Robotic arm signing tactile sign language (t-SL) to aid deaf-blind (DB) communication
Samantha Tatum Johnson · 2021
To communicate independently, the 1.5 million Americans with deaf blindness cannot utilize their primary conversational language, tactile sign language (t-SL), and instead must rely on a secondary language, Braille. The use of t-SL requires the presence of an interpreter, as deaf-blind (DB) individuals place their hands over their signing partner's hands while they sign. To provide the DB community with a tool for independent communication, TATUM (Tactile ASL Translational Use Machine) platform incorporates a robotic arm system that can sign t-SL and connect to mainstream communication devices (email, SMS, twitter, etc.). The TATUM hand-wrist system features 17 degrees of actuation (DoA). Designed using a tendon-driven mechanism (TDM), the active and passive tendons cause motion around flexible joints for user safety and to aid extension under contact pressure. Utilizing torsion springs, each finger achieves abduction and flexion at the metacarpophalangeal (MCP) joint, as well as flexion coupled at the distal and proximal interphalangeal (dIP and pIP) joints. The thumb attains 3 DoAs: flexion at the IP joint, as well as palmar and radial abduction. Lastly, the wrist achieves both flexion and abduction (2 DoAs). Utilizing an independent cloud-based service, Interpres, the TATUM platform can sign the 26-letter American Sign Language (ASL) alphabet and other one-hand signs. In several validation studies, the device was evaluated with both deaf and DB participants and improved iteratively based on their feedback. The TATUM hand-wrist system achieved a 94.7% recognition rate of the ASL alphabet with deaf participants. Additionally, in a fingerspelling validation, the participants remarked that the hand felt like a woman's hand and achieved a 100% recognition rate of the fingerspelled words. Furthermore, the TATUM platform was able to successfully sign both visual ASL and t-SL, based on both letter recognition and fingerspelling. Moving forward, the TATUM hand-wrist system will be expanded to include an elbow-shoulder system with bodily reference to sign more complex signs. Overall, the TATUM platform has shown promise to give DB users access to their primary conversational language without the use of an interpreter, this increasing their independence and access to a growing community.--Author's abstract