Walking Assistance Torque Control Using Gait Phase Feedback
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Solution Overview
Problem
Existing walking assistance devices lack an efficient method for calculating and providing optimal torque assistance to users, particularly during gait cycles, which can lead to inadequate support and increased effort for individuals with joint problems or for military applications requiring enhanced muscular strength.
Innovation Solution
A method and apparatus that utilize a combination of a particularly shaped adaptive oscillator (PSAO) and a finite state machine (FSM) to calculate and generate assistance torque by measuring joint angles and gait cycles, allowing for real-time adjustment of torque output based on gait parameters and states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a powered actuator supplies augmentation torque to a joint, then joint function is enhanced, but device complexity increases
Solution Approach 1:
The system employs feedback control by continuously monitoring joint angle and gait phase, then adjusting the augmentation torque accordingly. The controller receives input from sensors measuring joint position and uses this information to modulate the powered actuator output, creating a closed-loop control system that enhances joint function while managing complexity through intelligent control rather than mechanical complexity
Solution Approach 2:
The system dynamically adjusts the augmentation torque based on real-time gait phase and joint angle measurements. Rather than providing fixed torque, the powered actuator modulates its output according to the user's walking cycle and joint position, allowing the device to adapt to varying operational conditions and optimize performance across different gait phases
2Device complexity
If torque calculation is simplified, then device complexity is reduced, but torque accuracy deteriorates
Solution Approach 1:
The system changes the parameters used for torque calculation by incorporating multiple variables including joint angle, gait phase, and empirically derived coefficients. Rather than using a simple single-parameter model, the system employs a multi-parameter approach that captures the complexity of human gait mechanics while maintaining computational efficiency through predetermined coefficient values
Solution Approach 2:
The system performs preliminary action by pre-determining coefficient values and torque profiles based on empirical data and gait analysis. These pre-calculated parameters are stored and retrieved during operation, allowing the system to apply accurate torque calculations without performing complex real-time computations, thus reducing device complexity while maintaining torque accuracy
Data Source
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AI summary
A method and apparatus for calculating a torque of a walking assistance device, the method including receiving a measured joint angle, obtaining a gait parameter with respect to a transition among a predetermined number of gait states based on the joint angle, obtaining a gait cycle based on the joint angle, and obtaining an output torque based on the gait cycle and the gait parameter, is provided.