Search Results (153)

In order to alleviate the problems of lack of research on threshing and cleaning equipment and poor operational performance of castor harvester, an axial-flow threshing and cleaning device was designed and evaluated for a roller brush type castor harvester. This paper introduces the overall machine structure and elaborates on the working principles of the castor threshing and cleaning device. It clarifies the design and analysis of key components such as the conveyor design, rod-tooth structure design, collision force analysis between the fruit and rod-tooth, concave sieve design, and guide plate design. The main indicators for evaluating the castor threshing and cleaning device include the impurity rate, damage rate, and separation loss rate. Based on the previous experimental research, the working parameters of castor threshing and cleaning device are tested and studied by using the Box–Behnken central combined test method. The three-factor three-level quadratic regression orthogonal test design is carried out based on the forward speed, roller rotational speed, and threshing gap of concave sieve. A response surface mathematical model was established, analyzing the impact of various factors on work quality and conducting comprehensive optimization of influencing factors. The experimental results indicate that the significance order of factors affecting the impurity rate was forward speed > roller rotational speed > threshing gap of concave sieve; the significance order for damage rate was roller rotational speed > threshing gap of concave sieve > forward speed; and the significance order for separation loss rate was roller rotational speed > forward speed > threshing gap of concave sieve. The field test results show that the optimal working parameter combination is forward speed of 0.87 m∙s⁻¹, roller rotational speed of 462 r∙min⁻¹, and threshing gap of concave sieve of 30 mm, with an impurity rate of 2.95%, a damage rate of 1.75%, and a separation loss rate of 0.49%. The research findings can provide references for the structural improvement and operational parameter optimization of the castor harvester’s threshing and cleaning device. Full article

In response to the urgent need for full-process mechanization in Xinjiang’s cotton–cumin intercropping system, and to address the prominent bottlenecks of missing equipment for key harvesting steps and reliance on manual operations, we developed a cumin harvester and investigated its operating mechanisms. Guided by the agronomic parameters of the intercropping system, we executed a system-level design centered on the header unit, performed multi-objective optimization using orthogonal experiments and regression modeling, and conducted field validation. Results show: stubble height of 32.6 mm, harvester reel speed of 28 r/min, and forward speed of 3.26 km/h. Under this parameter configuration, the harvest rate was 89.54%, and the average damage rate was 7.33%. Field trials indicated a harvest rate of 88.2% and an average damage rate of 5.6%, with deviations from model predictions of 1.34% and 1.73%. The optimal reel index (λ = 1.69), the longitudinal component of the reel tine motion, prevents repeated impacts on the plants, reducing shattering and threshing damage; the axial component provide reliable support and smooth guidance to the stalks, ensuring continuous, steady cutting; the optimized stubble height is lower than the plant’s center of mass. Full article

The vibration of the combine harvester header assembly directly affects harvesting efficiency and operational quality. To address the insufficient dynamic characterization of the cantilever conveying trough under complex field excitations, this study systematically analyzes the vibration response characteristics of the header assembly under multi-source coupled excitation through field experiments and theoretical modeling. Acceleration sensors arranged at three measurement points on the header bottom collected vibration data, revealing that the dominant vibration frequency of the header has a deterministic harmonic relationship with the threshing drum’s operating frequency (3rd harmonic on the left side, 1.5th harmonic on the right side), demonstrating dynamic coupling effects within the integrated system. Through acceleration response analysis at four symmetric measurement points on the connection, the external excitation force was quantified as a sinusoidal function correlated to the feed quantity (F = 1094.4 sin(50πt/3)). A damped pendulum model of the cantilever conveying trough was established using the Lagrange method. Validation results show that the error between the predicted steady-state swing amplitude and measured values is only 1.11–4.3%, confirming the effectiveness of this simplified model in characterizing the system’s steady-state response. This research provides a theoretical foundation and methodological support for dynamic characterization, parameter optimization, and stability control of the cantilever header system in combine harvesters. Full article

Thinopyrum intermedium (c.n. intermediate wheatgrass), marketed under the trade name Kernza, is a promising species for perennial grain production based on seed size, ease of threshing, resistance to shattering, and grain quality. Although numerous generations of breeding for seed yield have been completed, the impact of selection on non-target traits is unknown. Here, we evaluated structural and functional changes brought about by selection for seed yield over a sequence of nine selection cycles (C0 to C9). In two experiments under semi-controlled environmental conditions, we compared gas exchange (A, E, gs, and A/Ci curves), leaf and root morphology, and the structure of seedlings from 10 generations. We found that the selection for yield throughout cycles indirectly changed the leaf structure (leaf size, leaf thickness, and leaf anatomy) and physiology (carbon acquisition and transpiration per unit area), with later cycles showing larger leaves with higher rates of CO₂ assimilation and transpiration. Changes in root structure followed similar trends: selection resulted in longer, more branched, and finer roots. These changes in non-target traits are linked to resource-use strategies and to ecosystem services provided by Kernza. Understanding how the domestication of perennial grains impacts non-target traits will aid in the design of integrated breeding programs for Kernza and other perennial grain crops. Full article

