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Timely and effective drying of agricultural products is crucial for ensuring the quality and yield of grains. Biomass drying enhances energy utilization and reduces energy pressure. To this end, a novel multi-channel circulating biomass hot air furnace was designed to provide precise control of the heat source for grain drying, thereby improving the efficiency and quality of the drying process. The combustion process utilizes a multi-channel combined air supply to ensure complete combustion of biomass pellet fuel. During the heat exchange process, heat exchange plates isolate hot and cold areas, discharging combustion exhaust, while ensuring a pure air output. Using rapeseed as the drying subject, a temperature controller based on adaptive fuzzy PID was designed, targeting the biomass hot air furnace's heat exchange system for modeling and verifying the model with the step response method. Model simulations were conducted in Matlab's Simulink module using both adaptive fuzzy PID and traditional PID controllers, for a given signal. The settling times for the conventional PID and fuzzy PID were 445 s and 364 s, respectively, with overshoots of 20.1% and 6.3%, showing that the fuzzy PID controller performed better in terms of control performance. The validation tests showed that both control methods could maintain the temperature within ±5 °C. Compared to traditional PID control, the adaptive fuzzy PID control achieved a precision of ±3 °C. At the target temperature of 90 °C, the error was reduced to 3.7%, with a stabilization time of 1014 s. The use of fuzzy PID control exhibited better dynamic response characteristics, meeting the drying needs of rapeseed. This study provides a theoretical basis for the structural design and control system design of biomass hot air furnaces. [ABSTRACT FROM AUTHOR]

In agricultural engineering, the discrete element simulation of the operational structure, object of movement, and force has become a standard method of modern agricultural equipment design. The selection and development of an appropriate contact model are critical factors affecting the accuracy of the process of the simulation calculation of the movement and force. Understanding how to choose or establish suitable contact models according to different research fields, objects, and purposes has become the focus of present research. This paper gives an overview of contact models for discrete element simulation, summarizes and analyzes the simulation calculation basis of different contact models, and focuses on the application status and scenarios of different models at this stage. It analyzes and summarizes the selection basis and application fields of contact models. The next direction in the development of discrete element simulation contact models should be the hybrid application of multicontact models and the precise development of specialized contact models. It is necessary to establish a standardized parameter-calibration process for different contact models to guarantee the accuracy of the models, to improve the application of computer arithmetic, and to establish an efficient and accurate simulation contact model selection and application in the field of agricultural engineering. Efficient and accurate simulation contact model selection, design theory, and calculation processes will improve the efficiency of modern agricultural machinery design. [ABSTRACT FROM AUTHOR]

In view of the current situation of the low degree of mechanized harvesting of rape shoots, combined with the study of the material characteristics of rape shoots, the core components of the harvester were designed and analyzed, and a rape shoots harvester was designed and manufactured. The front-end cutter of the harvester cuts the stalks of rape shoots, while the clamping and conveying device transports and steers the stalks flexibly to achieve low damage and orderly harvesting. The forward speed of the machine, the speed of the clamping belt and the clamping gap were selected as the test factors, while the rate of missed cut, missed clamping, and plant damage were selected as the evaluation indexes for the single-factor and response surface optimization tests. Field validation test showed that the machine could effectively cut and transport rape shoots at a forward speed, clamping belt speed and clamping gap of 0.42 m/s, 0.89 m/s and 11.43 mm, respectively (missed cut rate, 2.63%; missed clamp rate, 4.84%; and plant damage rate, 5.22%). This study provides a reference for the research and optimization of the flexible harvesting device for rape shoots. [ABSTRACT FROM AUTHOR]

Existing calibration methods for contact parameters of soil discrete elements are primarily based on a single physical property of soil (e.g., natural accumulation angle and shear characteristics). To solve this limitation, a calibration method based on the area difference method was proposed in accordance with the actual operation effect of ridge and furrow opener. The typical clay loam in the middle and lower reaches of the Yangtze River (moisture content of 20.66% ± 1%) was used as the research object. The Hertz–Mindlin with JKR Cohesion contact model was selected, and the static friction factor and rolling friction factor between soil and 65Mn steel were determined by inclined plane mechanics method. Soil tank ridge and furrow opening experiments and quadratic orthogonal rotation combined tests were carried out. MATLAB software was used to carry out polynomial fitting and the constant integral solution to the ridge and the cross-sectional contour data of the furrow obtained from the measured and simulated ridge and furrow opening experiments to establish the regression model of area difference. The optimization function in Design-Expert software was adopted. The optimal parameter combination was obtained by optimizing the regression model with the minimum area difference as the target. Based on the above parameter combination, the relative error of cross-sectional area of the furrow that was obtained by simulation test and soil tank test was 9.15%. Finally, the comparison of the traction resistance of the simulation and the soil tank test at the stable working stage indicated that the relative error between the simulated value and the measured value was 10.4%, which is less than the acceptable error of 15% in general statistics and within a reasonable range. The results showed that the particle movement and mechanical properties of the soil simulation model were basically consistent with the actual soil after parameter optimization and calibration. In this study, a precise discrete element simulation model of the typical clay loam in the middle and lower reaches of the Yangtze River based on the area difference method was constructed, which lays a theoretical basis for later exploration of the interaction mechanism between the typical clay loam and the soil contact components in the middle and lower reaches of the Yangtze River. [ABSTRACT FROM AUTHOR]

