Powered Prosthetic Knee with Segmented Passive and Active Modes
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Solution Overview
Problem
Powered prosthetic knees for transfemoral amputees are hindered by excessive weight due to motors, transmissions, and batteries, which do not significantly improve gait efficiency and are burdensome for users, especially during daily activities like walking.
Innovation Solution
A lightweight assistive device with a powered system that transitions between powered and passive modes, using a motor and linear actuator to provide additional power only during tasks like stair climbing, and relying on the user's power for level ground walking, with a clutch mechanism for efficient energy use and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a powered prosthetic knee with motor, transmission, and battery is used to provide power for tasks like stair climbing, then functionality and ability to perform demanding tasks is improved, but weight increases significantly making it burdensome for daily walking
Solution Approach 1:
The prosthetic knee is divided into two functional systems: a passive knee mechanism for continuous use during daily activities, and a separate powered assist system activated only when needed. This segmentation allows the device to provide power assistance for demanding tasks without requiring the user to carry the full weight of motor, transmission, and battery components during normal walking.
Solution Approach 2:
The prosthetic knee transitions dynamically between passive and powered modes based on the user's needs. The system activates the powered assist mechanism only during demanding tasks such as stair climbing or rising from a chair, and reverts to passive operation during level ground walking, thereby optimizing the weight-power tradeoff in real-time.
2Productivity
If a powered prosthetic knee is used continuously to improve gait efficiency, then mobility assistance is provided, but energy consumption increases and device lifespan decreases
Solution Approach 1:
The powered assist system operates periodically rather than continuously, activating only during demanding tasks that require additional power assistance. The system remains inactive during level ground walking and other routine activities, thereby significantly reducing overall energy consumption while still providing gait efficiency improvements when needed.
3Ease of operation
If a passive prosthetic knee is used to reduce weight, then ease of use during daily walking is improved, but functionality for demanding tasks like stair climbing deteriorates
Solution Approach 1:
The prosthetic knee is designed to perform multiple functions: it operates as a lightweight passive knee for routine daily walking, and simultaneously provides powered assistance for demanding tasks such as stair climbing, rising from chairs, and navigating uneven terrain. This multi-functionality allows a single device to meet diverse user needs without requiring separate prostheses for different activities.
Data Source
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AI summary
Systems and methods for assistive devices for replacing or augmenting the limb of an individual, such devices comprising a joint and a powered system; the powered system having a first configuration in which the powered system rotates the joint by applying power to the joint, and a second configuration that allows for rotation of the joint without actuation of the powered system.