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Assessment of BRRI Whole Feed Combine Harvester (Model BRRI WCH2021) for Mechanized Rice Harvesting in Bangladesh
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作者 Arafat Ullah Khan Akm Saiful Islam +5 位作者 Md. Kamruzzaman Pintu Subrata Paul Md. Durrul Huda Md. Anwar Hossen Md. Monirul Islam Md. Moudud Ahmmed 《Agricultural Sciences》 2024年第2期274-291,共18页
Agricultural mechanization plays a pivotal role in the transition from subsistence to commercial agriculture, with a particular focus on labour-intensive activities like harvesting. This study assesses the operational... Agricultural mechanization plays a pivotal role in the transition from subsistence to commercial agriculture, with a particular focus on labour-intensive activities like harvesting. This study assesses the operational characteristics of the BRRI Whole Feed Combine Harvester (Model BRRI WCH2021) at the field level. Developed under the SFMRA project, the harvester’s technical performance and loss assessment were conducted during the Boro 2022 and Aman 2022 seasons in farmer fields in Bangladesh’s Rangpur region. The field efficiency of the harvester was determined to be 62.5% and 57.9% in the Boro and Aman seasons, respectively. Fuel consumption rates were recorded at 2.77 l/ha and 2.31 l/ha for the Boro and Aman seasons. The total harvesting losses, encompassing cutter bar, shatter, cylinder, and separation loss, averaged 0.56% and 0.48% in the Boro and Aman seasons, respectively. Mechanized harvesting with the BRRI Whole Feed Combine Harvester significantly reduced paddy losses by 5.81% compared to manual methods. The field evaluation results indicate the combine harvester’s satisfactory performance, highlighting its potential to alleviate labour demands during peak harvesting. The development of the BRRI WCH offers a sustainable solution for rice harvesting mechanization among progressive farmers. It paves the way for the broader adoption of advanced agricultural technology in Bangladesh. 展开更多
关键词 BRRI Whole Feed combine harvester Field Efficiency Fuel Consumption harvesting Loss
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Effects of Rice Combine Harvester Application to Harvest Chinese Milk Vetch Seeds
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作者 廖育林 鲁艳红 +4 位作者 聂军 周兴 谢坚 杨曾平 吴浩杰 《Agricultural Science & Technology》 CAS 2015年第4期853-856,共4页
During the test, the seed yield, Iabor efficiency, harvesting costs and eco-nomic benefits were compared and analyzed between mechanical harvesting tech-noIogy and traditional artificial harvesting technoIogy of Chine... During the test, the seed yield, Iabor efficiency, harvesting costs and eco-nomic benefits were compared and analyzed between mechanical harvesting tech-noIogy and traditional artificial harvesting technoIogy of Chinese miIk vetch seeds to studied the mechanical harvesting technoIogy and appIication effects. The resuIts showed that mechanical harvesting technoIogy increased the yield of 92.7 kg/hm2, reducing the seeds Ioss. It improved the Iabor efficiency and reduced the harvesting cost. For exampIe, a rice combine harvester was the equal of 18-20 person in the harvest quantity in one day, which directIy reduced the Iabor cost of 2 175-3 000 yuan/hm2 and increased the economic income of 3 307-4 099 yuan/hm2. So it wiI pIay an important roIe in soIving the shortage of Chinese miIk vetch seeds and ac-ceIerating the deveIopment of Chinese miIk vetch green manure crop in south China rice region. 展开更多
关键词 Rice combine harvester Chinese mlik vetch seeds Mechanical harvest-ing technology Applicatlon effect
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Combine Harvester: Small Machine Solves Big Rice Harvesting Problem of Bangladesh
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作者 Bidhan Chandra Nath Subrata Paul +3 位作者 Md Durrul Huda Md Anwar Hossen MGK Bhuiyan AKM Saiful Islam 《Agricultural Sciences》 2022年第2期201-220,共20页
Bangladesh, a country with 87% of rural households that depend on agriculture and rice dominated diets (70%), engages the country’s food security. Therefore, there is strong advocacy for a mechanized paddy harvesting... Bangladesh, a country with 87% of rural households that depend on agriculture and rice dominated diets (70%), engages the country’s food security. Therefore, there is strong advocacy for a mechanized paddy harvesting system for food security in South Asia, mainly Bangladesh. Some harvesting machinery is available;however, the precise roles of a combine harvester during this process are little. This study attempts to understand the consequences of combining harvesters for paddy harvesting and compare them with hand harvesting. For