3D Rotary Drum Encoder for Compact Autolacing Footwear
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Solution Overview
Problem
Conventional optical encoders used in motorized lacing systems for footwear are fragile and have a high stack-up, which can compromise the performance and robustness of athletic footwear, and their manufacturing precision can lead to reliability issues.
Innovation Solution
A three-dimensional optical encoder based on a rotary drum design is developed, which is more compact, robust, and easier to manufacture, featuring a cylindrical shape with alternating dark and reflective segments on its exterior surface, and positioned with optical sensors on either side to detect these segments, allowing for greater variance in manufacturing processes and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional planar optical encoders are used, then rotational tracking function is achieved, but the encoder is fragile and has high stack-up
Solution Approach 1:
The patent transitions from a conventional two-dimensional planar encoder to a three-dimensional drum-shaped encoder. The drum encoder has a cylindrical geometry with alternating reflective and non-reflective segments arranged around its circumference, allowing optical sensors to detect rotational position from multiple angles and dimensions, thereby improving reliability while reducing the vertical stack-up height.
Solution Approach 2:
The encoder drum is designed with a curved cylindrical surface instead of a flat planar surface. This curvature allows the alternating reflective and non-reflective segments to be arranged in a three-dimensional configuration that improves mechanical robustness and reduces fragility while maintaining compact dimensions.
2Measurement precision
If conventional optical encoders are used, then rotational position is detected, but manufacturing precision requirements are high
Solution Approach 1:
By moving to a three-dimensional drum configuration, the patent distributes the encoding information across multiple dimensions (circumferential segments around the drum). This multi-dimensional approach provides redundancy and allows for more tolerant manufacturing, as errors in one dimension can be compensated by measurements from other dimensions.
Solution Approach 2:
The patent changes the physical parameters of the encoder from a flat two-dimensional pattern to a three-dimensional drum structure with alternating reflective and non-reflective segments. This parameter change allows the system to achieve high measurement precision through multi-angle optical detection while being more tolerant of manufacturing variations in the segment positioning.
3Reliability
If conventional optical encoders are used, then rotational tracking is achieved, but the system is not robust for athletic footwear
Solution Approach 1:
The drum-shaped cylindrical encoder provides superior mechanical strength and impact resistance compared to planar encoders. The curved geometry distributes stress more evenly and resists deformation under the high-impact conditions typical of athletic footwear, making the system more robust against harmful factors like drops, impacts, and repeated stress cycles.
Solution Approach 2:
The drum encoder is segmented into multiple alternating reflective and non-reflective segments around its circumference. This segmentation allows the encoder to maintain functionality even if one segment is damaged, providing redundancy that improves overall system reliability in harsh athletic environments.
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 three-dimensional optical encoder enhances the reliability and robustness of motorized lacing systems by reducing manufacturing costs and improving the accuracy of rotational tracking, leading to a more effective and durable athletic footwear solution.
Implementation Method 1
a cylindrical shape with alternating dark and reflective segments on its exterior surface, and positioned with optical sensors on either side to detect these segments
Data Source
AI summary
An article of footwear and related method includes a midsole, an upper secured with respect to the midsole, and a lace extending through the upper. A motorized lacing system positioned within the midsole, configured to engage with the lace to increase and decrease tension on the lace. The motorized lacing system includes a motor, including a motor shaft, a spool, coupled to the motor shaft, configured to spool and unspool the lace based on the turning of the motor shaft, a processor circuit, and an optical encoder. The optical encoder comprises a three-dimensional encoder defining a major axis and having a surface having a first plurality of segments positioned between a second plurality of segments, and an optical sensor, positioned within optical range of the cylindrical encoder, configured to output a signal to the processor circuit indicative of a detected one of a first and second plurality of segments.