Abstract:The competitiveness of modern equipment enterprises and their products largely depends on whether they can provide products to meet the market demand at the fastest speed, that is, whether they have advanced design methods to support the efficient research and development process. Aiming at the problem in low integral level of agricultural machinery research and development in China, as well as various types and significant regional differences result in a variety of professional knowledge, structural forms, practical experience and so on, making it difficult for individual designers to fully grasp, unable to guarantee the quality of research and development, and severely restricting the industrial development and independent innovation ability, thus the development process of design methods was comprehensively reviewed, the characteristics of times at each stage and the generation rules of advanced design methods were analyzed, the advanced design methods and development direction suitable for agricultural equipment was discussed, and the realization of the strategic goals set for agricultural equipment in major national development plans such as “Made in China 2025” was supported. The research showed that the trend of intelligent design based on digital technology was obvious, which represented the development direction and the highest level of advanced design by combining the current technological level and social background, making full use of the advantages of 3D-CAD virtual reality and the development results of computer technology. Intelligent design was characterized by knowledge reuse, based on digital model resource, carried by product data management (PDM) and product lifecycle management (PLM) platform, and organized and connected upstream and downstream design-related research links such as scheme reasoning, digital mockup (DMU), computer aided engineering (CAE), computer aided process planning (CAPP) by the generalized computer aided design concept. In this way, intelligent design can implement the high integration of CAX, which was the practical application of artificial intelligence (AI) in the field of design. The development ideas of current advanced design were clarified, basic theory and system architecture for the establishment of equipment intelligent design system were provided, and it had significant theoretical value and practical guiding significance for fully integrating industry resources, highly sharing achievements and professional knowledge, greatly improving research and development efficiency and level, and significantly enhancing the core competitiveness of Chinese equipment enterprises and their products.

Abstract:An adequate and consistent depth positioning of seeds is vital for uniform crop germination to achieve the optimum yield of agricultural crops. However, the downforce variations from the row units will affect the stability of sowing depth because of the irregular and inconsistent soil resistance of the seedbed. Therefore, controlling the seeding downforce to compensate for changes in soil resistance can improve seeding quality. At present, most of the downforce control methods are driven by hydraulic pressure, which requires a high level for the tractor hydraulic system. In addition, previous studies have found that the existing downforce detection methods have problems of low sensitivity and lack of fast and precise control model, which can not achieve real-time accurate downforce control. To solve the problems, a new downforce control method based on the air-spring pressure and the four-link angle was proposed, and a corresponding pneumatic downforce control system was designed. The system consisted of pneumatic driving device, tilt sensor for profiling mechanism, pressure sensor for air-spring, downforce sensor for gauge-wheel, date acquisition and control module, and an upper computer. The pneumatic driving device, which mainly included air-spring, electric-gas proportional valve, air pump, gas tank and oil separation filter, was used to provide the necessary downforce on the profiling mechanism to ensure the optimum and consistency of sowing depth. The downforce sensor and tilt sensor were applied to generate downforce and the four-link angle signals in real time. After first-order low-pass filtering and model calculation by the upper computer, these actual downforce was displayed on the interface programmed by LabVIEW and the control signals were sent to the electrical-gas proportional valve through the date acquisition and control module based on RS485 communication. A modeling experiment was conducted to establish the relationship between the sensor values and the actual downforce under different air-spring pressures and four-link angles. Regression analysis showed that the model fitted the best, being 0.9743 in adjusted determination coefficient (R2Adj) and 49.41N in root mean square error (RMSE). The verification test showed that the predicted root mean square error (PRMSE) was 39.51N, which showed that the model had better control accuracy for downforce. Further, an air-spring response test and a field test were carried out respectively to test system control performance. The results showed that the air-spring inflation step response average overshoot was 3.83%, the average steady state error was 0.0052MPa, and the average adjustment time was 0.42s when the pressure was set in the range of 0.1~0.6MPa. The field tests indicated that the system had stable and reliable control performance for sowing depth in the speed range of 6~10km/h. Within the industry standard error range of 10mm, the qualified rate of sowing depth of the system was not less than 98.91%. Especially when the speed of the planter was over 10km/h, the standard deviation (SD) of sowing depth was 3.46mm and the coefficient of variation (CV) was 6.97%, which was significantly better than the passive downforce control system with the SD of 6.70mm and the CV of 13.07% respectively.

Abstract:As a special machinery for field breeding experiments, the plot seeder has a very important role in improving efficiency of breeding, reducing labor intensity and costs, as well as ensuring scientific nature and accuracy of test results. In order to improve the mechanization and automation level of the plot seeder and solve the problem that it is difficult to adjust the operating parameters, a wheat plot seeding control system based on STM32 was developed. The system was mainly composed of an Android mobile phone terminal, main controller of STM32, lifting system of storage cylinder, control system of cone compartment tray for seed meter, and control system of seed dispenser. The stepper motor and direct current motor speed control model were established. And human-computer interaction interface was designed, which was used to set working parameters. For checking up the performance of wheat plot seeding control system in plot seeder and gaining better combination of parameters, indoor tests were carried out at three cone compartment tray rotation speed of 4r/min, 6r/min and 8r/min, and four seed dispenser rotation speed of 1100r/min, 1250r/min, 1400r/min and 1550r/min. Test results showed that the cone compartment tray rotation speed, seed dispenser rotation speed, and the interaction of them had a very significant effect on the uniformity between rows by the analysis of variance. With the increase of rotating speed of the cone compartment tray, the variation coefficient of the uniformity between rows was increased. With the change of rotating speed of seed dispenser at 1100~1550r/min, the variation coefficient of the seed uniformity was reduced firstly and then increased. When the rotating speed of the cone compartment tray and seed dispenser was 4r/min and 1250r/min respectively, the variation coefficient of uniformity between rows was 4.53%, of which the uniformity between rows was better and the grain damage rate was smaller. This control system could provide a research basis for the automation and intelligent control of plot seeding.

Abstract:In order to reuse the design knowledge of mechanical soybean seed metering device, shorten the design cycle and reduce the design cost, the design reuse technology of mechanical soybean metering device was studied. It’s difficult to describe the design knowledge qualitatively and quantitatively of the traditional knowledge representation method of case-based reasoning（CBR）, such as frame representation, semantic network representation, predicate logic representation and so on. In order to realize the visualization, standardization and unification of design knowledge, the product design knowledge was described in the form of case matter element which contained case name, characteristic attribute and measure value. The method was beneficial to the effective use of design knowledge. In order to facilitate case storage and retrieval, the organization structure and case creation method of the design reuse were studied, Classification of basic hierarchy by seed-metering device category, and a case base was constructed which case model was corresponding to the case matter element, and some case relational matter elements were contained in the case base. This kind of organization structure was beneficial to the retrieval and reuse of examples, which made the restorage of cases follow the rules and provided convenience for the management and maintenance of the case library. At the same time, the components of the products were no longer isolated individuals, which fully reflected the overall characteristics of the products. In order to quickly retrieve the instance that met the design requirements from the case library, the characteristic property parameters of the instance were divided into basic parameters, matching parameters and evaluation parameters. The retrieval range can be reduced to a specific type and operation speed of seed metering device for retrieval by the selection of basic parameters. Similarity of cases was calculated by using improved nearest neighbor algorithm. The weight of the attributes of an instance can be determined by expert scoring or analytic hierarchy process（AHP）method, which can reduce the amount of computation and improve the efficiency and accuracy of retrieval. In order to meet the specific design requirements of the user, the quantitative relationship between the design requirements and the structural parameters of the instance was established by using the method of rule association, and the rapid revision of the case was realized by modifying the key parts of the case-parameterized model. An example of mechanical soybean seed metering device design reuse was given, the case library was constructed by using Access and computer aided three-dimensional interactive application （CATIA）, and the retrieval, evaluation and correction system of metering device was developed by Visual Basic. According to the current job object, the feasibility of the similar metering device was verified by using engineering discrete element method （EDEM） software and the modification suggestions were put forward. Finally, the simulation and prototype test of the revised metering device were carried out. The results showed that the improved metering device can meet the current requirements. The feasibility and effectiveness of the design reuse technology was validated. At the same time, it can also provide technical reference for intelligent design of other types of mechanical equipment.

Abstract:Aiming at the problem that uneven vibration frequency, uneven amplitude adjustment and unreasonable structure of the seed dressing device, the seedlings had high weight loss rate and high damage rate. Breeding device for potato seeder seed metering device was designed. Through the kinematics and dynamics analysis of the cleaning operation process, the main factors affecting the seed cleaning effect were determined, and the structure of the seed cleaning device was designed. This plank can also reduce the horizontal velocity of potato seed to decrease the distance of potato drop into furrow. The eccentricity, the main driving wheel speed of the conveyor belt and the height of the seed layer were used as experimental factors. The field experiment was carried out with the re-broadcast rate and the missed-air rate as test indicators. The test results showed that the elastic-guided clean-up parts can effectively remove the seed potatoes between the spoons, and the vibration-cleaning device can effectively remove the excess seed potatoes in the spoon, which was significantly improved. When the eccentricity was 1.9mm, the main drive wheel speed of the conveyor belt was 40.61r/min, and the seed layer height was 33cm, the replay index was 3.04%, and the missed broadcast index was 2.01%. The index was better than standard of China. According to industry standards, the effect of seed cleaning was significantly improved. The device provided a theoretical reference for improving the design of the seeding device of the scoop potato planter.

