Pediatric Exoskeleton Energy Storage Subsystem
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Solution Overview
Problem
Children with gait disorders, such as cerebral palsy or stroke, face developmental delays due to limited walking time outside of therapy, which hinders the establishment of proper gait patterns and long-term mobility, as existing therapeutic methods are often expensive or require trained supervision.
Innovation Solution
A passive pediatric leg exoskeleton featuring a belt with a hip attachment mechanism, a leg frame extending along the user's leg, and an energy storage subsystem with an exotendon that stores energy as the leg moves posteriorly and releases it to aid in anterior movement, utilizing a two-way ratchet for tension adjustment, promoting fluid movement and adjustable fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive energy storage mechanism is used, then device complexity is reduced, but energy assistance capability is limited
Solution Approach 1:
The exotendon is configured to store energy during the stance phase when the leg moves posteriorly and release energy during the swing phase when the leg moves anteriorly. This periodic energy storage and release mechanism provides rhythmic energy assistance that matches the natural gait cycle, enabling effective passive energy return without complex active control systems
Solution Approach 2:
The biasing member is pre-tensioned using the two-way ratchet mechanism before gait initiation. This preliminary action stores potential energy in the biasing member in advance, ensuring that energy is available to assist the first step and subsequent steps without requiring real-time energy management or complex power systems
2Use of energy by moving object
If energy storage mechanism is added, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The exotendon-biasing member system automatically stores and releases energy based on the user's leg movement without external control. The two-way ratchet mechanism self-regulates the tension in the biasing member, allowing the system to service itself through the user's own gait motion, thereby improving energy efficiency while minimizing the need for complex control systems
Solution Approach 2:
The system dynamically adjusts energy storage and release based on the user's gait phase. The exotendon tension varies continuously as the leg moves, with the biasing member providing progressive resistance during stance and active assistance during swing, creating a dynamic energy management system that adapts to natural gait variations without complex electronics
3Device complexity
If fixed tension mechanism is used, then device simplicity is maintained, but adaptability to different users is reduced
Solution Approach 1:
The two-way ratchet mechanism allows the tension in the biasing member to be adjusted and locked at predetermined levels before use. This preliminary adjustment enables customization for different users, weights, and gait requirements while maintaining mechanical simplicity during actual operation, as the ratchet holds the selected tension without requiring active control
Solution Approach 2:
The two-way ratchet enables the system to transition from a static fixed-tension design to a dynamically adjustable one. The ratchet can be engaged at different positions along the biasing member, allowing the tension to be optimized for each user's specific needs while maintaining the mechanical simplicity of a passive system during gait 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 exoskeleton increases walking time outside of therapy, supports proper gait patterns, and reduces rehabilitation time by assisting users with energy-efficient movement, while being durable, adjustable, and safe for pediatric use.
Implementation Method 1
a biasing member disposed along the exotendon, the biasing member configured for storing and releasing energy
Implementation Method 2
a two-way ratchet disposed along the exotendon in proximity to the hip attachment mechanism, the two-way ratchet configured for adjusting tension in the biasing member
Data Source
AI summary
Disclosed herein is a leg exoskeleton configured to aid motion (e.g., walking) of a user in need thereof. In particular, the exoskeleton includes a belt configured to attach the exoskeleton to the waist of a user. The exoskeleton further includes a leg frame configured to attach to at least one leg of the user through a hip attachment mechanism on the belt. Finally, the exoskeleton includes an energy storage subsystem that is configured to store and release energy as the user walks, particularly aiding the user in the forward motion of the leg when walking. Methods of using the leg exoskeleton are also provided.