Stretchable Conductive Textile for EIT-Based Joint Movement Detection
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Solution Overview
Problem
Existing smart clothing technologies are unable to reliably measure human movements such as arm, shoulder, or knee extensions, which are crucial for health prevention against musculoskeletal disorders, due to limitations in existing Electrical Impedance Tomography (EIT) applications that are exclusively focused on pressure measurement.
Innovation Solution
A stretchable conductive fabric with electrodes and a neural network-based system that applies TIE principles to measure joint movements by exciting electrodes in various schemes and using a neural network inference engine to predict joint angles from voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Electrical Impedance Tomography (EIT) is applied to smart clothing, then pressure measurement capability is achieved, but movement detection capability is lost
Solution Approach 1:
The patent applies EIT technology to achieve multi-functionality in smart clothing, enabling both pressure measurement and movement detection through a single integrated system. The conductive fabric and electrode array can detect different types of physical stimuli (pressure and movement) using the same underlying electrical impedance measurement principle, thus resolving the contradiction between specialized pressure measurement capability and general movement detection versatility
2Measurement precision
If camera-based solutions are used for movement capture, then visual measurement is achieved, but device bulk increases
Solution Approach 1:
The patent replaces camera-based optical measurement systems with an electrical field-based EIT system. Instead of using cameras to visually capture movement, the invention uses electrodes and conductive fabric to detect movement through changes in electrical impedance, thereby eliminating the bulk associated with camera hardware while maintaining movement detection capability
3Device complexity
If inertial sensors are used for movement detection, then portability is improved, but measurement accuracy deteriorates
Solution Approach 1:
The patent replaces inertial sensors with an EIT-based electrical field sensing system. The conductive fabric and electrode array detect movement through electrical impedance changes, providing a portable solution without the bulky inertial measurement units while achieving accurate movement detection through the distributed sensing capability of the conductive fabric
4Measurement precision
If EIT uses traditional electrode arrangement, then pressure measurement is achieved, but extension measurement capability is lost
Solution Approach 1:
The patent segments the conductive fabric into multiple discrete electrode regions arranged in a specific pattern. This segmentation allows the system to differentiate between pressure-induced impedance changes and extension-induced impedance changes by analyzing the spatial distribution of electrical signals across the segmented electrode array, thereby enabling both pressure and extension measurement capabilities
Solution Approach 2:
The patent extends the measurement capability from two-dimensional pressure mapping to three-dimensional movement detection by arranging electrodes in a spatial pattern that captures impedance changes in multiple directions. This dimensional extension allows the system to detect not only pressure magnitude but also the direction and type of movement (compression vs. extension)
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 provides accurate joint angle measurements with minimal error, overcoming the limitations of existing technologies by being compact, cost-effective, and independent of visibility or occlusions, while enabling longitudinal measurement of human movements.
Implementation Method 1
The invention proposes a textile adapted for the detection of motion and/or deformation which makes use of principles of the TIE method
Implementation Method 2
an electrically conductive fabric that is stretchable in at least two directions, electrodes arranged substantially regularly along the periphery of the fabric
Data Source
Figure 1~2
Figure 3
AI summary
A textile suitable for detecting movement and/or deformation comprises an electrically conductive fabric (8) which can expand in at least two directions, electrodes (12) arranged substantially regularly along the periphery of the fabric (8), a controller (14) designed to control the excitation of the electrodes (12) two by two according to a pattern such that all the electrodes (12) are successively excited, and to measure each time the voltage in the non-excited electrodes (12), and a computer (22) comprising a neural network inference engine and designed to receive the voltage measurements taken at the non-excited electrodes (12) in a given excitation cycle, in order to supply them to the neural network inference engine and to return a characteristic measurement of a movement having caused a deformation of the textile.