Abstract:Under the narrow-row-dense planting mode of beans, it is difficult to achieve high-speed precision seeding. However, a pneumatic precision seed-metering device with single seed-metering plate for double-row was developed, which used single-channel and single-row seeding tray to realize double-row seeding operation. The basic structure and working principle were expounded. The working area of the seeding device was divided, the structural form of the seeding tray was determined, the key parameters of the main structure were analyzed and the mathematical model was determined. The experiment was employed through the method of Box-Behnken orthogonal rotating center combination of three factors and three levels according to the GB 6973—2005 national standard. In test, soybean seed Zhonghuang 37 was selected as experimental material. Combining with extensive pre-experiment and theoretical analysis, hole diameter, vacuum degree, forward speed were taken as main influencing factors, the seed qualified index and missing index were taken as response index. The results showed that the order of contribution rates on the effect of inner qualified index was the vacuum degree, hole diameter and forward speed, the order of contribution rates on the effect of inner missing rate was vacuum degree, forward speed and hole diameter, the order of contribution rates on the effect of outer eligible rate was vacuum degree，forward speed and hole diameter, the order of contribution rates on the effect of outer qualified index was hole diameter，vacuum degree and forward speed. The optimal combination of parameters was as follows: the hole diameter was 4.5mm, the vacuum degree was 4.5kPa, the working speed was 10km/h, and under the optimal combinations, the inner eligible rate was 97.83%, the inner missing index was 0.62%, the outer eligible rate was 98.24%, the outer missing rate was 0.47%. The verification test was repeated 10 times, the results indicated that the actual test results were in agreement with the optimization results. Then, a speed single factor test was carried out. The results showed that the inner and outer eligible rate were more than 93%, the inner and outer missing rate were not more than 5%, and the inner and outer multiple rate were not more than 2%. At last, the adaptation tests of peas, mung beans and adzuki beans were carried out. The results showed that the inner and outer circle eligible rate were more than 97%, the inner and outer missing rate were not more than 1%, and the inner and outer multiple rate were not more than 3%. The results of the research laid a foundation for the development of pneumatic precision seed-metering device for bean, and provided a reference for the research of bean narrow-row and flat-dense planter.

Abstract:In order to simplify the structure of seeding monomer, improve the quality of planting, and meet the agricultural requirements of narrow row of soy closely planting on planter, a centralized belt type soybean seed-metering device was designed. The method of circulating flow seed filling and vibrating seed cleaning of the seed-metering device was described. The key structural parameters, such as supporting wheel, vibration bench for clearing seed, seed conveyor belt, position of air inlet and sealing device were determined through theoretical analysis and simulation analysis. The mechanical model of seed filling process and seed cleaning process was established, and the basic structure and working principle of the seed-metering device were introduced. The experiment was employed through the method of quadratic orthogonal rotating center combination of three factors and five levels according to national standard (GB 6973—2005). In test, soybean seed Heinong 38 was selected as experimental material. Combining with extensive pre-experiment and theoretical analysis, the air pressure, working speed and clear vibration frequency were taken as the main influencing factors, and seed qualified index, multiple index and missing index were taken as the response index, the experimental research was carried out. The optimal combination of parameters were clear vibration frequency of 44.6Hz, air pressure value of 4.4kPa and working speed of 10.5km/h, and under the optimal combinations, the qualified index was 90.65%, the multiple index was 1.97%, and the missing index was 7.38%, the verification test was repeated five times, the results indicated that the actual test results were in agreement with the optimization results. This seed-metering device could meet the seeding requirements well. The research results provided a reference for the research of centralized precision seed-meter device.

Abstract:Aiming at the fact that the existing surface microtopography measuring device is difficult to achieve the accuracy and efficiency of surface measurement simultaneously after mechanical cultivation operations, a non-contact surface microtopography measuring device composed of LiDAR, linear guide, portable computer and bracket was developed. The stepping motor drive controller based on STM32 single-chip microcomputer was developed, and a complete acquisition system was built up combined with the upper computer software. The system can realize precise positioning of the LiDAR and quickly obtain the three-dimensional coordinates of the surface. The typical resolution of the device was 3.8~10mm in the LiDAR scanning direction, the vertical scanning direction can be arbitrarily set within the millimeter precision range, the ranging resolution was 1mm;the coverage area was 6.8m2 typically, when the vertical scanning direction resolution was 10mm, the single measurement time was less than 2.5min. By analyzing the source of measurement error, the system error compensation model was established. Under the condition of 15 mean filtering, the maximum absolute error of the device was 2.7mm and the maximum average absolute error was 0.9mm. The device was investigated on rapeseed surface area after direct seeding of the crop. Test results revealed that the surface three-dimensional model generated by Matlab can accurately reconstruct the original microtopography surface features, and the measurement results were consistent with the actual surface height fluctuation. The statistical analysis showed that for attaining stable results, the root mean square height and the correlation length in the fixed size area needed to be sampled 16 times and 64 times, respectively.

Abstract:In order to solve the problem that the characteristic parameters of soil surface groove are difficult to be measured after the operation of soil tillage parts，the traditional measurement methods have problems in measurement efficiency and error. A tillage soil groove measurement system based on laser triangulation was designed，the system included portable hardware structure and an interactive software system. The hardware structure was mainly composed of X/Y axis electric guides, laser range finder，rotary encoders，portable computer，level and aluminium profile. The interactive software based on LabView can realize high-precision scanning and positioning of X/Y electric guides based on motion controller and rotary encoder signals，the interactive interface displayed the groove width, groove depth，real-time plotting of soil disturbance and groove contour curve. The acquired points cloud was obtained by a spatial interpolation and the surface fitting algorithm to obtain a grooved 3-dimensional digital model. The field experiments and precision, method comparison experiments were conducted. The results showed that the measurement errors of horizontal direction and vertical direction were 0.59mm and 0.02mm, respectively. Compared with image detection method, the average relative errors of RMSH and CL were reduced by 2.1% and 1.1%, respectively. The measured value tended to be stable with the increase of sampling times, which can be used as the true value of measurement, and the measurement error was decreased exponentially. The average measuring time and relative error of the system measurement were 3.37% and 0.72m2, respectively. The measuring system had measuring accuracy and reliability, which can satisfy automatic measurement of furrow type after farmland soil tillage. The requirement of chemical measurement provided a new idea for the quality analysis of soil tillage components and evaluation of tillage machinery and equipment.

Abstract:In order to solve the problem of failure on clipping-seedling type transplanting mechanism of rice plug-seedling during seedling pick-up and not fully push-pull pushing that affect the upright degree of seedling, according to the design requirement of rice plug-seedling transplanting mechanism, a kind of clipping-plug type transplanting mechanism of rice plug-seedling was proposed. Firstly, according to the kinematic model of transplanting mechanism, an auxiliary analysis and optimization software of this kind of rice potted-seedling transplanting mechanism was independently developed with Visual Basic 6.0, and the influence of main parameters on the transplanting trajectory was also analyzed by the software. With the method of human-computer interaction based on visualization, a set of structural parameters satisfying the transplanting requirements was carried out. Then, according to the optimized parameters of mechanism, the overall structural design of the transplanting mechanism was completed. The correctness of the theoretical model and design of the transplanting mechanism was verified by the virtual simulation analysis of the transplanting mechanism. Finally, the test-bed for rice plug-seedling transplanting was designed, on which the seedling experiment of the transplanting mechanism was carried out. When the rotational speed of the transplanting mechanism was 50r/min, the average success rate of seedling pick-up was 93.06%, which was decreased with the increase of rotational speed. When the rotational speed was 80r/min,the average success rate of seedling pick-up dropped to 88.89%. It was showed that the mechanism had high seedling transplanting efficiency and high seedling success rate, so it can be applied to rice plug-seedling transplanting machine.