comparison of field performance of combine harvester with traditional harvesting, the experiment was conducted at Gazipur District, Bangladesh, in 2016. Results showed that the labor required for harvesting unit area 283, 15 and 9.87 man-h&#8729;ha<sup>&#8722;1</sup> for T<sub>1</sub> (Sickle + Head carry + Beating + Kula), T<sub>2</sub> (Reaper + Trolley carry + Close drum thresher + winnower), T<sub>3</sub> (Combine harvester) system, respectively. Likewise, the harvesting costs were 1.84 (T<sub>2</sub>) and 2.5 (T<sub>1</sub>) times higher than the combine harvester (T<sub>3</sub>). Also, the postharvest loss can be saved 1.84%, to use combine harvester over manual harvesting of paddy. The above result revealed that the semi-mechanized and mechanized harvesting system is a time, labor and cost-saving system;however, the manual reaping system is concerned with more postharvest losses (3.09%). This study highlights the importance of combine harvester;however, further research is required in other places with large and mini-combine harvesters under diverse cropping areas and to test a combine harvester’s detailed potentiality. 展开更多
关键词 combine harvester harvestING LABOR PADDY Postharvest Losses
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Optimization of Conventional Combine Harvester to Reduce Combine Losses for Basmati Rice (<i>Oryza Sativa</i>)
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作者 Manvendra Bhardwaj Ritu Dogra +2 位作者 Mohammed Javed Manjeet Singh Baldev Dogra 《Agricultural Sciences》 2021年第3期259-272,共14页
A study was conducted at PAU Regional Research Station, Gurdaspur (Punjab) to investigate the design and operational parameters of threshing mechanism of conventional combine harvester for basmati crop. This study was... A study was conducted at PAU Regional Research Station, Gurdaspur (Punjab) to investigate the design and operational parameters of threshing mechanism of conventional combine harvester for basmati crop. This study was aimed to investigate the suitable changes required in the self-propelled conventional combine harvester for harvesting the basmati crop with minimum grain losses. Field evaluation of experiment was carried out to assess the influence of independent design variable <em>i.e.</em>, arrangement of spikes (AS) and independent operational parameters such as concave clearance (CC) and cylinder speed (CS). The study was aimed to enumerate various combining losses<em> viz</em>., extent of visible and invisible grain damage and threshing efficiency at different AS, CC and CS levels. The first year data recorded during 2017 were processed for the optimization during 2018. The results of the present study revealed that during 2017, maximum visible and invisible losses was 5.49% ± 0.33% and 28.07% ± 3.21%, respectively whereas after modification, these losses remained only 4.00% ± 0.80% and 24.07% ± 2.86%, respectively. The threshing efficiency remained above 99.31% ± 0.47%, for both years. Thus, optimization of combine harvester was able to save the visible grain damage by 60% to 83% and invisible grain damage by 6% to 16%, respectively during 2018 than the year 2017. 展开更多
关键词 Conventional combine harvester Basmati Rice Visible and Invisible Grain Damage
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Comparison of Pile-Soil-Structure Interaction Modeling Techniques for A 10-MW Large-Scale Monopile Wind Turbine Model Under Wind and Wave Conditions 被引量:2
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作者 ZENG Yu-xin ZHANG Xiao-ming +3 位作者 ZHANG Li-xian SHI Wei WANG Wen-hua LI Xin 《China Ocean Engineering》 SCIE EI CSCD 2023年第3期471-483,共13页
Considering the large diameter effect of piles,the influence of different pile-soil analysis methods on the design of monopile foundations for offshore wind turbines has become an urgent problem to be solved.Three dif... Considering the large diameter effect of piles,the influence of different pile-soil analysis methods on the design of monopile foundations for offshore wind turbines has become an urgent problem to be solved.Three different pile-soil models were used to study a large 10 MW monopile wind turbine.By modeling the three models in the SACS software,this paper analyzed the motion response of the overall structure under the conditions of wind and waves.According to the given working conditions,this paper concludes that under the condition of independent wind,the average value of the tower top x-displacement of the rigid connection method is the smalle st,and the standard deviation is the smallest under the condition of independent wave.The results obtained by the p-y curve method are the most conservative. 展开更多
关键词 large-scale monopile offshore wind turbine pile-soil model wind-wave load combination
