Abstract:The performance simulation of a small-scale corn harvester for hilly area using ADAMS was presented. The 3-D parametric model of the corn harvester was established with Pro/E. Then, the model was put into UG to conduct Boolean operation to reduce the amount of constrains. Consequently, the model was simplified and workload was cut down. The preprocessed model was import to the ADAMS environment to build the virtual prototype model. A comparison between the simulation and the road test verified that the virtual prototype model met the requirements of virtual experiment. The extreme roll angle and maximum climbing slope were obtained by ADAMS simulation to avoid hazardous vehicle test on sloping area. In addition, the terrain trafficability of the corn harvester on the weak ground was analyzed with cone index.

Abstract:Corn harvester divider has a direct impact on maize seedling conveying, it is an important factor to influence the harvester operation. Corn straw physical property and max transverse offset distance were measured by experiment in corn filed and max offset angle was accounted. The relation equation between divider width and corn plant bending property was acquired by data process. An important factor on effecting dividing and conveying plants was found, that was the bending property of corn plants. A basis was provided for the divider design. It is interpreted in theory that the higher divider positioned the slighter the plants damaged. The difference between bending strength of different regional corn plants was compared and analyzed. In the optimum harvest period, corn plants resistance to bending in Shandong Province and Beijing regional was stronger than it in Jilin Province.

Abstract:Principle of double helix mechanism was analyzed. Through orthogonal tests, the prominent elements were defined. Though regression tests, the optimization parameters of prominent elements were calculated as below: helix-dragon rotating speed of 319r/min, distance between up and down helix dragons of 575mm,distance between helix top and cutting knife of 10mm, lift angle of helix dragon of 30°. And the transporting index reached to 89.8, which could meet the demand of transporting long-straws.

Abstract:Corn husker is one of important parts of the corn combine harvester, it would affect the seed loosen ratio, the seed broken ratio and the bract no-husking ratio. Aimed to the problems of bad exchange, the universal corn husker was designed, which could exchange the roller type, adjust the rotate speed, and adjust the angle between the axis of husking roller and horizontal direction. Taking Xianyu 335 as an example, three factors were chosen as the husking rollers, the speed of the husking rollers and the angle, and each factor had three levels. The test data analysis showed that the best combination plan could be found out, the husking roller was alternating arrangement of the spiral rubber roller and spiral rubber roller with convex edge, the husking roller speed was 350r/min, and the angle was 30°.

Abstract:Offset digging shovel and three-roller mechanism were developed to realize the complete working process of root stubble harvest, which included root stubble digging, picking up, stubble-soil separating and root stubble paving. Structural and kinematic parameters of a root stubble harvesting machine were determined by analyzing digging characteristics of the shovel and kinematics of the three-roller mechanism. In field tests, the offset digging shovel demonstrated competency of digging, and the three-roller mechanism showed capability of picking up, separating and paving. The stubble digging, picking up and paving rate of stubble harvest machine were more than 90%. Its work met the requirements of design and application.

Abstract:In order to harvest the serious lodging sugarcane, the whole stalk sugarcane harvester which was hung the right side of tractor was designed. Separating, cutting, conveying and gathering were implemented by the harvester, and productivity efficiency was 0.2hm2/h and walking forward speed was about 0.5m/s. The field experiment showed that the cut sugarcane ratoon rate was 11.3%, skin damage and broken cane were existed, and the broken rate was 33.33%.

Abstract:The crops with thick-tall stem are difficult to be harvested by machine due to hardness and stiffness of the stem. In the present study, a dynamic simulation model of Arundo donax L. penetration was established by finite element numerical simulation technology, of which based on a general rotary-chain cutter for thick-tall stem. The results showed that the optimized matching parameters of cutting process for cutting and feeding speed were 2.80m/s and 1.00m/s, respectively. The optimal correction factor of cutting process for Arundo donax L. was 1.22. The study provided a methodological basis for the analysis of cutting process for thick-tall stems.

Abstract:In order to analyze the rate of unthreshing and cleaning loss of small combine harvester with double axial cylinder, double axial cylinder was designed. Parameters of this small combine harvester’s structure were analyzed. The experiment showed that the unthreshing rate of small combine harvester with double axial cylinder was nearly 0, rate of cleaning loss reduce by 39% compared with the single axial cylinder. Small combine with double axial cylinder effectively solves the problem of separating and threshing.

