The structure of the doubleacting reciprocating cutter intended for green leafy vegetable harvesting was designed, and the performance of the cutter was optimized based on the cutting diagram. By analyzing the effect of the single cutting area, the repeat cutting area and the uncut cutting area in the cutting diagram on cutting performance, it is concluded that the cutting performance of the cutter is best when the area of the uncut cutting area is 0 and the rate of the repeat cutting area is minimal, this is used as a basis for optimizing the design of the cutter. To address the problem that the existing methods of drawing and analyzing cutting diagrams do not combine high accuracy and simple operation, combining SolidWorks and Adams to draw cutting diagrams, and using ImagePro Plus software to identify and measure the relevant data in the cutting diagrams to quantitatively analyze and evaluate the cutting diagrams. In order to solve the problem that the existing cutting diagram evaluation index does not significantly reflect the change of cutting performance under the joint influence of dimensional and kinematic parameters of the cutter, it is proposed to use the distance indicating the uncut area and the rate of the repeat cutting area as evaluation indexes to reflect the changes of the three regions in the cutting diagram, and using these two evaluation indexes as target values, optimizing the cutting performance of the existing doubleacting reciprocating cutter. The study proposes to use this method of drawing, analyzing and evaluating cutting diagrams to further optimize cutting performance, analyzing the effect of the cutters size parameters (width of moving blade front end, height of moving blade cutting edge, blade spacing) and motion parameters (cutting speed index) on the distance indicating the uncut area and the rate of the repeat cutting area, using BoxBehnken central combinatorial experimental design to conduct a fourfactor and threelevel simulation test, the experimental results show that width of moving blade front end, height of moving blade cutting edge, blade spacing and cutting speed index have significant effects on the distance indicating the uncut area and the rate of the repeat cutting area. Parameter optimization results showed that  when width of moving blade front end was 5 mm, the height of moving blade cutting edge was 32 mm, the blade spacing was 30 mm, and the cutting speed index was 0.7, the area of the uncut cutting area was 0, the rate of the single cutting area was 88.26%, and the rate of the repeat cutting area was 11.74%. Compared with the results before optimization, the area of the uncut cutting area was still 0, but the rate of the single cutting area was increased by 6.18% and the rate of the repeat cutting area was reduced by 6.18%.

 Astragalus sinicus (Chinese milkvetch) is one of the main rotation crops in rice field in the south of China, and also an important forage or green manure crop. During the fallwinter season and land fallow period, planting green manure could increase content of soil organic matter. This improves soil fertility and renews soil production. It plays a vital role not only in the sustainable development of agriculture, crop industry and grain quantitative safety, but also the sustainable development of environment, food qualitative safety and human health. In recent years, with the rapid growth of Astragalus sinicus planting area in China, Astragalus sinicus harvesting mechanization technology and equipment requirement have increased rapidly. The research on Astragalus sinicus mechanized harvesting technology appeared relatively late in China. Naturally, the refitted Astragalus sinicus harvesters from rice combine harvesters were used. The refitted Astragalus sinicus harvesters have inadequate stable performance due to the lack of special harvesters. Limited design of the key components also lacked supporting essential theory. The previous researches on mechanical properties and collision mechanism of grain seeds have mostly focused on big crop seeds, but Astragalus sinicus seeds have been rarely studied. In this research, from Contactimpact view, the surface compression mechanical properties of Astragalus sinicus seeds were measured, and the analysis on collision mechanism was explored during fullfeeding Astragalus sinicus threshing. The study found that the central deformation increased linearly with the increase of the pressure load. The central deformation changed a little slower under low pressure load. The distribution function of the maximum stress and the central deformation were derived during Astragalus sinicus threshing process. In the early stages of collision, the maximum stress of Astragalus sinicus seeds increased sharply when the central deformation increased. On the contrary the maximum stress changed gradually in the late stages. The relatively velocity function between the Astragalus sinicus seed and the threshing spiketooth was established. The critical approaching speed between them was obtained when damage occurred to Astragalus sinicus seeds during threshing. Through the theoretical analysis and calculation, the critical approaching speed was 27.31 m/s when damage occurred to Astragalus sinicus seeds during threshing. This means that the critical threshing speed was faster than 32 m/s when the broken rate of Astragalus sinicus seeds increased significantly. In this experiment, a typical Astragalus sinicus in Hefei District, Anhui Province, China, Yijiangli was selected as the experimental object. The average moisture content of Astragalus sinicus seeds was around 9.45% at harvesting stage. The data of Astragalus sinicus seeds in the test field were as follows: the average elastic modulus at length direction was 441.75 MPa, and the average ultimate strength was 189.24 MPa. The research also obtained the variation curve of the threshing rate and the broken rate with the threshing speed. According to experimental verification, the threshing speed was controlled less than 25 m/s in practical application, the indexes of Astragalus sinicus threshing could reach excellent performance. The threshing rate was more than 99.5%, and the broken rate was less than 0.33% when the threshing speed was 25 m/s. The research provided a theoretical foundation for further exploring the damage mechanism in Astragalus sinicus harvesting, and it also provided technological support for the design and optimization of Astragalus sinicus threshing.

