Upper-Body PHRI Hand Interface for Spasticity-Reducing Anchoring
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Solution Overview
Problem
Existing robotic exoskeletons for upper-body rehabilitation, such as those used for stroke recovery, face challenges in widespread use due to issues like muscle spasticity, discomfort, and inefficiency in anchoring the human limb to the device, leading to unwanted motion and neuromuscular tendencies.
Innovation Solution
A wearable robotic system with a Physical Human Robot Interaction (PHRI) interface that anchors the human hand to a mechanical device using a plastic-on-plastic ratcheting mechanism, ensuring contact with less provocative regions like the Thenar and Hypothenar Eminences, and includes a quick disconnect mechanism to minimize adverse neuromuscular responses and enhance user comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional anchoring methods are used to secure the human limb to the exoskeleton, then the device can maintain mechanical power transfer, but it causes muscle spasticity and discomfort
Solution Approach 1:
The interface distributes contact forces to specific anatomical regions (dorsal hand, metacarpal heads, thenar and hypothenar eminences) that are less provocative of flexor synergy, rather than applying force uniformly or to sensitive areas. This localized quality approach maintains mechanical transfer while avoiding harmful neuromuscular responses
Solution Approach 2:
Instead of anchoring the palmar surface of the hand (which triggers flexor synergy), the invention inverts the approach by anchoring the dorsal surface and specific eminences, achieving secure attachment while avoiding the harmful effects of traditional methods
2Stability of the object's composition
If the exoskeleton interface applies force to anchor the hand securely, then mechanical stability is improved, but adverse neuromuscular tendencies increase
Solution Approach 1:
The interface is designed to apply forces locally to specific anatomical structures (dorsal hand, metacarpal heads, thenar and hypothenar eminences) that can tolerate secure anchoring without triggering adverse neuromuscular responses, thus maintaining stability while avoiding harmful effects
Solution Approach 2:
The invention converts the potentially harmful effect of secure anchoring (which typically triggers flexor synergy) into a beneficial outcome by selecting anchor points that provide mechanical stability while avoiding the triggering of adverse neuromuscular tendencies
3Reliability
If traditional hand anchoring is used, then the device can be attached securely, but user comfort decreases
Solution Approach 1:
The interface distributes contact forces to specific anatomical regions (dorsal hand, metacarpal heads, thenar and hypothenar eminences) that are less sensitive and more tolerant of secure anchoring, maintaining attachment security while improving user comfort by avoiding pressure on sensitive areas
4Power
If the exoskeleton uses conventional interface design, then mechanical power transfer is achieved, but unwanted motion occurs
Solution Approach 1:
The interface is designed with specific contact regions (dorsal hand, metacarpal heads, thenar and hypothenar eminences) that provide stable anchoring points, reducing unwanted motion while maintaining effective mechanical power transfer through the hand-wrist-elbow complex
Data Source
AI summary
An embodiment includes an apparatus for coupling a user to a robot to provide robot-assisted physical therapy to the user. Other embodiments are described herein.