Self-Teaching Knee Prosthesis Control for Speed Adaptation
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Solution Overview
Problem
Existing lower limb prostheses for above-knee amputees do not adapt effectively to varying walking speeds, leading to suboptimal gait and requiring lengthy prosthetist intervention for adjustments.
Innovation Solution
A self-teaching lower limb prosthesis with a dynamically adjustable knee movement control unit that automatically adjusts flexion and extension movements based on monitored walking speed, using a control unit that stores target relationships between flexed and extended state durations and walking speed, and iteratively adjusts resistance to optimize gait.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed resistance setting is used for the knee joint control device, then the device structure is simple, but the gait quality deteriorates at varying walking speeds
Solution Approach 1:
The control device transforms from a static fixed-resistance system to a dynamic adjustable-resistance system. The resistance to knee joint movement is continuously modified based on real-time detection of walking speed and gait parameters, enabling the device to adapt to varying locomotion conditions while maintaining manageable complexity through automated control algorithms.
Solution Approach 2:
The system incorporates feedback mechanisms that continuously monitor gait parameters and walking speed, then automatically adjust the resistance setting accordingly. This closed-loop control enables the prosthesis to maintain optimal performance across different walking speeds without requiring complex manual intervention, resolving the contradiction between adaptability and complexity.
2Productivity
If manual adjustment by prosthetist is used, then the control system is simple, but the time required for optimization increases significantly
Solution Approach 1:
The control device enables self-service functionality where the prosthesis automatically monitors the amputee's gait patterns and adjusts resistance settings without requiring continuous prosthetist intervention. The system learns and adapts to the user's preferred walking patterns over time, dramatically reducing the time needed for gait optimization while maintaining or improving adjustment quality.
Solution Approach 2:
The system performs preliminary analysis of gait parameters and pre-calculates optimal resistance settings based on detected walking patterns. This preliminary action allows the control device to be proactive in making adjustments rather than waiting for manual intervention, thereby accelerating the optimization process and reducing prosthetist session duration.
3Reliability
If dynamically adjustable control is implemented, then gait quality improves at different speeds, but the device complexity increases
Solution Approach 1:
The control device is designed with multi-functionality, serving both as a resistance control mechanism and as a gait analysis system. By integrating multiple functions into a single unified control unit, the system achieves consistent gait performance across different walking speeds without proportionally increasing overall device complexity, as the same hardware performs multiple roles.
Data Source
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AI summary
A self-teaching lower limb prosthesis, for an above-knee amputee, including a dynamically adjustable joint movement control unit arranged to control operation of the joint automatically. A control unit electrically stores a target relationship between a kinetic or kinematic parameter of locomotion and walking speed. The relationship defines a number of values of the parameter associated with different walking speeds. The control unit generates monitoring signals representative of walking speed values and values of the parameter occurring at different walking speeds. An adjustment system adjusts the control unit automatically when the monitoring signals indicate deviation from the target relationship so as to bring the parameters close to that defined by the target relationship.