Wearable Joint Angle Sensor With Magnetic Self-Alignment

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing goniometers for measuring joint angles during physical therapy suffer from inaccuracies due to variable attachment locations by clinicians, affecting reproducibility and accuracy of measurements.

Innovation Solution

A wearable device with a center hub and pivotally coupled arms, equipped with a magnet and sensor, allows for precise alignment and measurement of joint angles, utilizing a magnet for rotation detection and a printed circuit board for data transmission, enhancing accuracy and reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a standard goniometer is used with manual attachment by clinicians, then the device can measure joint angles, but the accuracy and reproducibility of measurements are compromised due to variable attachment locations

Engineering Contradiction:

Improvejoint angle measurement accuracyVSAvoidmeasurement reproducibility

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the manual mechanical attachment system with a magnetic coupling system. Magnets embedded in the goniometer arms interact with magnetic components on the user's body, enabling automatic alignment and attachment without manual positioning by clinicians. This magnetic substitution eliminates variability in attachment location and ensures consistent, reproducible measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The goniometer device performs self-alignment through magnetic attraction forces. The magnetic components automatically draw the goniometer arms to the correct positions on the user's body without requiring clinician intervention for positioning. This self-service mechanism ensures that attachment locations are consistent and reproducible across different users and clinicians.

Inventive Principle:

Principle #25Self-service

2Ease of operation

If manual attachment and positioning is performed by clinicians, then the device can be positioned on the user, but the accuracy is affected by clinician experience and variability in placement

Engineering Contradiction:

Improvedevice attachment easeVSAvoidjoint angle measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The manual mechanical positioning process is replaced with an automated magnetic alignment system. The magnetic forces automatically position the goniometer arms at the correct locations on the user's body, eliminating the influence of clinician experience and skill level on measurement accuracy. This makes the device equally accurate whether used by an expert or novice clinician.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Magnetic fields serve as an intermediary between the goniometer device and the user's body. The magnets on the goniometer arms interact with magnetic components embedded in the body or clothing, creating an automatic alignment mechanism that bridges the gap between the device and the measurement target without requiring manual positioning intervention.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the goniometer uses a fixed attachment system, then the structure is simple, but the ability to accommodate different users and body types is limited

Engineering Contradiction:

Improveattachment system complexityVSAvoiduser adaptability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The fixed mechanical attachment system is replaced with a flexible magnetic coupling system. The magnetic forces can adapt to different users, body types, and joint positions without requiring complex adjustable mechanisms. The simplicity of the magnetic interaction provides both ease of use and versatility across different applications.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 device achieves accurate joint angle measurements up to a hundredth of a degree, improving patient monitoring and therapy effectiveness by reducing variability in attachment placement.

Implementation Method 1

The sensor is disposed in the center hub and configured to detect a rotation of the magnet

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS12495987B2Wearable device for coupling to a user, and measuring and monitoring user activity

Publication Date: 2025.12.16 ROM TECH INC

AI summary

A system for measuring an angle of a joint of a user includes a center hub, a first arm, a second arm, a magnet, and a sensor. The center hub includes a first hub and a second hub. The first arm is configured for attachment to a first limb portion of the user at a first outer end and to the first hub at a first inner end. The second arm is configured for attachment to a second limb portion of the user at a second outer end and to the second hub at a second inner end, wherein the first hub is pivotally coupled to the second hub. The magnet is coupled to the second hub. The sensor is disposed in the center hub and configured to detect a rotation of the magnet.