Through the lens of his video camera, Hirose intently watched a pink flamingo walk past. How does a flamingo walk? How about a hippopotamus? Hirose was so fixated on filming the animals that on occasion a suspicious zoo keeper would ask him what he was doing.
Animals were not the only objects of Hirose’s constant observation. People on the street, fashion models, sumo wrestlers – Hirose watched them all and he became more and more absorbed the more he discovered. He would even enlist the help of associates in his experiments, wrapping them up like mummies to learn in detail how each part of the body contributed to walking.
Thanks to these efforts, Honda was finally able to create a robot with dynamic movement incorporating complex, human-like shifts in its center of gravity. Five years had passed since Hirose had been yelled at by Kawamoto.
The barriers to progress were not merely technological. Since everyone at the Center, regardless of his or her seniority, was a novice in robot R&D - a field in which they were attempting to create something entirely new - debates got heated and conflict was common. When associates could not achieve a consensus and had to put a matter to vote, Hirose sometimes found only himself on the losing side.
On weekends when Hirose was clearly suffering from work-related stress, his wife would buy plastic models for him to put together with their children—Hirose’s most effective stress-relief therapy.
Returning to the Center refreshed after one such weekend, Hirose was greeted by an unexpected breakthrough. An excited subordinate blurted out, “Over the weekend, I was watching a gymnastics competition on TV, and it came to me: the upper body is the key to maintaining balance!” This insight led to the development of the E4, a robot capable of walking on an uneven surface without losing its balance. The E4 had a defined upper body and was closer in appearance to a true humanoid robot.