Abstract:Aiming at the threshing loss during super-rice and round-grained rice harvesting, the head-feed coaxial differential rotor was designed. The threshing test between the different speed and single speed rotor was preceded. The 3-D image and mathematical modal were built by Matlab on the basis of measured data of mixture and its compositions. The results showed that the 0.06% grains were not threshed clearly by differential rotor, which reduced by 61.25% compared to the single speed one. The 3-D image showed that uniform distribution of mixture and its compositions along on sieve was better than the single speed one. The coaxial differential threshing rotor set the benefit of high-speed and low-speed in one, which can solve the problem of the threshing loss during super-rice and round-grained harvesting and reduce the loss rate, the damage rate and impurity loss.

Abstract:Taking the horizontal axial threshing unit of the miniature wheat combine for hills and mountains as the research object, the speed of the roller, concave gap, and angle of the guide plates were researched in the orthogonal mesh size experiment under the rated capacity feed. The roller speed, concave gap, angle of the guide plates were researched in the regression testing. Then by using the DPS and other software, the statistical analysis of test data was got. The influence curve of the roller speed, the concave gap, the angle of the guide plates, mesh size to the ratio of the long-stem, the grain breakage, entrainment, threshing without a net were obtained. The regression equation was built. The optimum operating point for the mini-combine was the mesh size of 14 mm, the angle of guide plate of 10°, the concave clearance of 16 mm and roller speed of 660 r/min. Accordingly, long-stem rate was 3.1%, impurity rate was 39.5%, entrainment rate was 0.6%, the rate of threshing without a net was 0.01%, and grain breakage rate was 0.01%.

Abstract:Comparative experiments of free grain movement and collision under different drum speeds were carried out by using high-speed video camera on a self-designed axial flow threshing and separating device with nails teeth. The movement discipline of free grain and the movement discipline after the collision of free grain and nail tooth under different drum speeds were obtained. The results showed that the free grains movement speed increased with the increasing of drum speed. Most of the free grains moved in a medium-speed and showed a tendency of accelerating motion after crashed by the nail teeth.

Abstract:Taking a self-developed axial flow threshing and separating device with nails teeth as the research object, the overall process of movement, broken rice spike movement and threshing process as well as the movement process of free kernel were photographed on line in threshing and separating space by using the high-speed photography equipment. Through the slow playing analysis of high-speed video image, it could be concluded that when the rice entered into the threshing and separating space and interweaved together, the valley logistics along the axial spiral surging moved forward under the combined action of the rotary nail teeth and guide plate. The trajectory of broken ear was a parabola and presented to be unstable and fluctuate. Single free kernel without external interference followed approximately a uniform linear motion. Its motion direction formed a certain angle with the drum axis direction.

Abstract:The grain impurity rate of the combine harvester with across axial flow roller was high for the grain surplus could enter into the bin. By measuring the quantity and composition of grain surplus in unit time, the developed re-threshing system could calculate the speed and total amount of the material, and be tested in field. The statistics showed that this system could make the grain surplus amounting to 9%～10% smoothly be collected, transmitted, threshed, then sent into the bin again, which reduce the trash content from 7% to below 2%.

Abstract:Modified k—εturbulent differential equations and discrete phase model of Lagrange in Fluent software were used to simulate grain moving in the separation and cleaning chamber in 4ZTL—1800 grain—wheat combine harvester threshing prior to cutting. The grain trajectories, the laws of grain particles separating and depositing, debris including chaff and short straw being cleaned in the chamber were obtained. Furthermore, the relationships between inlet airflow velocity and grain mass flow respectively and grain cleaning rate were also simulated and analyzed, which are beneficial to increase cleaning rate of grain and to decrease the power consume of the machine.

Abstract:The airflow field was measured and the cleaning test of rice was carried out on the self-developed-air-and-screen cleaning unit. The airflow field was studied by the neural network techniques. Three BP neural network models were developed, which were built between two wind factors and distribution of airflow field, distribution of airflow field and cleaning performance, two wind factors and cleaning performance, respectively. Predict test was carried out with the experimental data. Forecasting results proved the effectiveness of the neural network model.