Soybean–corn intercropping in the hilly–mountainous regions of Southwest China poses unique challenges to mechanized harvesting because of complex topography and agronomic constraints. Addressing the soybean-harvesting bottleneck in these fields requires advanced sensing and perception rather than purely mechanical redesigns. Prior reviews emphasized flat-terrain machinery or single-crop systems, leaving a gap in sensor-centric solutions for intercropping on steep, irregular plots. This review analyzes how sensors enable the next generation of intelligent harvesters by linking field constraints to perception and control. We frame the core failures of conventional machines—instability, inconsistent cutting, and low efficiency—as perception problems driven by low pod height, severe slope effects, and header–row mismatches. From this perspective, we highlight five fronts: (1) terrain-profiling sensors integrated with adaptive headers; (2) IMUs and inclination sensors for chassis stability and traction on slopes; (3) multi-sensor fusion of LiDAR and machine vision with AI for crop identification, navigation, and obstacle avoidance; (4) vision and spectral sensing for selective harvesting and impurity pre-sorting; and (5) acoustic/vibration sensing for low-damage, high-efficiency threshing and cleaning. We conclude that compact, intelligent machinery powered by sensing, data fusion, and real-time control is essential, while acknowledging technological and socio-economic barriers to deployment. This review outlines a sensor-driven roadmap for sustainable, efficient soybean harvesting in challenging terrains. Full article

In response to the dust pollution issue during the harvesting operations of peanut pickup combines, this study involved conducting bench tests to explore the variation patterns of dust emission parameters and harvesting operation indicators under diverse working parameter conditions of the combine’s working components. A multi-factor mathematical model was established to predict both the dust emission rate of peanut pickup combines and the quality of harvesting operations. The model was utilized to identify the optimal combination of operation parameters for achieving high-quality and low-emission performance. The optimal parameter combination was determined as follows: a pod threshing roller speed of 313 r/min, a cleaning fan speed of 2535 r/min, a vine crushing roller speed of 1970 r/min, and a lifting fan speed of 1604 r/min. Under these conditions, the theoretical dust emission rate was calculated to be 10,603 mg/s, with a pod loss rate of 4.73% and a pod impurity rate of 5.21%. Compared to previous settings, the optimized operation parameters effectively reduced the combine’s dust emissions by 9.95%. Notably, the harvesting operation quality still complies with the industry standards for peanut harvesters. These research findings offer theoretical insights and robust technical support for minimizing dust pollution during the whole-feed harvesting of peanuts, contributing to more environmentally friendly and efficient peanut harvesting practices. Full article

The valorization of agri-food by-products represents a promising approach to advancing sustainable agriculture while contributing to climate resilience efforts. Leguminous crops, cultivated extensively across diverse agroecological zones, play a central role in global food systems and soil fertility dynamics. Waste from leguminous crops can contribute essential nutrients to the soil, such as nitrogen, helping the growth of associated or subsequent crops, thereby reducing the need for inorganic fertilizers. Additionally, they can help improve soil biological activity, physical soil properties, and increase nutrient availability. As nitrogen-fixing crops, the waste obtained after threshing pulses probably still contains large amounts of nutrients, which can replenish part of the nutrient needs required for other crops. However, there is little information available about the amount of nutrients these residues may contain, as well as their decomposition rate and release. In this review, we explore the role of agri-food waste, particularly leguminous residues, in promoting sustainable agricultural practices, identifying main knowledge gaps in legume crop residue characterization (i.e., nutrient content and decomposition rates). We also identify potential risks in using leguminous waste and discuss mitigation strategies for using these residues safely. Additionally, we propose new strategies to promote more sustainable agricultural practices and highlight future research directions. Full article

