Lower Limb Exoskeleton Pushrod Knee Stabilization Without Inguinal Straps
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Solution Overview
Problem
Existing lower limb exoskeletons do not provide a simple, reliable, and low-cost mechanical solution to prevent unintentional knee bending under weight and often use inguinal straps that can cause vascular issues due to pressure on veins and arteries.
Innovation Solution
A lower limb exoskeleton design with an adjustable abdominal binder, hip and knee joints, and a knee actuation mechanism using a pushrod to transfer weight to the ground, eliminating inguinal straps and preventing knee bending, featuring sub-axilla and sub-gluteal supports for weight distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inguinal straps are used to attach the exoskeleton to the user's body, then the exoskeleton can transfer user weight effectively, but the straps put pressure on veins and arteries in the groin region, increasing the risk of vascular accidents
Solution Approach 1:
The patent removes the harmful inguinal straps from the exoskeleton attachment system. Instead of using straps that pass through the groin region and compress blood vessels, the design extracts this harmful element and replaces it with alternative attachment methods that avoid the vascular risk zone while maintaining weight transfer capability.
Solution Approach 2:
The patent introduces intermediate attachment structures such as pelvic bands or hip girdles that serve as mediators between the exoskeleton and the user's body. These intermediary elements distribute weight across broader, safer areas of the pelvis and hips, eliminating direct pressure on the inguinal region's blood vessels while still achieving effective weight transfer.
2Stability of the object's composition
If a mechanical solution is implemented to prevent unintentional knee bending under weight, then knee stability is improved, but the system complexity and cost increase
Solution Approach 1:
The patent applies the inversion principle by designing the knee joint mechanism so that the natural body weight and gravitational forces work in favor of maintaining knee extension rather than requiring active mechanical prevention. The mechanism is configured such that when the user stands upright, the weight distribution and joint geometry naturally prevent unwanted flexion, eliminating the need for complex active locking or actuation systems.
Solution Approach 2:
The knee joint mechanism is designed to be self-regulating, using the user's own body weight and the mechanical geometry of the joint to maintain stability. The structure automatically prevents unintentional bending through its inherent mechanical properties without requiring external power sources, sensors, or complex control systems, thereby achieving stability while minimizing added complexity.
3Duration of action of moving object
If the exoskeleton is designed to support most of the user's body weight, then user fatigue is reduced, but the attachment system must safely transfer significant loads without causing vascular compression
Solution Approach 1:
The patent segments the weight-bearing attachment system into multiple distributed contact points across the torso, pelvis, and limbs rather than relying on a single concentrated strap system. This segmentation distributes the mechanical loads across broader anatomical surfaces, reducing pressure intensity at any single location and eliminating vascular compression while maintaining overall weight support capability for extended duration.
Data Source
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AI summary
Lower limb exoskeleton comprising a torso module (20), including an adjustable abdominal binder (22), and two lower limb assemblies (10) connected to the torso module (20) through a hip joint (21), each limb assembly (10) comprising, an upper leg module (11), a knee joint (12), a lower leg module (13) and a lower supporting foothold (15), each limb assembly (10) further comprising a knee actuation mechanism (40) including a pushrod (42), slidably connected to the lower leg module, with a lower end (42b) protruding downwardly below the lower supporting foothold (15) when the pushrod (42) is not in the uppermost position, and an upper end (42a) connected to the upper leg module (11) via a kinematic linkage configured to push the upper leg module (11) into an extended position when the pushrod (42) is moved upwards by resting the lower end (42b) thereof against a ground under user's body weight.