Active soft pinnae for robots

Sound localization is one of fundamental abilities of auditory robots that is necessary for human-machine communication. Especially for autonomous robots, it is also necessary to make the system as simple as possible, and binaural configuration is thought to be the minimum setup for auditory systems as animals achieve practical hearing with two ears. However, the limitation of the number of ears leads insufficient performance such as accuracy in sound localization, or sound source separation. In order to overcome those difficulties, this paper proposes a novel artificial soft pinna that can move, or deform its shape actively. The developed pinna has deformable skin of silicon rubber with wires controlled by motors, and it is covered by a fur cover. Considering applications of the proposed device for auditory robots, fundamental characteristics such as accuracy of motion and auditory characteristics were investigated through experiments, which is the main contribution of the paper.