Asimov Isaac, Asimov Janet. The Norby Chronicles

Norby, the Mixed-Up Robot (1983),
Norby's Other Secret (1984).Norby was originally a robot named the Searcher, created by the robot Mentor First on the planet Jamya. On his initial mission, Norby's ship crashed in Earth's asteroid belt and was discovered many years later by a salvager and inventor named McGillicuddy. McGillicuddy welded much of the remaining parts of the Seeker into a steel barrel that originally contained Norb's Nails, later becoming the basis for Norby's name. He eventually fell into the possession of a used-robot shop where he was sold to Jefferson Wells, a space cadet looking for a teaching robot.Norby's body reflects his outer origins as a barrel, while his arms are retractable and have double-sided palms (and two thumbs). His head is round with four eyes, two on each side, and the top is a dome which he can retract into his barrel. His feet are also extendable/retractable. Norby has a tenor voice but can communicate through telepathy by touch.Norby is equipped with a miniature anti-gravity device allowing him to float. He also possesses hyperspace technology, although his choices of locations can be limited to Earth, Jamya, Izz, or somewhere else he has been due to his mixed-up nature. He also has the capability to travel through time via hyperspace. Norby's many features make him a target for scientists, the army, and the rogue Inventor's Guild for disassembly and study.