Digital simulation of combine reel and forward speed controllers

Abstract A mathematical model of a rotary combine's dynamic characteristics was developed and converted into ACSL and CSMP-III digital time domain simulation programs. It includes processing and header losses, sensors, and forward speed and reel speed controllers. The combine's loss performance in the simulations was highly dependent upon controller and combine parameters and the variations in the encountered crop. Forward speed controllers are beneficial for responding to gradual yield changes but may actually increase processing losses for more rapid changes. Reel speed control has a similar response. Due to the inevitable interaction between the control systems, rapid changes of forward speed in response to yield changes may cause increased header losses due to improper reel indices which may reduce or eliminate the value of forward speed control. The simulations imply that there would be benefits in communication between the controllers.