@article{shah_fleming_nalam_liu_huang_2022, title={Design of EMG-driven Musculoskeletal Model for Volitional Control of a Robotic Ankle Prosthesis}, volume={2022-October}, ISSN={["2153-0858"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85146352781&partnerID=MN8TOARS}, DOI={10.1109/IROS47612.2022.9981305}, abstractNote={Existing robotic lower-limb prostheses use autonomous control to address cyclic, locomotive tasks, but are inadequate in adapting to variations in non-cyclic and unpredictable tasks. This study aims to address this challenge by designing a novel electromyography (EMG)-driven musculoskeletal model for volitional control of a robotic ankle-foot prosthesis. The proposed controller ensures continuous control of the device, allowing users to freely manipulate the prosthesis behavior. A Hill-type muscle model was implemented to model a dorsiflexor and a plantarflexor to function around a virtual ankle joint. The model parameters for a subject specific model was determined by fitting the model to the experimental data collected from an able-bodied subject. EMG signals recorded from antagonist muscle pairs were used to activate the virtual muscle models. This model-based approach was then validated via offline simulations and real-time prosthesis control. Additionally, the feasibility of the proposed prosthesis control on assisting the user's functional tasks was demonstrated. The present control may further improve the function of robotic prosthesis for supporting versatile activities in individuals with lower-limb amputations.}, journal={2022 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS)}, author={Shah, Chinmay and Fleming, Aaron and Nalam, Varun and Liu, Ming and Huang, He}, year={2022}, pages={12261–12266} }
 @article{upadhye_shah_liu_buckner_huang_2021, title={A Powered Prosthetic Ankle Designed for Task Variability - A Concept Validation}, ISSN={["2153-0858"]}, url={http://dx.doi.org/10.1109/iros51168.2021.9636324}, DOI={10.1109/IROS51168.2021.9636324}, abstractNote={Ankle joints play key roles in everyday locomotion, such as walking, stair climbing, and sit-to-stand. Despite the achievement in designing powered prosthetic ankles, engineers still face challenges to duplicate the full mechanics of ankle joints, including high torque, large range of motion (ROM), low profile, backdrivability, and efficiency, using electric motors and related transmissions. In this study, our goal was to develop a new active prosthetic ankle, Variable Spring embedded Motor-ball screw (VSeM) ankle, to meet all these requirements at the same time. Using a manually adjustable elastic element, which is parallel with our motor actuator, we can readjust the ROM of VSeM to handle all normal locomotion tasks. VSeM’s capability to mimic human ankle was validated through both bench tests and human subject tests.}, journal={2021 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS)}, publisher={IEEE}, author={Upadhye, Sameer and Shah, Chinmay and Liu, Ming and Buckner, Gregory and Huang, He}, year={2021}, pages={6153–6158} }