In order to solve the problems of large loss rate and high damage rate of 4UZL-1 sweet potato combine harvesters during the operation process, the working principle of 4UZL-1 sweet potato combine harvester was described in detail based on the analysis of its overall structure, the conveyer mechanism of arc grid handover scraper chain was designed, and the working parameters were determined. Relying on the machine and sweet potato planting mode, the arc grid handover scraper chain conveying test bench was built. With potato tuber of loss rate and damage rate in the process of transferring of potato tubers as the main evaluation index, the single factor bench test was carried out with the angle of excavating and conveying mechanism, the angle of scraper chain conveying, the speed of excavation and conveying mechanism, the speed of scraper chain conveying, scraper angle and arc grid installation distance as test factors. The significance of the influence of each factor on each performance index, the influence rule, and the cause were analyzed. The test results showed that the angle of excavating and conveying mechanism, the conveying angle of scraper chain, the speed of excavating and conveying mechanism, and the conveying speed of scraper chain had significant impacts on the performance indexes, while the angle of the scraper and the installation distance of the arc grid had no significant impact on the performance indexes. When the angle of excavating and conveying mechanism was 24°, the conveying angle of the scraper chain was 60°, the speed of excavating and conveying mechanism was 1.15 m/s, and the conveying speed of the scraper chain was 0.69 m/s.The arc grid transfer scraper chain conveyor mechanism was more effective. The loss rate and the damage rate were 075% and 013%, respectively. The research results can provide a reference for the structural improvement and parameter optimization of the sweet potato combine harvester.

In view of the lack of research on the by-product management specifications of agricultural machinery research institutes in China, in order to formulate the by-product management specifications in line with its characteristics and reduce the loss of state-owned assets, the characteristics of the by-product production of agricultural machinery research were analyzed and put forward based on the description of the by-product management of planting agricultural research. The first characteristic was that the production of scientific by-products of agricultural machinery was not targeted at agricultural breeding. The second characteristic was the small amount of research by-products produced. The third characteristic was that agricultural machinery scientific research by-products damage was difficult to reach the requirements of marketing. The fourth characteristic was that there were fewer scientific research by-products such as scientific research machines or spare parts that can be marketed. The fifth characteristic was that agricultural machinery products on the market sales need qualification appraisal or certification of the subject was not scientific research units. And the management measures of scientific by-products in representative agricultural machinery research institutes were analyzed. New measures were put forward, such as the need to clarify the subject of responsibility for the management of scientific research by-products, ledger registration, disposal principles, methods and procedures, requirements for revenue and expenditure management, supervision and “red line”. It can be used as a reference for other domestic agricultural machinery research institutes to improve the management of scientific by-products.