Speech Analysis of the Talking Robot with Human-like Artificial Vocal Tract

The authors are building a mechatronic speaking system using biological inspired approach by referring to the geometry and shape of human vocalization system. The vocal cords of this talking machine are built using functionally approach of a human vocalization system. A transparent plastic container encloses a thin layer of elastic band generates an artificial sound source when vibrating. For human, the frequency of a sound source varies from 100Hz to 300 Hz relies on mutually pressure acting on the rubber band in combination with rubber band tension. The air pressure applied to the rubber band and the rubber band tension can be respectively changed by a reducing valve and a rotating mechanism. The performance evaluation of this mechanical vocalization system with a human-like vocal tract is analyzed from the generation of the five basic Japanese vowel sounds. The spectrum peaks and volume of each vowel sound are extracted to evaluate the influence of the shape of vocal tract on the sound regenerated by the talking robot. The results verified that this newly restructured vocal tract derives a pretty good sound from a mechanical vocalization system.