Abstract:Aiming to elucidate the effects of 3WQF120-12 single-rotor unmanned aerial vehicle (UAV) on the effect of droplet, deposition distribution, ground loss droplets, drift, and applicability when spraying areca palm. The impact of different working heights of UAV on the spraying effect of areca palm canopy was mainly studied. In this experiment, the red stain aqueous solution with a mass fraction of 0.5% was selected and instead of pesticides. The droplets were collected on coated paper and analyzed by an image processing software (DepositScan). The results showed that when the operation height was 12.09m, 11.46m and 10.40m, respectively, the operation height had no significant influence on the droplets deposition amount of the sampling points in each layer of the areca palm. Meanwhile, the deposition level in the upper canopy could reach 53.27%, that of the lower canopy and fruit layer can reach 59.19% and 27.91% of the upper canopy. The results of the droplets deposition at the ground loss sampling points showed that the droplets deposition of the three column sampling points on the ground was significantly affected by different operation heights. When the operation height was 10.40m, the droplets loss on the ground was the least, and the average deposition level was about 19.9%. The data of the drift area showed that the three working heights had no significant influence on the droplets deposition of the sampling points in the drift line. When the working height was 12.09m, the drift line sample location measured the largest amount of drift and the working height of 10.40m had the smallest. At the same time, it was found that the downwind distance corresponding to 90% drift accumulation could reach as far as 36.35m. Therefore, sufficient safety distance must be left for practical operation. The areca aerial spraying was very different from that of conventional crops, mainly in working speed and height. The speed of areca aerial spraying was about 1.5m/s, which was much lower than usual speed (3~5m/s), and the working height can usually be more than 10m. The wake vortices were mainly influenced by working height, as the working height increased, the amount of droplets deposition was decreased, especially in the upper layer of the areas’ canopy. Due to the operation speed was slow, the acting time of the rotor wind field was relatively long. The combined action of downwash airflow and crosswind in the rotor wind field can significantly improve the penetration of droplets. In this experiment, there were three different working heights, and the droplet volume median diameter (VMD) of droplets in each layer was changed significantly with the working heights. With the increase of crosswind and working height, the droplet volume median diameter (VMD) of droplets in each layer was decreased, and the mean deposition and percent area coverage rate in the fruit layer could increase by up to 53.75% and 62.20%, respectively. In actual operations, appropriate operation parameters can be selected according to the growing period and the occurrence part of diseases and pests.

Abstract:In order to solve the problem of synthetic void pre-judgment and anti-leakage spray, a new canopy partied volume method of fruit tree was developed based on void pre-judgment. The measurement sensors required were NU40F15TR-2M non-contact ultrasonic ranging sensor and SICK-DT35 non-contact laser ranging sensor, which were fixed on caterpillar self-propelled orchard sprayer. When information of fruits was collected, the vehicle’s traveling speed was 1.0m/s, and the sensor was 1.4m away from the tree trunk. Firstly, NU40F15TR-2M non-contact ultrasonic ranging sensor and SICK-DT35 non-contact laser ranging sensor were used to obtain orchard information point cloud pictures, ahead of nozzle 46cm distance, which were distances between ranging sensor and fruits canopy. Continuous canopy width was calculated based on point cloud picture, and canopy width calculation formula was designed. At the same time, fruits void was reasoned by the formulas, and the abnormal data point was chosen with a negative canopy width value and replaced with data points of zero. Secondly, length of discrete canopy volume model was determined by E6B2-CWZ10C speed, because speed of caterpillar self-propelled orchard sprayer was nonuniform motion in actual travelling. Thus caterpillar self-propelled orchard sprayer travelling distance of a certain period time was calculated by uniform speed of caterpillar self-propelled orchard sprayer and variable rate spraying decision time. And variable spraying decision time was designed by a required time formula, which was satisfied with responsing time, effective spray time of the actuator and the real-time requirement of variable spray. Pulse number of E6B2-CWZ10C speed encoder was calculated based on the principle of itself and caterpillar self-propelled orchard sprayer driving distance of a certain period time. Thus discrete canopy length was obtained by E6B2-CWZ10C speed encoder and variable rate spraying decision time. Finally, fruits void and fruits canopy were judged by a model, which was used to distinguish fruits void, fruits canopy and the mixture of fruits void and fruits canopy. There were fruits void, when the average width was less than one tenth of the maximum width in the distance of discrete canopy length. Therefore, the discrete canopy width value was got and fruit tree canopy volume model was partied. This anti-leakage spray decision was made by designing logic operation. The testing results showed that the fusing sensor array and the blowout prevention strategy were the best. But there was the problem of overspray. By improving the fusion sensor array and testing, compared with the conventional fusion sensor array, the number of droplets in the upper, middle and lower canopy of the continuous dense orchard was decreased by 6.95%, 3.85%, and increased by 4.40%, respectively;the deposition amount was decreased by 11.11%, 8.33% and 3.57%, respectively. The number of droplets in the upper, middle and lower canopy of the spindle-type sparse orchard was decreased by 27.08%, 30.37% and 18.55%, respectively;the sedimentation was decreased by 64.71%, 60.87% and 40.38%, respectively. The number of droplets in the upper, middle and lower canopy of the single plant type sparse orchard was decreased by 18.44%, 26.26% and 15.54% respectively;the sedimentation was decreased by 40%, 42.43% and 41.46%, respectively.

Abstract:Most of cleaning devices in maize harvester are parallel-mounted double screen. In order to improve the screening performance of the double screens, a four DOF double-layer non-parallel vibrating screen mechanism and test bench were designed by using the bias crank slider mechanism. The mathematical model of mechanism motion was obtained by using matrix analysis method. The results showed that the sieve movement was non-harmonic periodic motion. The factors were the installation spacing of double screens, the mounting inclination of upper screen, and the transverse amplitude of screen. The indexes were the loss and impurity rate of maize. The test data were analyzed by the response surface method and the regression mathematical models were multi-objectively optimized by using Design-Expert software. When the mounting inclination of lower screen was 3.5°, the optimal parameters were the installation spacing of double screens of 292.99mm, mounting inclination of upper screen of 3.04°, and transverse amplitude of screen of 5.55mm. Test of driving mechanism size was done based on optimized parameter adjustment. Under the condition of the normal feed quantity of maize mixture of 5.05kg/s,the loss rate of grain was 1.61% and the impurity rate of grain was 2.17% after screening, which can meet the performance requirement of maize harvester. Compared with the traditional double plane reciprocating vibrating screen cleaning device, the loss rate of grain was reduced by 1.59 percentage points.

Abstract:A combined cutting and throwing longitudinal axial flow threshing and separating device was designed to solve the problems like long transport distance and high probability of blockage in threshing device due to the low adaptability of the chain conveyor to rape with high and thick stems in traditional rape combine harvester. The functions of forced feeding, cutting, throwing, threshing and separating were combined, and the key parts of the rape combine harvester were all hydraulically driven to ensure their stepless speed regulation and smooth operation. The structural and working parameters of feeding roller, cutting cylinder and threshing cylinder were determined based on kinematics and dynamics analysis of stem. The orthogonal experiment of cutting cylinder speed, threshing cylinder speed and threshing clearance were carried out while the entrainment loss ratio and power consumption were used as indexes. The results of orthogonal experiment showed that the optimal parameters were 450r/min for the cutting cylinder speed, 450r/min for the threshing cylinder speed and 30mm for the threshing clearance. Under this combination of parameters, the total loss ratio was 0.415%, the mass percentages of short stems in the threshing outlets was 10.43%，the total power consumption for cutting cylinder and threshing cylinder was 4.16kW and the average length of the stems discharged from the outlet of stems was 134.8mm. In addition, the loss ratio and cleaning ratio of cyclone separation cleaning system were 6.13% and 91.97%, respectively. The field experiment showed that the combined cutting and throwing longitudinal axial flow threshing and separating device could realize the uniform continuous conveying, threshing and separating of materials from the header to the threshing device and it could meet the operation demand of the rape combine harvester.

Abstract:Cleaning is one of the most important working processes of corn kernel harvester. However, high loss and high impurity seriously restrict the effect of cleaning process. The impurity rate and loss rate were directly affected by working parameters of cleaning devices. So working parameters optimization experiment of cleaning devices was carried out by using corn kernel harvester. Fan speed, vibration frequency and opening degree of upper screen were selected as experiment factors. The better levels of three experiment factors were obtained by single factor experiment. The better levels of fan speed were ranged from 800r/min to 1000r/min. The better levels of vibration frequency were ranged from 6Hz to 8Hz. The better levels of opening degree of upper screen was ranged from 15mm to 25mm. Based on single factor experiment results, the optimal combination of three test factors and regression model were obtained by orthogonal experiment. The optimal factor combination of cleaning impurity rate was fan speed of 1000r/min, vibration frequency of 7Hz, and opening degree of upper screen of 20mm. The optimal factors combination of cleaning loss rate was fan speed of 900r/min, vibration frequency of 6Hz, and opening degree of upper screen of 20mm. The optimal factor combination of cleaning comprehensive weighted index was fan speed of 900r/min, vibration frequency of 7Hz, and opening degree of upper screen of 20mm. Three regression models were verified by field test. The relative error of regression model of cleaning impurity rate was 5.56%. The relative error of regression model of cleaning loss rate was 5.10%. The relative error of regression model of cleaning comprehensive weighted index was 4.60%. The results showed that three regression models were reliable.

