Update Oct-12-2004: HOAP-2 wowed them again at the 2004 Intelligent Robotics and Systems (IROS) conference in Sendai, Japan, last week. HOAP-2 can be purchased commercially for $1,500 and owners can customize their hardware and software. Be sure to check out the remarkable HOAP-2 sumobot roboshiko traditional moves in this 2 Mb Windows Media file. (Note: Shiko is the traditional sumo move in which the wrestler stamps down the dirt; it combines a useful training posture with a Shinto ritual of stamping underfoot any evil spirits that might lurk in the ground. RoboShiko!)
Is a wrestling robot possible? Recently, at CEATEC 2003 (Combined Exhibition of Advanced Technologies) in Japan, visitors were treated to an exhibition by HOAP-2. This robot performs moves from the Chinese martial art taijiquan; it also does Sumo wrestling stances. All that and it's Linux-based!
Update 15-Nov-2009: Take a look at this video of HOAP-2 practicing his sumo moves. Robo-Shiko!.
The particular idea of a robotic wrestling companion can be found in Rolem, the exercise partner of Konstantin Kharageosis, the main character from This Immortal, created by Roger Zelazny in 1966.
Robots are, obviously, a common theme in sf. Try the original Robot, from Karel Capek's R.U.R. (1920). You probably wouldn't want to get into a fight with the mechanical hound from Ray Bradbury's 1953 novel Fahrenheit 451.
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