Hand impairments have a significant impact on quality of life and career performance. This effect is specially bold in the agricultural community, since farming activities involve continuously carrying and lifting heavy objects. Assistive robotic technologies hold considerable promise in alleviating such impairment issues. However, no portable assistive device is developed for farming applications, which requires additional considerations to ensure functionality of the device and its practicality in agricultural settings. In this work, a bi-layered structure for a robotic glove is presented, which consists of a passive extension and an active flexion layers. The former is responsible for extending the fingers, using a set of elastic bands. The flexion layer, which helps with flexing the fingers and grasping of objects, is a lightweight, self-contained, portable, cable-driven, and single-actuated robotic glove. The cable configuration is inspired from the human hand flexor tendons. Due to uncertainties associated with the fabric's flexibility and potential slippage between the cable and the glove, the designed mechanisms and sensory and control systems are initially implemented on a robotic hand. The rigid structure of the robotic hand provides a suitable proving ground for the design and control ideas. The novel power transmission system design enables the active layer to perform adaptive grasp of objects with unknown shapes, sizes, and material textures. The sensory system includes a bend sensor to detect the wearer's intention to perform grasp or release actions. Additionally, a PVDF-based sensor is developed for slip-detection, which is used as feedback to prevent further slipping of the grasped objects. Overall, the active flexion layer weighs 265 gr and can provide the maximum grasping force of 122 N, which is a noticeable improvement in comparison to the literature. / Doctor of Philosophy / Hand impairments have a significant impact on quality of life and career performance. This effect is specially bold in the agricultural community, since farming activities involve continuously carrying and lifting heavy objects. Assistive robotic technologies hold considerable promise in alleviating such impairment issues. However, no portable assistive device is developed for farming applications, which requires additional considerations to ensure functionality of the device and its practicality in agricultural settings. In this work, a bi-layered structure for a robotic glove is presented, which helps with grasping objects. The first layer is responsible for extending the fingers, using a set of elastic bands. The second layer, which helps with flexing the fingers, is a lightweight, self-contained, and portable robotic glove. A novel cable-driven power transmission system is designed to perform reliable grasps using only one actuator. The power transmission system design enables the robotic glove to grasp objects with unknown shapes, sizes, and material textures. The intention of the wearer for performing a grasp or releasing an object is detected using a bend sensor. Additionally, a vibration sensor is utilized for detecting the slip of the grasped object and preventing further slipping and dropping the object. The functionality of the developed robotic gloved is evaluated through experiments, where different geometry and weight of objects are grasped.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/109359 |
| Date | 18 March 2022 |
| Creators | Nikafrooz, Negin |
| Contributors | Mechanical Engineering, Leonessa, Alexander, Asbeck, Alan T., Srinivasan, Divya, Akbari Hamed, Kaveh |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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