Walking Assistance System Upper Leg Fitting Dynamics
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Solution Overview
Problem
Conventional walking assistance systems cause discomfort due to the upper and lower leg fittings rubbing against the user's skin, as they lack the necessary degree of freedom to follow the natural movement of the knee joint, leading to slippage and weight distribution issues.
Innovation Solution
The walking assistance system includes an upper leg fitting with a movable upper leg coupling member that slides along the upper leg frame and rotates around a support shaft, allowing it to follow the user's leg movement smoothly, and a knee joint actuator with a driving force transmission mechanism that accommodates the fore-and-aft movement of the knee joint, preventing rubbing and enhancing comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the upper leg supports are fixed to the upper leg with a fixed angle, then the structure is simple and rigid, but the upper leg coupling member rubs against the user's skin causing discomfort
Solution Approach 1:
The upper leg coupling member is changed from a fixed rigid structure to a dynamic structure that can rotate around a support shaft. This rotation capability allows the coupling member to adapt to the natural movement of the upper leg, preventing rubbing against the skin while maintaining structural simplicity
Solution Approach 2:
The upper leg coupling member is divided into multiple functional parts: a first arm part for hip joint connection, a second arm part for knee joint connection, and a rotation mechanism around the support shaft. This segmentation allows each part to perform its specific function while reducing overall structural complexity
2Ease of operation
If the second link is made from soft flexible material to follow upper leg movement, then comfort is improved, but the framework rigidity decreases and weight burden increases
Solution Approach 1:
Only the upper leg coupling member, which directly contacts the upper leg, is given rotation freedom around the support shaft. The rest of the framework maintains its rigid structure to provide necessary support and minimize weight burden. This localized flexibility achieves comfort without compromising overall structural integrity
Solution Approach 2:
The upper leg coupling member incorporates a rotation mechanism that provides dynamic adaptation to upper leg movement. This localized dynamic element eliminates the need for making the entire framework flexible, thereby avoiding increased weight burden while maintaining comfort
3Ease of operation
If the upper leg coupling member is fixed to the upper leg frame, then the structure is simple, but it cannot follow the user's leg movement smoothly causing rubbing and discomfort
Solution Approach 1:
The upper leg coupling member is equipped with a rotation mechanism around the support shaft, enabling it to dynamically follow the user's upper leg movement. This single rotational degree of freedom provides the necessary adaptability without introducing complex multi-axis mechanisms
Solution Approach 2:
The coupling member is segmented into first and second arm parts connected by a rotation mechanism. This segmentation allows independent movement of each arm part, enabling smooth following of leg movement while keeping the overall mechanism simple and manageable
Data Source
AI summary
A walking assistance system includes an upper leg fitting which is attached along a user's upper leg. The upper leg fitting is formed from an upper leg frame that forms a framework of the upper leg fitting, and an upper leg coupling member that is vertically slidably supported on a guide rail provided on the upper leg frame, rotatably supported around a support shaft, and joined to the upper leg. When the upper leg fitting is made to swing in the fore-and-aft direction relative to the user's hip by a hip joint actuator, the position of the center of swing of the upper end of the upper leg fitting and the position of the hip joint are displaced, but it is possible to make the upper leg coupling member follow the upper leg by moving the upper leg coupling member relative to the upper leg frame, thus eliminating any uncomfortable sensation.