Patients suffering from brachial plexus injury or other spinal cord related injuries often lose their hand functionality. They need a device which can help them to perform day to day activities by restoring some form of functionality to their hands. A popular solution to this problem are robotic exoskeletons, mechanical devices that help in actuating the fingers of the patients, enabling them to grasp objects and perform other daily life activities. This thesis presents the design of a novel exoskeleton glove which is controlled by a neural network-based controller. The novel design of the glove consists of rigid double four-bar linkage mechanisms actuated through series elastic actuators (SEAs) by DC motors. It also contains a novel rotary series elastic actuator (RSEA) which uses a torsion spring to measure torque, passive abduction and adduction mechanisms, and an adjustable base. To make the exoskeleton glove grasp objects, it also needs to have a robust controller which can compute forces that needs to be applied through each finger to successfully grasp an object. The neural network is inspired from the way human hands can grasp a wide variety of objects with ease. Fingertip forces were recorded from a normal human grasping objects at different orientations. This data was used to train the neural network with a R2 value of 0.81. Once the grasp is initiated by the user, the neural network takes inputs like orientation, weight, and size of the object to estimate the force required in each of the five digits to grasp an object. These forces are then applied by the motors through the SEA and linkage mechanisms to successfully grasp an object autonomously. / Master of Science / Humans are one of the few species to have an opposable thumb which allows them to not only perform tasks which require power, but also tasks which require precision. However, unfortunately, thousands of people in the United States suffer from hand disabilities which hinder them in performing basic tasks. The RML glove v3 is a robotic exoskeleton glove which can help these patients in performing day to day activities like grasping semi-autonomously. The glove is lightweight and comfortable to use. The RML glove v3 uses a neural network based controller to predict the grasp force required to successfully grasp objects. After the user provides the required input, the glove estimates the object size and uses other inputs like object orientation and weight to estimate the grasp force in each finger linkage mechanism. The motors then drive the linkages till the required force is achieved on the fingertips and the grasp is completed.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/104663 |
| Date | 17 August 2021 |
| Creators | Pradhan, Sarthak |
| Contributors | Mechanical Engineering, Ben-Tzvi, Pinhas, Southward, Steve C., Sandu, Corina |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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