Shoulder Exoskeleton Kinematic Chain Design
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Solution Overview
Problem
Existing exoskeleton designs for supporting the shoulder joint restrict natural mobility and are bulky, causing mechanical limitations and collision risks, especially during overhead movements.
Innovation Solution
A compact, kinematically coupled device with five pivot bearings that provide 360° rotational mobility and transverse movement, featuring a serial arrangement with non-intersecting axes of rotation, and incorporating actuators like electric motors for force relief, ensuring unobstructed arm movements without protrusions beyond the shoulder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid connecting struts with serial kinematic chain are used to support shoulder joint movement, then joint stability and stress relief are improved, but natural mobility is restricted and device bulk increases
Solution Approach 1:
The device divides the support structure into multiple independent pivot bearings (first through fifth pivot bearings) with distinct axes of rotation, each segment contributing to overall stability while maintaining individual mobility. The serial kinematic chain is segmented into manageable rotational joints rather than rigid connections.
Solution Approach 2:
The device transitions from rigid connecting struts to dynamic pivot bearings that allow rotational movement. The five pivot bearings with different axes of rotation enable adaptive movement that follows natural shoulder joint kinematics, providing stability when needed while allowing freedom of movement during natural motion.
2Reliability
If support structures extend beyond shoulder area to provide stability, then joint support is improved, but collision risk and mechanical limitations increase
Solution Approach 1:
The device uses five pivot bearings with axes of rotation arranged in three-dimensional space, where the first axis traverses the scapula/frontal plane and the fifth axis traverses the humeral head. This spatial arrangement provides comprehensive joint support without requiring structural extensions beyond the shoulder area that would create collision hazards.
Solution Approach 2:
The pivot bearings serve multiple functions: the first pivot bearing provides scapular movement support, while the fifth pivot bearing provides humeral movement support. The intermediate pivot bearings (second through fourth) connect these two functional elements, creating a unified structure that provides comprehensive support without extending beyond the shoulder.
3Ease of operation
If actuators are integrated into pivot bearings for force relief, then movement assistance is improved, but device weight and complexity increase
Solution Approach 1:
The device provides movement assistance through actuators integrated into only some of the pivot bearings rather than all five. This partial actuation provides sufficient force relief to assist natural movement while avoiding the excessive complexity and weight that would result from fully actuating every pivot bearing in the kinematic chain.
Data Source
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AI summary
A device for supporting the movement of a human shoulder joint is described, with a first rotary bearing (L1) for applying a rotation of a first bearing part (1) about a first rotation axis (D1), a second rotary bearing (L2) for applying a rotation of a second bearing part (2) about a second rotation axis (D2), wherein the second rotation axis (D2) is connected indirectly or directly to the first bearing part (1), a third rotary bearing (L3) for applying a rotation of a third bearing part (3) about a third rotation axis (D3), wherein the third rotation axis (D3) is connected indirectly or directly to the second bearing part (2), a fourth rotary bearing (L4) for applying a rotation of a fourth bearing part (4) about a fourth rotation axis (D4), wherein the fourth rotation axis (D4) is connected indirectly or directly to the third bearing part (3), and a fifth rotary bearing (L5) for applying a rotation of the fourth bearing part (4) about a fifth rotation axis (D5), wherein a) the first rotation axis (D1) is connected in a spatially fixed manner to a first fastening means (5) which is suitable for the detachable mounting and orientation of the first rotary bearing (D1) on the shoulder area of a person, b) the fifth rotation axis (D5) is connected in a spatially fixed manner to a second fastening means (6) which is suitable for detachable mounting and orientation of the fifth rotary bearing (D5) on the upper arm area of the shoulder blade of a person, such that the rotation axis (D5) traverses the head of the humerus of the person, c) the second and third rotation axes (D2, D3) are oriented parallel to each other and span a plane (E) with respect to which the fourth rotation axis (D4) is oriented in parallel, and d) at least the first and/or fifth rotary bearings have/has an actuator that supports the rotation.