This study presents a multivariate regression-based analysis aimed at quantifying the influence of key vibration-generating components in two types of grain combines—C110H (with straw walker) and CASE IH (axial flow)—on the operator’s seat (OS). Using triaxial accelerometers, vibrational measurements were performed under both stationary and operational working mode. RMS acceleration values were recorded for major subsystems (engine, threshing unit, chassis, chopper/header) and processed via multiple linear regression. The models generated for each combine and axis (Ox, Oy, Oz) revealed high coefficients of determination (R² > 0.85), confirming the linear model’s validity. Influence maps and standardized coefficients were used to rank the sources of vibration. Results indicate that the straw walker dominates vibration transmission in the C110H, while the header and threshing system are more significant in the CASE IH. The findings support the development of predictive algorithms for real-time vibration monitoring and ergonomic improvements in combine design. Moreover, the proposed methodology provides a cost-effective diagnostic tool for early fault detection, targeted maintenance, and the long-term reduction of operator fatigue and injury risks. Full article

Intelligent control algorithms are essential for enhancing combine harvester efficiency and minimizing losses, especially as global food demand rises and labor shortages become more severe. This paper provides a comprehensive overview of the evolutionary progression from single-subsystem control to the current core challenge of multi-system co-optimization. We examine the technological development of the cutter, threshing, scavenging, and motion control systems, highlighting persistent bottlenecks that impede global performance improvements due to parameter coupling and conflicting objectives. This review serves as a reference for future advancements in the field. Future research should focus on lightweight reinforcement learning, hybrid control strategies, multimodal perception, and dynamic optimization frameworks for digital twins to drive technological breakthroughs and practical applications. Full article

Complex mechanical systems, such as agricultural combine harvesters, are subjected to dynamic excitations from multiple coupled sources, compromising structural integrity and operational reliability. Disentangling these vibrations to identify dominant sources and quantify their transmission paths remains a significant engineering challenge. This study proposes a robust diagnostic framework to address this issue. We employed a multi-condition vibration test with sequential source activation and an improved Operational Transfer Path Analysis (OTPA) method. Applied to a harvester chassis, the results revealed that vibration energy is predominantly concentrated in the 0–200 Hz frequency band. Path contribution analysis quantified that the “cutting header → conveyor trough → hydraulic cylinder → chassis frame” path is the most critical contributor to vertical vibration, with a vibration acceleration level of 117.6 dB. Further analysis identified the engine (29.3 Hz) as the primary source for vertical vibration, while lateral vibration was mainly attributed to a coupled resonance between the threshing cylinder (58 Hz) and the engine’s second-order harmonic. This study’s theoretical contribution lies in validating a powerful methodology for vibration source apportionment in complex systems. Practically, the findings provide direct, actionable insights for targeted structural optimization and vibration suppression. Full article

Simulation is an important technical tool in corn threshing operations, and the establishment of the corn kernel model is the core part of the simulation process. The existing modeling method is to treat the whole kernel as a rigid body, which cannot be crushed during the simulation process, and the calculation of the crushing rate needs to be considered through multiple criteria such as the contact force, the number of collisions, and so on. Aiming at the issue that kernel crushing during maize threshing cannot be accurately modeled in discrete element simulations, in this study, a sub-area crushing model was constructed; representative samples with 26%, 30% and 34% moisture content were selected from a double-season maturing region in China; based on the physical dimensions and biological structure of the maize kernel, three stress regions were defined; and mechanical property tests were conducted on each of the three stress regions using a texturometer as a way to determine the different crushing forces due to the heterogeneity of the maize structure. The correctness of the model was verified by stacking angle and mechanical property experiments. A discrete element model of corn kernels was established using the Bonding V2 method and sub-area modeling. Bonding parameters were calculated by combining stacking angle tests and mechanical property tests. The flattened corn kernel was used as a prototype, and the bonding parameters were determined through size and mechanical property tests. A 22-ball bonding model was developed using dimensional parameters, and the kernel density was recalculated. Results showed that the relative error between the stacking angle test and the measured mean value was 0.31%. The maximum deviation of axial compression simulation results from the measured mean value was 22.8 N, and the minimum deviation was 3.67 N. The errors between simulated and actual rupture forces at the three force areas were 5%, 10%, and 0.6%, respectively. The decreasing trend of the maximum rupture force for the three moisture levels in the simulation matched that of the actual rupture force. The discrete element model can accurately reflect the rupture force, energy relationship, and rupture process on both sides, top, and bottom of the grain, and it can solve the error problem caused by the contact between the threshing element and the grain line in the actual threshing process to achieve the design optimization of the threshing drum. The modeling method provided in this study can also be applied to breakable discrete element models for wheat and soybean, and it provides a reference for optimizing the design of subsequent threshing devices. Full article

