Hydraulic Prosthetic Ankle With Passive Standing-Walking Response
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Solution Overview
Problem
Prosthetic ankle joints struggle to mimic the natural movement of a healthy ankle, failing to provide both dynamic walking and stable standing states without electronic control, leading to unnatural movements and instability.
Innovation Solution
A hydraulically regulated prosthetic ankle joint with a passive, mechanical response system that uses fluid flow paths and occlusions controlled by a non-electronic mechanism responsive to joint position and rate of change, allowing for controlled dorsiflexion and plantarflexion during walking and full support during standing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid attachment is used to counteract the ground-reaction-force moment during standing, then standing stability is improved, but the ability to mimic natural ankle movements during walking is worsened
Solution Approach 1:
The patent applies a hydraulic damping system that dynamically adjusts resistance based on the ankle joint's position and velocity. During standing, the system provides high resistance to counteract ground-reaction-force moments and maintain stability. During walking, the system allows controlled dorsiflexion and plantarflexion by adjusting hydraulic flow based on movement rate, mimicking natural ankle behavior without requiring a rigid attachment.
Solution Approach 2:
The hydraulic system changes its damping parameters (resistance level) based on the joint's operational state. By monitoring position and velocity parameters, the system transitions between a stiff configuration for standing stability and a more compliant configuration for natural walking movements, resolving the contradiction between these two opposing requirements.
2Adaptability or versatility
If electronic control elements are added to switch between walking and standing states, then functionality is improved, but device complexity and susceptibility to faults increase
Solution Approach 1:
The hydraulic control system operates autonomously by using the ankle joint's own motion characteristics (position and velocity) to regulate fluid flow and damping resistance. The system self-adjusts between walking and standing modes based on natural movement patterns without requiring external electronic sensors, microprocessors, or power sources, thereby maintaining simplicity while achieving adaptive functionality.
Solution Approach 2:
The patent replaces electronic control systems with a purely mechanical-hydraulic control mechanism. The occlusion mechanism responds passively to the joint's kinematic state, using mechanical linkages and hydraulic principles to achieve state-dependent behavior without electronics, thus reducing complexity and fault susceptibility.
3Ease of manufacture
If the prosthesis is made light-weight with minimal components, then ease of manufacture and reliability are improved, but the ability to provide both dynamic and static support is worsened
Solution Approach 1:
The patent employs a hydraulic damping system that integrates multiple functions into a single lightweight component. The hydraulic chamber and occlusion mechanism provide both dynamic movement control during walking and static support during standing without requiring separate actuators or complex mechanisms, achieving multi-state functionality while maintaining manufacturing simplicity and light weight.
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 solution enables a prosthetic ankle joint to mimic natural ankle movements during walking and provide stability during standing, eliminating the need for electronic control and reducing the risk of instability, thus enhancing user mobility and comfort.
Implementation Method 1
a first chamber and a second chamber, wherein the chambers are connecting via one or more fluid flow paths
Implementation Method 2
an occlusion configured to restrict fluid flow between the chambers, and a non-electronic mechanism for controlling the flow, the mechanism being responsive to a position of the joint and/or a rate of change of position of the joint
Data Source
AI summary
A prosthetic joint and a method of controlling dorsiflexion and plantarflexion of the hydraulic prosthetic ankle joint. The method includes generating ground reaction forces with a hydraulic prosthetic ankle, wherein the prosthetic hydraulic ankle comprises a first chamber and a second chamber, and the ankle is connected to a prosthetic foot; rotating the prosthetic foot in response to the ground reaction force; transferring fluid between the forward and rear chambers in response to rotation of the foot; providing a feature to occlude or partially occlude the fluid transfer between chambers; providing a non-electronic mechanism for controlling the flow responsive to both a position of the joint and a rate of change of position of the joint, and wherein the mechanism is arranged such that a dwell at a particular joint location or locations will occlude the flow path.