Walking Assistance Apparatus Gait Phase Tension Control
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Solution Overview
Problem
Existing assistance technologies for walking, such as those described in Japanese Unexamined Patent Application Publications 2009-213538 and 2016-528940, do not provide differentiated assistance based on the user's state, such as carrying luggage, leading to inefficient support and potential discomfort or unsteadiness.
Innovation Solution
An assistance apparatus comprising an upper-body belt, left and right knee belts, and wires coupled to motors that generate specific tensions during distinct phases of the gait cycle to provide tailored assistance for flexion and extension, adjusting tensions to match the user's state and phase of movement, with the motor controlling wire tensions to ensure smooth transitions and prevent discomfort or unsteadiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor generates continuous tension in the wires to assist walking, then the user receives constant support, but the user may experience discomfort or unsteadiness during transition phases between gait cycles
Solution Approach 1:
The control unit preemptively reduces motor tension during boundary periods (transition phases between gait cycles) before the user experiences discomfort or unsteadiness. By anticipating the harmful effect during stance-to-swing phase transitions, the system applies counter-action in advance by lowering tension to below the second threshold value, preventing the discomfort rather than reacting to it afterward.
Solution Approach 2:
The system dynamically adjusts motor tension based on real-time gait phase detection. Rather than maintaining static continuous tension, the motor operates in two distinct modes: generating tension above the first threshold during assistance periods (35-90% of gait phase) and reducing tension below the second threshold during boundary periods (transition phases). This dynamic adaptation matches the user's changing mechanical needs throughout the gait cycle.
2Force
If the motor generates high tension to provide strong assistance, then the user receives adequate support during walking, but the user may feel excessive force during transition phases
Solution Approach 1:
The motor applies tension periodically rather than continuously, synchronized with the gait cycle phases. Tension above the first threshold is generated during assistance periods (35-90% of gait phase for left leg, 35-90% for right leg) when support is needed, and reduced below the second threshold during boundary periods (0-25% and 65-100% of gait phase) when transition forces naturally occur. This periodic modulation ensures adequate assistance force during walking while avoiding excessive force during transitions.
3Device complexity
If the assistance apparatus uses simple continuous tension control, then the device complexity is low, but the adaptability to different user states (e.g., carrying luggage) is insufficient
Solution Approach 1:
The control unit continuously monitors gait phase through sensors detecting user movement, creating a feedback loop that informs tension adjustments. Based on this feedback about the user's current gait state, the system adapts motor tension in real-time, enabling differentiation between assistance needs during various gait phases and potential user states such as carrying luggage, without requiring complex manual configuration.
Solution Approach 2:
The system changes the tension parameter dynamically based on detected gait phase and user state. By adjusting the tension threshold (switching between operating above the first threshold and below the second threshold) according to the gait cycle timing and user conditions, the apparatus achieves adaptability to different user states while maintaining relatively simple control logic based on phase-dependent parameter modification.
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 apparatus effectively assists users by providing appropriate forces during different phases of walking, enhancing mobility and comfort by matching assistance to the user's state, thereby reducing the burden and preventing unsteady movements.
Implementation Method 1
at least one motor... generates a tension greater than or equal to a first threshold value in the first wire during a first period
Data Source
AI summary
There is provided an assistance apparatus in which when assistance provided to a user in walking is to be stopped, a motor reduces a tension of a first wire and a tension of a second wire, which couple an upper-body belt and a left knee belt to each other on or above a front part and a back part of a body of the user, to less than a second threshold value during a first stop period in a gait phase of a left leg of the user, the first stop period being a period from a period included in a first period and including a timing at which the left leg shifts from a stance phase to a swing phase to a start period of a second period, and reduces a tension of a third wire and a tension of a fourth wire, which couple the upper-body belt and a right knee belt to each other on or above the front part and back part of the body of the user, to less than the second threshold value during a second stop period in a gait phase of a right leg of the user, the second stop period being a period from a period included in a third period and including a timing at which the right leg shifts from the stance phase to the swing phase to a start period of a fourth period.