Abstract:Three degree of freedom hybrid vibration screen was designed to sort granular material based on the theory of parallel mechanism. The vibration screen composited of screen box, vibration motor, motor fixed seat, spring, angle adjusting device, support frame, longitudinal vibration chain, transverse vibration chain and base. The support and excitation function of screen box was separated. The support of screen box was suspension support. The main excitation mechanism was complete decoupling hybrid mechanism 2PRRR—P(2R) which could realize the three dimensional vibration of X, Y and Z of the screen box. Test results showed that the three dimensional vibration of X, Y and Z of the screen box improved the performance of dispersion function by 33.23% on average and the function of leaking screen by 73.55% on average. This vibration screen has the good adaptability to various materials.

Abstract:Numerical simulation method was introduced to study the micro flow field on the adjacent screen layer (0~10mm in height range) of bionic nonsmooth screen, in which the draught angle and surface feature were chosen as factors. Bionic nonsmooth rape cleaning screen was made to compare with the common smooth screen in the field. The result showed that the draught angle basically had no influence on the micro flow field on the adjacent screen layer. The bionic feature would destruct the little vortex among the holes into two smaller vortexes which reduced the contact possibility between tiny rape materials and cleaning screen and lowered the adhesion degree. The result also showed that the bionic convex surface could lower adhesion better than bionic concave surface.

Abstract:Considering that it’s inconvenient to the experiment of measure and control system for combine harvester in the field, design and experiment of intelligent control test-bed for combine harvester was developed. Test-bed could simulate lots of intelligent control arithmetic on the environment of laboratory. Intelligent controller, sound-light alarm equipment, LCD screen, sensor used on speed and losing measuring were integrated on the test-bed, these sensor could collect the data of experiment in time. The test showed that test-bed could make the experiment of intelligent control arithmetic on laboratory, reduce the research cycle of intelligent control device and lay the foundation of intelligent control for combine harvester.

Abstract:Feed rate of combine harvester was affected by many factors and difficult to be detected directly. A hydraulic stepless transmission system of threshing cylinder was designed, and the oil pressure was monitored. The oil pressure was used to represent the feed rate. By the engine bench tests, the relation equation between feed rate and oil pressure was obtained, and the distinguished method of oil pressure and threshing cylinder rotate speed which indicated feed rate was compared. Experiment results showed that the oil pressure could indicate feed rate timely and accurately, oil pressure was linear with the feed rate when the combine harvester was in the stable operation and crop properties were in the same. The threshing cylinder rotate speed could be considered as a constant.

Abstract:A multi-channel vibration system for testing and analysis based on virtual instrument platform were established using the advanced graphical language LabVIEW. The header vibration signal (horizontal, vertical and axial direction) of Lovol combine harvester GN601—CR2Q at different sites under different conditions was measured by using the acceleration sensor. Time domain vibration and frequency domain were analyzed. The results of the header vibration test showed that the main excitation of the vibration sources was header transmission system, the horizontal vibration of header was largest and the largest header vibration position was the header conveyer. The frequency of inertia force of the cutter driving system was 10Hz. The frequency of inertia force of the engine was 30Hz. The natural frequency of the header was 68.8Hz.

Abstract:Different materials, different sizes of load plate grain mass flow sensor and different ranges of grain mass flow sensor elastic component were designed. Experiments were finished in the grain mass flow load simulation test device. The experiment results showed that parameters were closely related with precision. On the basis of this test, the grain flow effect on the measurement accuracy was researched. The experiment results showed the error of this load plate grain mass flow sensor was within 2% during the grain flow rate was 0~2kg/s. When the grain flow rate was more than 2.5kg/s, the error exceeded 5%.

Abstract:A yield monitoring software was developed by VB programming language could be applied to combine harvester based on weighing. The data collected by yield monitor system could be displayed and saved by the software in real time. The software could get the harvesting total mass and the area, and draw the grain flow diagram by computing the grain flow data. It can also convert the latitude and longitude data received from GPS into Gauss coordinate, and then draw GPS locus diagram in rectangular plane coordinate system. Finally, the software can draw the yield map automatically by using the grain flow data and GPS locus data at the same time. During the process of drawing the map, the map will move itself far away from the border of interface to ensure the real time curve displaying normally before the curve arrives the border of interface. After finishing drawing, the map could be dragged in the interface freely to check the whole map. The yield monitor precision was less than 2% in laboratory and less than 3% in field.

