Abstract
The field experiment of the digital sampled-data feed rate adaptive control system was done using a 9 P. S. small combine harvester with the hydrostatic drive. The control system controlled the traveling speed of combine with the electronic logic equipment, sensing with digital sample method of 3 inputs of the threshing cylinder speed, the feed rate and its change.
The traveling speed, the threshing cylinder torque, the engine speed and the other phenomena were put in steady states quickly by adapting to the field conditions.
The straw layer setting value was also put in an optimum range by adapting operation, when its initial setting value was lower enough for starting the combine; but when it was too high, the response of this control system was a little unstable.
The dead zone width of the straw layer setting value had an optimum range and when it was too wide or narrow, the adapting time was longer and the control was a little unstable.
When the traveling speed changing ratio was too large, this control system showed oscilation, and when it was too small, the time that the control system was in stability was too long. So it had an optimum value, but it is concerned with the sampling frequency.
This control system is effective to the step input which the ordinary control system (ON-OFF control system) has not revealed good results.