Abstract:In order to realize the design innovation of harvesting equipment and the simulation test of the machine operation behavior and performance, the corn harvesting equipment was taken as an example, the 3D simulation model of harvesting equipment was built by Unity3D virtual platform. In order to simulate the deformation of the plant, according to the rheological properties, the plant model was constructed by connecting multiple cylinders with virtual springs and virtual walls. Then, establishment of behavioral models achieved interaction between harvesting equipment and plants. Finally, the harvesting simulation platform was used to verify the harvesting simulation test under different conditions, including the state change test of the plant under wind and rain, the harvesting behavior observation test of the harvesting process and the harvesting performance test of harvesting equipment with the traveling speed and planting density as factors. The result was that the fruit loss rate was decreased rapidly with the increase of speed, but the rate was decreased slowly when the speed exceeded 0.385m/s. At the same time, the higher the planting density was, the slower the fruit loss rate was decreased. Further analysis of variance showed that both the traveling speed and the planting density had significant effects on the harvesting performance of the harvesting equipment (P<0.01), which showed that the simulation platform can effectively simulate the harvesting situation and evaluate the performance of the harvesting equipment.

Abstract:Threshing is an important working operation in wheat harvesting process. However, low threshed rate is an important problem restricting threshing operation, so it is urgent to innovate threshing mechanism and improve threshing parts. Cattles were typical ruminants and their tongues provided a natural biological model for bionic threshing. The filiform papillae was observed on the surface of the tongue tip of cattle by scanning electronic microscope. The distribution density of filiform papillae was large, and its structural characteristics were obvious. Its outline was conical, and its tip was hemispherical. The filiform papillae was inclined and the inclination angle was 35°~40°. The “papillae-material” contact working interface was constructed, including four working steps of complete separation, initial contact, papillaematerial insertion and complete contact. Based on structural characteristic parameters of filiform papillae, the bionic tooth model was constructed and the simulation test of bionic tooth threshing was carried out. The optimal combination of parameters for bionic tooth threshing was obtained. The optimal combination was 2.5 times magnify ratio, 15mm/s movement speed, 38° inclination angle, contact position for 0.2 times the height of tooth form the whole place, Q345 material. The bionic tooth threshing bench test was carried out and the threshing process was analyzed by camera. The regression model and response surfaces were established by orthogonal test. Response surface analysis showed that the threshing performance of bionic tooth was good, and the threshed rate was ranged from 97.5% to 99.5%. The optimal structure parameter combination of bionic tooth was obtained. The magnify times was 2.565, the inclination angle was 39.8°, and the threshing clearance was 9.11mm.

Abstract:The distribution of water resources and the application of seawater desalination pumps in China were analyzed. Based on the traditional water pump, a water pump named two-dimensional cartridge pump composed of some pairs of unit pumps was proposed. Depending on the basic components of the unit pump set, namely the combined characteristics of two unit pumps were studied. Through the theoretical analysis and comparison with the traditional axial piston pump and centrifugal pump for water, the working principle and potential advantages of the two-dimensional cartridge water pump were expounded. The advantages included structural force balance, large displacement, oil and water separation, no structural flow ripple and so on. In the meantime, the mathematical modeling and analysis of the contact surface between cam and roller were carried out. Being different from the method of obtaining contact points by taking points in two dimensions after compensation, the mathematical model of contacting surface was established based on the analysis of the spatial contacting relationship between the roller and cam. The mathematical model of contacting surface was more precise which offered theoretical basis for the further research. The correctness of the mathematical model of contact surface and the advantage of no structural flow pulsation in two-dimensional cartridge pump were verified by the experimental study of piston movement and flow characteristics of two unit pump set.

Abstract:Timely monitoring of cow estrus is very important in dairy cow breeding. At present, artificial estrus monitoring of dairy cows is time-consuming and laborious. Pedometer contact monitoring can easily cause stress discomfort to cows. Aiming at the problems existing in cow estrus monitoring, according to cows span behavior characteristics during oestrus, a method of cow’s oestrus behavior recognition based on convolutional neural network (CNN) was proposed. The convolution neural network was constructed to improve the network training speed by batch normalization. Max-pooling was used as the down sampling, rectified linear units (ReLU) was used as the activation function, and softmax regression classifier was used as the output layer. Through the theoretical analysis and experimental verification, the network structure and parameters of 32×32-20c-2s-50c-2s-200c-2 were designed. Through video surveillance of dairy cow activity area, 150 video segments with oestrus span behavior were extracted from 50 cows behavior videos within 6 months. The network training data of 23000 frames and the test data of 7000 frames were randomly selected from selected video segments, which were used to train and test the CNN. The results showed that the recognition accuracy of estrus behavior in dairy cows was 98.25%, the missed detection rate was 5.80%, the false recognition rate was 1.75%, and the average recognition time of single frame image detection was 0.257s. It proved that the method could realize the contactless realtime monitoring of the cow’s estrus span behavior and had a high recognition rate for cow estrus. It can significantly improve the management efficiency of large-scale farming, and had a good application prospect.

Abstract:Considering the difficulties of obtaining the body temperature of pigs timely in the process of large-scale pig breeding, an inspection system based on infrared technology was designed to realize the rapid monitoring of body temperature in the facility pig farm. The hardware of system included an infrared mobile acquisition device, a system control device, and the power supply device. The infrared mobile acquisition device was comprised of a slide rail, a mobile car, an infrared thermal imager, and a protective shell;the system control device was comprised of a HP MINI microcomputer, a XP2-18R/RT integrated controller, and a DM542 digital motor driver;the power supply included cables and cable blocks. The control system of equipment integrated infrared image acquisition, storage control, mobile car operation control and data communication with remote server, etc. The equipment was deployed and experimented in the limit bar pig farm for 28days. The experiment showed that the system worked stably and the average loss rate of infrared images in the inspection process was 1.12%, which could effectively collect the infrared images of pigs in the limit bar pig farm. The ear roots area was selected as the temperature sensitive area in the experiment. According to the statistics, the periodic inspection accuracy of the ear roots area of pigs was over 90%, which can effectively monitor the temperature of the ear roots area of pigs. The experiment also monitored the maximum temperature of the ear roots region of No.3 to No.6 pigs for five consecutive days and counted their daily mean value. The analysis verified the scientific value of temperature, which could provide effective monitoring information for the breeding personnel, and was of great significance for the health monitoring and epidemic prevention of pigs in the field of pig breeding.

Abstract:In order to deal with the problem of low automation and low recognition accuracy in the current rice planthopper image recognition research, an image classification algorithm based on transfer learning and Mask R-CNN was proposed. Firstly, according to biological characteristics of rice planthopper, the self-developed wild insect image collection device was utilized to obtain insect images automatically. Then, the dataset was divided into two categories: rice planthopper and non-rice planthopper by the image label tool VIA, and was trained in the ResNet50 framework with transfer learning. Finally, the Mask R-CNN image classification experiments were carried out based on rice planthopper images, non-rice planthopper images, insect images with disturbances and those images which were adhesive and overlapping, respectively. Moreover, experiments were compared with SVM, BP neural network, which were traditional image classification algorithms, and Faster R-CNN algorithm. Experiment results showed that the method based on transfer learning and Mask R-CNN could distinguish the rice planthopper and non-rice planthopper images effectively and the average classification accuracy reached 0.923 under the same sample conditions, which could provide information support for the prevention and early warning of rice planthoppers.

Abstract:Plant phenotyping is an important research topic in the field of botany. The similarity of plant phenotypes is widely used in plant taxonomy, ecology and digital agriculture etc. It is one of the important contents of plant phenotype research. Chrysanthemum is an important plant in China as well as in the world, and the phenotype similarity evaluation of chrysanthemum plays an important role in chrysanthemum classification and phenotypic research. The feature of high-dimension of massive chrysanthemum data brings great challenge for chrysanthemum phenotype analysis, from this point of view, the chrysanthemum phenotypic similarity query and evaluation were studied based on multiprobe locality sensitive hashing technique. For evaluating the similarity of chrysanthemum image, the SIFT features of the chrysanthemum images were extracted and clustered based on the K-means method. Hereafter, the bag of visual words (BoVW) model was built. Due to the high-dimensional nature of the image features, especially for the massive chrysanthemum images, the computing efficiency of the query was a big challenge for the high dimensional problem. The multi-probe locality sensitive hashing (LSH) was applied for chrysanthemum phenotype similarity computing. The multiprobe locality sensitive hashing technique was an optimization technique for high-dimensional data similarity query. By means of the technique, a hash data structure of chrysanthemum image data was constructed, which improved query efficiency in chrysanthemum similarity query and ensured the query result quality. The theory of the multi-probe locality sensitive hashing was analyzed, in addition to this, extensive experiments were conducted and important results were gained as well. Experiments showed that compared with linear scanning, the average success probability of the query can reach above 090, and the average acceleration ratio was 3.3~19.8,furthermore, it was also compared with the typical method in the aspects of query quality and query efficiency, and the results demonstrated that the method was better than the entropy based LSH in quality and performance. The experimental results revealed that the query quality and query efficiency could be tuned flexibly through the parameter settings of hash function number and the hash tables, which provided an elastic way for the choice for tuning the quality and efficiency. In addition, it can provide technical reference for massive chrysanthemum phenotypic similarity calculation.

