Mechanical arm
Other robotic arms were invented in 1961 by Unimate, evolving to the PUMA arm. In 1963, the Rancho arm was designed, along with many others in the future. Even though Joseph Engelberger marketed Unimate, George Devol invented the robotic arm. It focused on using Unimate for tasks that are harmful to humans. In 1959, a 2700 pound Unimate prototype was installed at the General Motors die-casting plant in Trenton, New Jersey. The Unimate 1900 series became the very first produced robotic arm for die-casting. During a very short period of time, it had produced at least 450 robotic arms were being used. It still remains one of the most significant contributions in the last one hundred years. As years went by, technology seemed to evolve, helping to build better robotic arms. Not only companies invented different robotic arms, but so did colleges. In 1969, Victor Scheinman from Stanford University invented the Stanford arm, where it had electronically powered arms that could move through six axes. Marvin Minsky, from MIT, built a robotic arm for the office of Naval Research, possibly for underwater explorations. This arm had twelve single degree freedom joints in this electric- hydraulic- high dexterity arm. Robots were initially created to perform a series of tasks that humans found boring, harmful, and tedious.
William Grey Walter
Grey Walter's most well-known work was his construction of some of the first electronic autonomous robots. He wanted to prove that rich connections between a small number of brain cells could give rise to very complex behaviors - essentially that the secret of how the brain worked lay in how it was wired up. His first robots, which he used to call "Machina speculatrix" and named Elmer and Elsie - ELectroMEchanical Robot, Light-Sensitive, were constructed between 1948 and 1949 and were often described as "tortoises" due to their shape and slow rate of movement - and because they "taught us" about the secrets of organisation and life. The three-wheeled tortoise robots were capable of phototaxis, by which they could find their way to a recharging station when they ran low on battery power.