Hydraulic Hip Prosthesis Damping for Gait Control
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Solution Overview
Problem
Current hip joint prostheses struggle to replicate a natural gait pattern due to uncontrolled movements of the hip, knee, and ankle joints, leading to instability and limited stride length adjustment, which restricts walking speed and stability, especially during heel strike.
Innovation Solution
A hip joint prosthesis with a control unit and damping device that allows adjustable damping in both extension and flexion movements, enabling controlled stride length and natural gait through a hydraulic system with progressive damping characteristics, integrated into the prosthesis for enhanced stability and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the joint axes of the hip joint prosthesis are arranged anterior to the joint axes of a natural hip joint to ensure hip joint stretching after heel strike, then the hip joint can achieve extended position shortly after heel strike, but the extension movement cannot be controlled and leads to uncontrolled hip flexion
Solution Approach 1:
The patent applies parameter changes by introducing a damping device that dynamically adjusts the damping force parameter during the hip joint movement cycle. The damping force is varied as a function of the movement phase: low damping during early extension to allow rapid hip joint stretching after heel strike, then increasing damping to control and limit hip flexion, and finally high damping to ensure stable heel strike. This dynamic parameter adjustment resolves the contradiction between achieving rapid extension and preventing uncontrolled flexion.
2Reliability
If a fixed stride length is chosen to ensure stable heel strike, then heel strike stability is improved, but different walking speeds cannot be accommodated
Solution Approach 1:
The patent applies dynamics by making the damping characteristic variable rather than fixed. The damping device is designed to automatically adjust its damping force based on the movement phase and can be manually adjusted by the user to accommodate different walking speeds. During swing phase, the damping progresses from low to high to control the transition from hip flexion to extension. During stance phase, the damping is adjusted to ensure stable heel strike. This dynamic adjustment mechanism allows the same prosthesis to accommodate various walking speeds while maintaining heel strike stability.
3Adaptability or versatility
If variable stride length is provided to accommodate different walking speeds, then walking speed adaptability is improved, but uncontrolled hip flexion and unstable heel strike occur
Solution Approach 1:
The patent resolves this contradiction by dynamically changing the damping parameter based on the movement phase and user-adjustable settings. The damping device provides different damping levels for different phases of the gait cycle and different walking speeds. During swing phase, progressive damping controls the transition while allowing variable stride length. During stance phase, the damping is optimized to ensure stable heel strike regardless of the stride length. This parameter-based control ensures both adaptability to different walking speeds and reliability of heel strike.
4Ease of operation
If no damping is provided during hip joint movement to allow natural gait, then movement freedom is improved, but uncontrolled hip flexion and instability occur
Solution Approach 1:
The patent applies local quality by providing differentiated damping characteristics for different phases of the gait cycle rather than uniform damping throughout. During swing phase, the damping is low in the initial phase to allow natural hip flexion and movement freedom, then progressively increases to control the transition to extension. During stance phase, the damping is high to ensure stable heel strike and prevent uncontrolled hip flexion. This localized application of damping quality achieves both movement freedom and gait stability.
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 allows for a more natural and stable gait by controlling the extension movement and stride length, preventing sudden hip flexion and ensuring a secure heel strike, while accommodating different walking speeds and user preferences through adjustable damping.
Implementation Method 1
control the extension movement in the stance phase and the stride length of the leg prosthesis, for example via a hydraulic control system
Implementation Method 2
the control unit has at least one damping device for damping the flexion and/or extension movement in the hip joint
Implementation Method 3
at least one damping device for damping the flexion and/or extension movement
Data Source
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AI summary
The invention relates to a hip joint prosthesis (1) for an artificial leg, comprising connection means (21, 31) for securing to a securing device. Said hip joint prosthesis also comprises a control unit (6) for controlling an extension movement in the hip joint and the length of the step. The extension movement whilst standing and the length of the step of the leg prosthesis can be controlled by means of the control unit, for example, by means of a hydraulic control system.