In order to reduce the chopping power consumption of a flat hob chopper (referred to herein as chopper) on the premise of ensuring the chopping effect of the chopper, the mathematical model of optimal design of chopper is established in this paper with the minimum chopping power as the objective. With the help of MATLAB software, the mathematical model is solved. The chopping power curves of each point on the chopper blade edge line before and after the optimization of structural parameters are generated. The results indicate that when the coordinate value of point A on the blade edge line on the Z axis is 0.7 m; the included angle between the bottom surface of the blade and the axis of the cutter roll is 6°. When the radius of the chopper is 0.11 m, the chopper can obtain the theoretical minimum chopping power. The analysis result of chopping power curve is the chopping power after structural parameter optimization is reduced by about 25.50% compared with that before optimization. The choppers before and after the optimization of structural parameters was trial manufactured and sequentially mounted on the performance test bench of the chopping system of the forage ramie harvester. The test results show the standard-length rate of ramie stalk chopped by the choppers before and after the optimization of structural parameters were 92.96% and 92.84%, respectively, which were extremely close to each other, indicating that the optimization of structural parameters has no influence on the chopping effect of the chopper. The chopping power of the chopper is reduced by 22.25% after optimization, which is close to the software analysis value (25.50%), indicating that the optimization result is accurate and reliable. This study can provide parameter foundation and an optimization method for lowering chopping power consumption of the chopper. [ABSTRACT FROM AUTHOR]

To address the problem whereby the size of the hole formed by the existing hole-forming device of hole-punching transplanters is significantly inconsistent with the theoretical size as it is impacted by the inserting and lifting methods, a scheme for eliminating the forward speed of the whole machine by the horizontal linear velocity of reverse rotation of the hole-forming mechanism is proposed to vertically insert and lift the hole-forming device in accordance with the working characteristics of hole-punching transplanting and the agronomic requirements of rapeseed transplanting. In addition, a novel type of reverse-rotating soil-taking-type hole-forming device for the pot seedling transplanting machine for rapeseed was developed. A test bench for the hole-forming device was set and its effectiveness was verified in the soil bin. It was found, from the test results, that, when the forward speed of the hole-forming device was between 0.25 m/s and 0.45 m/s, the average qualified rates of hole forming of the device were 95.2%, 94.0% and 93.3%, respectively; the average change rates of the hole size were 2.3%, 2.9% and 5.5%, respectively; and the average error between the theoretical value of effective depth and the experimental value was between 2.0% and 5.6%. The average angle between the hole-forming stage trajectory of the hole opener and the horizontal direction at different forward speeds was higher than 88.0°; the coefficient of variation was between 0.16% and 0.64%; the perpendicularity of the hole-forming operation was high; the change rates of soil porosity of the hole wall were between 8.2% and 9.3%; and the average soil heave degrees at the hole mouth after the completion of the hole-forming operation were 3.9%, 4.1% and 4.2%, respectively. The average soil stability rates of the hole wall were 91.9%, 91.2% and 91.0%, respectively. The different performances of the hole-forming device were confirmed to meet the requirements of rapeseed pot seedling transplanting. This study can provide a reference for the structural improvement and optimization of the hole-punching transplanter for rapeseed pot seedlings. [ABSTRACT FROM AUTHOR]

The mechanized harvesting of lily fruit in Southern China is affected by a high damage rate of lily fruit and low rate of soil breakage. The existing fruit–soil separation device is not suitable for heavy soil in Southern China. This study aimed to design a flexible fruit–soil separation device that can effectively reduce the damage rate of lily and improve the crushing rate of the soil. Thus, it would meet the requirements of southern lily fruit harvesting. In this study, the soil breaking rate and lily damage rate in the fruit–soil separation were taken as the assessment indexes, and the linear speed of the front conveyor belt, the inclination angle and the rotating speed of the fruit–soil separation device were recognized as the test factors. By performing the Box–Behnken test, three-factor and three-level experimental research on the fruit–soil separation device of the lily harvester was conducted. On this basis, a multiple regression model of the assessment indexes to the respective was built, the effect of various factors on the operation quality was analyzed and optimal operation parameters were determined. When the optimal parameter was adopted in the test (e.g., the linear speed of the front conveyor belt, the inclination angle and the speed of the fruit–soil separation device reaching 1.2 m·s−1, 36° and 98 r·min−1, respectively), the soil crushing rate was 92.8% and the lily damage rate reached 8.9%, and the fruit–soil separation effect satisfied the requirements of lily fruit harvest. The results could be referenced for other subsoil fruit harvesters and fruit–soil separation devices under heavy clay soil in Southern China. [ABSTRACT FROM AUTHOR]