Prediction Model of Rotary Tillage Power Consumption in Paddy Stubble Field Based on Discrete Element Method

Abstract

The rotary burying blade roller is suitable for soil cultivation and straw returning in paddy stubble field in the middle and lower reaches of the Yangtze River, but the power consumption is too high. Because of the complex interaction mechanism of the structure parameters of blade roller, the high cost of trial production, the short suitable cultivation period of farmland and the long test period cycle, it is impractical to optimize the design of the cutter roller simply by the field test method. Based on the discrete element method, a prediction model of rotary tillage power consumption the paddy stubble field was constructed to assist the detection of power consumption of the rotary burying blade roller. According to the monitoring of soil moisture content in the paddy stubble field for three consecutive years, it was found that the soil moisture content was close to its plastic limit, which indicated that the soil plasticity in the paddy stubble field was poor. Combined with the form of soil damage, HertzMindlin with Bonding particle contact model was selected to characterize the adhesion and damage of the soil in the paddy stubble field. In view of the particularity of rotary tillage operation and the structural characteristics of the rotary burying blade roller, the scale of the blade roller was reduced along the width direction, and the calibration reference test was completed with the help of rotary tillage test platform. In the discrete element software, the model of rotary tillage was established, and the functional relationship between contact parameters and power consumption index was established through the equal step climbing test. Combined with the power consumption value of calibration reference test, the contact parameter value of the rotary tillage power consumption prediction model in the paddy stubble field was finally determined, and the model was established. In order to further verify the applicability of the model, the error comparison test was carried out on the universal blade roller and the rotary burying blade roller under different working conditions. The results showed that the average prediction error was 6.65%, and the range was between 3.63% and 9.48%. Combined with variance analysis, the prediction model of rotary cultivation power consumption in paddy stubble field was suitable for the prediction of power consumption under different rotary cultivation blade roller and working conditions. The average error of power consumption prediction of the real scale field test of reduction roller was 7.28%, and the range was between 2.50% and 12.81%. In the process of scaling, the error of the roller structure was changed little, which showed that the model could be used in the field test.

Keywords: rotary tillage, power consumption, prediction model, paddy stubble field, discrete element