CHAD: Compact Hand-Assistive Device for enhancement of function in hand impairments[Formula presented]

Fady Alnajjar, Hassan Umari, Waleed K. Ahmed, Munkhjargal Gochoo, Alistair A. Vogan, Adel Aljumaily, Peer Mohamad, Shingo Shimoda

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Hand-assistive devices are used to help post-stroke victims encumbered with hand impairments perform activities of daily living (ADL). Unlike robotic rehabilitation devices used in restricted medical conditions for designated periods, hand-assistive devices are designed to be portable and to be used for extended periods by individuals engaging in ADL. Several hand-assistive device designs have been proposed. With these, designers have focused on key elements, such as size, weight, motion profile of the fingers, and generated grip/pinch force. In this paper, we propose a unique compact hand-assistive device (CHAD) that incorporates most of these design parameters, but with less trade-offs. CHAD consists of a single unit worn on the patient's forearm, which includes all necessary components. It is compact and does not compromise functionality. The novelty of this design can be found in the use of a unique cable-driven mechanism. This mechanism uses dual linear actuators to achieve the flexion of both the index and the middle fingers via the pull of tendon-like structures originating in two selected interphalangeal joints. This permits the numerous necessary sequences in the motion profiles of the digits. The thumb is also made able to flex with a single linear actuator. Finger extensions, in contrast, are achieved passively via adjustable flexible rubber cords joined to the dorsal side of the glove. Experimental results demonstrate that CHAD generates sufficient force and motion profiles for the comfortable execution of ADL. Additionally, CHAD produces a grip and pinch motion profile similar to that of a natural hand and does not force unwanted muscle activities.

Original languageEnglish
Article number103784
JournalRobotics and Autonomous Systems
Publication statusPublished - Aug 2021


  • Activities of daily living
  • Assistive wearable robot
  • Post-stroke
  • Soft robotic glove

ASJC Scopus subject areas

  • Software
  • Control and Systems Engineering
  • General Mathematics
  • Computer Science Applications


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