Finger Motion Capture Using 3D Magnetic Sensors
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Solution Overview
Problem
Current finger motion capture technologies for virtual reality are costly, complex, and lack precision in measuring four degrees of freedom, often requiring external cameras or sensors that are prone to errors and high manufacturing costs.
Innovation Solution
A three-dimensional magnetic sensor-based finger motion capture interface device with a mechanism having four degrees of freedom, utilizing a low-cost non-contact type three-dimensional magnetic sensor and a multi-joint exoskeleton structure with bevel gears to accurately measure finger motion, combined with a touch feeling generating actuator for realistic feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical markers and external camera systems are used to track finger motion, then motion tracking can be achieved, but the system becomes complex and expensive while suffering from marker overlapping and blocking phenomena
Solution Approach 1:
The patent replaces the optical camera-based tracking system with a magnetic field-based sensing system. Magnetic sensors detect the position and orientation of magnets attached to finger joints, eliminating the need for external cameras and optical markers. This substitution resolves the complexity issue while maintaining measurement precision through direct magnetic field detection that is not affected by line-of-sight blocking.
2Measurement precision
If bending sensors or potentiometers are used in gloves or exoskeletons to measure finger motion, then finger motion can be measured, but the manufacturing cost becomes expensive and only 1 to 2 degrees of freedom per finger are measured
Solution Approach 1:
The patent replaces expensive mechanical bending sensors and potentiometers with a magnetic sensing system. Magnets are attached to finger segments and their positions are detected by magnetic sensors, enabling measurement of multiple degrees of freedom simultaneously. This approach reduces manufacturing cost while improving the ability to measure all relevant finger motions.
Solution Approach 2:
The magnetic sensing system serves multiple functions: it tracks position, orientation, and multiple degrees of freedom of finger motion simultaneously. A single magnetic sensor can detect the state of multiple magnets, providing comprehensive finger motion data without requiring separate sensors for each degree of freedom, thus reducing overall system cost.
3Adaptability or versatility
If image sensors and IR sensors are used to measure finger motion, then motion in the viewing field can be measured, but measurement accuracy decreases due to overlapping problems of the fingers
Solution Approach 1:
The patent replaces image and IR sensors with magnetic sensors that detect magnetic field changes. Since magnetic fields penetrate through materials and are not blocked by finger overlapping, this substitution eliminates the measurement accuracy problems caused by finger occlusion while maintaining the ability to measure motion in all directions.
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 cost-effective measurement of finger motion with four degrees of freedom, providing users with a realistic touch feedback experience by using low-cost sensors and reducing manufacturing costs while improving accuracy and usability.
Implementation Method 1
a three-dimensional magnetic sensor based finger motion capture interface device which precisely measures a motion at a low manufacturing cost by applying a mechanism having four degrees of freedom which is capable of precisely detecting and measuring a motion of a finger using a low-price non-contact type three-dimensional magnetic sensor
Data Source
AI summary
Provided is a three-dimensional magnetic sensor based finger motion capture interface device, including a back-of-hand fixing member; a finger wearing member; at least one link member which is disposed between the back-of-hand fixing member and the finger wearing member and includes at least one magnetic sensor; at least one fixing member which connects between a plurality of link members; and a controller which receives sensor coordinate values corresponding to the change of a magnetic line of force sensed by the at least one magnetic sensor, extracts pitch and yaw motions of each link member based on the received sensor coordinate values, and calculates a user's finger position based on the extracted pitch and yaw motion values.