Hydraulic Prosthetic Knee Valve for Sensorless Damping Control
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Solution Overview
Problem
Conventional prosthetic knee joints with dual sensor technology are complex, prone to errors, costly, and require electrical energy or intricate non-electrical sensors, which makes them large, cumbersome, and heavy, failing to adequately control damping during different phases of the gait cycle.
Innovation Solution
A valve design where the inlet is arranged to exert a total force perpendicular to the displacement direction, blocking or reducing fluid flow between extension and flexion chambers, using a piston with a one-way valve and a throttle outlet, eliminating the need for electronic sensors by leveraging fluid pressure and friction to control the valve's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual sensor technology is used to control damping during different phases of gait cycle, then damping control precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the complex electronic sensor system from the prosthetic knee joint. Instead of using dual sensors to detect gait phase and control damping, the invention uses a purely mechanical valve system that automatically responds to hydraulic pressure changes generated by the user's natural movement, thereby achieving damping control without electronic sensors
Solution Approach 2:
The mechanical valve system is designed to be self-regulating, using the hydraulic pressure generated by the user's own movement to automatically control the damping. The valve body responds to pressure differential forces that naturally occur during gait, eliminating the need for external sensing and control systems
2Measurement precision
If electronic sensors are used to detect gait phase, then measurement precision is improved, but weight increases
Solution Approach 1:
The patent replaces the electronic sensor system with a mechanical detection and response system. The valve body and valve seat form a mechanical pressure-sensitive switch that detects gait phase through hydraulic pressure changes and automatically adjusts damping, eliminating the need for electronic sensors and reducing weight
3Ease of manufacture
If conventional valve design is used with fluid flow parallel to displacement direction, then manufacturing simplicity is improved, but control reliability deteriorates
Solution Approach 1:
The patent introduces an asymmetric force component by designing the inlet to direct fluid flow at an angle to the valve body displacement direction. This creates a perpendicular force component that pushes the valve body against the valve seat, ensuring reliable valve closure. The asymmetric flow configuration guarantees that the total force on the valve body always has a closing component, preventing leakage and improving control reliability
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
This configuration simplifies the prosthetic knee joint, reducing size, production costs, and eliminating the need for electronic sensors, while providing controlled damping by using fluid pressure and friction to maintain stability and prevent uncontrolled flexion.
Implementation Method 1
a fluid entering through the inlet exerts a total force on the valve body that at least also acts in a force direction which is perpendicular to the displacement direction
Implementation Method 2
the friction between the valve body and the wall of the housing on which it rests increases. This results in a holding force that counteracts a displacement of the valve body
Implementation Method 3
hydraulic arrangement with an extension chamber (16), a flexion chamber (18) and a valve (20), by means of which the extension chamber (16) is connected to the flexion chamber (18)
Data Source
AI summary
A valve with an inlet, an outlet that is connected to the inlet via a fluid connection, and a valve body, which can be brought by displacing it along a displacement direction into a first position, in which the fluid connection is blocked, and a second position, in which the fluid connection is open, wherein the inlet is designed and arranged in such a way that a fluid entering through the inlet exerts a total force on the valve body that at least also acts in a force direction which is perpendicular to the displacement direction when the valve body is in the first position.