On the one hand, drying technology is used in many industries, including major energy consumption: agriculture, biology, food, textiles and minerals, medicine, papermaking, polymer materials, etc. It may also be the purpose of ^ ancient chemical unit operations to reduce the moisture content in the product through the application of heat energy to dry the product to the desierd properties of the application. The control of the dryer is mainly manual. The emergence of automatic control in the early days is only recently in the industrial drying equipment, especially with the introduction of PID control (in the control of a dirst paradigm) 1942 with Ziegler and Nichols, and the control technology has been in Widely used in the chemical industry since the mid-1970s, the number of applications to control drying is relatively static, and the transportation phenomenon involves the complexity of drying. No single controller can be applied to all dryers. And most of the research is also focused on the understanding of the drying mechanism, and the quality of the product rather than its own operation and control. Therefore, it is not surprising to see that relatively few published works deal with the control of drying. At the same time, it is very important to pay attention to the main cost of the dryer. With a deeper understanding of drying, the new "smart" machine can be more reliable and cost-effective than the classic dryer.