Augmented Grasps: Supernumerary Robotic Fingers and Their Practical Uses

Research on supernumerary robotic fingers has grown in recent years, both for augmentation and assistance purposes. Unlike other wearable robotics, these devices do not replace a missing finger or assist finger movement, but provide an additional one to extend the workspace and enhance grasp capabilities in healthy patients. In addition, patients with physical disabilities can use them as assistive devices for basic grasping in activities of daily living. While research in this field moves forward consistently, a classification of the grasps performed with extra fingers has not yet been proposed. In the literature, we find a number of papers that focus on improving finger control but do not present which grips are similar to a natural five finger grasp. In this paper, a brief classification of supernumerary grasps will be made based on the most common ones developed in the literature. In addition, the usefulness of these additional robotic fingers will be described in order to encourage more researchers to opt for the development and improvement of these devices.