Abstract:Traditional methods of image processing for crop detection under agricultural natural environment are easily affected by small samples and subjective judgment, so they have many disadvantages such as low recognition rate and low robustness. Deep learning can self-study according to data set, and has a strong ability to express feature. Therefore, a new broccoli seedlings detection approach based on Faster R-CNN model was proposed. Data acquisition was the first step to build deep learning model, and the diversity of data can improve the generalization ability of the model. According to the characteristics of field environment, broccoli seedlings images with different light intensities, different ground moisture contents and different weed densities were collected. The sample size was expanded by images rotation and noise enhancement, and data set was transformed as PASCAL VOC format. And then the Faster R-CNN model was trained by using data set. Contrast experiment was designed on ResNet101, ResNet50 and VGG16 networks. The results showed that ResNet101 network with the deepest network layer and smaller parameter space was the best feature extraction network. The average detection accuracy was 90.89%, and the average time-consuming was 249ms. Based on that, the network super-parameters were optimized and the average accuracy of model detection reached 91.73%, when Dropout value was 0.6. The results showed that this approach can effectively detect broccoli seedlings in agricultural natural environment, and provided a hopeful solution for crop detection in the field of agriculture.

Abstract:The 3D structure reconstruction of plants is one of the important methods to realize the no-destructive measurement of plant morphological structure. Consumer depth cameras are widely used to acquire 3D spatial information because of their advantages of noncontact, quick acquisition of data and low cost. In 3D reconstruction, feature points were usually extracted from the point cloud, then paired with feature points, and the registration matrix T was calculated. However, it was difficult to extract the characteristic points of plants because of their slender body. According to the need of plant phenotypic analysis for 3D reconstruction and aiming at the problem that it was difficult to extract plant feature points which resulted in a bad 3D reconstruction, a 3D reconstruction method based on depth camera was proposed. Firstly, the depth camera was calibrated internally and the depth value distortion was corrected by which the accurate depth value can be obtained. Then the relative position of the camera and the turntable were fixed, and the matrix T corresponding to a fixed angle θ of turntable was accurately calculated. The matrix T was calculated in the coordinate space of the current depth camera with the help of a chessboard. After obtaining the matrix T, the turntable was rotated at an interval of θ to get a series of point clouds which were registered as a whole one with the help of transformation matrix T to complete 3D reconstruction. By comparing the reconstruction results of commercial software Skanect, this method needs only one registration, and has higher reductive degree, better efficiency and robustness, which meets the needs of plant morphology measurement.

Abstract:The characteristic parameters of light response can indicate the process of photosynthesis, capacity of photosynthesis, and response of adversity stress in crops. In order to explore the feasibility of using cellphone photos to predict the light response characteristic parameters of maize, canopy images at the big flare stage of the drip irrigation maize under different nitrogen levels were obtained by the selfdeveloped portable image acquisition device. Feature parameters were extracted from the canopy image, and the photosynthetic physiological characteristics parameters were calculated, such as apparent quantum efficiency (α), dark respiration rate (Rd), light compensation point (LCP) and maximum net photosynthesis rate (Pnmax). A normalized canopy cover factor (CC) was highly correlated with the light response characteristic parameters, as an independent variable was used to predict these parameters. The optimal model was selected according to the model evaluation indicators such as R2, RMSE and nRMSE. The results showed that the optimal model of CC and α was the rational function model, the optimal model of Pnmax was the power function model, the optimal model of LCP was the exponential function model and the optimal model of Rd was the quadratic polynomial model. The R2 values of each model were greater than 0.876, the values of RMSE were between 0.002μmol/(m2·s) and 3.673μmol/(m2·s), and the nRMSE was no more than 9.071%. Meanwhile, the R2 values of each model validation set were greater than 0.833, the RMSE values were less than 5.989μmol/(m2·s), and the nRMSE values were no more than 9.659%. Combining the digital image feature parameters with the maize light response curve characteristic parameters method, it was recommended to quickly acquire characteristic parameters of maize light response curve, which provided a theoretical basis for the light response.

Abstract:Dynamic monitoring of crop growth and accurate estimation of crop yield can provide effective support for agricultural operators’ field management and national food policy formulation. In order to improve the estimation accuracy of maize yield, a study was carried out in central plain of Hebei Province, including Baoding City, Shijiazhuang City, Cangzhou City, Hengshui City and Langfang City, from 2010 to 2018. The experiment was characterized by remotely sensed vegetation temperature condition index (VTCI) and Savitzky-Golay filtered leaf area index (LAI), which were closely related to maize growth and yield. Because the effects of water stress on maize yield at different growth stages were different, the weights of VTCI and LAI in the main growth stages (seedling-jointing, jointing-booting, booting-milking, milking-mature) of maize were determined by using the random forest regression method. The results showed that the weights based on the random forest regression were consistent with the actual growth of maize. Based on the determined weights, the weighted VTCI and LAI at the main growth stages of maize in each county (district) were calculated, and the univariate and bivariate estimation models of weighted VTCI and LAI with maize yield in 2010—2016 (except 2012) were constructed. The results showed that the accuracy of the bivariate estimation model (R2=0.303) was higher than that of the univariate estimation models, and the bivariate model reached a very significant level (P<0.001), indicating that maize yield was related to VTCI and LAI. In summary, the bivariate estimation model based on the random forest regression had the highest accuracy. The bivariate estimation model based on the random forest regression was used to estimate the maize yield in each county (district) of the study area in 2012. The results showed that the average relative error between estimated yield and actual yield of 53 counties (districts) was 985%, and that of 31 counties (districts) were below 10%, 7 counties (districts) were between 10% and 15%, 15 counties (districts) were more than 15% and the root mean square error was 824.77kg/hm2. In order to further verify the accuracy of the bivariate estimation model, a linear regression analysis model between actual yield and estimated yield of maize in 2012 was established. It could be seen that there was a significant positive correlation between estimated yield and actual yield (P<0.001) and R2 reached 0.540, further indicating that the accuracy of the bivariate estimation model based on random forest regression was high. The bivariate estimation model based on the random forest regression was used to estimate the yield of maize in the region from 2010 to 2018. The results showed that the spatial distribution of maize yield was the highest in the western region of the plain, the next was in the north and south regions, and the lowest was in the eastern region. The distribution in time was characterized by a tendency to decrease first in the fluctuations and then increase. This was consistent with the actual spatial and temporal distribution characteristics of maize yield. The research result can provide reference for maize growth monitoring and yield estimation.

Abstract:Rapid acquisition of soil moisture content (SMC) in crop root zone is the key to drought supervision and precision irrigation. The relationship between the unmanned aerial vehicle (UAV) multispectral remote sensing and SMC was mainly studied based on the field maize data of experimental station in Zhaojun Town, Dalate Qi, Inner Mongolia. The canopy images of field maize with five irrigation treatments were obtained at different growth stages (vegetative stage, reproductive stage and maturation stage) through the six-rotor UAV equipped with 5-band multispectral camera, and the SMC values at corresponding time was acquired by drying method on the field at five soil depth (10cm, 20cm, 30cm, 45cm and 60cm). Then the spectral reflectance of field maize canopy was extracted to calculate a number of vegetation indexes (VIs). Firstly, data was adopted to analyze the grey relationships between SMC and the selected typical VIs，and the selected typical VIs were used to determine the sensitivity of different VIs to SMC at different growth stages. Secondly, machine learning models of Cubist, back propagation neural network (BPNN) and support vector machine regression (SVR) were constructed and verified. The result showed that the three machine learning models showed good performance on modeling and prediction at different growth stages. The effectiveness of the SVR model was optimal among the three machine methods. The effect of the BPNN model followed, and the Cubist model was relatively the worst. The optimal model was the SVR model at M stage, the modeling R2 and validation R2 for the SVR model were 0.851 and 0.875, and the root mean square error (RMSE) both were 0.7%, and the normalized root mean square error (nRMSE) were 8.17% and 8.32%, respectively. The inversion accuracy of the SVR model at R stage performed badly, the modeling R2 and validation R2 for the SVR model were 0.619 and 0.517, respectively. The research result was of great significance to monitor the soil moisture content in root area of crops and meaningful to precision irrigation.

