sentences:  It has been first introduced in the late 1930s by William Pollard and Harold A. Roseland, where they developed a sprayer that had about five degrees of freedom and an electric control system.Pollard's was called “first position controlling apparatus.” William Pollard never designed or built his arm, but it was a base for other inventors in the future.Other robotic arms were invented in 1961 by Unimate, evolving to the PUMA arm.