Artificial Knee Joint Control for Automatic Cycling Mode Detection
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Solution Overview
Problem
Existing artificial knee joints struggle to seamlessly transition between walking and cycling movements, particularly during inconsistent pedaling scenarios such as going downhill or overcoming obstacles, without requiring user intervention.
Innovation Solution
A method for controlling an artificial knee joint that detects cyclic movements by analyzing the flexion angle and absolute angles of the joint components using inertial sensors, determining the phase space of angular parameters, and adjusting resistance levels based on these detections to facilitate cycling without additional user actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If resistance is reduced for cyclic movements detected by analyzing time intervals between maxima and minima of knee angle, then cycling performance is improved, but the system fails to detect inconsistent pedaling movements such as going downhill or standing up to ride over obstacles
Solution Approach 1:
The patent transitions from analyzing only temporal characteristics (time intervals between maxima and minima) to incorporating spatial dimension by analyzing absolute angles of the lower part in space. This additional dimensional information enables detection of inconsistent pedaling movements that were previously undetectable, such as going downhill or standing up to ride over obstacles.
Solution Approach 2:
The system dynamically adjusts resistance based on real-time detection of cyclic movements using both temporal and spatial parameters. The resistance control adapts to varying pedaling conditions, maintaining optimal performance during consistent cycling while also responding to inconsistent movements through the enhanced detection capability.
2Ease of operation
If resistance is continuously reduced during detected cyclic movement, then ease of cycling is improved, but safety is compromised when termination criteria are not properly met
Solution Approach 1:
The system continuously monitors multiple parameters (flexion angle, absolute angles, time intervals) and uses feedback loops to determine whether cyclic movement termination criteria are met. Resistance is only reduced when detection criteria are satisfied, and the system continuously verifies these criteria to ensure safe mode transitions, preventing premature or unsafe resistance reduction.
Solution Approach 2:
The system establishes clear termination criteria before resistance reduction occurs. By pre-defining the conditions that must be met (proper detection of cyclic movement end, verification of termination criteria), the system ensures that resistance changes only occur when safe and appropriate, maintaining both ease of operation and reliability.
Data Source
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AI summary
The invention relates to a method for controlling a prosthesis or orthesis of the lower extremity, the prosthesis or orthesis comprising an upper part (10) and a lower part (20) which is connected to the upper part (10) via a knee joint and is mounted so as to be pivotable relative to the upper part (10) about a joint pin (15); wherein an adjustable resistance device (40) is situated between the upper part (10) and the lower part (20), by means of which resistance device a resistance (Rf) is modified on the basis of sensor data; wherein state information is detected by sensors, a cyclical movement different from walking is determined and the resistance (Rf) is adjusted to a low level during the cyclical movement; wherein determining the cyclical movement comprises the following steps: a. detecting the flexion angle (αK) and at least one absolute angle (αS) of the lower part (20) and/or the upper part (10) over at least one movement cycle, b. identifying the cyclical movement from the relative movement of the upper part (10) and the lower part (20) and the absolute movements of the upper part (10) and/or the lower part (20) in space.