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Design of High Precision Horizontal Control Network for Large-Scale Hydropower Project
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作者 ZHANG Zhenglu LUO Changlin +1 位作者 DENG Yong XIE Niansheng 《Geo-Spatial Information Science》 2006年第4期235-239,共5页
A new solution of combination network of GPS and high precise distance measurements with EDM is proposed. Meanwhile, it’s inadvisable only using GPS network without distance measurements. Three schemes: terrestrial n... A new solution of combination network of GPS and high precise distance measurements with EDM is proposed. Meanwhile, it’s inadvisable only using GPS network without distance measurements. Three schemes: terrestrial network, GPS network and combination network are discussed for horizontal control network design of Xiangjiaba Dam in view of precision, reliability, coordinate and outlay in detail. 展开更多
关键词 large-scale hydropower project terrestrial network GPS network combination network of GPS and high precise distance measurements with EDM
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Parameter matching and experiment of the combined cyclone separation and cylinder sieve cleaning system for rape combine harvester
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作者 Jiacheng Yuan Qingxi Liao +2 位作者 Xingyu Wan Jia Yang Caixia Shu 《International Journal of Agricultural and Biological Engineering》 SCIE 2024年第1期128-136,共9页
Existing rape combine harvester with a cyclone separation cleaning device has the challenge that the loss rate and the cleaning rate increase and decrease simultaneously.A cleaning process route was proposed,which inv... Existing rape combine harvester with a cyclone separation cleaning device has the challenge that the loss rate and the cleaning rate increase and decrease simultaneously.A cleaning process route was proposed,which involves the cyclone separation cleaning device removing light and tiny impurities,and the cylinder sieve device removing coarse and long impurities such as pod shells and short stems.A novel cleaning system combining the cyclone separation cleaning device and cylinder sieve cleaning devices was designed.The ranges of the structure and operation parameters for each component were analyzed based on kinematics and dynamic analysis.A four-factor five-level quadratic orthogonal test was carried out,in which the loss rate and cleaning rate were taken as the evaluation indexes.The velocity at the suction port,the rotation speed of the cylinder sieve,the screw pitch of the spiral blade and the diameter of the sieve hole were taken as the influencing factors.The orthogonal test results showed that the cleaning system performed best at a rotation speed of the winnower is 600 r/min,an airflow velocity at the suction port is 18.25 m/s,a rotation speed of the cylinder sieve is 87 r/min,a screw pitch of the spiral blade is 440 mm and a diameter of the sieve hole is 4.48 mm.At this time,the loss rate of the cleaning system is 3.22%,and the cleaning rate is 95.67%.Compared to the conventional cyclone separation cleaning device,the loss rate is reduced by 2.17%and the cleaning rate is increased by 1.05%.This study can provide a reference for the optimal cleaning system design for rape combine harvesters. 展开更多
关键词 agricultural engineering cleaning system cyclone separation cylinder sieve rapeseed combine harvester
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基于视觉传达设计的农机操作界面优化研究
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作者 魏亚敏 《农机化研究》 北大核心 2025年第1期199-204,共6页
近年来,随着农业机械智能化的不断发展与应用,农户对农业机械操控功能性、便捷性、易学性和人机交互的良好体验等提出了更高的要求;但是,目前市场上各类农业机械APP界面出现大量“雷同化”特点,难以满足不同农业机械的田间使用要求。为... 近年来,随着农业机械智能化的不断发展与应用,农户对农业机械操控功能性、便捷性、易学性和人机交互的良好体验等提出了更高的要求;但是,目前市场上各类农业机械APP界面出现大量“雷同化”特点,难以满足不同农业机械的田间使用要求。为此,将“人机交互行为”作为设计目标,基于视觉传达技术,以谷物联合收获机操作界面为研究对象开展相关设计。同时,对谷物联合收获机操作界面图形、文字、色彩和设计风格进行分析,结果表明:优化后的农机操作界面能够显著提高操作员的操作效率和工作体验,降低操作错误率和疲劳程度。研究结果可为农业机械智能化操作界面的设计提供可参考的过程设计模型。 展开更多
关键词 操作界面 视觉信息 交互 谷物联合收获机
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Mechanical Harvesting Effects on Seed Yield Loss,Quality Traits and Profitability of Winter Oilseed Rape (Brassica napus L.) 被引量:13
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作者 MA Ni ZHANG Chun-lei +4 位作者 LI Jun ZHANG Ming-hai CHENG Yu-gui LI Guang-ming ZHANG Shu-jie 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第8期1297-1304,共8页
China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cu... China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 (Brassica napus L.) was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C (CHA, CHB, and CHC) were designed and manual harvesting (MH) as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting (MS/CH) showed an input/output ratio of 1:1.6, and it was 1:1.2 in mechanical sowing/manual harvesting (MS/MH). Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River. 展开更多
