including six in each leg. In addition, it incorporates a “predicted movement control.” Like a walking man seeing a corner coming up and shifting his stance to accommodate a turn, ASIMO looks ahead to the next stage of its motion and shifts its center of gravity accord- ingly.With its greater flexibility and improved cognitive skills,ASIMO is a smoother and better walker than P3.
ASIMO can maintain its balance standing on a steeply tilting seesaw, using a telescoping knee joint rather than bending a knee as a human would. It can neatly execute a turn (which P3 does only awk- wardly in a series of shuffling steps), balance on one leg, and climb confidently up and down stairs, although it must know the stair height in advance. In fact, to a human observer, both ASIMO and P3 radiate a certain self-assurance in walking that H6 and H7 do not.The reason is that the Honda robots swing their arms in human fashion while walking, giving the impression of a confident robot that knows what it’s doing and where it’s going—one more illustration of the effective- ness of humanlike clues built into artificial creatures.
CRAWLING AND MORPHING
Although humanoid robots offer great versatility, and walking on two legs is an important achievement, there are reasons to consider other body shapes and ways to move. Many living creatures progress by crawling, slithering, or skittering rather than walking. For all its versa- tility, a humanoid body cannot efficiently emulate these motions, which might prove to be the best choice for certain applications. Hence some roboticists are developing robots with nonhumanoid body shapes and means of locomotion.
The robots made by Shigeo Hirose of theTokyo Institute ofTech- nology, for instance, are not humanoid. His ACM R-1 (active cord mechanism, revised model) is long, skinny, and snakelike and slowly slithers along at about 40 centimeters a second (just less than one mile per hour). Hirose was, in fact, inspired by studying the movements of snakes, and his choice of body type also fits into an engineering phi- losophy that takes the simplest solution to be best. Instead of trying to