One of the most popular designs for an industrial robot is the robotic arm. Just like your arm, a robotic arm requires arm segments, joints, a way to move those joints, and a sense of touch. A typical robotic arm is made up of several metal segments, joined by joints. The computer controls the robotic arm by rotating individual step motors connected to each joint. Sometimes larger arms use hydraulics or pneumatics for joint control. Unlike ordinary motors, step motors move in exact increments. This allows the computer to move the robotic arm very precisely, repeating exactly the same movement over and over again. The industrial robot uses motion sensors to make sure it moves just the right amount. An industrial robot can often do this repetitive work more efficiently than human beings because they are so precise. Many industrial robots work in auto assembly lines, putting cars together. An industrial robot is very strong, lifting large car pieces easily, and never get tired.Even though an industrial robot is capable of great strength, it is also capable of performing very delicate operations as well.