Abstract:In order to monitor grain loss of combine harvester real-time during the working process, a grain loss monitoring system was designed. PVDF piezoelectric films were used as the sensitive element, and signal process circuit which is composed of voltage amplifier, band-pass filter, precision full-wave rectification, envelope detector was constructed to measure the grain impact signal. A double-layer vibration isolator was proposed to eliminate the vibration influence of combine harvester. Grain impact performance tests were carried out within the impact velocity of 1.1~2.6m/s，which showed that the peak voltage of the impact signals within 2~4V, and peak voltage increased with increasing impact velocity.Using AT89C52 microcontroller as the core chip, a secondary instrument was developed to acquire the grain impact signal which is output from detecting sensor. Field experimental results showed that the instrument could identify grain impact signal effectively, and the grain separation loss ratio and cleaning loss ratio could be real-time displayed, the system also had the alarm and communication functions.

Abstract:In order to analyze the effect of sensor structure on the character of grain impulse response, 3-D models of grain detecting sensor were established and their vibration modal were simulated by using software SolidWorks. It was found that the dimension of the upper panel was an important factor which influenced the modal nature. With the increasing of upper panel width b , its natural frequency f monotonically increased, and its relative deformation ratio γ quickly decreased at first and then decreased to a constant value gradually. With the increasing of thickness h , monotonic increasing tendency of f and γ was received. Then, experiments were carried out by assembling the sensor on a support stand which fixed on the vibrating cleaning sieve, the results showed that the sensor can identify grain impact signal effectively from vibrating noise. The time band of grain impact signal acquired using sensor with b of 30mm width was less than 2ms which was much small than the signal acquired using sensor with b of 120mm.

Abstract:Multi-sensor signals acquisition and data processing is the basis for combine harvester workflow control and monitoring. In this paper, the multi-hall speed sensor signal acquisition was implemented by timer/counter and standard input/output interface (I/O) in microprocessor C8051F020, and feed quantity sensor data and loss quantity sensor data was received through the serial communication. Microprocessor C8051F020 can process and save data, control the 240×128 dot-matrix LCD that could display the current data and fault alarm, and control speed depend on the results of data processing, then deal with classified faults. The data acquisition could be send and print. The experimental result showed this system worked steadily and reliably, which could realize the integration of combine harvester workflow control and monitoring system, and it could save the production cost and increase efficiency for combine harvester measure and control system.

Abstract:Aiming at the problem of high fault rate and unperceivable working fault, a fault diagnosis alarm system for the combine harvester was introduced. PLC and display were the control terminals in the system. The PLC collected the signals in the operation process such as feed-in screw conveyor, conveying channel, threshing cylinder, transporting auger, cleaning loss and attachment loss, then calculated and treated in the manner of fault diagnosis subroutine based on the trend of the signals. The test showed that the fault diagnosis method could realize the early warning for the combine and improve the working quality and efficiency of combine harvester.

Abstract:In order to meet the need of multi-sensor information collection in the autonomous navigation control system for combine harvester, an information collection control network was designed. A distributed control network with two serial ports and CAN bus was designed. Two serial ports were used to collect the data from the GPS and the inertial sensor. Multi-threading programming technology could satisfy the need of the real time and multi-tasking. The CAN bus communication protocol was designed to make the network ordered and reliable. The experiment results showed that the system worked well and the communication between the sensors to the PC was reliable.

Abstract:For the difficult problem of detecting large curvature path of nature image processing, a double tangent-line detection algorithm for turning radius based on rotation and projection line detection arithmetic was put forward. On the base of kinematics of simplified two-wheel vehicle model, an intelligent controller was constructed for the vision navigation test platform of combine harvester. The controller could select different control mode according to the different path (including straight path and curve path). The tests on road with tag line and in wheat field with curvature cut boundary showed that the double tangent-line detection algorithm was valid to detect turning radius and the system could trace the curvature path whose radius was greater than 10m. During the normal working speed, the maximum error of tracing large curvature path on road was 0.19m and in field the change of harvesting width was within 0.29m. 

