Today, the toy industry is driving much of the research. Tilden's Robosapien is a 14-inch (36-centimeter), bipedal humanoid. WowWee, Robosapien's Hong Kong-based manufacturer, claims it is the first affordable intelligent entertainment humanoid of its kind. It retails for U.S. $100.
"My job is to try and pull bio-form robots out of science fiction and into the real world so they can establish a market," said Tilden, who designed robots at the United States' Los Alamos National Laboratory before joining WowWee.
Tilden has pioneered so-called biomorphic robotics. The field emulates the mechanics of animals by using simple logic circuitry and analog waves instead of microprocessors and digital technology.
Honda Motor Company has created one of the most advanced humanoids: ASIMO, a four-foot-tall (1.2-meter-tall) robot that looks like a beefier version of one of the stormtroopers from Star Wars.
ASIMO, short for Advanced Step in Innovative Mobility, has 24 "degrees of freedom" (similar to human joints). It can walk forward and backward, climb stairs, and maintain balance on uneven surfaces.
This fall, ASIMO will be inducted into the Robot Hall of Fame at Carnegie Mellon University, along with four other real and fictional robots.
Sony, meanwhile, claims its latest humanoid robot, QRIO, is the world's first running humanoid robot. If it loses its balance, QRIO reacts to protect itself against the impact. If it falls, it can get up on its own.
That still makes robots far from independent. But as the technology improves, humanoid robots could turn into electronic servants. Many scientists see them as the ideal nurses, assisting the elderly and disabled.
Nonhumanoid robots are already employed at many hospitals, where they ferry linens, medical supplies, and x-rays around. Both the United States and Japan, where much of the robotics industry is centered, suffer from a chronic shortage of nurses.
Future robots could perform important tasks, like helping patients to the bathroom, bringing them food and drinks, and even administering medicines.
But would patients and robots get along?
"Most of the research on humanoid robots is focused on hardware and software development," said Judy Matthews, an assistant professor at the School of Nursing at the University of Pittsburgh in Pennsylvania. "Little has been done to evaluate their performance with people."
This summer, Matthews and others are planning a test program to see how college students and senior citizens interact with Pearl, a humanoid robot developed at the University of Pittsburgh.
Kiesler, who studies psychological aspects of technology, says the social research on robots is in its infancy. "Will humanoid robots reduce social contact or increase it?" she asked. "Will they reduce even further our level of physical exercise, or encourage us to get out more?"
Humanoid robots of the future could also perform tasks that are dangerous to humans, such as moving harmful chemicals or fighting fires. But as Matthews noted, "We are a very long way from having robots replace people."
Some experts believe it will be ten years before we see a truly useful humanoid robot. Others predict it will be longer. But everyone agrees that fears of robots running amok are unfounded.
"Having lived with robots for more than a decade, I can assure you they have no desire to take over or become human," Tilden said. "They will never force you to sleep in your guest bedroom."
Tilden laments that Hollywood often portrays robots as evil. He said, "But the motivation [of the writers] is that humans watch movies, robots don't. Not yet."
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