We present the kinematics, optimal dimensional synthesis, series-elastic actuation, control, characterization and user evaluation of AssistOn-Ankle, a reconfigurable, powered exoskeleton for ankle rehabilitation. AssistOnAnkle features reconfigurable kinematics for delivery of both range of motion (RoM)/strengthening and balance/ proprioception exercises. In particular, through lockable joints, the underlying kinematics can be configured to either a self-aligning parallel mechanism that can naturally cover the whole RoM of the human ankle, or another parallel mechanism that can support the ground reaction forces/torques transferred to the ankle. Utilizing a single device to treat multiple phases of treatment is advantageous for robotic rehabilitation, since not only does it decrease the device cost and help with the space requirements, but also shorten the time it takes for patients to familiarize with the device. Bowden cable-based series-elastic actuation of AssistOn-Ankle allows for a remote placement of the motors/drivers to result in a compact design with low apparent inertia, while also enabling high-fidelity force/impedance control and active backdriveability of the device. This is one of several papers published in Autonomous Robots comprising the "Special Issue on Assistive and Rehabilitation Robotics".
B Volkan Patoglu
We present a systematic approach that enables online modification/adaptation of robot assisted rehabilitation exercises by continuously monitoring intention levels of patients utilizing an electroencephalogram (EEG) based Brain-Computer Interface (BCI). In particular, we use Linear Discriminant Analysis (LDA) to classify event-related synchronization (ERS) and desynchronization (ERD) patterns associated with motor imagery; however, instead of providing a binary classification output, we utilize posterior probabilities extracted from LDA classifier as the continuous-valued outputs to control a rehabilitation robot. Passive velocity field control (PVFC) is used as the underlying robot controller to map instantaneous levels of motor imagery during the movement to the speed of contour following tasks. In other words, PVFC changes the speed of contour following tasks with respect to intention levels of motor imagery. PVFC also allows decoupling of the task and the speed of the task from each other, and ensures coupled stability of the overall robot patient system. The proposed framework is implemented on AssistOn-Mobile--a series elastic actuator based on a holonomic mobile platform, and feasibility studies with healthy volunteers have been conducted test effectiveness of the proposed approach. Giving patients online control over the speed of the task, the proposed approach ensures active involvement of patients throughout exercise routines and has the potential to increase the efficacy of robot assisted therapies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.