“Hold-and-manipulate” with a single hand being assisted by wearable extra fingers

Functionality of a human hand can be augmented with extra robotic fingers attached to the forearm. These wearable extra fingers can work together with the human fingers and perform tasks that are usually difficult for a single hand. Such technology may benefit amputees and surviving stroke patients who are forced to live with only one functional arm. In this paper, we present a novel method, exploiting redundancies in the elbow, to control a pair of extra robotic fingers, termed Supernumerary Robotic Fingers or SR Fingers for short, to perform “hold-and-manipulate” tasks. Two control protocols are explored here. One protocol enables discrete transition between different modes of motion, while the other continuously controls grasping behavior of the SR Fingers. Four robot assisted “hold-and-manipulate” tasks are examined, including twisting off the cap of a water bottle, opening the lid of a food container, plugging a cable into an electronic device, and mixing salad in a bowl. Through the successful completion of these tasks, we demonstrate that wearable extra fingers have the potential to provide those with impaired hands the opportunity to live with more independence and work more productively.