hitachi unveils  fastest robot  japanese electronics firm hitachi has unveiled its first humanoid robot  called emiew  to challenge honda s asimo and sony s qrio robots.  hitachi said the 1.3m (4.2ft) emiew was the world s quickest-moving robot yet. two wheel-based emiews  pal and chum  introduced themselves to reporters at a press conference in japan. the robots will be guests at the world expo later this month. sony and honda have both built sophisticated robots to show off developments in electronics. explaining why hitachi s emiew used wheels instead of feet  toshihiko horiuchi  from hitachi s mechanical engineering research laboratory  said:  we aimed to create a robot that could live and co-exist with people.   we want to make the robots useful for people ... if the robots moved slower than people  users would be frustrated.  emiew - excellent mobility and interactive existence as workmate - can move at 3.7m/h. its  wheel feet  resemble the bottom half of a segway scooter. with sensors on the head  waist  and near the wheels  pal and chum demonstrated how they could react to commands.  i want to be able to walk about in places like shinjuku and shibuya [shopping districts] in the future without bumping into people and cars   pal told reporters. hitachi said pal and chum  which have a vocabulary of about 100 words  could be  trained  for practical office and factory use in as little as five to six years.  robotics researchers have long been challenged by developing robots that walk in the gait of a human. at the recent aaas (american association for the advancement of science) annual meeting in washington dc  researchers showed off bipedal designs. the three designs  each built by a different research group  use the same principle to achieve a human-like gait.  sony and honda have both used humanoid robots  which are not commercially available  as a way of showing off computing power and engineering expertise. honda s asimo was  born  five years ago. since then  honda and sony s qrio have tried to trump each other with what the robots can do at various technology events. asimo  has visited the uk  germany  the czech republic  france and ireland as part of a world tour. sony s qrio has been singing  jogging and dancing in formation around the world too and was  until last year  the fastest robot on two legs. but its record was beaten by asimo. it is capable of 3km/h  which its makers claim is almost four times as fast as qrio. last year  car maker toyota also stepped into the ring and unveiled its trumpet-playing humanoid robot. by 2007  it is predicted that there will be almost 2.5 million  entertainment and leisure  robots in homes  compared to about 137 000 currently  according to the united nations (un). by the end of that year  4.1 million robots will be doing jobs in homes  said the report by the un economic commission for europe and the international federation of robotics. hitachi is one of the companies with home cleaning robot machines on the market.