Chapter 6 Electromechanical Systems 123 Copyright Goodheart-Willcox Co., Inc. includes pulleys, belts, or gears that connect the motor to a conveyor belt. Control is accomplished by changing speed or direction of the motor. Indicators in this type of mechanical system can measure speed or flow rate to determine the move- fl ment of boxes along the conveyor belt. 6.3 Electrical Systems There are many different types of electrical systems used in robotics. Electrical systems include those used for sensing, timing, control, and providing rotary motion (motors). The fi rst three systems are discussed in this section of the chap- fi ter. Rotary motion systems are discussed in the following section. 6.3.1 Sensing Systems A sensing system consists of components that signal a response to a particular form of energy, such as light. The light source, transmission path, control, and load device are essential parts of the system. The light is produced by electrical energy and may be in the form of incandescent lamps, fl ames, glow lamps, electric fl arcs, solid-state light, or laser light. Sensing systems have become one of the fast- est growing and most diversifi areas of industrial robotics. New systems that fied combine optics, electromagnetics, and electronics have revolutionized automated manufacturing. Light systems are the most common form of sensing systems. Other sensing systems include sound, pressure, fl ow, and magnetic sensors. fl The transmission path of a sensing system is somewhat unique. In Figure 6-3, light energy travels in a straight line in the form of an intense beam of electromag- netic waves. If the light must go around corners or be directed to unusual loca- tions, light pipes could be used as the transmission path. Light pipes are fl exible, fl fi ber-optic rods that may be extended over long distances to transfer light energy fi from its source to a distant location. Light source Transmission path Conveyor belt Photoelectric counter unit (detector) Goodheart-Willcox Publisher Figure 6-3. This sensing system counts the units moving along the conveyor using system responses to light energy.