Walking Assistance Apparatus with Dynamic Wire Stiffness Control
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Solution Overview
Problem
Existing walking assistance apparatuses primarily focus on generating torque around joints, neglecting the importance of developing stiffness to support proper footing and weight-bearing during walking.
Innovation Solution
A walking assistance apparatus comprising a suit with wires and motors that generate tension in the wires to provide stiffness, with adjustable stiffness levels based on the gait cycle phases to assist in both weight-bearing and leg-lifting phases, utilizing a control circuit to manage motor operations and wire tensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If motors generate high tension in wires continuously, then stiffness is improved for weight-bearing support, but energy consumption increases and movement flexibility decreases
Solution Approach 1:
The wire tension is dynamically adjusted based on gait phase detection. During weight-bearing phases (stance phase), high tension is applied to provide stiffness. During leg-lifting phases (swing phase), tension is reduced to allow flexible movement. This dynamic adjustment resolves the contradiction by providing high stiffness only when needed for support, reducing energy consumption while maintaining movement flexibility.
Solution Approach 2:
The motor generates tension periodically according to the gait cycle, applying high tension during weight-bearing periods and reducing tension during leg-lifting periods. This periodic action pattern matches the natural walking rhythm, providing necessary stiffness during support phases while conserving energy and allowing flexibility during movement phases.
2Strength
If motors generate high tension in wires, then stiffness is improved for proper footing, but ease of operation deteriorates during leg-lifting phases
Solution Approach 1:
The system dynamically adjusts wire tension based on detected gait phase. During weight-bearing phases, high tension provides stiffness for proper footing. During leg-lifting phases, tension is reduced to improve ease of movement. This dynamic adaptation resolves the contradiction by providing high stiffness only when needed for support, not during movement phases.
Solution Approach 2:
The motor applies tension periodically synchronized with the gait cycle, generating high tension during weight-bearing periods for proper footing and reducing tension during leg-lifting periods for ease of operation. This periodic pattern resolves the contradiction between stiffness and ease of movement.
3Stability of the object's composition
If wire stiffness is increased during weight-bearing phases, then walking stability is improved, but device complexity increases due to gait cycle detection and control requirements
Solution Approach 1:
The control circuit detects the user's gait cycle and uses this feedback to adjust motor tension accordingly. The system monitors walking phase and modulates wire tension to provide high stiffness during weight-bearing phases for improved stability. This feedback mechanism achieves walking stability while keeping the control system relatively simple by using straightforward gait phase detection and corresponding tension adjustment.
Data Source
AI summary
A walking assistance apparatus includes a suit to be worn on a knee and waist of a user, a first wire that couples a portion included in the suit and worn above the knee to a portion included in the suit and worn on the waist, a second wire that couples a portion included in the suit and worn above a back of the knee to a portion included in the suit and worn on the waist, and motors coupled to the first and second wires. The motors are controlled to generate tensions so that each of the first and second wires has a stiffness greater than 200 N/m during a first period including a period of 95% or more and 100% or less of a first gait cycle of the user and a period of 0% or more and 50% or less of a second gait cycle subsequent to the first gait cycle.