you move your wrist up and down. Yaw is when you move your hand left and right. Rotate your entire forearm as if you are drilling a hole. Your arm would rotate around an axis that goes through the center of your wrist bone. This motion is called roll. What a robot does is stated in its program. The program tells a microprocessor what to do. The microprocessor sends signals to joint boards, which in turn, send signals to a motor. Then the motor moves the joint the way the program wants it to. Robots can be programmed by a computer. An operator enters the work movements into a computer which tells the robot what to do. Robots can also be "taught" what to do by having its arm moved. The operator moves the robot's arm with his own arm through all the movements. The robot performs the movements over and over again. ROBOTS IN INDUSTRY In factories today, industrial robots perform such tasks as welding, machine loading and unloading, material handling, spray finishing, assembly, and machine applications. In nuclear power plants and other facilities where radiation is hazardous to humans, robotic arms that are partly machine and human controlled are used for maintenance, repair, and waste removal. Similar arms on diving vehicles facilitate undersea salvageand exploration by navies and offshore oil industry. WELDING Industrial robots can perform two kinds of welding operations – spot and arc welding. For spot welding, two metal sheets are welded by laying one sheet on top of the other and fusing them with an electric gun at several points. This is a difficult and unpleasant task for humans because the welding gun is heavy. Also, assembly lines only allow a short time to move the gun, and welds can be placed inconsistently or missed. The partsmove on a conveyor belt and as they pass by, the robot welds them. The robots remember the position of each weld that is to...
