Upper limb assistive system for throwing motions

Upper Limb Assistive System for Throwing Motions Combining Torsion Springs and Functional Electrical Stimulation

This technology is an upper limb assistive system that supports arm flexion and extension through a brace worn on the user's arm and a torsion spring-based hinge structure, while inducing active contraction of wrist and arm muscles via functional electrical stimulation to perform throwing motions.

Rehabilitation programs for patients with upper limb impairment due to conditions like stroke have traditionally relied on passive, repetitive electrical stimulation, often resulting in low patient engagement and limited therapeutic outcomes.

This technology integrates a latch-based trigger unit that locks and releases the arm's folded state with a torsion spring that provides elastic restorative force. A control unit synchronizes the timing of electrical stimulation with the trigger release, assisting the patient in performing an actual throwing motion. By being applicable to both stroke rehabilitation and sports-oriented therapy, it encourages active patient participation and interest, significantly enhancing rehabilitation effectiveness.

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Key Features:

• Multiple wrist stimulation electrodes that provide electrical stimulation to muscles involved in wrist extension and flexion
• First and second braces for the upper and lower arm, respectively, connected by a hinge axis that allows for joint movement
• A torsion spring installed on the hinge axis to move the braces from a folded to an extended state using elastic force
• A control unit that synchronizes the timing of electrical stimulation and trigger release to assist in throwing motions

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This invention was developed with support from the Ministry of Culture, Sports and Tourism’s project for hybrid smart clothing and monitoring systems for athletic performance enhancement, and the Ministry of Science, ICT and Future Planning’s Human-Centered Soft Robot Technology Research Center.