| In order to solve the problem of short growth period of crops and the temperature changeslowly, soaking and pregermination technology as one of cultivation techniques apply to thenorthern region is developed. It makes the seed of crops immerge in a certain time at a certaintemperature water to complete the process of raw sprouts.This topic designed and made rice soaking and pregermination temperature controlexperimental system based on single chip processor. In accordance with the requirements ofsystem model identification, determined the input signal M sequence system identification andsampling time and sampling period. Through the given system step input signal and the pulsesignal, then collecting the corresponding output signal. According to the correlation analysis, amathematic model of non-parameter identification was founded, the fitting degree is86.13%;Based on the least square method, ARX and ARMAX mathematical model of two kinds ofsystem parameter identification were founded, processed by the final prediction error criterionFPE, ARMAX3331model was determined as system mathematical model which fitting degreeis95.24%. Making the mathematical model continuous and using of the critical proportionmethod to set PID parameters. From the system dynamic performance and steady-stateperformance of the system experimental study, the results show that the system track the stepsignal, the adjusting time T=20s, overshoot; When the square wave signal was tracked, becauseof the system temperature lag, tracking square wave signal had poor performance. Systemcontrol the temperature between15℃and32℃and the steady-state error is less than5%.This topic using system identification method to establish the rice soaking and pregerminationtest chamber which system operation is stable and temperature control is precise. This method isbetter able to control the water temperature in the process of soaking and pregermination andachieve agricultural production’s demand. |
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