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 improves on WT-2 (Waseda Talker-No.2) and is 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 can reproduce human-like articulatory motion; the total DOF is 18. The oral cavity is designed based on the MRI images of the human sagittal plane, although the cross section of the vocal tract is rectangular in shape except for the mouth. The width of the vocal tract is 30 [mm]. The average length of the vocal tract is approximately 175 [mm] and the same as that of a human's. Compared to the previous robots, WT-3 can produce vowels more clearly, and produce stops, fricatives and nasal sounds with the new flexible mechanisms that function as the human vocal tract area and the other mechanisms. WT-3 can mechanically reproduce human speech.