Exoskeleton Hip Joint With Rotation Limits for Stump Load Relief
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Solution Overview
Problem
Existing lower body braces and prosthetic limbs are unsuitable for individuals with pelvic resections or lower limb amputations as they rely on intact skeletal structures for load bearing, leading to overloading of remaining limbs and discomfort, and traditional exoskeletons do not provide adequate support for individuals with high loading forces at the stump interface.
Innovation Solution
An exoskeleton design with a torso and leg portion coupled via a hip joint, featuring rotation limiting joints and a buttock support arm, which captures vertical load and prevents over-rotation, along with detachable engagement with shoes for improved flexibility and comfort, using materials like carbon fiber and Kevlar for support and ease of donning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lower body braces or orthoses are used for individuals with pelvic resection or lower limb amputation, then the skeletal structure is relied upon for load bearing, but this causes overloading of the remaining limb and rapid fatigue
Solution Approach 1:
The exoskeleton divides the load bearing function into separate modular components: a hip joint with rotation limiting joints, torso arm, leg arm, and buttock support arm. This segmentation allows the load to be distributed across multiple independent elements rather than concentrated on the residual limb, solving the contradiction between providing reliable load bearing and preventing user fatigue
Solution Approach 2:
The exoskeleton acts as an intermediary load-bearing structure between the user's torso and the ground. The hip joint and its rotation limiting joints serve as the mediator that transfers load through the exoskeleton structure rather than through the vulnerable residual limb interface, enabling reliable load bearing while protecting the user from excessive forces
2Strength
If traditional exoskeletons are used for individuals with lower limb amputations, then support is provided, but high loading forces at the stump interface cause discomfort and skin injury
Solution Approach 1:
The invention extracts the load-bearing function from the residual limb-stump interface and relocates it to the exoskeleton's hip joint and rotation limiting joints. By taking out the harmful loading forces from the vulnerable skin interface and placing them in the robust exoskeleton structure, strong support can be provided without causing skin injury
Solution Approach 2:
The rotation limiting joints serve as an intermediary mechanism that controls and distributes forces away from the stump interface. This mediator prevents high loading forces from concentrating at the skin interface while still providing necessary support, resolving the contradiction between strength and preventing harm
3Stability of the object's composition
If rotation limiting joints are added to the hip joint to prevent over-rotation, then stability is improved, but device complexity increases
Solution Approach 1:
The rotation limiting joints are implemented as localized mechanical features within the hip joint assembly rather than complex control systems. Each rotation limiting joint (torso arm and leg arm) has specific geometric constraints that passively limit rotation to appropriate ranges. This local quality approach provides stability through simple geometric design rather than complex active control, resolving the contradiction between stability and device complexity
Data Source
Figure 1A
Figure 1B~1C
Figure 2A
AI summary
An exoskeleton for providing support to a human user, the exoskeleton comprising a torso portion and leg portion, the torso portion and leg portion coupled via a hip joint. The hip joint comprises a torso arm for detachably coupling to the torso portion and leg arm for detachably coupling to a leg portion, wherein the torso arm and leg arm are both coupled to a central portion of the hip joint via respective rotation limiting joints. The rotation limiting joint for the torso arm has a first range of motion about the central portion, and the rotation limiting joint for the leg arm has a second range of motion about the central portion, wherein the second range of motion is less than the first range of motion.