Application Of Single Chip Fuzzy Control In The Auto-Control System For Threshing Cylinder

The combine harvester is a farm machinery which can complete cut, threshing, separation and clearing, obtain the clean kernel directly. Its widespread use enormously reduces the farmers'labor intensity and enhances the labor productivity. But there are many defects such as high jam rate, bad reliability and low work quality. Threshing device is a key unit of combine; its performance directly affects the work quality of the entire machine. Therefore it is necessary to use automatic control system and the monitoring device for combine in order to enhance reliability and improve threshing performance. It is significant to realize agricultural mechanization, automatization and intelligentization.This paper analyzed many significant factors, which influence threshing performance, not only including some controllable factors but also some uncontrollable factors. For this reason, threshing device is a system with a complex nonlinear character. So it is difficult to establish a precise mathematical model between cylinder rotary speed and other factors. This brings enormous inconvenient for the application of traditional control theory.The fuzzy control technology does not need to know the mathematical model of the research object, provides an effective method for the non-linear complicated system control. According to the characteristic of complexity and time delay, it is not easy to establish a precise mathematical model. Based of SCM technology and fuzzy-control theory, this paper has designed a speed automatic control system of threshing cylinder by using 8031 SCM as a fuzzy controller. The purpose was to keep the angular speed in the anticipated scope by controlling walk velocity of combine.The paper introduced the basic principle of fuzzy control. According to the power loss model of cylinder, determining the cylinder angular speed deviation and the deviation change rate as input variables and putting the voltage on the walk electromotor as an output variable, the paper designed SCM fuzzy controller of threshing cylinder. The system design includes two major parts about the hardware and the software. The hardware design mainly includes rotate speed sensor circuit, A/D and D/A switch circuit, output control circuit and display and alarm circuit. We select the Hall rotate speed sensor and SCM carries through data processing by A/D switch circuit. We adopted frequency conversion circuit to control the rotate speed of...