Capacitive Foot Presence Sensing for Proper Automated Lacing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motorized lacing systems for footwear face challenges such as high cost, complexity, assembly issues, lack of serviceability, and fragile mechanical mechanisms, while premature activation of automated tightening mechanisms can detract from user experience.
Innovation Solution
A modular footwear platform with a capacitive foot presence sensor integrated into the mid-sole plate, allowing for interchangeable lacing engines and providing tactile and visual feedback, which accurately detects foot presence and orientation using capacitive sensors to initiate automated lacing only when the foot is properly seated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If motorized lacing systems are implemented in footwear, then automated tightening function is achieved, but device complexity and cost increase
Solution Approach 1:
The lacing system is divided into modular components: a motorized spool unit, a ratchet mechanism, and a lace tensioning system. This segmentation allows each component to perform a specific function independently, simplifying the overall system design and reducing complexity while maintaining automated functionality.
Solution Approach 2:
The ratchet mechanism provides automatic one-way locking of the lace tension without requiring active control or feedback systems. Once the motor tensions the lace, the ratchet maintains tension passively, eliminating the need for continuous power or complex control algorithms, thus reducing device complexity.
2Extent of automation
If complex motorized mechanisms are used for automated lacing, then tightening function is achieved, but reliability decreases due to fragile mechanical parts
Solution Approach 1:
The ratchet mechanism is designed with inherent mechanical tolerance and stress distribution features that prevent sudden failures. The gradual engagement of ratchet teeth distributes load over multiple contact points, preventing catastrophic failure from single-point stress concentrations.
Solution Approach 2:
The lacing system uses simple, replaceable components such as the lace itself and basic mechanical elements that can be easily replaced if worn. This approach prioritizes overall system reliability by making critical wear components inexpensive and user-replaceable rather than designing for indefinite component life.
3Extent of automation
If traditional presence sensors are used to detect foot insertion, then automation control is achieved, but manufacturing cost and assembly complexity increase
Solution Approach 1:
The foot presence detection functionality is merged with existing structural components of the shoe, such as the insole or tongue. Pressure-sensitive materials or conductive elements are integrated directly into these components during manufacturing, eliminating separate sensor assemblies and reducing assembly steps.
Solution Approach 2:
Existing structural components of the footwear are designed to serve multiple functions: providing structural support, comfort, and simultaneously acting as the sensing element for foot presence detection. This multi-functionality reduces the total number of components and simplifies manufacturing.
4Speed
If automated lacing systems are activated prematurely before proper foot seating, then automation speed is improved, but user experience deteriorates
Solution Approach 1:
The system incorporates real-time feedback from pressure sensors distributed across the footwear interior to continuously monitor foot positioning. The automated lacing sequence is dynamically adjusted based on this feedback, ensuring activation occurs only when proper foot seating is detected, thereby maintaining both speed and user experience.
Solution Approach 2:
The system performs preliminary detection of foot presence and positioning before initiating the automated lacing sequence. This preliminary action ensures the foot is properly seated and ready for tightening, preventing premature activation while maintaining efficient overall operation through immediate subsequent lacing execution.
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 solution enhances user experience by ensuring proper foot alignment and reducing sensor complexity and costs, while offering reliable, robust, and customizable automated lacing systems.
Implementation Method 1
the sensor system includes a capacitive sensor configured to sense changes in a capacitance signal in response to proximity of a body
Implementation Method 2
A dielectric member can be provided between the capacitive sensor and the body to enhance an output signal from the sensor
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A foot presence sensor system for an active article of footwear can include a sensor housing configured to be disposed at or in an insole of the article, and a controller circuit, disposed within the sensor housing, configured to trigger one or more automated functions of the footwear based on a foot presence indication. A capacitive sensor, such as disposed within or upon the sensor housing, can be configured to provide the foot presence indication. In an example, foot presence can be detected using time-varying characteristics of a signal from the capacitive sensor.