In order to improve the efficiency of peanut harvesting in China, realize the deep integration of agricultural machinery and agronomy in peanut production and promote the development of peanut industry. According to the research on peanut planting agronomy and plant biological characteristics, this paper focuses on the analysis of the clamping and collecting scheme of the three-ridge six-row peanut combine harvester, and designs the structure of the clamping and collecting device to solve the situation that the peanut clamping and collecting process is prone to congestion under large feeding volume. By analysing the forces on the peanut plant, the structure of the core fruit picking device has been designed, and the factors and parameters affecting the effectiveness of the peanut picking operation have been optimised through experimental research using the peanut leakage and crushing rates as indicators. The whole machine structure of the three-ridge six-row peanut combine harvester was designed to ensure that the peanut combine harvester can complete the processes of harvesting, digging, clamping and conveying, soil removal, collecting, fruit picking, cleaning and fruit collection at one time. Finally, through field tests on the three-ridge six-row peanut combine harvester, it was verified that the peanut leakage rate was 1.92% and the crushing rate was 0.84% at different forward speeds, and all of them were congested, which met the national peanut harvesting standards.

At present, there is a lack of accurate discrete element simulation model and parameters in the equipment in Huang Huai Hai double cropping production area, which hinders the optimization and improvement of equipment operation effect. In this paper, the discrete element method is used to study the interaction between soil-touching components and wheat straw-soil mixture to improve the performance of equipment. Firstly, the Hertz-Mindlin with JKR Cohesion contact model is selected for the wheat straw-soil mixture to calibrate the parameters. Then, the method of combining physical test and simulation test is used to calibrate the parameters, the cylinder lifting method is used to determine the buildup angle of wheat straw soil mixture, and the Plackett-Burman screening method and the steepest climbing test are used to determine the optimal combination range of soil-straw static friction coefficient, soil-straw dynamic friction coefficient and soil-soil dynamic friction coefficient contact model parameters. Using Box-Behnken optimization research and development of key components such as soil contact of seedbed preparation test, the regression equation of the stacking angle of wheat straw soil mixture was obtained, and the variance and interaction effect of the regression model were analysed. The regression model was used to find the optimal solution in Design-Expert software with an angle of repose of 41.23°, which yielded a soil-straw static friction factor of 0.072, a soil-straw dynamic friction factor of 0.78, and a soil-soil dynamic friction factor of 0.068, with an angle of repose error of 1.43%, indicating that the contact model parameters are reliable, and the parameters can provide a reference and theoretical basis for the study of the key components of the seedbed preparation equipment such as touching soil in the Yellow and Huaihai Sea two-maturity zone.

Considering the problems of low soil fragmentation rates, high working resistance, and high energy consumption in the harvesting process of Cyperus esculentus in China, a method of Cyperus esculentus harvesting based on counter-rotation digging is proposed. The mechanism of interaction between the rotary tillage blade and Cyperus esculentus–soil is systematically investigated, and the vertical and horizontal disturbance performance of the positive and counter-rotating harvesting methods on soil and Cyperus esculentus is compared and analyzed. The results of the experiment showed that the intensity of soil and Cyperus esculentus disturbance by counter-rotation increased by 166.67% and 297.78%, respectively, and the effective disturbance time of soil and Cyperus esculentus increased by 133.33% compared to that of positive rotation. The working depth and rotation speed of the rotary tillage blade were the most significant for soil and Cyperus esculentus disturbance intensity. The working depth increased from 150 mm to 170 mm, and the soil disturbance intensity increased by 17.91% and 21.37% for positive and counter-rotating operation, respectively, and the rotation speed of the rotary tillage blade increased from 270 rpm to 330 rpm, and the soil disturbance intensity increased by 28.85% and 35.29%, respectively. Compared with the positive rotation operation, the Cyperus esculentus counter-rotation soil fragmentation rate increased by 4.09%, the Cyperus esculentus damage rate decreased by 10.69%, and the buried fruit rate decreased by 7.38%. This paper helps to understand the interaction mechanism between the rototiller and Cyperus esculentus–soil and lays a theoretical foundation for the subsequent design and optimization of the Cyperus esculentus digging device.