Robotic Actuation of a 2d Mechanical Vocal Tract

Here we present a robotic vocal apparatus incorporating a tongue body that is moved by stepper motors under computer control. The vocal tract consists of a central mouth region with a 2-dimentional tongue, a lip section and a nasal cavity. Movement of the articulators changes the vocal tract cross-sectional area, and thereby its acoustic properties, thus providing a means to generate different vocalic sounds. Numerical optimization in Matlab was used to design the mechanism, which was achieved by fitting its various dimensions to published articulatory data. The vocal tract was then built using 3D printing technology. We present some examples of vowel and nasal sound production using simulated voiced sound excitation. Finally, we demonstrate that by blowing air into the lower larynx end of the vocal tract while making appropriate constrictions, the apparatus can also generated different fricative sounds.