Exoskeleton Stability Strap Counteracts Asymmetric Moment
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Solution Overview
Problem
Unilateral upper-body exoskeletons face stability issues due to asymmetric weight distribution, leading to misalignment between anatomical and robotic joints, and potential disengagement or discomfort for users.
Innovation Solution
The interface includes a shoulder strap configuration and an additional stability strap that counteracts the moment of rotation caused by asymmetric weight distribution, with length adjusters for user comfort and a one-size-fits-all belt configuration for customizable fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a unilateral upper-body exoskeleton is used to assist impaired side, then rehabilitation effectiveness is improved, but interface stability deteriorates due to asymmetric weight distribution causing rotation toward the actuated side
Solution Approach 1:
A counterweight mechanism is introduced to balance the asymmetric weight distribution caused by the unilateral exoskeleton. The counterweight applies an opposing force to the asymmetric moment generated by the exoskeleton, preventing the interface from rotating toward the actuated side and maintaining stable alignment between anatomical and robotic joints throughout the rehabilitation process
2Force
If shoulder straps are used to support the exoskeleton, then load distribution is improved, but misalignment between anatomical and robotic joints occurs due to rotation
Solution Approach 1:
The counterweight mechanism compensates for the asymmetric moment that causes joint misalignment. By applying an opposing force equal to the asymmetric moment generated by the unilateral exoskeleton, the counterweight prevents rotation and maintains precise alignment between anatomical and robotic joints while still allowing the shoulder straps to distribute the load effectively
3Ease of manufacture
If a fixed interface configuration is used, then manufacturing cost is reduced, but user comfort and fit deteriorate due to varying body sizes and preferences
Solution Approach 1:
The interface incorporates adjustable components that allow users to customize the fit and positioning according to their individual body sizes and comfort preferences. This dynamic adjustability enables a single standardized interface design to accommodate varying user requirements, maintaining ease of manufacture while improving user comfort and preventing discomfort from pressure points or interference with sensitive body parts
Data Source
AI summary
A physical human-robot interface is provided for use with a unilateral upper-body exoskeleton having a strut, a belt, and a pair of shoulder straps extending from the strut to the belt. A stability strap is arranged for counteracting the moment caused by the asymmetrically connected unilateral upper-body exoskeleton. The stability strap extends from the strut in a direction opposite the upper-body exoskeleton across a user's back to a position located anterolaterally along the belt. The belt includes a plurality of fastening locations configured to receive the stability strap.