In view of the problems of long coating time, complicated manual operation, high multi-seed rate of coated seeds, low qualified rate, and low degree of automation of control equipment in traditional rotary coating machine, a new type of rotary coating machine was designed while using LabVIEW with a complete electric control system, which can effectively improve the speed and quality of coating. The system uses single-chip microcomputer as the lower computer, LabVIEW as the upper computer, and uses programming electronic control technology to set seed coating parameters in advance, precisely control each part and achieve precise supply. Batch supply of powder and liquid greatly improves the automation and intelligence of the operating system, improves the coating efficiency, reduces the multi-seed rate and the seedless rate, and increases the coating pass rate. In order to improve the coating quality and the supply accuracy of the coating machine, the error analysis and calibration test of the seed supply system, powder supply system and liquid supply system were carried out. After the test verification, the supply error was controlled within 2% to meet the demand for precise supply. The test results show that the pass rate of the seeds coated by the new rotary coating machine is increased by 15% to 20% compared with the seeds coated by the traditional manual coating.

In order to quantitatively describe the influence between the mixing process and the pelleting quality of the vibration pelletizer, this paper uses EDEM to conduct a numerical simulation study on the uniformity of the seeds and powder mixing of the pelleting machine under vibration force field. Meanwhile, a single factor test was established to verify the feasibility of numerical simulation. The results show that the coefficient of variation CV is the smallest and the mixing uniformity between the seeds and powder is the highest when the vibration frequency is 20Hz, the rotation speed is 45r/min, the tilt angle is 40° during numerical simulation. The pelleting qualified rate J and single seed rate P as the test index of the mixing uniformity of seed pelleting shows the optimum value in the single factor test, EDEM can be used to analyse the mixing uniformity and pelleting quality in pelletizer. The results of orthogonal experiment indicated that the best combination of parameters was obtained as follows: vibration frequency of 20Hz, rotation speed of 45r/min and tilt angle of 40°, the mixing uniformity of seeds and powder and the pelleting quality of Agropyron seeds are the highest. This study can effectively provide reference for design of pelleting machine of small seeds under vibration force field.

It is of great significance to acquire the soil surface roughness accurately for the study of the interaction between tractors and soil. Based on the laser sensor, this paper proposed the non-contact measuring instrument of the soil surface roughness with the data acquiring system by using Lab-View software. By using W-M theory, three commonly used fractal dimension calculation methods are compared and analyzed.. The result showed that the Root-mean-square method has the highest accuracy and clear physical meaning, which is ideal method to calculate the soil surface roughness characteristics. When the fractal dimension is between 1.4 and 1.6, the acquired data is analysed by the Root-mean-square method to obtain the fractal features of the soil surface roughness. The experiment results indicated that the fractal dimension of the ploughed surface is 1.39, that of disc harrow surface is 1.550, and that of rolled surface is 1.46-1.54. Obviously, the fractal dimension can accurately distinguish the soil surface roughness with the different treatments. However, the fractal dimension selected from different scales showed an obvious instability during calculations. The surface roughness index combined with the two parameters can effectively represent the soil surface roughness, and the larger the surface roughness index is, the greater the surface roughness is.

In order to explore the temporal and spatial distribution and motion state of the grains of wheatgrass (Agropyron) seeds and powder in pelleting process, and to find the optimal inlet air speed of pelleting premixer, the pelleting forming mechanism was revealed. Based on Herz-Mindlin contact theory, the contact mechanics model of seed and powder was established. Besides, CPFD software was used to model and simulate the pelleting premixer, and the contact, collision and friction rules among particles were analysed. The simulation and experimental results show that with the increase of inlet wind speed, the bed expansion increases and the unit volume particle concentration decreases, while the air pressure difference only slightly increases. When the inlet wind speed is set at 3.5 m/s, the atomizing nozzle velocity is set at 4.1 m/s, and the seed coating agent flow rate is 0.36 L/min, the particles are suspended due to air isolation, forming a spouted fluidized bed. It is good for seed and powder contact and rapid prototyping. In this time, the pelleting qualified rate was 95.8%. The results provide theoretical basis and technical support for the research of small irregular seeds pelletizing technology.

The calibration of the powder simulation parameters could improve the accuracy of the pelletizing and coating simulation process. In this paper, we take coated powder (after this referred to as powder) as the research object, based on particle amplification theory, combined with physical tests to calibrate the contact parameters of powder and seeds (after this referred to as seeds), conduct the angle of repose simulation tests of powder, carry out Plackett-Burman test, steepest climb test, and Box-Behnken test in turn, and establish quadratic regression equation to obtain the best combination of powder simulation parameters. The difference between the contact parameter combinations obtained from the simulation tests and the physical test results is less than 1%, providing some reference for calibrating similar powder material parameters.