Magnetic Coil Bend Angle Sensing for Wearable Biomechanics
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Solution Overview
Problem
Existing methods for measuring bending angles between body segments, such as camera-based and inertial sensor systems, are either computationally intensive or limited in mobility and field of view, necessitating the development of a more accurate, less complex, and mobile Human Activity Recognition (HAR) technique.
Innovation Solution
A system utilizing magnetic field coupling between electromagnetic transmitting and receiving sensors, which includes coils disposed about body segments to measure angular displacement through the induction of electromagnetic fields, allowing for high-resolution and wide-range bending angle measurements with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based HAR systems are used to capture whole-body motion, then measurement precision is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent replaces complex camera-based optical measurement systems with a simple magnetic field sensing system. By using a transmitting coil and receiving coil that sense magnetic field coupling changes, the system achieves accurate bending angle measurement without requiring complex image processing or multiple cameras, thus reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent introduces magnetic field coupling as an intermediary mechanism to transmit bending angle information. Instead of directly capturing visual data with complex cameras, the system uses magnetic fields as a mediator between the body segment movement and the sensing system, simplifying the overall measurement apparatus while preserving measurement accuracy.
2Ease of operation
If inertial sensor based systems are used for measuring body movement, then device mobility is improved, but measurement precision deteriorates
Solution Approach 1:
The patent replaces inertial sensors (accelerometers, gyroscopes) with a magnetic field coupling-based sensing system. This substitution maintains the mobility advantage of wearable sensors while improving measurement precision by directly sensing angular position through magnetic field changes rather than integrating acceleration data, which accumulates errors.
3Device complexity
If capacitive coupling sensors are used for angle measurement, then device complexity is reduced, but measurement range and resolution deteriorate
Solution Approach 1:
The patent changes the physical parameter used for sensing from capacitive coupling to magnetic field coupling. By utilizing magnetic field strength and coupling efficiency as the measurement parameter, the system achieves both low complexity (simple coil structures) and high measurement range and resolution (sensitive magnetic field detection across various bending angles).
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 achieves high-resolution and wide-range bending angle measurements with low complexity and power consumption, suitable for applications in sports biomechanics, ergonomics, physical therapy, and prosthetics design.
Implementation Method 1
A real-time system for sensing bending angles between body segments can include a transmitting sensor including, a first set of one or more coils disposed about a first body segment; and a current source to drive a current having a predetermined frequency and predetermined peak-to-peak amplitude through the first set of one or more coils to radiate an electromagnetic field
Implementation Method 2
a receiving sensor including, a second set of one or more coils disposed about a second body segment; and a voltage detector to determine an open circuit voltage induced in the second set of one or more coils by the electromagnetic field radiated from the first set of one or more coils
Data Source
AI summary
Systems and methods for sensing angular displacement between body segments of users include disposing an electromagnetic transmitting sensor about a first body segment and an electromagnetic receiving sensor about a second body segment. Data related to the magnetic field coupling between the transmitting and receiving sensors can be captured for determining the angular displacement between the first and second body segments.