Walking Assistance Apparatus with Phase-Dependent Wire Tension Control
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Solution Overview
Problem
Existing assistance technologies for walking, such as those described in Japanese Unexamined Patent Application Publication No. 2009-213538 and Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2016-528940, fail to provide tailored assistance based on the user's state, particularly when carrying objects, leading to inefficient support and potential burden on the user.
Innovation Solution
An assistance apparatus comprising an upper-body belt, left and right knee belts, and wires coupled to motors that adjust tension according to specific phases of the gait cycle to provide tailored assistance for flexion and extension, with tension thresholds managed by a control circuit to optimize support and reduce burden, especially when carrying objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed tension is applied to the wires throughout the gait phase, then the structure is simple, but the assistance cannot be tailored to the user's state (e.g., carrying objects)
Solution Approach 1:
The wire tension is dynamically adjusted based on the gait phase and user state. The control circuit varies tension levels (first threshold vs second threshold) across different periods of the gait phase, transforming a static tension system into a dynamic one that adapts to walking conditions and object-carrying states.
Solution Approach 2:
The system changes the tension parameter of the wires according to the gait phase and detected user state. By modifying the tension magnitude (using different threshold values) at different times, the system provides differentiated assistance for normal walking versus object-carrying scenarios without requiring structural changes.
2Force
If high tension is applied to assist walking with objects, then assistance effectiveness improves, but user burden increases
Solution Approach 1:
The high tension (first threshold) is applied periodically only during specific phases of the gait cycle (first period: 35%-90%, second period: 0%-25% and 65%-100%) when assistance is most needed, rather than continuously. This periodic application provides effective assistance during critical moments while reducing overall burden compared to continuous high tension.
Solution Approach 2:
The system applies tension selectively during specific gait phases rather than throughout the entire cycle. By providing assistance only when needed (partial action during critical phases) and using two different tension thresholds, the system achieves effective support while avoiding excessive continuous tension that would increase user burden.
3Duration of action of moving object
If tension is applied during all gait phases, then continuous support is provided, but energy consumption increases
Solution Approach 1:
The motor applies tension periodically during specific gait phases rather than continuously. By limiting high-tension application to the first and second periods (covering critical assistance moments) and using lower tension (second threshold) during third and fourth periods, the system maintains necessary support duration while significantly reducing energy consumption compared to continuous full-tension operation.
Solution Approach 2:
The system provides assistance during all gait phases but uses differentiated tension levels. Full assistance (first threshold) is provided only when necessary, while reduced assistance (second threshold) is provided during other phases, achieving comprehensive coverage with optimized energy usage.
Data Source
AI summary
In an assistance apparatus, when assisting a user in walking with an object, a motor generates, in a gait phase of a left leg, a tension less than a second threshold value in a first wire during a fifth period other than a first period during which a tension greater than or equal to a first threshold value is generated in the first wire, and a tension greater than or equal to the second threshold value in a second wire during a sixth period other than a second period during which a tension greater than or equal to the first threshold value is generated in the second wire, and generates, in a gait phase of a right leg, a tension less than the second threshold value in a third wire during a seventh period other than a third period during which a tension greater than or equal to the first threshold value is generated in the third wire, and a tension greater than or equal to the second threshold value in a fourth wire during an eighth period other than a fourth period during which a tension greater than or equal to the first threshold value is generated in the fourth wire.