Prosthetic Knee Joint Automatic Resistance Control
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Solution Overview
Problem
Existing prosthetic and orthotic joints lack automatic resistance adjustment to ensure stability and safety, particularly in standing situations, as they require manual mode activation and fail to prevent buckling on inclined surfaces.
Innovation Solution
A method and device that automatically increase resistance and lock the knee joint based on ground reaction force and joint angle, using sensors to detect the standing phase and adjust resistance dynamically to prevent buckling and facilitate smooth transitions between standing and swinging phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If resistance devices are used to provide flexion and extension resistance, then the joint can be adapted to different gait and movement situations, but the joint may buckle on inclined surfaces when the ground reaction force vector lies behind the joint axis
Solution Approach 1:
The control device continuously monitors sensor data including ground reaction force vectors and joint angles, and automatically adjusts resistance in real-time based on this feedback. When the ground reaction force vector lies behind the joint axis, the control device increases flexion resistance to prevent buckling, while maintaining adaptability to different gait phases through continuous sensor-based adjustment
Solution Approach 2:
The resistance device transitions from static resistance settings to dynamic resistance adjustment based on real-time sensor data. The control device modifies flexion and extension resistance continuously during movement, adapting to changing gait phases, ground reaction forces, and joint angles to maintain stability while preserving natural movement patterns
2Reliability
If the knee joint is locked during standing phase, then stability and safety are improved, but the patient cannot move unhindered when sitting or transitioning between positions
Solution Approach 1:
The resistance device dynamically adjusts its characteristics based on detected movement phase. During standing phase, the control device increases flexion resistance to provide stability and prevent unwanted bending. During sitting phase and transitions, the control device reduces resistance to allow unhindered movement. This dynamic adaptation is achieved through continuous monitoring of joint angles, ground reaction forces, and movement velocity
Solution Approach 2:
The control device changes key resistance parameters (flexion resistance, extension resistance, damping characteristics) based on detected phase. The system transitions between high-resistance standing mode and low-resistance movement mode by adjusting actuator settings, friction elements, and damping coefficients according to sensor feedback about current activity state
3Reliability
If high flexion resistance is provided during standing phase, then unwanted bending is prevented, but the joint requires manual mode activation and cannot automatically respond to changing conditions
Solution Approach 1:
The control device uses sensor feedback (ground reaction force, joint angle, acceleration) to automatically detect standing phase and manually activate locking mode. The system monitors the ground reaction force vector position relative to the joint axis and automatically adjusts resistance accordingly, eliminating the need for manual mode selection while maintaining joint stability
Solution Approach 2:
The resistance device automatically monitors its own operational conditions through integrated sensors and self-adjusts resistance levels without external intervention. The control device detects phase transitions and condition changes (such as ground reaction force vector position) and autonomously modifies resistance characteristics to maintain optimal performance across varying conditions
Data Source
AI summary
The invention relates to a device and method for controlling an artificial orthotic or prosthetic joint of a lower extremity, comprising a resistance unit with which at least one actuator is associated, via which the bending and/or stretching resistance is varied depending on sensor data. During the use of the joint, status information is provided via sensors. According to the invention, the resistance is increased in the standing phase or while standing from a starting value depending on the ground reaction force up to a locking point of the joint.