ArmArmSome type of arm is found on most industrial robots. It may be jointed and resemble a human arm, or it may be a slide-in/slide-out type used to grasp something and bring it back closer to the robot. A jointed arm consists of a base rotation axis, a shoulder rotation axis, and an elbow rotation axis. This type of arm provides the largest working envelope per area of floor space of any design thus far. If this is a six-axis type of arm, it requires some rather sophisticated computer control (Figure 2-9). Most arms now have some type of joint. From one to six jointed arms may be attached to a single base for special jobs. The expense of controlling this type of movement is rather high because of its complexity.
Mark R. Miller; Rex Miller: Robots and Robotics: Principles, Systems, and Industrial Applications. Arm, Chapter (McGraw-Hill Professional, 2017), AccessEngineering