Automatic Feed-Rate Control for Hydrostatic-Drive Combine of Head Feeding Type (II)

Simulation of the Control System

Abstract

Dynamic responces of the automatic feed rate control for the head feed type combine was simulated on the digital computer.
(1) Input and output responces of the elements, especially non-linear elements, in the combine and the control system were analysed respectively. The operations of combine and control system were simulated by connecting these elements.
(2) The threshing cylinder torque of the headfeed type combine with respect to the feed-rate was assumed as hereditary phenomenon and represented by the integral equation. Hereditary function was determined from the experiment of one sheaf threshing.
(3) The dynamic response of the servomechanism of the hydrostatic drive was analysed and the travel speed was determined. Smoothing action of the straw layer thickness and the time delay on the feeding conveyer were simulated with the moving average method and with the sliding of the dimension respectively.
(4) Calculations were done with giving the initial conditions and the field conditions of the plant density changes of step function and sinusoidal function.
(5) Hunting occured at the control of the cylinder torque sensing because of the time delay on the feeding conveyer. In case of the two input control, it is desirable to control mainly with the straw layer sensing and subsidiarily with the cylinder torque sensing.
(6) The cylinder torque was not influenced by the plant density change under 0.5m wave length, due to the smoothing action of the feeding conveyer and the hereditary of the cylinder.