Flexible Wearable Circuits for Drift-Resistant Motion Calibration
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Solution Overview
Problem
Conventional wearable devices using inertial measurement units (IMUs) are expensive and experience drift over time, leading to inaccurate motion tracking, which is crucial for applications like rehabilitation and virtual simulations, and existing flexible electronics lack durability and reliability in stretching and flexing.
Innovation Solution
The use of flexible circuits with deformable conductors, particularly conductive gel traces, that maintain electrical conductivity and resilience, allowing for accurate motion tracking by correlating electrical parameters with physical motions and storing motion data in a repository.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wearable devices using inertial measurement units (IMUs) are used, then motion tracking capability is provided, but the devices are expensive and experience drift over time leading to inaccurate motion tracking
Solution Approach 1:
The patent replaces conventional IMUs with a flexible circuit system using deformable conductors and strain sensors that mechanically sense motion through electrical resistance changes. This substitution eliminates drift issues associated with IMUs while maintaining motion tracking capability, and significantly reduces device cost through simpler sensor architecture.
Solution Approach 2:
The patent changes the measurement parameter from accelerometer data (IMU) to electrical resistance variations in deformable conductors. By monitoring resistance changes as conductors stretch and flex during motion, the system achieves accurate motion tracking without the drift problems of conventional IMUs.
2Adaptability or versatility
If flexible electronics are used in wearable devices, then device flexibility and comfort are improved, but durability and reliability in stretching and flexing are reduced
Solution Approach 1:
The patent uses a flexible substrate with deformable conductors formed as thin film traces that can repeatedly stretch and flex without failure. The conductor geometry is specifically designed to accommodate elastic deformation while maintaining electrical connectivity, enabling durable flexible electronics for wearable applications.
Solution Approach 2:
The patent designs the flexible circuit with dynamic conductor paths that adapt their shape during stretching and flexing. The deformable conductors are configured to elastically deform with the substrate, maintaining electrical functionality throughout the range of motion and ensuring long-term reliability under repeated mechanical stress.
3Reliability
If conventional rigid circuits are used, then electrical connectivity is reliable, but the wearable device cannot stretch and flex with the body
Solution Approach 1:
The patent replaces rigid circuit boards with flexible substrates containing deformable conductor traces. These thin film conductors are engineered to stretch and flex elastically while maintaining electrical connectivity, enabling the wearable device to conform to and move with the body without compromising electrical reliability.
Solution Approach 2:
The patent employs composite flexible circuit structures combining conductive materials with flexible substrate materials. This composite approach provides both the electrical connectivity of conventional circuits and the flexibility needed for wearable applications, allowing the device to stretch and flex with the body.
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
Enables precise and durable motion capture and calibration of wearable devices, providing real-time accurate simulations in virtual environments and enhancing rehabilitation monitoring without the need for continuous calibration.
Implementation Method 1
a strain sensor including a first trace defined by a deformable conductor, wherein the strain sensor is configured to generate a second signal
Implementation Method 2
a flexible circuit mechanically coupled to the flexible substrate via an adhesive layer
Data Source
AI summary
A wearable article configured to characterize motions of a user is disclosed herein. The wearable article can include a flexible substrate and a flexible circuit, wherein the flexible circuit includes an inertial measurement unit and a strain sensor comprising a first trace defined by a deformable conductor. The flexible circuit can further include a bus line including a first trace defined by a deformable conductor, wherein the bus line is configured to transmit electrical power and data to the inertial measurement unit and the strain sensor, and an integrated circuit configured to provide the electrical power to the bus line for transmission to the inertial measurement unit and the strain sensor. The motions of the user can be characterized based on a correlation of the signals generated by the flexible circuit to motion data stored in a repository.