关键词 winter oilseed rape (Brassica napus L.) combine harvesting harvesting loss seed quality economic profit
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Influence of two-stage harvesting on the properties of cold-pressed rapeseed(Brassica napus L.)oils 被引量:5
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作者 NING Ning HU Bing +8 位作者 BAI Chen-yang LI Xiao-hua KUAI Jie HE Han-zi REN Yi-lin WANG Bo JIA Cai-hua ZHOU Guang-sheng ZHAO Si-ming 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第1期265-278,共14页
Rapeseed(Brassica napus L.)harvesting method is critical since it significantly determines the seed yield,oil quality,and industrial efficiency.This study investigated the influences of harvesting methods on the quali... Rapeseed(Brassica napus L.)harvesting method is critical since it significantly determines the seed yield,oil quality,and industrial efficiency.This study investigated the influences of harvesting methods on the quality of cold-pressed rapeseed oil of two varieties.Oil color,peroxide value(POV),tocopherol content,fatty acid composition,and polarity of total polyphenols(PTP)contents of two rapeseed varieties in Huanggang and Xiangyang were compared through artificially simulated combined harvesting and two-stage harvesting.Results showed significant differences in the quality of rapeseed oil between the two harvesting methods.The red value(R-value),POV,total tocopherol contents,linoleic and linolenic acid content,and PTP content of the pressed rapeseed oil prepared by the combined harvesting method were about 27.6,5.7,15.8,2.0,0.5,and 28.6%lower than those of the oil produced from the two-stage harvesting method,respectively.Xiangyang and Huayouza62 performed better in the two regions and two varieties,respectively.To sum up,the rapeseed oil obtained 41–44 days after final flowering of combined harvesting,35 days after final flowering,and six days of post-ripening of the two-stage harvesting had the best quality. 展开更多
关键词 RAPESEED two-stage harvesting combined harvesting oil quality
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Can harvest outsourcing services reduce field harvest losses of rice in China? 被引量:4
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作者 QU Xue Daizo KOJIMA +2 位作者 Yukinaga NISHIHARA WU La-ping Mitsuyoshi ANDO 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2021年第5期1396-1406,共11页
The purpose of this study is to quantify the rice harvest losses in China and to evaluate the impacts of machinery and harvest outsourcing services on these losses,given the background of high-speed mechanization and ... The purpose of this study is to quantify the rice harvest losses in China and to evaluate the impacts of machinery and harvest outsourcing services on these losses,given the background of high-speed mechanization and outsourcing services.Data were collected from a national survey conducted in 2016 by the research team in conjunction with the Research Center for the Rural Economy of the Ministry of Agriculture and Rural Affairs of China.A non-parametric method was used to test whether combine harvesting and outsourcing services could significantly reduce harvest losses.Next,quantile regression was used to estimate the real effects of machinery and outsourcing services on harvest losses.The analysis yielded four main study outcomes.First,the harvest loss rate of rice in China was 3.65%.Second,mechanical reaping and winnowing caused greater losses than manual methods,while the opposite was true of field transportation.Third,combine harvesting increased the losses.Fourth,the effects of an outsourcing service on losses differed among the different harvesting methods.Outsourcing services increased losses in segmented harvesting but they reduced losses in combine harvesting. 展开更多
关键词 rice harvest outsourcing service combine harvesting harvest loss RICE
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Development of uncut crop edge detection system based on laser rangefinder for combine harvesters 被引量:8
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作者 Zhao Teng Noboru Noguchi +2 位作者 Yang Liangliang Kazunobu Ishii Chen Jun 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2016年第2期21-28,共8页