Abstract:Baotou is a typical semi-arid city in Northwest China. The hierarchical ecological network model was used to construct the hierarchical ecological network of Baotou City. Based on the complex network theory, the static characteristic index and spatial robustness index were calculated, and the topological structure of the complex hierarchical ecological network was analyzed. The results showed that the first, second and third ecological sources and the first, second and third ecological corridors were extracted by using the hierarchical ecological network model, and the important ecological nodes were identified. The number of ecological sources in the first, second and third layers was 8, 31 and 123, the number of ecological corridors was 8, 35 and 151, and the number of important ecological nodes was 7, 28 and 47, respectively. The first layer of ecological network had the lowest connectivity and two cores. Its structure was simple but its importance was the highest. The stability of the first layer of ecological network affected the stability of the whole region’s hierarchical ecological network. The second layer of ecological network can increase the small-scale ecological stability by increasing the ecological nodes with low connectivity, and had no obvious effect on the stability improvement of the largescale ecological network. The third layer had four cores, and the highest connectivity structure of the ecological network was complex. Malicious attacks were more destructive than random attacks. The number of source nodes in the second layer and the third layer ecological network was large, but the proportion of lowlevel source sites was high, and the antiattack ability and recovery ability of the network were not obviously enhanced.

Abstract:The cultivated land quality grading results are an important reference for the implementation of the trinity protection of cultivated land quantity, quality and ecology. Crop production potential index is one of the most important parameters in the evaluation of cultivated land quality, and its accuracy determines the scientific nature of the survey results of cultivated land quality grades in China. By using the method of geodetector, a total of 70 counties, including Ping’an county and its surrounding counties were used as research objects to detect the interpretation of production potential index by different stratification methods of topography and meteorological factors, and revise the production potential index of appointment crop. The key results were as follows: in the study area, the factors that significantly affected the crop production potential index were altitude and annual average rainfall;the stratification method of altitude with the highest explanatory power for crop light temperature production potential index was based on 1100m, and 200m as interval;the stratification method of annual average rainfall with the highest explanatory power for crop light temperature production potential index was based on 0mm, and 100mm as interval;for the climate production potential index, the stratification method of altitude with the highest explanatory power was based on 1100m, and 200m as interval, and the stratification method of annual average rainfall was based on 25mm, and 50mm as interval. According to the correction result of Ping’an county, the crop light temperature production potential index was reduced to a different extent compared with the light temperature production potential index used in cultivated land quality grade survey and evaluation;while the climate production potential index was generally rose. Using the model proposed, natural grade of nonirrigated cultivated land was rose overall, but natural grade of irrigated cultivated land was reduced in different extents.

Abstract:Based on the high-throughput DNA sequencing of Illumina，the microbial community composition of the compost ofmushroom residue added with cow dung and turf as the nitrogen source was entirely clarified，respectively. The results showed that the biodiversity of organic manure produced by “cow dung + mushroom residue” was higher than that of “turf + mushroom residue”, and the fungal difference was greater than that of bacteria;compared with the compost of “turf + mushroom residue”, the compost of “cow dung + mushroom residue” had 10 dominant bacteria and six dominant fungi at genus level, at the same time, the compost of “turf + mushroom residue” had 14 dominant genus and four dominant fungal genus relative to “cattle manure + fungus”. Therefore, the microbial communities had no significant difference between two formula composts. At the same time, it was found that a variety of functional bacteria with agricultural value can provide a scientific basis for the development and utilization of functional microorganisms in the future，such as Chaetomium. In addition, some potential hazard factors, such as Aspergillus_flavus and Aspergillus_subversicolor were found to be highly abundant in the “cow dung + mushroom residue” organic fertilizer, which produced the toxin was likely to cause crop pollution. Agricultural producers and related management departments should pay attention to the risks.

Abstract:Observing soil erosion process at fine spatial and temporal scale is of great significance to the study of soil erosion mechanism. A digital close range photogrammetric observation system based on wireless networking technique was explored and established. The evolution of soil surface topography was dynamically monitored by instantaneous image acquisition at different time intervals during ongoing rainfall. Noises on the images such as raindrops was removed by K-means clustering, digital point clouds were calculated and digital elevation model (DEM) was then generated. The results showed that the measurement precision of the established system could reach a sub-millimeter level, and the minimum measurement error was 0.0062mm. The maximum relative error between the measured value and the actual value was -2.9683%. According to the experimental observations, the average relative error of soil loss was -1.73%, and the accuracy of single observation was up to 99.26%. The established digital photogrammetric observation system could accurately calculate the digital point cloud from the underlying surface with 1min time interval and 2mm spatial resolution. The observation methods explored provided a reliable way to monitor soil erosion processes, especially under rainfall conditions, which was of great importance in understanding soil erosion mechanisms.

Abstract:It is significant to explore planting alfalfa on process of the water consumption and salt changes in fields. Taking alfalfa field as the research object and the corn field as the control, the variation of leakage, groundwater recharge, evaporation and transpiration in fields of alfalfa was analyzed. Stable hydrogen and oxygen isotope was used to analyze of the contribution rate of each potential water source, and the changes of salt in the soil was analyzed. The results showed that the total water consumption of alfalfa fields was increased by 20.17%, evapotranspiration ratio was decreased by 66.64% on average. among which the evaporation was decreased by 6.21%, the transpiration rate was increased by 35.80%, the variation of soil water storage was decreased by 8.08%, the leakage was reduced by 39.68% and the supply of groundwater to crops was increased by 153.45%. Relative to corn field, the change of soil volumetric water content was divided into severe fluctuation phase and linear decline phase in 0~100cm soil layers during the growing period. In July, alfalfa field change of soil volume and water content in 0~60cm presented a “U” shape, and the change of soil water content in 0~60cm soil of corn field showed type of “V”. The average soil moisture of 0~30cm in alfalfa field was more evenly distributed than that in corn field during the growing period. There was no clear bias in the absorption, utilization of soil water, irrigation water and groundwater in alfalfa field. However, the water use of maize farmland was biased, and the soil water in soil layer of 0~40cm was mainly used in each potential water sources. By studying soil water in soil layer of 0~100cm at different times, it was flexible to use soil water in a certain soil layer of 0~40cm in the different periods of alfalfa farmland. The corn farmland mainly used water in 30~40cm soil. During the growing period, the average desalting rates of 0~100cm in alfalfa field and corn field were 53.90% and 12.43%, respectively. The absolute difference values of soil salt were 0~0.06mS/cm and 0~0.13mS/cm of soil conductivity in 10~30cm and 30~60cm in the alfalfa field and corn field respectively. The soil conductivity of 10~60cm in the alfalfa field was relatively concentrated and more evenly distributed compared with the corn field. In May, except for 0~10cm and 30~40cm soil layers of the alfalfa field were in a state of salt accumulation and the average rate of change of soil storage salt was smaller than that of corn farmland. From June to August, the soil conductivity of 0~100cm in alfalfa field was larger than that in corn farmland, which was in the state of salt accumulation. In September, the overall soil salinity of different soil layers in the alfalfa field was in a desalted state, and the maximum salt storage rate of the soil was -15.31%.As the depth increase, the change of soil salinity was increased first, and then tended to be stable. However, the overall soil salinity of the corn field was in a salt accumulation state. The change rate of soil salinity was the largest in 80~100cm soil. Therefore, replanting alfalfa was beneficial to enhancing the groundwater use, reducing evapotranspiration ratio, and inhibiting soil salinity. Changing and increasing forage yield (feeding) and developing alfalfa planting was beneficial to the local salinization of fields.

Abstract:In order to investigate the prolonged actions of biochar on soil fertility and soybean yield in sloping farm land of the black soil region of Northeast China, an experiment about the prolonged actions of biochar in sloping farm land with three typical slope gradients was conducted in 2016—2018. The prolonged affects of biochar on soil agglomeration and its stability, soil nutrients, soybean yield and its components were analyzed, and the soybean yield was predicted based on an improved grey theory prediction model. And then the affecting period of biochar on yield increasing after onetime application was clarified. The results showed that the contents of soil aggregates with diameter of d<0.25mm and d>0.25mmwere significantly decreased and increased, respectively. The application of biochar made the waterstable aggregate content ratio R0.25, the average mass diameter (MWD) and the geometric mean diameter (GMD) all increased and the soil unstable group LT grain index (ELT) decreased, that was the stability of soil aggregates was decreased with the increase of land slope gradients and prolonged period after biochar application. Biochar made the pH value, ammonium nitrogen, available potassium and organic matter content increased significantly(P<0.05), the highest increasing rate of them were 17.88%, 27.23%, 20.31% and 17.51%, and the soil nutrient level was risen, and soil fertility was improved after biochar application, and the effect of them was negatively correlated with the years of biochar application. However, biochar had no significant effect on available pH contents. After applying biochar, the number of pods and grains for per plant, the quality of 100 grains, and yield were significantly increased (P<0.05), and the yield was increased by 26.29%. The bigger the land slop gradients and the longer the biochar applying were, the smaller the increasing amplitude of each index was. The order of the influence degree of various factors on soybean yield from big to small was biochar application, slope gradients and years after biochar application. The improved multivariate grey model had higher precision of yield prediction, and the effective time of biochar for soybean yield increase should be 5~6 years after biochar application. The results could provide a theoretical basis for the application of biochar in the black soil region of Northeast China.

