Speech production of an advanced talking robot based on human acoustic theory

This paper describes the mechanisms and the speech production of a new advanced talking robot WT-3 (Waseda Talker-No.3) that improved on WT-2 (Waseda Talker-No.2) and based on human acoustic theory for the reproduction of human speech. WT-3 consists of 1-DOF lungs and 3-DOF vocal cords and articulators (the 7-DOF tongue, 5-DOF lips, 1-DOF teeth, nasal cavity and 1-DOF soft palate), and could reproduce human-like articulatory motion; the total DOF was 18. The oral cavity was designed based on the MRI images of a human sagittal plane, although the cross section of the vocal tract was rectangular in shape except for the mouth. The width of the vocal tract was 30 [mm]. The average length of the vocal tract was approximately 175 [mm] and the same as that of a human's. Compared to the previous robots, WT-3 could produce vowels more clearly, and produce stops, fricatives and nasal sounds with the new flexible mechanisms that functioned as the human vocal tract area and the other mechanisms. WT-3 could mechanically reproduce human speech.