The He-Man robot was one of Man-At-Arms' inventions seen in He-Man and the Masters of the Universe.
Man-At-Arms had been construction a robot when Prince Adam was kidnapped by Skeletor and his sword had been lost in time. Skeletor demanded that He-Man would try to rescue the prince, but Man-At-Arms was one of the few people who knew that this was impossible as Adam and He-Man were in fact the same person.
Therefore, Man-At-Arms decided to make his mechanical work in progress look and sound as much like He-Man as possible so it could be used as a double. He first tried out the robot on Orko and Cringer, who thought it was the real He-Man.
Driving the Attak Trak, the robot also managed to fool Skeletor for a while, but when the vehicle was hit by a blast from the Collector and was forced off the road, the robot's faceplate had been damaged and fell off, revealing his 'true identity'.