Hydraulic Orthotic Knee Control for Low-Resistance Flexion Support
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Solution Overview
Problem
Existing orthotic knee control devices face challenges such as high resistance during motion, especially during activities like stair descent and sitting. The conventional devices are not suitable for users with weakness of the quadriceps. The devices are not suitable for users with paralysis. The devices are not suitable for users with paralysis. The devices are not suitable for users with paralysis.
Innovation Solution
The device includes a hydraulic piston connected to a hydraulic chamber, accumulator springs connected to an accumulator chamber, and a non-return valve connected between the hydraulic chamber and the accumulator chamber. The non-return valve allows the flow of an oil from the accumulator chamber to the hydraulic chamber and does not allow the flow of the oil from the hydraulic chamber to the accumulator chamber. Further, the orthotic knee control device includes a motorized valve connected between the hydraulic chamber and the accumulator chamber. The motorized valve controls the flow of oil based on one or more sensors to provide appropriate resistance for the user, ensuring that following maximum flexion, the motorized valve can move to a relatively high resistance to provide support to the user when the user stumbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydraulic damper control is used to provide natural knee joint flexion and controlled support, then knee joint flexion control is improved, but resistance opposing motion increases making extension movement difficult
Solution Approach 1:
The patent employs a dynamic valve control system that adjusts hydraulic resistance based on real-time knee joint position and motion detection. The valve controller modulates the opening degree of the valve to dynamically change fluid flow resistance, providing appropriate damping during flexion while minimizing resistance during extension, thus resolving the contradiction between flexion control and extension ease.
Solution Approach 2:
The system changes the hydraulic resistance parameter dynamically by adjusting valve opening degree based on detected knee joint parameters (position, velocity, acceleration). During flexion phase, higher resistance is applied for control; during extension phase, resistance is reduced to facilitate movement, allowing the system to adapt resistance levels to match the required motion characteristics.
2Reliability
If high resistance is provided during flexion for support, then stumble recovery is improved, but extension movement becomes restricted
Solution Approach 1:
The valve controller implements periodic adjustment of hydraulic resistance based on the gait cycle phases. During the swing phase when stumble recovery is needed, the valve opens to provide high resistance for support. During the stance phase when extension is required, the valve closes to minimize resistance, creating a periodic pattern of resistance that matches the alternating requirements of flexion control and extension movement.
Solution Approach 2:
The system uses sensors to detect knee joint position, velocity, and acceleration in real-time, feeding this information back to the valve controller. The controller processes this feedback to determine the appropriate valve opening degree, providing high resistance when flexion control is needed for stumble recovery while allowing free extension when the user intends to move, thus resolving the contradiction between reliability and ease of operation.
3Adaptability or versatility
If hydraulic control provides controlled support during sitting and stair descent, then functional support is improved, but device complexity increases
Solution Approach 1:
The hydraulic control system with valve controller serves multiple functions: it provides damping during walking, support during sitting, control during stair descent, and stumble recovery assistance. By using a single valve mechanism that can be controlled in different ways (manual override, automated sensor-based control), the system achieves multi-functionality without proportionally increasing complexity, as the same basic hydraulic components perform all these diverse functions.
Solution Approach 2:
The system incorporates automated sensor-based control that operates without continuous user intervention. Sensors detect knee joint parameters and automatically adjust valve opening to provide appropriate support during various activities. This self-service capability reduces the need for complex manual control mechanisms while maintaining adaptability across different functional scenarios.
4Device complexity
If manual lock and unlock mechanism is used, then structural simplicity is maintained, but natural knee joint flexion is lost
Solution Approach 1:
The patent replaces the purely mechanical lock-and-unlock mechanism with a hybrid system that incorporates hydraulic damping and sensor-based electronic control. The valve controller uses sensors to detect knee joint position and automatically adjusts valve opening to enable natural flexion without mechanical locking. This substitution maintains structural simplicity by using straightforward hydraulic components while eliminating the need for complex mechanical locking mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The orthotic knee control device provides ease of movement by reducing resistance in the direction of motion, aiding knee extension, and providing stumble recovery and support during activities involving large knee flexion angles, such as stair descent and sitting, while also supporting users with lower limb paralysis.
Implementation Method 1
accumulator springs connected to an accumulator chamber... the accumulator springs apply pressure to the hydraulic piston, to resist knee joint flexion and aid in extension of the knee joint
Implementation Method 2
hydraulic piston connected to a hydraulic chamber... The orthotic knee control device includes a hydraulic piston connected to a hydraulic chamber
Implementation Method 3
non-return valve connected between the hydraulic chamber and the accumulator chamber. The non-return valve allows the flow of an oil from the accumulator chamber to the hydraulic chamber and does not allow the flow of the oil from the hydraulic chamber to the accumulator chamber
Implementation Method 4
motorized valve connected between the hydraulic chamber and the accumulator chamber. The motorized valve controls the flow of oil based on one or more sensors to provide appropriate resistance for the user
Data Source
AI summary
Embodiments herein discloses an orthotic knee control device providing ease of movement. The orthotic knee control device includes a hydraulic piston connected with a hydraulic chamber, accumulator spring(s) connected with an accumulator chamber, a non-return valve connected in between the hydraulic chamber and the accumulator chamber. The non-return valve allows the flow of an oil from the accumulator chamber to the hydraulic chamber and does not allow the flow of the oil from the hydraulic chamber to the accumulator chamber. Further, the orthotic knee control device includes a motorized valve connected between the hydraulic chamber and the accumulator chamber. Further, the accumulator springs apply pressure to the hydraulic piston, to resist flexion of a knee joint and to aid extension of the knee joint.