To meet the timeliness and reliability required by electric drive combine, this paper which regarded series of MCU (P89C51RX2 with PCA) as the core discussed the design of reel automation system about position controlled by EP solenoid valves and velocity controlled by frequency motor based on electric drive combine.

By establishing mathematical model of the reel, the track of reel is really imitated to make it intelligible, dynamic imitation of reel is more visible, and we should make full use of these objects that Visual Basic automatically produces to demonstrate teaching curriculum and science research.

According to the two points of basic assumption,the equations of the maximum value of the combine reel forward adjustˉment(bmax)and function range of the reel(△X)were established.