Wrist-Worn Piezoelectric Sensor Array for Accurate Finger Motion Estimation
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Solution Overview
Problem
Conventional portable terminal devices using piezoelectric sensors struggle to measure finger motion with high accuracy.
Innovation Solution
An operation estimation technology that includes a plurality of sensors worn on the wrist, an upstream signal processing portion, and an estimation portion to learn and estimate finger operations by analyzing sensor signals, utilizing a range setting portion to determine feature points and calculate activity levels for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric sensors are placed on the back side of the wrist to measure finger motion, then the device can detect finger operations, but the measurement accuracy is insufficient
Solution Approach 1:
The patent divides the wrist into multiple measurement regions by placing multiple sensors at specific locations (anterior surface, posterior surface, and lateral surfaces). Each sensor detects displacement in its local region, and the results are combined to calculate the overall finger motion. This segmentation allows the system to capture complex wrist movements more accurately, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent transitions from single-point measurement to multi-dimensional measurement by adding sensors on the lateral surfaces and using three-dimensional displacement calculations. The system computes displacement vectors in multiple directions (anterior-posterior, left-right, up-down) and combines them to determine comprehensive finger motion, significantly improving measurement accuracy and reliability.
2Measurement precision
If multiple sensors are placed on the wrist to improve measurement accuracy, then finger motion can be detected more precisely, but the device complexity increases
Solution Approach 1:
The patent designs the sensor system to serve multiple functions: detecting displacement in different directions, identifying various finger operations (typing, scrolling, gaming), and providing both raw data and processed results. The same sensor array performs measurement, validation, and operation recognition, reducing the need for separate specialized components and managing overall system complexity.
Solution Approach 2:
The system incorporates feedback mechanisms where the arithmetic portion validates sensor signals against predetermined criteria and adjusts measurements accordingly. The range setting portion dynamically determines operational ranges based on detected displacement patterns, allowing the system to adapt to different users and situations. This feedback loop improves accuracy while managing complexity through intelligent control.
3Measurement precision
If the sensor signal processing is enhanced to reduce noise and improve clarity, then operation estimation accuracy improves, but the processing time and computational load increase
Solution Approach 1:
The patent performs preliminary signal processing by pre-defining operational ranges and validation criteria in the arithmetic portion. The range setting portion establishes predetermined thresholds and patterns before actual operation detection occurs. This preliminary preparation allows the system to quickly validate and interpret sensor signals during real-time operation, reducing processing time while maintaining high accuracy.
Solution Approach 2:
The system extracts only the most relevant information from the sensor signals by focusing on displacement features that indicate finger operations. The arithmetic portion selectively processes signals based on predetermined criteria, filtering out irrelevant noise and concentrating computational resources on the most significant measurement components. This extraction approach improves accuracy while minimizing unnecessary processing time.
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 accurate detection and estimation of finger operations by reducing noise and enhancing signal clarity, leading to improved accuracy in motion measurement and reduced discomfort for the wearer.
Implementation Method 1
uses a piezoelectric sensor... measures a motion of a finger of a user (e.g., a wearer), by using a detection signal of a plurality of piezoelectric elements
Data Source
AI summary
An operation apparatus is provided that includes a plurality of sensors, a range setting portion, and an arithmetic portion. The plurality of sensors are worn on a wrist, and output a sensor signal according to a motion of a tendon of the wrist. The range setting portion sets an operation learning time range including time of a feature point of a measurement signal based on the sensor signal. The arithmetic portion learns an operation based on the measurement signal based on the sensor signal of the plurality of sensors in the operation learning time range. The arithmetic portion then estimates the operation based on criteria according to the learned content.