Talk to robots soon

Robots will soon be able to talk just like human beings. In fact, Hideyuki Sawada, a Japanese scientist, is currently designing an entire artificial voice system, complete with its own lung, windpipe, vocal cords and throat for the purpose, reports New Scientist.
It is hoped that once the system is complete, the robots created by Sawada at Kagawa University in Japan will have a natural-sounding voice just like humans.
Sawada uses a compressed air tank, which forces air into a plastic voice-box chamber where it makes rubber "vocal cords" vibrate, to act as a lung. The basic sounds generated in the voice box are then fed to a flexible tube that mimics a human vocal tract.

The sound this produces depends on the speed of the airflow, the tension of the rubber vocal cord and the shape of the vocal tract's cross-section.

The tract is made from a flexible silicone tube, so that motor-powered rams positioned along it can alter its shape. Our throats and mouths work in a similar way to damp out certain frequencies generated by the vocal cords.

To control the robot's vocal system, Sawada uses a neural network that can learn how to produce particular sounds by listening to its own utterances and then adjusting the airflow and the shape of the vocal tract to get closer to a desired sound.

Although teaching consonants are harder, Sawada has already taught his system a full range of vowel sounds, and has found that the shape taken up by the artificial vocal tract as it makes the sounds is similar to the shape seen in X-rays of a person making the same sounds.

The end of the artificial vocal tract behaves much like a pair of lips and allows it to pronounce the sounds "p" and "t".

But there is one difficulty. Sawada isn't sure how to give the system a tongue. He has, however, added a vent to the resonance tube that does the same job, vocally speaking, as the nasal tract, making the vowel sounds more authentic.

Sawada, who built the system with Shuji Hashimoto at Waseda University, says this is just the beginning. He feels quite optimistic about the future and says that someday he will be able to make his system more realistic by installing a complete version into a humanoid robot. Bureau Report