THREE DIMENSIONAL SIMULATION OF OIL FLOW CHARACTERISTICS IN LUBRICATION SYSTEM OF ROTARY TILLAGE ENGINE

Taking the lubrication system of rotary tillage engine as the research object, this paper makes a three-dimensional simulation study on the oil flow characteristics in the lubricating oil passage. The oil supply of the oil pump shall be greater than the circulating oil required by the lubrication system to ensure the lubrication of the rotary cultivator. Lubrication system is an important part to ensure the reliability and durability of rotary cultivator. The key component to achieve its performance is the oil pump. The geometric model of lubricating oil flow field in rotary tiller lubrication system is established by using FLUENT software. The results show that the pressure drop in the lubricating oil passage of the main bearing is the largest under the same working conditions. In the oil passage of the cylinder head, the pressure drop of the front main oil passage is the largest and the oil discharge is the largest. Add 1.6mm oil pump rotor on the basis of the thickness of the original oil pump rotor, the oil flow at the connecting rod nozzle reaches the flow index of the original rotary cultivator, and there is no cylinder pulling phenomenon of the rotary cultivator.

DESIGN AND EXPERIMENT OF CENTRIFUGAL COLLISION TEST DEVICE FOR MILLET AND SWEET BUCKWHEAT GRAIN

This critical collision damage force of millet and sweet buckwheat grain and the shelling force of shelled granular materials are important basic data for research of threshing and shelling technology and equipment. In order to master the linear velocity and collision force of grain with different moisture content when collision damage occurs, a centrifugal collision test device is designed. Based on the dynamic and kinematic analysis of grain in the centrifugal rotary table, the collision force between grain and steel plate was measured by PVDF piezoelectric pressure sensor and data acquisition system. The results showed that: under the same moisture content, the higher the rotational speed, the higher the grain crushing rate; at the same rotational speed, with the increase of moisture content, the crushing rate first decreased and then increased. When the moisture content of Jingu-21 and Yuqiao-4 is 19.7% and 17.8%, respectively, the grain crushing rate was the lowest. In terms of the anti-collision ability of grain, the optimum moisture content of threshing is between 19.7% and 21% for millet. For sweet buckwheat, the optimum moisture content of threshing is 17.8% ~19%, while the optimum moisture content of shelling by centrifugal sheller is about 11%. The faster the rotational speed of centrifugal rotary table is, the greater the linear speed of grain is, and the greater the collision force is. When the linear velocity of grain was 8.32 m/s and 11.30 m/s respectively, the millet grain moisture content was 11.1% and 20.9% respectively, damage began to appear, and the corresponding collision force was about 5.51 N and 10.6 N, respectively. When the linear velocity of grain was 8.32 m/s and 11.30m/s respectively, and the moisture content was 11.1% and 22.8% of the sweet buckwheat grain respectively, damage began to appear, the corresponding collision force was about 8.92 N and 12.79 N, respectively. When the rotating speed of rotary table was 910 r/min, the linear speed of grain was 27.05 m/s, the crushing rate of millet and sweet buckwheat grain in harvest period were 56.30% and 63.76%, respectively, and the crushing rate of millet and buckwheat grain with 11.1% moisture content were 86.27% and 89.4%, respectively. The research results can provide theoretical basis for design and optimization of millet and sweet buckwheat combine harvester, threshing device and shelling device.

WORK MOTION STUDY OF PIVOT TYPE TRAILER OPERATION ON TWO WHEEL TRACTORS

This study aims to analyze the pivot type trailer operation with an ergonomic approach and the necessary interventions required to minimize work risks. Data collection was carried out using questionnaires and video recordings of the operators when the tractors as well as trailers were being operated at various conditions such as track, load, speed, straight motion or turn. Based on the Range of Motion (ROM) analysis, it was discovered that while operating this pivot type trailer, the upper body segments, such as neck, shoulders, elbows and back of the operator, comfortably controlled the tractor. Meanwhile, in the lower body segments, such as the thighs and knees, the operator generally felt discomfort. Furthermore, the analysis of the operator's subjectivity perception showed that discomfort was felt at several segments of the upper and lower body, such as the hands and knees. Therefore, several ergonomic interventions are required to increase the comfort of operating this pivot type trailer.

LONGITUDINAL COMPRESSING AND SHEARING PROPERTIES OF SILAGE CORN STALK IN NORTH CHINA PLAIN

During silage harvesting, silage corn stalk is compressed by a feeding device and fed into the shearing device to be sheared into qualified segments to make silage fermentation easier. To optimize the working quality of the existing silage harvester and reduce energy consumption, it’s necessary to make a comprehensive analysis of the longitudinal compressing and shearing properties of the silage corn stalks and get a reliable shearing model. According to the different structural properties of the silage corn stalks, the main factors affecting the shearing energy consumption and their levels were obtained by compressing and shearing tests on internodes and nodes in this paper. The results of three-level and three-factor experiments showed that the overall shearing energy consumption for nodes was much higher than that for internodes. Compressing the silage corn stalk to some extent before shearing at the loading direction of 0° and lower shearing speed was beneficial to saving energy during the process of shearing off the silage corn stalk. The reduced energy requirements of the silage corn stalk could be exploited advantageously to present new reference for the feeding and cutting mechanisms of silage harvester. The research results can provide a reference for silage corn harvesting.

