Artificial Knee Joint Damping Control for Stance Phase Safety
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Solution Overview
Problem
Existing artificial knee joints face challenges in providing adaptive damping to ensure safe and comfortable walking across various environments, including stairs and ramps, as excessive initial flexion damping can lead to shock loads and reduced wearing comfort.
Innovation Solution
A method for controlling the stance phase damping of an artificial knee joint, where the flexion damping is dynamically adjusted based on sensor data to prevent excessive flexion, with increased damping during heel strike and loading responses, and decreased damping during terminal stance and pre-swing phases to allow toe lift-off and smooth movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excessive initial flexion damping is provided to prevent knee flexion during stance phase, then safety and stability are improved, but shock loads increase and wearing comfort deteriorates
Solution Approach 1:
The patent applies dynamics by making the damping resistance adjustable rather than fixed. The resistance device can dynamically change its damping characteristics based on the gait phase and detected knee angle, transitioning from high damping during initial stance to lower damping during terminal stance, thereby preventing shock loads while maintaining safety.
Solution Approach 2:
The patent changes the damping parameter adaptively. By detecting knee angle and gait phase, the system modifies the damping resistance parameter in real-time, increasing it when needed for stability and decreasing it to allow natural knee motion and reduce shock loads during appropriate phases of the gait cycle.
2Stability of the object's composition
If high flexion damping is provided during initial stance phase, then knee stability is improved, but natural gait pattern and comfort are reduced
Solution Approach 1:
The system dynamically adjusts damping based on gait phase detection. During initial stance, high damping provides stability. As the gait phase progresses and knee angle increases, the damping is reduced to allow natural knee flexion and extension, thereby maintaining both stability and natural gait pattern throughout the cycle.
Solution Approach 2:
The patent uses feedback from sensors detecting knee angle and gait phase to control the damping resistance. This closed-loop control ensures that the damping level is continuously adapted to match the current gait phase, providing stability when needed while allowing natural motion during other phases.
3Reliability
If damping resistance is increased to prevent excessive flexion, then safety is improved, but toe lift-off and terminal stance movement are restricted
Solution Approach 1:
The damping resistance is made dynamic and phase-dependent. The system provides high damping during initial stance to prevent excessive flexion and ensure safety. As the gait phase progresses into terminal stance, the damping is automatically reduced to allow necessary knee movement and toe lift-off, thereby maintaining both safety and adaptability.
Solution Approach 2:
The system preliminarily establishes high damping during initial stance to prevent dangerous flexion. As the gait cycle progresses and the knee angle approaches the threshold for terminal stance, the damping is preemptively reduced to facilitate smooth transition to toe lift-off, avoiding restrictions on natural movement.
Data Source
AI summary
A method for controlling the standing-phase damping of an artificial knee joint comprising an upper part and a lower part which are secured together in a pivotal manner about a pivot axis, a resistance unit which is arranged between the upper part and the lower part and has an adjustment device via which the damping resistance can be modified, and a control unit which is coupled to the adjustment device and which is connected to at least one sensor. The adjustment is carried out on the basis of sensor data, and the knee angle is detected by the at least one sensor during the standing-phase inflexion up to the terminal standing phase. The flexion damping is increased to a level above an initial flexion damping in order to prevent a further inflexion upon reaching a specified maximum knee angle.