Adaptive Prosthesis Knee Joint Resistance Control
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Solution Overview
Problem
Artificial knee joints in prostheses and orthoses often lack comfortable movement transitions, particularly during special situations like setting off from a standing position, due to fixed resistance levels that do not adapt effectively to changing gait situations.
Innovation Solution
A method that adjusts flexion resistance in artificial knee joints based on sensor data, reducing resistance when a decreasing axial force or vertical leg cord position is detected, and increasing it if no knee flexion occurs within a fixed period or if the knee joint is unloaded, to facilitate easier movement and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed resistance levels are used in artificial knee joints, then the device structure remains simple, but movement transitions become uncomfortable and do not adapt to changing gait situations
Solution Approach 1:
The patent applies dynamics by making the resistance device adjustable based on detected gait situations. The resistance level changes dynamically according to the detected situation (walking, climbing stairs, sitting down), transforming a static resistance system into an adaptive one that responds to user needs without requiring overly complex control mechanisms.
Solution Approach 2:
The system uses self-service by automatically detecting gait situations through sensors and autonomously adjusting resistance levels without requiring manual input from the user. The control unit processes sensor data and modifies resistance settings independently, making the system self-regulating and responsive to actual usage conditions.
2Stability of the object's composition
If high flexion resistance is maintained for stability, then knee joint stability improves, but movement transitions become difficult and uncomfortable
Solution Approach 1:
The patent implements dynamics by varying flexion resistance based on the detected gait situation. During stable phases like standing or walking, higher resistance maintains knee joint stability. During transition phases like sitting down or climbing stairs, the resistance is reduced to facilitate smooth movement, thus dynamically balancing stability and ease of operation.
Solution Approach 2:
The system changes the resistance parameter according to detected gait situations. By modifying the resistance level (a key parameter) based on whether the user is walking, climbing stairs, or sitting down, the system optimizes both stability during steady states and ease of movement during transitions, resolving the contradiction between these two requirements.
Data Source
AI summary
The invention relates to a method for controlling a prosthesis or orthosis of the lower extremity, which prosthesis or orthosis has an upper part (10) and a lower part (20), which lower part is connected to the upper part (10) by means of a knee joint (1) and is mounted for pivoting relative to the upper part (10) about a joint shaft (15); wherein an adjustable resistance device (40) is disposed between the upper part (10) and the lower part (20), by means of which resistance device a flexion resistance (Rf) is changed on the basis of sensor data; wherein an axial force (FA) acting on the lower part is sensed by at least one sensor (54) and is used as the basis for a change of the flexion resistance (Rf); wherein, in the case of decreasing axial force (FA) and/or an approximately vertical position of a leg tendon (70) and/or of an extended knee joint (1), the flexion resistance (Rf) is reduced; and wherein the flexion resistance (Rf) is increased again if, within a temporally defined interval, no knee flexion is detected and/or the knee joint (1) and/or the leg tendon (70) and/or the axial force (FA) fall below or exceed specific limit values.