Abstract:In order to study the effects of the compound microbial organic fertilizer on photosynthetic characteristics and yield of rice under watersaving irrigation conditions in cold region and black glebe, experiment with four compound microbial organic fertilizer application levels, which were 20kg/hm2(OF20),40kg/hm2(OF40), 60kg/hm2 (OF60) and 80kg/hm2(OF80) were carried out under the water-saving irrigation regime, meanwhile the inorganic fertilizer was taken as control treatment (CK). The photosynthetic characteristics and yield were studied. The results demonstrated that the net photosynthetic rate (Pn), the maximum photochemical quantum efficiency (Fv/Fm), the reaction center potential activity (Fv/Fo) and the excitation energy capture efficiency (F′v/F′m) were increased firstly and then decreased with the increase of compound microbial organ fertilizer at each stage, so did the actual photochemical quantum efficiency (ΦPSⅡ) and photochemical fluorescence quenching coefficient (qP) at heading and milky stage, and approaching the best values in OF60 plot. However, the stomatal limit value (Ls) was decreased firstly and then increased with the increase of compound microbial organic fertilizer, which was less than CK. Across all treatments, for the nonphotochemical quenching coefficient (qN), no significant difference was found at 5% level. Among the different treatments, the highest yield was obtained in OF60 plot as well as the rice quality was better. Therefore, under OF60 regime was the best. It could provide a theoretical basis and reference for the application compound microbial organic fertilizer under watersaving irrigation conditions in cold region and black glebe.

Abstract:A two-year field experiment was conducted to investigate soil electric conductivity (EC1∶5), soil pH value, and soil water repellency (SWR) in response to mulching method (M1: fully mulched, M2: partially mulched) and dripped irrigation frequency with brackish saline water in the Hetao Irrigation District under arid growing conditions. SWR was assessed by using the water drop penetration time (WDPT) method, and soilwater repellency characteristic curves (SWRCC) were built. Results demonstrated that SWR and EC1∶5 showed a significant positive correlation in mulched drip irrigated saline-alkali field;while it was not so obvious between SWR and soil pH value. Under the experiment condition with weak alkaline and brackish irrigation water, WDPTs of the soil near drip emitters were decreased on the 7th day after each drip irrigation at low irrigation frequency;whereas, WDPTs of the soil away from drip emitters were increased on the 7th day after a single irrigation. WDPTs were overall decreased after high frequency irrigation (once every three days). SWRCC in mulched drip irrigated saline-alkali soil can be well fitted by Gaussian and Lorentzian equations. The SWRCC curves showed that drip irrigation showed no effect (P<0.05) on θm (the volumetric soil moisture when WDPT was maximum), whereas significantly changed θc (the volumetric soil moisture when WDPT was less than 5s).Lorentzian equations showed better performance for SWRCC regression than Gaussian equations, and θm and θc can be obtained from Lorentzian curve. The research result can provide assistance for utilization of drip irrigation with brackish saline water and water repellent soil.

Abstract:By analyzing the effects of different straw mulching amounts and tillage methods on the soil porosity, soil water retention property, soil water supply capacity and soil water effectiveness in 0~20cm, 20~40cm and 40~60cm soil layers, the mechanism of straw mulching and tillage methods on soil water characteristics in black soil region was revealed. The result showed that soil water retention property, soil water supply capacity and soil water effectiveness were closely related to soil porosity. Under conventional tillage treatment, the soil total porosity, soil capillary porosity, soil water content under the same soil water suction, specific water capacity and available water content under straw mulching treatment were higher than those under bare soil in 0~20cm, 20~40cm and 40~60cm soil layers. Under straw mulching treatment, the soil total porosity, soil capillary porosity, soil water content under the same soil water suction, specific water capacity and available water content under no-tillage treatment were higher than those under conventional tillage treatment in 0~20cm, 20~40cm and 40~60cm soil layers. No-tillage with straw mulching treatment affected soil porosity, soil water retention property, soil water supply capacity and soil water effectiveness. Under no-tillage treatment, soil total porosity, soil capillary porosity, soil water content under the same soil water suction, specific water capacity and available water content were increased with the increase of straw mulching. Soil porosity, soil water retention property and soil water supply capacity were decreased gradually with soil depth. The most suitable straw mulching and tillage method in the study area was no-tillage with 150% straw mulching.

Abstract:Diglyceride borate was successfully prepared from boric acid and glycerol by clean and efficient microwave esterification. Then glycerol propylene borate was synthesized successfully from glycerol borate and acryloyl chloride. Boron sustainedrelease super absorbent resin with hydroxypropyl methyl cellulose (HPMC) as the framework was successfully prepared using propylene glycerol borate as the functional monomer containing boron. At the same time, the water absorption ratio, water absorption rate, water holding capacity, structure and morphology of the product were characterized. From the results of infrared spectra, it can be seen that glycerol propylene borate with double bond structure was successfully prepared and boroncontaining super absorbent resin was successfully synthesized by graft copolymerization. The results showed that with the increase of boron-containing functional monomers, the absorption ratio of boroncontaining HPMC superabsorbent resin was decreased gradually. When the addition of boroncontaining functional monomers was 1% of the mass of acrylic acid, the water absorption ratio of HPMC boroncontaining super absorbent resin was 344.06g/g and the salt absorption ratio was 44.71g/g. When the amount of boroncontaining functional monomers was 5% of the mass of acrylic acid, the water absorption ratio of HPMC boron-containing super absorbent resin was decreased to 213.69g/g and the salt absorption ratio was decreased to 26.03g/g. The super absorbent resin had good water retention and could hold water for more than 72h at 35℃. The super absorbent resin had good water retention. The water retention rate could still reach 23.46% after 72h of water absorption to saturation at 35℃. The super absorbent resin had good reusability. After 6 times of reuse, the repetitive absorbent water could still reach more than 60% and the repetitive salt absorption rate could still reach more than 40%. The super absorbent resin had good sustained-release property of boron, and it could sustainably release boron in deionized water for 10d. The sustained release amount of boron reached 182.77μg. It could sustainably release boron in seedling matrix for more than 25d. When the addition amount was 0.5% of the quality of seedling matrix, boron leaching from mixed substrates was 0.80μg/g more than that from common substrates. In addition, HPMC boron-containing super absorbent resin also had good thermal stability, and its morphological characteristics were conducive to promoting the absorption of liquids.

Abstract:Fresh beef is more expensive than frozen-thawed beef for its good quality and taste. Some unscrupulous traders labeled frozen-thawed beef as fresh beef for sale. The feasibility of using ultrasonic imaging technology to analyze and identify fresh and frozen-thawed beef was studied. Firstly, the texture, microstructure and some physical and chemical indexes of the fresh and frozen-thawed beef were collected to analyze their differences. Secondly, a total of 60 ultrasound images of fresh and frozenthawed beef were collected by ultrasound imaging system. Twenty common texture characteristic values defined by grey level cooccurrence matrix were collected. Then, principal component analysis (PCA) for data dimension reduction was used, and linear discriminant analysis (LDA) and support vector machine (SVM) were used to discriminate the samples. The result showed that there were significant differences (P＜0.01) in texture index, L* and cooking loss between fresh and frozenthawed beef. These differences combined with microstructural images showed that the tissue structure of frozen-thawed beef was damaged and the internal texture of frozen-thawed beef was poor. The ultrasound images of fresh and frozen-thawed beef showed significant differences, which could be well explained by the above studies. The texture features of the ultrasound image of fresh and frozenthawed beef were significantly different (P＜0.01).Both LDA and SVM had good discriminant results, especially LDA. When principal component signals were five, the precision rates of train set and test set of LDA were both 100%. The results showed that it was feasible to distinguish the fresh and frozen-thawed beef by using ultrasound imaging technology.

Abstract:Aiming to explore a new way to reduce the allergenicity of egg allergens. The influence of different microwave treatments on egg white was demonstrated by SDS-PAGE, circular dichroism spectroscopy, ultraviolet spectroscopy, exogenous fluorescence spectroscopy and indirect ELISA to analyze molecular weight changes, secondary structure, tertiary structure, hydrophobic changes and changes in IgG binding capacity, respectively. Results showed that the microwave treatment reduced the potential allergenicity of egg white proteins, and the IgG binding capacity of egg white was the lowest when it was treated under 400W for 30s. The secondary and tertiary structure of protein were obviously changed by microwave treatment. Under 80W, the structure of egg white proteins was folded, however, when treatment time was more than 30s, the structure of egg white proteins was unfolded again. When the power of microwave treatment was increased to 640W, part of egg white proteins was aggregated. Changes in the structure could induce changes in potential allergenicity of egg white proteins, however, the relationship of structure and potential allergenicity of egg white proteins under microwave treatment should be further analyzed.

