自脱型コンバインの供給量適応制御 : パワー・シフト変速機を用いた時のディジタル・サンプル値適応制御(農業生産工学)

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The digital sampled-data adaptive control system using power-shift transmission with the logical operation of the head feeding type combine was investigated. In this control system, 3 inputs of the engine load, the feed rate and its fluctuation were sensed, and the traveling speed was controlled. The setting value of the feed rate was automatically adjusted to adapt to the change of the grain conditions. The straw layer thickness at the lower conveyor was detected as the feed rate by a linear variable differential transformer. The threshing cylinder speed was detected as the engine load by a tachometer generator. Sampling and holding were done by RST flip-flop after transforming two input signals into ON-OFF signals. The fluctuation of the feed rate was detected by comparing the feed rate with that of 4.5 seconds previous (the time required for the crop detected by the differential transformer to reach the threshing chamber). Increasing the traveling speed is done in case that the load in the threshing chamber is expected to decrease or the engine output has surplus. Decreasing is done in reverse condition. When the engine speed is under the setting speed R2 and both signals of the feed rate are lower than its lower limit (LL), the setting value of the feed rate is lowered by judging from the logical operation that the setting value is too high and the engine is overloaded. When the engine speed is over the upper limit (RH) and both signals of the feed rate are higher than its upper limit (LH) in reverse, the setting value is shifted up, because the setting value is too low and the engine has enough power. With Boolean algebra, these logical operations were calculated and simplified to construct the electronic logical circuit. The change of the traveling speed was done to move the power-shift lever by a hydraulic cylinder. If the change of the traveling speed is done continuously, the response of this control system will be in bad, so the traveling speed hold circuit is built in this system. The field experiment of this adaptive control system was done using a 9 PS (rated) combine of the head feeding type with power-shift transmission. The traveling speed, the threshing cylinder torque, the engine speed and the other phenomena were put in steady states quickly by adapting the field conditions. The straw layer setting value was also put in an optimum range by adadpting operation. Thus the adapting control of the combine whose traveling speed changes stepwise is done. But in this control system, the engine has a little enough power to work, because the traveling device is the mechanical transmission. The simulation was done by the computer of FACOM M-190 using FORTRAN in order to research the response of the combine for some parameters that were not experimented in the field and to analyse this control system including some non-linear elements. From the results of the simulation, the initial setting values of the straw layer thickness and the traveling speed have optimum range and value. But the dead zone width of the straw layer setting value and the holding time of the traveling speed have little influence upon the control system.

自脱型コンバインの供給量適応制御 : パワー・シフト変速機を用いた時のディジタル・サンプル値適応制御(農業生産工学)

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