The objective of this research was to develop an uncut crop edge detection system for a combine harvester.A laser rangefinder(LF)was selected as a primary sensor,combined with a pan-tilt unit(PTU)and an inertial measu... The objective of this research was to develop an uncut crop edge detection system for a combine harvester.A laser rangefinder(LF)was selected as a primary sensor,combined with a pan-tilt unit(PTU)and an inertial measurement unit(IMU).Three-dimensional field information can be obtained when the PTU rotates the laser rangefinder in the vertical plane.A field profile was modeled by analyzing range data.Otsu’s method was used to detect the crop edge position on each scanning profile,and the least squares method was applied to fit the uncut crop edge.Fundamental performance of the system was first evaluated under laboratory conditions.Then,validation experiments were conducted under both static and dynamic conditions in a wheat field during harvesting season.To verify the error of the detection system,the real position of the edge was measured by GPS for accuracy evaluation.The results showed an average lateral error of±12 cm,with a Root-Mean-Square Error(RMSE)of 3.01 cm for the static test,and an average lateral error of±25 cm,with an RMSE of 10.15 cm for the dynamic test.The proposed laser rangefinder-based uncut crop edge detection system exhibited a satisfactory performance for edge detection under different conditions in the field,and can provide reliable information for further study. 展开更多
关键词 laser rangefinder technology crop edge detection combine harvester NAVIGATION field profile modeling
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Review of combine harvester losses for maize and influencing factors 被引量:3
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作者 Keru Wang Ruizhi Xie +3 位作者 Bo Ming Peng Hou Jun Xue Shaokun Li 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2021年第1期1-10,共10页
The high harvest losses associated with the mechanical harvesting of maize in China are currently a major barrier to the adoption of this technology.This paper summarizes works of literature regarding harvest losses f... The high harvest losses associated with the mechanical harvesting of maize in China are currently a major barrier to the adoption of this technology.This paper summarizes works of literature regarding harvest losses from the combine harvesting of maize in China and abroad.The main findings are as follows:(1)In 2012-2019,2987 samples data obtained from the major maize production areas of China showed that the average harvest loss was 345.2 kg/hm2(3.5%of the average yield),with losses ranging from 0 to 9288.5 kg/hm2;(2)The harvest losses from combine harvesting are mainly caused by the dropping of ears.The ear losses include the pre-harvest loss caused by ear abscission,damage caused by maize borer,lodging,and the ear loss during combine harvesting,and the main pre-harvest loss is caused by lodging;(3)Harvest losses are affected by maize variety,planting mode,cultivation management,pests and diseases,weather conditions during harvesting,harvest date,combine harvester type,harvester adjustment,operator proficiency,and the terrain conditions of the maize field;(4)The harvest losses from combine harvesting are also related to the type of header,feeding and threshing methods,the adjustment of header stripping clearance,feeding amount,forward speed,cylinder or rotor speed,and the clearance between the cylinder and the concave of the harvester.However,the combine losses mainly come from header losses.In order to reduce the harvest losses,the following solutions were proposed:(1)Breed and select maize varieties which are resistant to lodging,especially during the field drying of mature grains,as well as those resistant to maize borer and stalk rot;(2)Select varieties suitable for grain harvest-which requires matching the accumulated-temperature demand of the maize hybrids,optimal plant density,row spacing,and irrigation and fertilizer management with the light and heat conditions of the production area while cultivating uniform populations and healthy plants-as well as preventing and controlling damage from maize borer,stalk rot,and ear rot,harvesting at the appropriate time;(3)Develop and select advanced maize combine harvesters,formulate standardized operating procedures for harvesting machinery,and standardize field operation;(4)select appropriate agricultural machinery and agronomic practices,and improve the training of maize producers and harvester operators. 展开更多
关键词 MAIZE grain combine harvest ear dropping kernel dropping harvest loss influence factors
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Real-time grain breakage sensing for rice combine harvesters using machine vision technology 被引量:6
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作者 Jin Chen Yi Lian +3 位作者 Rong Zou Shuai Zhang Xiaobo Ning Mengna Han 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第3期194-199,共6页
