Flexible Wire Finger Motion Measurement System
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Solution Overview
Problem
Existing systems for measuring thumb and finger motions are hindered by bulkiness and limited mobility, as they obstruct natural hand motion and are not compact or simple enough to accurately measure angles within the limited space of the hand.
Innovation Solution
A system comprising flexible wires and a sensing module with linear potentiometers and elastic members, attached to a glove, measures angles at joints by tracking changes in wire length, allowing for lightweight and compact measurement of flexion/extension motions without hindering hand motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical linear encoder is used to measure finger motions, then measurement precision is improved, but the system becomes bulky and interferes with natural hand motion
Solution Approach 1:
The patent extracts the measurement function from a bulky optical encoder system and implements it using simple flexible wires attached to finger segments. The wires directly measure joint angle changes through their deformation, eliminating the need for complex optical encoding mechanisms while maintaining measurement capability.
Solution Approach 2:
The patent replaces the optical mechanical system with a purely mechanical flexible wire system. The flexible wires use elastic deformation and geometric relationships to measure joint angles, substituting complex optical-mechanical integration with simpler mechanical principles that are more suitable for wearable applications.
2Measurement precision
If a 3D magnetic position sensor is used to measure joint angles, then three-dimensional motion measurement is improved, but peripheral devices obstruct unconstrained hand motion
Solution Approach 1:
The patent uses thin flexible wires that can be easily attached to finger segments without creating bulk. These flexible elements conform to the finger geometry and allow natural hand motion while providing measurement data through their deformation characteristics.
3Ease of operation
If an optical fiber sensor is mounted on a glove to measure joint angles, then ease of wearing is improved, but mobility is limited by peripheral devices such as laser diode and optical power system
Solution Approach 1:
The patent removes the complex optical power system and laser diode components from the glove-mounted sensor system. Instead, it uses passive flexible wires that derive measurement capability from their geometric deformation, eliminating the mobility-limiting peripheral devices while maintaining the ease of wearing advantage.
4Measurement precision
If a flexible resistor is used for measurement, then resolution and repeatability are improved, but economic efficiency deteriorates and integration with hand exoskeleton system becomes difficult
Solution Approach 1:
The patent designs a universal flexible wire measurement system that can be integrated with various hand rehabilitation systems including exoskeletons. The simple wire-based architecture provides both measurement functionality and ease of integration, serving multiple system configurations without requiring specialized components like flexible resistors.
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 and unobtrusive measurement of thumb and finger angles, maintaining tension with elastic members and using linear potentiometers, ensuring natural hand motion is not restricted, with a compact design that effectively calculates joint angles.
Implementation Method 1
a sensing module which includes first and second linear potentiometers respectively connecting with second ends of the first and second flexible wires
Implementation Method 2
including elastic members for maintaining tension of the flexible wires
Data Source
AI summary
A method for measuring motions of a thumb and fingers, which can relatively easily measure angles at joints of a thumb and fingers within a limited space of the thumb and fingers, using a system that may be lightweight and compact enough not to hinder a natural motion of a hand. To this end, the method measures motions of a thumb and fingers of a user who wears a glove, and includes: attaching first ends of first and second flexible wires to positions of the glove respectively corresponding to middle and proximal phalanxes of each finger; connecting second ends of the first and second flexible wires to a sensing module so that the first and second flexible wires can move forward and backward while maintaining tension thereof in accordance with a motion of the finger; and by the sensing module, measuring moved distances of the first and second flexible wires, wherein rotary angles at corresponding joints in the thumb and fingers are calculated based on the measured moved distances.