In order to reduce their own labor during the long-term production and life, ancient humans gradually developed the desire to use natural power to replace human and animal power, and to use automatic devices to replace some of people's arduous mental activities. Exploring, they independently built some primitive automatons. Around the middle of the third century BC, Thesibius of Alexandria first used a float in a kettle. According to the sample restored by Diels at the beginning of this century, the injected water was controlled by a conical float. This mode of control already contains the idea of ??negative feedback (although it was not clear at the time). In 500 BC, the Chinese army already used the clepsydra as a timekeeping device. Around 120 AD, the famous scientist Zhang Heng (78-139, Eastern Han Dynasty) proposed an ingenious method of using a compensation pot to solve the problem of inaccurate timing as the water head decreased. In his "Leaky Armillary Sphere", there are not only floats and leaky arrows, but also siphons and at least one compensating pot. The most famous Chinese water clock, the "Copper Kettle Drip", was built in 1316 AD (the third year of Yanyou in the Yuan Dynasty) by the coppersmith Du Zisheng and Xirun, and was in continuous use until 1900. In addition, in 350 BC, my country had already used water mortars similar in structure to water wheels to grind rice; in 50 BC, water wheels were used to divert water for irrigation; in 31 BC, water-driven bellows were used in forges, etc. . Greatly reduces people's labor. Although these automatic devices are not as advanced as some current automatic control devices and are not supported by systematic theory, the invention of these devices played a leading role in the formation of automatic control. With the continuous improvement and development of these automatic control devices, automatic control technology gradually formed. We set the formation period of automatic control technology from the end of the 18th century to the 1930s. People use automatic control methods to replace manual control of various mechanical equipment, which is a major innovation in the history of human history. There were many representative inventions during this period. In 1750, Andrew Meeker introduced a "fantail" transmission device for windmills to automatically face the wind. Later, William Cupid improved the automatically opening and closing louvered wings so that they could automatically adjust the transmission speed of the windmill. This adjustable regulator was patented in 1807. In 1788, British mechanic J. Watt invented the centrifugal speed regulator. Watt connected it with the valve of the steam engine to form a closed-loop automatic control system for the speed of the steam engine. Watt's invention ushered in a new era in the application of modern automatic regulating devices and had an important impact on the first industrial revolution and the subsequent development of control theory.