DESIGN AND PARAMETER OPTIMIZATION OF LAYERED FERTILIZATION OPENER FOR WHEAT, BASED ON EDEM

Applying different types of fertilizers to different depths of soil according to demand is advantageous in that it can optimize the distribution of nutrients in arable soil, adjust the nutrient supply of each growth stage of wheat, and increase grain yield. In the study, a layered fertilization opener that could realize the layered fertilization was developed. The interaction model between the opener, fertilizer and soil was established using EDEM simulation software. A response surface analysis was used to determine the optimal parameters of the opener. Specifically, the horizontal distance between the fertilizer drop openings was 140 mm, the machine speed was 1.05 m/s, and the angle of the opener was 37°. Furthermore, field experiments demonstrated that the average depth of upper layer was 8.39 cm, the average depth of middle layer was 16.465 cm, the average depth of lower layer was 24.025 cm, the average spacing of upper layer was 8.075 cm, and the average spacing of lower layer was 7.6 cm. The corresponding findings demonstrated that the layering effect of the opener met the requirements of the fertilization standard.

STUDY ON PRECISE FEEDING CONTROL OF DAIRY COWS BASED ON WIRELESS COMMUNICATION TECHNOLOGY AND DAIRY COW INFORMATION MANAGEMENT TECHNOLOGY

In order to improve the quality of modern dairy industry, it is an inevitable trend to implement intensive control feeding of dairy cows, which is also the development direction in the future. Different feeding methods have different important effects on the health of dairy cows. For example, calves grow and develop rapidly during lactation, change their physiological structure quickly, have strong plasticity, poor inversion and imperfect digestive function. In the production of dairy farms, the scientific feeding mode of calves indirectly affects the overall benefits of dairy farms. Therefore, aiming at the above problems, this paper studies how to accurately control the quality of dairy cows. A cow precise feeding control system based on wireless communication technology and cow information management technology is studied, which solves the problems of wireless information transmission, automatic and accurate cow identification and dual-mode operation of feeder, and ensures the accurate supply of cow concentrate.

THE FUNCTIONAL CONTROLABILITY OF MILK EJECTION OF THE ADAPTIVE MILKING SYSTEM

The concept of functional controllability of the milk ejection is considered, which makes it possible to predict the intensity of milk ejection in the online mode of the milking machine. The architecture of the functional controllability by intensity of milk ejection is developed. Input and output parameters of the structural-functional scheme of adaptive control of milk ejection intensity are described. An analytical model of milk ejection intensity based on Pearson's distribution is developed. The milk ejection intensity for different productivity and duration of cows milking is modelled. The microprocessor unit is designed using a single-chip microcontroller. It ensures the algorithm set by the central computer and implements a step of changing the pulsation frequency of 0.1 Hz, the ratio between the cycles of 0.25%, the phase shift step of 0.1 s.

RESEARCH STATUS AND DEVELOPMENT TREND OF MECHANIZED STRAW RETURNING TECHNOLOGY. A REVIEW

As the application of agricultural mechanized production technology becomes more and more extensive, the application of mechanized straw returning technology has become more and more valuable. The mechanized return of straw to the field is a time-saving and labor-saving technology. It is an effective way to achieve sustainable agricultural development and is of great significance to the development and progress of modern agriculture. This article analyzes the current research status of mechanized straw returning to the field, discusses the process structure and characteristics of different mechanized straw returning methods, and focuses on the analysis of the composite technology of straw returning to the field. At the same time, the key problems of straw returning to the field, such as the length of straw not meeting the standard, the shallow depth of straw returning to the field, and the uneven distribution of straw, are put forward and analyzed. By taking the cover and burial rate of straw on the soil surface and the spatial distribution uniformity of straw in the soil as the performance evaluation indexes of straw mechanized field return, each index is elaborated. Finally, two major development trends are proposed: the development of mechanized straw returning to the field from a single process to a composite process, and the effect of straw returning to the field towards uniform mixed burying and precise control.

DEVELOPMENT AND TESTING OF SOIL IMPURITIES REMOVING APPARATUS FOR POTATO

Aiming at the problem that contain more soil impurities of potato post-harvest, which affects subsequent deep processing, an apparatus for removing soil impurities from potato was developed. The whole structure is mainly composed of frame, feeding port, flexible rubber finger conveying mechanism, slender filament rotary brushing mechanism, discharging port and the like. The research and analysis determined that the main parameters influencing the soil impurities removal performance were the movement speed of conveying mechanism, the movement speed of brushing mechanism and the clearance between conveying mechanism and brushing mechanism (hereinafter referred to as the mechanism clearance). Taking the main influencing parameters as test factors, and the soil impurities removal rate and potato damage rate as indexes, the orthogonal test with three factors and three levels was carried out. The optimal parameter combination was obtained as follows: the movement speed of conveying mechanism was 0.35m/s, the movement speed of brushing mechanism was 0.40m/s, and the mechanism clearance was 55mm. At this time, the average soil impurities removal rate was 87.18%, and the potato average damage rate was 1.95%, which met the requirements of potato cleaning operation.

RESEARCH PROGRESS OF AGRICULTURAL IMPLEMENT GUIDANCE SYSTEMS. A REVIEW

Automatic navigation system for agricultural vehicles have become a widely used technology in precision agriculture over the last few decades. More and more sophisticated tractor control systems, however, revealed that exact positioning of the actual implement is equally or even more important. Based on literature sources and patent databases, the aim of this review is to introduce implement guidance systems and describe its current application in agricultural implement. Agricultural implement guidance is an essential technology for autonomous vehicle operations. In addition, applications and new technologies associated with navigation sensors on passive and active implement guidance are analyzed. Finally, challenges and future perspectives of agricultural implement systems are summarized and forecasted. This study can enrich the application of automatic navigation sensors on agricultural implements and provide a reference for the application of automatic navigation on more field operations.