Design and Development of a Cybernetic Rehabilitative Hand-Wrist Exoskeleton
Robotic devices are excellent candidates for delivering repetitive and intensive practice that can restore functional use of the upper limbs, even years after a stroke. Rehabilitation of the wrist and hand in particular are critical for recovery of function, since hands are the primary interface with the world. However, robotic devices that focus on hand rehabilitation are limited due to excessive cost, complexity, or limited functionality. A design and control strategy for such devices that bridges this gap is critical. The goals of the research effort are to analyze the properties and role of passive dynamics, defined by joint stiffness and damping, in the human hand and wrist during grasping and manipulation, and then mimic such properties in a wrist-hand exoskeleton for stroke rehabilitation. The project will culminate with device testing in collaboration with rehabilitation clinicians.
A significant problem in robotic rehabilitation is how to provide assisted movement to the multiple degrees of freedom of the hand in order to restore motor coordination and function, with a system that is practical for deployment in a clinical environment. Armed with a clearer understanding of the mechanisms underlying passive dynamics and control of systems exhibiting such behavior, this project informs the design of more effective wrist/hand rehabilitation devices that are feasible for clinical use. In addition, the project has created a unique interdisciplinary environment enabling education, training, and co-advising of graduate students, undergraduate research, and significant and targeted outreach activities to underrepresented groups in science and engineering.
In the fifth year of the project the team has developed improved versions of the hand and wrist exoskeleton systems and carried out experiments with human subjects with the intent of integrating the two systems for robot-assisted stroke rehabilitation. Specifically for the hand exoskeleton we have made improvements in the attachment interface and carried out experiments with spinal cord injury subjects to assess the effectiveness of the device as an EMG-driven assistive device. We have also developed a framework for robot-assisted rehabilitation that incorporates task variability, haptic guidance and error augmentation based training and feedback for improved rehabilitation. For the wrist exoskeleton we redesigned RiceWrist-S for improved range of motion and force output. Also, clinical evaluation of an assist-as-needed controller implemented on the wrist exoskeleton is carried out for rehabilitation after neurological injury.
Outreach activities: Concurrently, several outreach activities have also been undertaken, including laboratory tours for K-12 groups of underrepresented students at both the University of Texas and Rice University and course development.
Synergistic activities: The PIs helped in the organization of session titled Texas Biorobotics during ASME’s 2014 DSCC conference. PIs Deshpande and O’Malley also organized a workshop on exoskeletons for upper limb at 2015 IEEE ICRA in Seattle. PI O’Malley collaborated with National Instruments to develop online materials for haptic paddle dissemination.