Minor cereals are an important part of the Chinese grain industry, accounting for about 8 percent of the country’s total grain-growing area. Minor cereals include millet, buckwheat, Panicum miliaceum, and other similar grains. Influenced by topographical and climatic factors, the distribution of minor cereals in China is mainly concentrated in the plateau and hilly areas north of the Yangtze River. In addition, there are large concentrations of minor cereals in Inner Mongolia, Heilongjiang, and other areas with flatter terrain. However, the level of mechanized harvesting in these areas is still low, and there is little research on the whole process of mechanized harvesting of minor cereals. This paper aims to discuss the current status of the minor cereal industry and its mechanization level, with particular attention to the challenges encountered in research related to the mechanized harvesting of minor cereals, including limited availability of suitable machinery, high losses, and low efficiency. The article provides a comprehensive overview of the key technologies that must be advanced to achieve mechanized harvesting throughout the process, such as header design, threshing, cleaning, and intelligent modular systems. It also summarizes current research progress on advanced equipment for mechanized harvesting of minor cereals. In addition, the article puts forward suggestions to promote the development of mechanized harvesting of minor cereals, focusing on aspects such as crop variety optimization, equipment modularization, and intelligentization technology, aiming to provide a reference for the further development and research of mechanized harvesting technology for minor cereals in China. Full article

The threshing drum, a core component in combine harvesters, experiences significant unbalanced vibrations during high-speed rotation, leading to severe mechanical wear, increased energy consumption, elevated noise levels, potential safety hazards, and higher maintenance costs. A primary challenge is that excessive interference signals often obscure the fundamental frequency characteristics of the vibration, hampering balancing effectiveness. This study introduces a signal conditioning model to suppress such interference and accurately extract the unbalanced quantities from the raw signal. Leveraging this extracted vibration force signal, an automatic optimization method for the balancing counterweights was developed, solving calculation issues inherent in traditional approaches. This formed the basis for an automatic balancing control strategy and an integrated system designed for online monitoring and real-time control. The system continuously adjusts the rotation angles, θ₁ and θ₂, of the balancing weight disks based on live signal characteristics, effectively reducing the drum’s imbalance under both internal and external excitation states. This enables a closed loop of online vibration testing, signal processing, and real-time balance control. Experimental trials demonstrated a significant 63.9% reduction in vibration amplitude, from 55.41 m/s² to 20.00 m/s². This research provides a vital theoretical reference for addressing structural instability in agricultural equipment. Full article

To address the issues of high pod damage rate and unpicked pod rate in the picking device of peanut picking combine harvesters during the harvesting of sun-dried peanuts, a low-damage peanut picking device was developed. This device combines flat pin teeth with a two-stage round steel concave screen. Contact models between the picking components and peanut pods, as well as between pods and the concave screen, were analyzed to determine the optimal structural parameters of the picking components and the most suitable concave screen type. Using peanut plants that had been dug, windrowed, and naturally sun-dried in the field for 3–5 days as test material, bench tests were conducted with pod breakage rate and unpicked pod rate as evaluation indices. The installation direction of the picking elements and the combination form of the concave screen were used as experimental factors. The optimal configuration was determined to be flat pin teeth installed with parallel axial forward bending with a tip fillet radius of 6 mm, and a concave screen composed of right round steel + straight round steel with front sparse and rear dense type. Field comparative experiments with a conventional picking device—comprising cylindrical bar teeth and a straight round steel concave screen—showed that the pod breakage rate decreased from 1.92% to 1.17%, and the unpicked pod rate decreased from 1.14% to 0.62%. This study provides a theoretical basis for the structural optimization and performance enhancement of the threshing device in peanut picking combine harvesters. Full article

There is a poor mechanization level among the existing chili seed extractors. The separation operation still relies on manual labor, with low efficiency and high costs. In this study, a fresh chili seed extractor for small-scale operations was designed, and the relevant parameters were optimized. The rotational speed of the drum, feeding speed, sieve diameter, threshing gap, number of peg teeth, and inclination angle of the frame were used as test factors, and the comprehensive score (loss rate, crushing rate, and impurity rate) of the effect of the chili seed extractor was set as an evaluation index. The initial parameters were selected via the Plackett–Burman test. The steepest climb test was carried out to determine the ranges of significance for the parameters. Moreover, a Box–Behnken test were conducted to obtain the optimal parameter combination: the drum rotation speed was 661 r/min, the sieve diameter was 8.5 mm, and the disengagement gap was 9.4 mm. The test results showed that the loss rate was 3.83%, the crushing rate was 2.01%, and the impurity rate was 11.31%, which met the actual production requirements for chili seeds. This study is expected to provide a necessary reference for the design of chili seed extractors. Full article