Multibend Sensor Finger Segmentation for Accurate Joint Tracking
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Solution Overview
Problem
Existing sensing technologies face challenges in accurately determining bending movements due to limitations in sensitivity, precision, and error accumulation, particularly in systems with multiple joints, where bend sensors require custom fitting and suffer from cascaded error issues, and alternative methods like cameras and inertial tracking have their own drawbacks such as bulkiness, expense, and drift issues.
Innovation Solution
The development of a multibend sensor system comprising two flexible strips, a reference strip, and a sliding strip, separated by a spacer, which measures relative shifts to determine bending accurately, reducing the impact of measurement errors and allowing for precise calculation of shape and curvature through capacitive or optical sensing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bend sensor is used per finger, then the device complexity is reduced, but the measurement precision deteriorates because only a single overall bend measurement is obtained
Solution Approach 1:
The patent divides each finger into multiple segments (proximal, intermediate, distal phalanges) and places individual bend sensors at each segment. This segmentation allows independent measurement of each joint's bending angle, providing precise multi-point data without requiring a single complex sensor system.
2Measurement precision
If bend sensors are custom fitted for spacing between joints, then the measurement precision improves, but the ease of operation deteriorates due to fitting requirements for size variation in people
Solution Approach 1:
The patent employs adjustable sensor mounting mechanisms that allow the spacing between sensors to be dynamically adjusted to match different finger sizes and joint positions. This dynamic adaptability enables precise measurement for various users without requiring custom-fitted sensors for each individual.
3Device complexity
If inexpensive bend sensors are used, then the device complexity is reduced, but the measurement precision deteriorates due to poor angular precision causing cascaded joint error
Solution Approach 1:
The patent implements a feedback mechanism where the microcontroller processes bend sensor readings from multiple segments, calculates joint angles using trigonometric relationships, and continuously monitors for measurement inconsistencies. This feedback loop allows the system to compensate for individual sensor inaccuracies and correct cascaded errors through mathematical reconstruction of finger position.
4Measurement precision
If camera-based techniques are used to directly measure finger positions, then the measurement precision improves, but the device complexity increases due to difficulty of finding good viewpoints and system bulkiness
Solution Approach 1:
The patent replaces complex optical/mechanical measurement systems (cameras requiring multiple viewpoints and bulky infrastructure) with simple flex-based bend sensors that directly measure joint angles. This mechanical-to-electrical substitution achieves accurate position measurement through trigonometric calculation from segment angles, eliminating the need for complex camera systems.
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 multibend sensor system provides accurate and robust bending measurements with reduced sensitivity to measurement errors, enabling precise determination of complex shapes and curvatures, suitable for applications in robotics, human motion tracking, and other deformation monitoring tasks.
Implementation Method 1
capacitive or optical sensing techniques
Implementation Method 2
capacitive or optical sensing techniques
Data Source
AI summary
A multibend sensor is able to provide information regarding bending of the sensor data in a manner able to mitigate error propagation. A reference strip and a sliding strip are separated from each other by a spacer. Electrodes are located on the reference strip and the sliding strip. The bending of the multibend sensor will be reflected in the shifting of the sliding strip with respect to the reference strip and the measurements obtained from the electrodes. A finger may be operably connected to the reference strip, wherein the finger extends in the direction of the sliding strip, wherein movement of the reference strip with respect to the sliding strip is translated through the finger.