Dr. Kato and his amazing robot friends. David H. Ahl.
If the Long Island Expressway is the world's longest parking lot, the city of Tokyo may well be the biggest, especially at 5:00 p.m. Takayoshi Shiina, president of Sord, had kindly lent us his car and driver for our trip from downtown Tokyo to Waseda University, but we weren't making much progress. We called Dr. Kato from the phone in the car. "Which Dr. Kato?" the switchboard operator demanded. "Kato of robotics," we replied. We were connected immediately and the good professor said he would wait a few more minutes for us.
Six or eight people in New York, California, and Japan had told us about Dr. Kato, widely regardes as the father of robotics in Japan. But when we arrived at the dark, box-like, concrete buildings of Waseda University, we wondered if this dreary place could possibly be the home of the most sophisticated robots in the world.
After a few words of greeting, the energetic Professor Ichiro Kato soon set our doubts to rest. He showed us a videotape of the three latest projects at the university. Turning down the sound, he animatedly described (in Japanese) what was going on. Later, we saw one of the three robots "in the flesh," along with the start of another project.
First of the three robots is a fingers and arm model that plays a piano or organ. According to Kato, "the purpose of building such a robot is to improve dexterity, speediness, and intelligence." He feels that in the future, robots will not only play an important part in secondary industry (assembly-line functions), but also in tertiary industry (service functions). The necessary functions for such robots, which must function in human-like surroundings, are dexterity, speed, flexible handling, and intelligence.
Thus it was felt that many of these functions could be studies by trying to build a robot that played a keyboard just like a human. Today the keyboard-playing WAM-7R robot has 14 degrees of freedom for the fingers and seven more for the arm.
The control system is hierarchical in nature with three levels; it is modeled on the human nervous/brain system. Finger and arm motions are produced by DC motors. As with a human, sensors provide positional feedback on some but not all of the joints.
The robot can currently play a keyboard faster tan any human. Hence, the researchers have moved on to the next stage which is to equip the robot with "eyes" so it can read sheet music and play automatically. A second hand and legs may also be added so it can play more complex pieces and use the pedals.
Perhaps someday, the WAM-7R will be combined with the legs of the WL- 10R biped walking robot. This robot walks exactly like a human, bending its hip, knee, ankle, and foot joints appropriately. Moreover, it not only walks in a straight line, but can turn around, walk sideways, and even walk as though on a narrow beam.
Currently, the walking period is somewhat slower than that of a human, a limitation of both the hydraulic mechanism and the computer control system. Dr. Kato told us he expects the walking period to be nearly as fast as a human (1.1 sec.) by the end of the year.
While the keyboard-playing hand and walking biped are primarily research studies, the third device promises to be of more immediate benefit. It is an above-knee prosthesis which is adaptable to a voluntary walking period with full knee, ankle, and foot motion.
The WLP-6 (Waseda Leg Prosthesis- 6) is able to regulate its damping coefficient according to an amputee's voluntary walking period and can even generate a small driving force without any external power source.
Of course, the amputee must carry around a small control box which includes a one-chip microcomputer. The main job of this computer is to pick up the amputee's intention to take a step. This is done by means of a surface electrode, one of the trickiest elements of the system, since EMG potential is affected by a person's fatigue and perspiration. Furthermore, it is a minute signal, easily contaminated by stray electromagnetic or current noise.
Nevertheless, the WLP-6 has been successfully used by two subjects, Mr. Harada, 20 years old, and Mr. Sagano, 57. When worn with trousers, it was quite impossible to tell that the device was in use. While the WLP-6 is probably many years away from being commercially marketed, it holds the promise of allowing amputees to take a giant step beyond the pegleg of old.