Breakage rate is one of the most important indicators to evaluate the harvesting performance of a combine harvester.It is affected by operating parameters of a combine such as feeding rate,the peripheral speed of the ... Breakage rate is one of the most important indicators to evaluate the harvesting performance of a combine harvester.It is affected by operating parameters of a combine such as feeding rate,the peripheral speed of the threshing cylinder and concave clearance,and shows complex non-linear law.Real-time acquisition of the breakage rate is an effective way to find the correlation of them.In addition,real-time monitoring of the breakage rate can help the driver optimize and adjust the operating parameters of a combine harvester to avoid the breakage rate exceeding the standard.In this study,a real-time monitoring method for the grain breakage rate of the rice combine harvester based on machine vision was proposed.The structure of the sampling device was designed to obtain rice kernel images of high quality in the harvesting process.According to the working characteristics of the combine,the illumination and installation of the light source were optimized,and the lateral lighting system was constructed.A two-step method of“color training-verification”was applied to identify the whole and broken kernels.In the first step,the local threshold algorithm was used to get the edge of kernel particles in a few training images with binary transformation,extract the color spectrum of each particle in color-space HSL and output the recognition model file.The second step was to verify the recognition accuracy and the breakage rate monitoring accuracy through grabbing and processing images in the laboratory.The experiments of about 2300 particles showed that the recognition accuracy of 96%was attained,and the monitoring values of breakage rate and the true artificial monitoring values had good trend consistency.The monitoring device of grain breakage rate based on machine vision can provide technical supports for the intellectualization of combine harvester. 展开更多
关键词 combine harvester breakage rate monitoring sampling box structure machine vision color classification
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Selection of proper combine harvesters to field conditions by an effective field capacity prediction model 被引量:2
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作者 Khunnithi Doungpueng Khwantri Saengprachatanarug +1 位作者 Jetsada Posom Somchai Chuan-Udom 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第4期125-134,I0013,共11页
Farmers have to finish their harvesting with high efficiency,because of time and cost.However,farmers are lacking knowledge and information required for selecting suitable combine harvesters and giving the conditions ... Farmers have to finish their harvesting with high efficiency,because of time and cost.However,farmers are lacking knowledge and information required for selecting suitable combine harvesters and giving the conditions of their rice fields,because both information factors(combine harvester and field condition)impact the field capacity.The field capacity model was generated from combine harvesters with the Thai Hom Mali rice variety(KDML-105).Therefore,this study aimed to determine the prediction model for effective field capacity to combine harvesters when harvesting the Thai Hom Mali rice variety(KDML-105).The methods began by collecting data of 15 combine harvesters,such as field,crop,and machine conditions and operating times;to generate the prediction model for the KDML-105 variety.The prediction model was then validated using 12 combine harvesters that were collected similarly to the model creation.The results showed a root mean square error(RMSE)of 0.24 m^(2)/s for the model.The prediction model can be applied for farmers to select the proper combine harvesters and give their field conditions. 展开更多
关键词 rice harvesting combine harvester prediction model effective field capacity selection of combine harvester
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Assessing the influence of harvesting intensities on structural diversity of forests in south-west Germany 被引量:2
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作者 Felix Storch Gerald Kadler Jürgen Bauhus 《Forest Ecosystems》 SCIE CSCD 2019年第3期249-260,共12页
Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest own... Background: To increase ecosystem resilience and biodiversity, the maintenance and improvement of structural and compositional diversity of forests has become an important goal in forest management for many forest owners and jurisdictions. At the same time, future harvesting intensity (HI) may increase to meet the demand for woody biomass by an increasing bioeconomy sector. Yet, the influence of HI on forest structural diversity is largely unknown. Here, we address this issue by analyzing the relationship between HI and structural diversity based on large-scale national forest inventory (NFI) data, where the latter is quantified using a previously developed Forest Structure Index and HI is expressed as wood volume removal during the period 2002-2012 for the same inventory plots. Results: Our results show a surprisingly small impact of harvesting intensity on changes in structural diversity for most of the analysed types of forests. Only intense harvesting (> 80%-90% of initial growing stock) led to a significant reduction in structural diversity. At low to moderate HI most aspects of structural diversity were positively influenced. Only the quadratic mean DBH and the volume of large trees (≥ 40 cm DBH) were substantially negatively influenced at HI > 60% and 70% of initial growing stock, respectively. Conclusions: In several forest types, HI could be increased without a reduction in overall structural diversity. Hence, structural diversity in these selectively managed forests appears to be a very resistant forest property in relation to HI. Other indicators at stand and landscape scale may be needed to adjust levels of HI that are suited to maintain forest biodiversity. 展开更多
关键词 large-scale INVENTORY STRUCTURAL DIVERSITY index harvestING intensity Changes in STRUCTURAL DIVERSITY
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Modeling of working environment and coverage path planning method of combine harvesters 被引量:2
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作者 En Lu Lizhang Xu +2 位作者 Yaoming Li Zhong Tang Zheng Ma 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2020年第2期132-137,共6页
This paper mainly studied the working environment modeling and coverage path planning of combine harvesters.The boundaries of the farmland to be harvested were extracted through the farmland satellite imagery and cann... This paper mainly studied the working environment modeling and coverage path planning of combine harvesters.The boundaries of the farmland to be harvested were extracted through the farmland satellite imagery and canny algorithm.The polygon approximation method was used to fit the extracted boundaries as polygons.The edge offset of the farmland and obstacles was realized based on the principle of straight skeleton.According to the structure data of the split points which were obtained through the improved scan line algorithm,the coverage path planning of the combine harvester was realized.Moreover,the circular arc transition algorithm was used to optimize the harvesting paths to achieve the smooth turning of the combine harvester at the edge of farmland and when encountering obstacles.The simulation results show that the proposed the proposed polygon approximation method can accurately depict the boundaries of the farmland to be harvested,and reduce the amount of data to be stored.Additionally,the designed path planning method can realize the coverage path planning of the combine harvester in irregular and internal obstacle farmland. 展开更多
关键词 combine harvester environmental modeling path planning farmland turning
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Experimental study on driver seat vibration characteristics of crawler-type combine harvester 被引量:2
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作者 Lizhang Xu Xiaoyu Chai +2 位作者 Zhipeng Gao Yaoming Li Yading Wang 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2019年第2期90-97,共8页
To improve the driving comfort of combine harvesters,driver seat low-frequency vibration and related driver ride-comfort problems were investigated on a Chinese CFFL-850 crawler-type full-feed combine harvester based ... To improve the driving comfort of combine harvesters,driver seat low-frequency vibration and related driver ride-comfort problems were investigated on a Chinese CFFL-850 crawler-type full-feed combine harvester based on ISO2631.Driver vibration and driving seat transmission characteristics were measured under the following conditions:no-load idling,driving on the road,driving in the field,and simulated harvesting.The root mean square values composite vibration under four conditions were 3.63 m/s^(2),2.35 m/s^(2),3.34 m/s^(2),and 2.67 m/s^(2),respectively.For the same condition,the maximum root mean square scores of vibration component on driver whole-body occurred in the seat support surface(test point 1)and vertical direction(Z direction),which were 3.56 m/s^(2),2.05 m/s^(2),3.15 m/s^(2),and 2.43 m/s^(2),respectively.The test point 2 to test point 1 vertical-transfer function curve trends were nearly identical.Nearly all of the transfer coefficients were greater than 1 in the range of 1-50 Hz,therefore,the seat vibration attenuation performance was poor.Based on the analysis results,the driver seat structure was altered and a verification test was performed.The test results indicated that after an X-damping mechanism was installed,vibration acceleration,on the surface of the seat support under the road-driving conditions,decreased from 2.35 m/s^(2) to 1.68 m/s^(2).Under the simulated harvesting condition,the vibration acceleration decreased from 2.56 m/s^(2) to 1.46 m/s^(2).Nearly all of the seat vertical transfer coefficients were less than 1 within the frequency range of 1-80 Hz,therefore the dynamic comfort of the seat was ameliorated after structural improvement. 展开更多
