Mechatronics and Control System Design of a Hand Exoskeleton with a Sensorized Soft Glove

Post-stroke patients and individuals undergoing hand rehabilitation often grapple with prolonged and discomforting recovery processes. Hand exoskeleton products currently available in the market do not leverage precise input of therapist-assisted movements. Recognizing these challenges, technological solutions have emerged to assist and expedite rehabilitation, demanding practicality in lightweight design and user-centric features. Controlled with a sensorized soft glove (SSG), the designed hand exoskeleton focuses on user-centric attributes, including lightweight construction, durability, and comfort. The constructed hand exoskeleton leverages printable finger segment mechanisms and other lightweight components, enhancing replicability. The mechatronic system, featuring flex sensors and micro linear actuators, adopts a modular design, streamlining setup, storage, troubleshooting, and component replacement. A central microcontroller-driven main board ensures immediate communication between flex sensors on the soft glove and actuators on the hand exoskeleton, facilitating replication of individual finger flexion and extension movements. Experiments were performed to assess the hand exoskeleton’s performance across various hand configurations using flex sensors placed where individual finger metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints are located on the printed segments, with RMSE between input rotational movements from the SSG and output rotational movements from the hand exoskeleton is less than 9.03°. Integrating printed finger segments promotes adaptability to diverse hand shapes and guarantees each user a personalized and comfortable fit. The flex sensor-based results show that the intended flexion or extension of the MCP or PIP joint on the SSG can be replicated by the hand exoskeleton.