Abstract:In order to solve the problem of long drying time and high breakage rate of Poria cocos cubes during industrial drying process, the infrared drying technology of carbon fibers was combined with the vacuum pulsating drying technology, and a pulsed vacuum drying equipment was designed based on characteristic carbon fibers infrared plate. The pilot-scale drying equipment consisted of drying chamber, vacuum system, single-layer drying unit and control system. For convenience of analysis, the actual vacuum pulsed process was divided into four stages: vacuum stage, vacuum holding stage, breaking stage and atmospheric pressure holding stage. The touch screen was connected with the slave controllers by RS232/485 to form a network, and communicated with each other through the MODBUS protocol. Based on the monitoring of vacuum degree in drying chamber, the continuous conversion from vacuum to atmospheric pressure in drying chamber was realized by time sequence control. Based on the monitoring of the temperature of carbon fiber infrared board and the feedback of the drying temperature, the drying temperature can be effectively controlled. Poria cocos cubes with size of 12mm×12mm×12mm was used as experimental material to verify the results. The results showed that the design and control scheme of the drying equipment were reliable, and the continuous pulsation of vacuumatmospheric pressure can be realized, and the material can be dried effectively. The shortest drying time was about 480min when the vacuum duration time and atmospheric pressure duration time were 5min and 4min, respectively. Compared with continuous hot air drying, the breakage rate of pulsed vacuum drying was obviously reduced. The drying equipments and results can be applied to the drying of Poria cocos cubes, which can provide theoretical basis for the combined application of infrared drying technology and pulsed vacuum drying technology.

Abstract:The soluble dietary fiber （SDF） was extracted after pretreatment of bean dregs by irradiation technology. The microstructure, crystallinity and basic structure were observed by scanning electron microscopy, X-ray diffraction and infrared spectroscopy to analyze the effects of irradiation technology for SDF. The yield and water holding capacity of SDF, expansion force, cation exchange capacity, combined hydraulic power, α-glucosidase activity and antioxidant activity were obtained to explore the effect of irradiation technology on its physical and chemical properties. The results showed that the microstructure, the crystallinity, the physical and chemical properties of irradiated SDF were significantly improved compared with the unirradiated bean dreg SDF. The microstructure of irradiated SDF was finer and fluffy, and the crystallinity was improved by 3.78 percentage points. And the extraction rate was improved from 2.36% to 4.15%, the expansion force was increased from 4.24mL/g to 5.36mL/g, the combined hydraulic power was increased from 2.93g/g to 3.21g/g, the water holding capacity was increased by 0.52g/g, the antioxidant capacity was increased by 1.23mmol/g, cation exchange capacity and α-glucosidase activity were also significantly increased. Irradiation affected the physical and chemical properties of the bean dregs by changing the structure of the SDF. This experiment provided a theoretical basis for the study of the mechanism of irradiation on bean dregs SDF and the technology of bean dregs storage, and also provided a method for the extraction of soluble dietary fiber.

Abstract:To ensure safe operation, enhance productivity and improve operation comfort for the tractors in hill area, a dual-closed-loop-PID-based active attitude adjustment system was designed. Based on the special requirements for operation in mountainous regions, an active attitude adjustment system was designed, which included pose regulation mechanism, hydraulic actuation system and the corresponding control system. Then the system dynamic model was proposed along with the dual-closed-loop PID algorithm, which were verified numerically. Numerous experiments were conducted on a tractor system designed by Shandong Wuzheng Group. The experimental results showed that the proposed active pose regulator can achieve regaining of horizontal pose in 7.5s with a maximum angular error of 0.5° and the difference of the absolute rotation angle of both rear wheel rotary mechanism was in the range of ±1°, which satisfied the application requirement. Additionally, when the tractor system was operated at firstgear speed (1.98km/h) on slopes with relatively large variation in height, the slope angle of the tractor system can be conttrolled with in ±3°, and the absolute difference of the sway angle of the wheels on both sides were within ±5°. In conclusion, the proposed active pose regulator system design can adapt to the harsh application requirement.

Abstract:A practical output-feedback control strategy using saturated super-twisting algorithm was proposed for the modelfree vibration control problem of vehicle active suspension systems. Sensor noises and perturbed unknown dynamics were considered in the control design, and a higher order sliding mode observer was employed to estimate the total disturbance term and system states. To achieve second-order sliding mode using continuous control on the chosen sliding surface in finite time, a novel saturated super-twisting algorithm was used to design the closedloop regulator. The exact feedback linearization was no longer required, and only one sensor was used to measure the output variable so as to decrease the control cost and complexity in the proposed control scheme. The asymptotical stability and boundedness of the system could be guaranteed by tuning the controller gains. Finally, the experimental validation based on hardware-in-loop test was implemented to demonstrate the effectiveness of the proposed method. The simulation and experimental results for different road excitations showed the proposed control could achieve better ride comfort than the traditional proportiondifferentiation (PD) and linear quadratic regulator (LQR) control methods, and the vibration damping performance was accomplished with less control chattering. The frequency response results showed that the maximum acceleration gain of passive control was 44.7dB, and that of the LQR control was 29.4dB, whereas that of the proposed control method was decreased to 13.5dB, thus the ride comfort was significantly improved.

Abstract:A kind of nonlinear double-end fixed trapezoidal beam piezoelectric energy harvester (PEH) was designed to collect the vibration energy in the environment, piezoelectric energy harvester can transform vibration energy to electricity to supply for miniature electronic components. The vibration frequency of vibration sources was mostly below 100Hz in natural environment, in order to reduce the resonant frequency, widen bandwidth and improve output performance of the piezoelectric energy harvester, the non-contact magnetic force was introduced. On the basis of theoretical analysis, Matlab/Simulink simulation model was established and experiment was carried out to compare the resonant frequency, bandwidth and output performance of linear and nonlinear double-end fixed trapezoidal beam piezoelectric energy harvester. Meanwhile, the response of output performance when three parameters (the space d between fixed magnet and mass block magnet, external load resistance R and the external excitation acceleration a) change was studied. The results of simulation and experiment showed that the introduction of non-contact magnetic force can reduce the resonant frequency of the piezoelectric energy harvester by 9Hz, widen its bandwidth by 20% and increase its output power by 7.5%. 

Abstract:There is a wide range of industrial application for the 4-DOF parallel mechanism (PM) which can achieve SCARA type output motion (i.e., three translations and one rotation). However, due to the constraints of kinematic chains, most of them have small rotational capacity and cannot meet the actual demand sometimes. A type of 3T1R PM which can realize full cycle rotary motion was proposed. Firstly, a two-dimensional moving unit which consisted of revolute joint only was constructed. According to the mechanisms and machine theory, modular principle of the pantograph mechanism for scaling two-dimensional planar graph was explained as the mechanism can be divided into three types of modules which were all derived from the two-dimensional moving unit. And then a 3T1R PM with four legs was designed by taking the obtained pantograph mechanisms as sub-chains. Secondly, the structure coupling-reducing optimization design for this PM was performed, whose POC and DOF were unchanged with lower coupling degree (k=1)．Finally, the modeling method and the numerical solutions for forward and inverse position equations of the PM were established based on ordered single-open-chain (SOC) units. The working space and the rotational ability of this parallel mechanism were obtained and the rotational capacity map was drawn by using the inverse position equations. According to the map, the range of workspace that can realize the full rotational capability was selected which can be treated as a theoretical basis for the design and applications for this mechanism.

Abstract:Magnetorheological (MR) valves are widely used in hydraulic systems due to their fast response speed and stable pressure regulation. It is easy to increase the valve dimension size and block the fluid flow channel by changing the valve’s internal structure to improve the pressure drop. The multi-objective optimization of pressure drop and adjustable coefficient of the single coil radial flow MR valve was carried out. A single coil radial flow MR valve with magnetic isolation sleeve was designed. The working principle was expounded, and the mathematical model of pressure drop was also deduced based on Bingham model. Simulation model was established by using the finite element method, and the constraint conditions were established to analyze the influence of the dimension size on shear yield stress and pressure drop. The optimization of geometrical parameters of MR valve was carried out by using ANSYS zero-order and first-order optimization tools. The average magnetic flux density and pressure drop at the effective damping gap were simulated and compared. The pressure drop performance of MR valve was tested on the dynamic performance test rig. The experimental results showed that the pressure drop of the MR valve before optimization was 1.84MPa at the applied current of 1.8A, while after optimization was 2.58MPa, the increment was 40.22%. At the same time, the adjustable coefficient of pressure drop was 7.94 before optimization and 10.07 after optimization, which was increased by 26.83%. Moreover, the load cases had no influence on the pressure drop.