedom are involved, and do not adapt well to the user's movement, making them feel unnatural and less effective.

Innovation Solution

The use of magnetorheological (MR) fluid clutch apparatuses with a higher bandwidth than human muscles, which provide dynamic force modulation, allowing for smooth and natural interaction by varying resistance based on position and direction, enabling more effective and personalized training.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional strength training devices use gravity or springs to provide force modulation, then the device structure is simple, but the force modulation is linear or unidirectional and does not match muscle strength variations

Engineering Contradiction:
Improveforce modulation adaptabilityVSAvoiddevice structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical force modulation systems (gravity, springs, pulleys, cams) with an electromagnetic brake system. This substitution enables dynamic, time-dependent force modulation that can adapt to muscle strength variations throughout the range of motion, transforming the linear or unidirectional force characteristics into non-linear, position-dependent force profiles that better match physiological requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces dynamic force modulation capabilities by making the resistance variable throughout the range of motion. The electromagnetic brake system allows the force characteristics to change dynamically based on position and movement phase, enabling the device to provide appropriate resistance levels during concentric and eccentric phases of exercise, rather than maintaining constant or linear force modulation.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If conventional devices provide direct force modulation only within a limited range of movement, then the device structure is simple, but there is no direct force modulation at many points and no time-dependent force modulation

Engineering Contradiction:
Improveforce modulation coverageVSAvoidcontrol system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces limited-range mechanical force modulation mechanisms with an electromagnetic brake system controlled by a processor. This enables continuous force modulation across the entire range of motion, with the ability to provide time-dependent force profiles that adapt to the specific phase of movement, eliminating the limitation of force modulation being available only at specific positions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a control system that monitors movement parameters and adjusts force modulation in real-time based on the user's position and velocity. This feedback mechanism enables the electromagnetic brake to provide appropriate resistance throughout the complete range of motion, ensuring continuous direct force modulation that matches the physiological demands of the exercise.

Inventive Principle:
Principle #23Feedback

3Productivity

If the force modulation does not match the strength generated by human muscles at different bending angles and movement directions, then the device structure is simple, but sticking points are encountered and training efficiency is reduced

Engineering Contradiction:
Improvetraining efficiencyVSAvoidforce modulation system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements dynamic force modulation that varies throughout the range of motion to match muscle strength characteristics. The electromagnetic brake system adjusts resistance based on the current position and movement phase, providing lower resistance when muscles are stronger and higher resistance when muscles are weaker, thereby eliminating sticking points and optimizing training efficiency across all phases of exercise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the force modulation parameters dynamically based on movement phase and position. By adjusting the electromagnetic brake characteristics in real-time, the system transforms the force profile to match physiological requirements, enabling different resistance levels during concentric and eccentric movements and at different joint angles, thereby eliminating sticking points and improving overall training effectiveness.

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 MR fluid clutch system ensures a more natural and effective strength training experience by providing consistent and adaptive resistance, improving muscle engagement and reducing the risk of injury through optimal force modulation and higher bandwidth interaction.

Implementation Method 1

magnetorheological (MR) fluid clutch apparatuses

Methodology Applied
Scientific EffectMagnetorheological effect: Magnetorheological Fluid

Data Source

PatentEP3341089B1Strength training device using magnetorheological fluid clutch apparatus
Publication Date: 2021.04.14 EXONETIK INC
  • EP3341089B1 patent drawingFigure 1~2A
  • EP3341089B1 patent drawingFigure 2B~3
  • EP3341089B1 patent drawingFigure 4~5b

AI summary

A system for assisting a user in strength training with a strength training device comprises a torque source. One or more magnetorheological (MR) fluid clutch apparatuses has an input coupled to torque source to receive torque from the torque source, the MR fluid clutch apparatus controllable to transmit a variable amount of torque via an output thereof. A modulation interface couples the output of the at least one MR fluid clutch apparatus to a force transmission of the training device. One or more sensors provide information indicative of a training action by the user. A training processor comprises a training effort calculator module for receiving the information indicative of the training action and for characterizing the training action, a training assistance controller module for determining a level of force assistance from the characterizing of the training action, and an assistance generator module for controlling the at least one MR fluid clutch apparatus in exerting the force assistance at said level on the force transmission of the training device to assist the user in the training action. A method for assisting a user in strength training with a MR fluid clutch apparatus is also provided.