Increasing Input Accuracy of Embodied Devices via Electrical Muscle Stimulation

This paper evaluates interaction techniques to increase input accuracy with embodied devices—an emergent type of interactive system where the user’s body serves as both the input and output medium (e.g., gestural input via cameras/IMUs; gestural output via motors/muscle stimulation). A shortcoming of existing embodied devices is their failure to enforce alignment between users’ proprioceptive inputs and interface state. Thus, we present and evaluate interaction techniques that use muscle stimulation to enable embodied devices to: (1) recall previous interface states; (2) provide confirmation cues on state transitions; and (3) constrain inputs to valid ranges. In our study, participants performed pairs of interactions with an embodied slider, separated by a distraction task. The results showed that, compared to the same embodied slider without EMS, the combination of our techniques increased users’: (1) absolute input accuracy; (2) relative input accuracy; and (3) confidence.