关键词 crawler-type combine harvester driver seat vibration characteristics ride comfort DAMPING structure optimum
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Inertial force balance and ADAMS simulation of the oscillating sieve and return pan of a rice combine harvester 被引量:2
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作者 Chuncai Wei Lizhang Xu +1 位作者 Jianting Wang Yaoming Li 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2018年第1期129-137,共9页
To reduce the inertial force of the oscillating sieve and return pan of a rice combine harvester,partial equilibrium was adopted.Firstly,based on the kinematic analysis of a slider-crank mechanism,the appropriate mass... To reduce the inertial force of the oscillating sieve and return pan of a rice combine harvester,partial equilibrium was adopted.Firstly,based on the kinematic analysis of a slider-crank mechanism,the appropriate mass of counterweight intervals was achieved.Then,an ADAMS dynamic simulation was used to determine the optimum balance mass of the oscillating sieve and return pan individually.Considering the relative motion between the return pan and the oscillating sieve,the overall inertial force of the two parts would be reduced.The simulation results indicated that the optimum counterweight of the oscillating sieve was 15.5 kg based on an analysis of the movement tracks of the mass center and overall inertial force.The results also showed that the overall balance of inertial force not only reduced the counterweight but also decreased the overall inertial force of the oscillating sieve and return pan.Finally,a search for the most suitable crank initial angle of the return pan to reduce the overall inertial force and optimize the overall balance revealed three groups of initial angles:φ=0°,φ=45°,andφ=90°.The results indicated that arranging the initial angle of the crank of the oscillating sieve and return pan in the same position(φ=90°)was the most favorable for reducing the overall inertial force.In this situation,the optimum counterweight of the oscillating sieve was only 14.0 kg.The results can provide references for the design of the overall balance of the inertial force in the cleaning components of a combine harvester. 展开更多
关键词 rice combine harvester oscillating sieve return pan inertial force balance ADAMS
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Proportional distribution method for estimating actual grain flow under combine harvester dynamics 被引量:2
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作者 Wang He Bai Xiaoping Liang Hongbin 《International Journal of Agricultural and Biological Engineering》 SCIE EI CAS 2017年第4期158-164,共7页
The yield monitors use a constant delay time to match the grain flow with location.Therefore,mixing and smoothing effects on the grain flow are neglected.Although constant time delay compensates for time mismatch,actu... The yield monitors use a constant delay time to match the grain flow with location.Therefore,mixing and smoothing effects on the grain flow are neglected.Although constant time delay compensates for time mismatch,actual grain flow at a combine harvester head is not equal to the grain flow measured by a sensor due to the dynamics effects.In order to eliminate the dynamics effects,a new method for estimating actual grain flow,called proportional distribution(PD),is proposed.This method assumes that actual grain flow is directly proportional to the feedrate.Based on this assumption,the actual grain flow results from redistributing accumulated grain mass over a certain time according to the profile of the feedrate.The PD can avoid the dynamics effects because the feedrate is measured at a combine harvester’s head.Compared with constant time delay,the proposed method can effectively estimate actual grain flow and be applied to improve the accuracy of yield maps. 展开更多
关键词 grain flow combine harvester estimation method proportional distribution time delay yield map yield monitoring sensor
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