Prosthetic Knee Joint Control for Stable Backward Walking
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Solution Overview
Problem
Existing artificial orthotic and prosthetic knee joints face challenges in maintaining appropriate resistance during walking backward, leading to unwanted bending and instability, as current systems require deliberate activation or deactivation of modes.
Innovation Solution
A method and device that automatically increase or maintain resistance when walking backward by using sensors to detect inertial angle and loading changes, preventing the reduction of flexion resistance and ensuring the knee joint remains locked or highly resistant to flexion, thereby allowing safe backward movement without a special locking mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the bending resistance is reduced during the standing phase to facilitate the swing phase, then the ease of operation is improved, but the stability deteriorates when walking backward
Solution Approach 1:
The resistance device dynamically adjusts the bending resistance based on detected movement phase. During normal forward walking, the system reduces resistance to facilitate the swing phase. When walking backward is detected (through sensors monitoring inertial angle and loading changes), the system increases or maintains high resistance to prevent unwanted knee bending and maintain stability.
Solution Approach 2:
The control system continuously monitors sensor data including inertial angle and forefoot loading to detect the user's movement intent. Based on this feedback, the system automatically adjusts the bending resistance in real-time, preventing unwanted bending when walking backward while still allowing normal swing phase movement during forward walking.
2Stability of the object's composition
If a special locking mechanism is added to prevent unwanted bending when walking backward, then the stability is improved, but the device complexity increases
Solution Approach 1:
The patent replaces a mechanical locking mechanism with a control system that uses sensors (inertial sensors, force sensors) and a resistance device to detect movement phase and adjust resistance accordingly. This electronic/control-based approach achieves the same stability function without adding complex mechanical locking components.
Solution Approach 2:
The system changes the resistance parameter dynamically based on detected movement conditions. When walking backward is detected, the bending resistance is increased or maintained at high levels, effectively creating a stable condition without a physical lock. This parameter-based control is simpler than adding mechanical locking hardware.
3Ease of operation
If the flexion resistance is automatically adjusted based on movement detection, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The resistance device serves multiple functions: it provides controlled resistance during normal walking, facilitates swing phase initiation, and prevents unwanted bending during backward walking. By making the resistance device multi-functional and controlled by a unified sensor system, the patent avoids adding separate mechanisms for each function, thereby limiting the increase in overall device complexity.
Data Source
AI summary
A method for controlling an artificial orthotic or prosthetic joint of a lower extremity with a resistance unit to which at least one actuator is associated, via which the bending and/or stretching resistance is changed depending on sensor data. During the use of the joint, status information is provided via sensors. A device for carrying out such a method provides bending resistance that is increased or not lowered in the standing phase, when an inertial angle of a lower leg part is decreasing relative to a vertical direction and a front foot under pressure at the same time are identified.