Abstract:To increase accuracy and efficiency of terrain labeling in agricultural environment, a method based on Iterative-RELIEF was proposed. In this method, training samples were generated by super-pixel segmentation, and then the feature selection algorithm Iterative-RELIEF output a feature weight vector with its elements representing to which extent the corresponding feature influenced the results of terrain labeling. A large amount of irrelevant features were discarded by setting the feature weight threshold. In the labeling experiment over DARPA datasets, the proposed method not only raised the accuracy of ground labeling and the recall rate of obstacle labeling by 1% and 0.8%, respectively, but reduced the computational complexity of the SVM terrain classifier by about 40%. In the navigation experiment, the method increased the efficiency of the agricultural robot by about 15%. 

Abstract:In research of the optimal walking path and best travel speed of the tangential-axial combine harvester in the field wheat threshing and separating, three typical walking paths of tangential-axial combine harvester which header width was 4.75m were analyzed. It also derived from the point of the minimum consumption of time when combine harvester turned direction at the end of the field. Experiments of the relationship between grain loss rate and the travel speed were conducted, and the mathematical model was established. So were experiments of the relationship between threshing-separating consumption power and the travel speed, and the mathematical model. Based on these experiments and mathematic model, the best travel speed formula was derived. It turned out that rotary walking path should be used to harvest the wheat by the tangential-axial combine harvester. When the harvesting travel speed was less than 1.0 m/s, the equivalent feed rate was less than 7.79kg/s, the total grain loss rate was less than 19.33g/s (that was 0.609%), and the total power consumption of the threshing-separating equipment was less than 83.94kW.

Abstract:According to the characteristics of garlic cultivation and original design experience, the half-feed and self-propelled garlic combine was developed which is suitable for main garlic producing areas in China. The combine body was configured on the side position of the chassis. It employed the chassis of 450 type head-feed rice and wheat combine, and equipped with hydraulic continuously variable transmission system. The main working parts contained the devices for stalk dividing, stalk lifting, stalk clamping and conveying, clod removing, garlic alignment and cutting, as well as the garlic collecting system, etc. To keep the effect and stability of digging, the combine had been utilized the working principle of combining digging and lifting. The combine performance testing could be known as: garlic loss rate was not more than 1.8%, garlic picking broken rate was not more than 2.1%, with soil rate was not more than 12.8%, combine harvester had complied with the design requirements.

Abstract:Motion analysis and experiment of clod cleaning effect were conducted on clod cleaner of 4HLB—2 type peanut combine harvester. Linear velocity and angular velocity of flap plate varied with time according to sinusoidal law. During one clod cleaning cycle, two flapping processes were completed, and the most intense flapping status appeared twice. Clod cleaning effect of the second half of the flapping path was better than that of the first half. The flapping strength of the plates decreased from the ends to the middle, and some of the middle path was viewed as invalid section. Clod cleaning experiment showed that clod cleaning rate was mainly affected by flapping times taken by peanut clusters, and dropped peanut loss was mainly determined by angle amplitude of the flap plates. Higher vibration frequency and smaller angel amplitude were preferred during field working. 

Abstract:The basic structure and work principle of engine-driven constant frequency rectangular pickup baler were introduced. The general structure, pickup, feeding mechanism and pressing mechanism were designed and computed. The result indicated that the baler which could pick up, press and tie grass and crops straw had the characteristics of reasonable structure and high degree of automation. The fully bale rate of the baler was 99.1%，the regular bale rate was 98%，and bale density was 130～230kg/m3.

Abstract:Structure and moving trajectory of reel device which was the key parts of silage harvest machine mower table were analyzed. Guide rail curves of reel device were optimized by using computer aided design software. The tooth shape trajectory was simulated to fit the silage harvester to operate. The wheel speed ratio interval for the silage harvester to work normally was (0.78, ∞). It could provide theoretical reference, improve the working efficiency and enhance the performance of silage harvester.

Abstract:An embedded system for grading of pre-harvest cotton was designed on overall. ARM (TMS320DM365) was regarded as main processor of the embedded terminal, and DSP (TMS320DM6437) was regarded as slave processor. Linux system environment was built on ARM, and video capture and man-machine interaction were executed in parallel. Simulation video flows were captured by camera and decoded in decoder chip (TVP5146). Digital video flows were displayed real-timely on user interaction interface and the video process request was sent to DSP by SPI. After DSP received the request signal during video flows capture synchronously, the current frame was segmented and discriminated by features extraction, and the result was returned to ARM. Field experiment showed that the system could recognize the grades of raw cottons quickly with an accuracy of 90.48%.

Abstract:In order to research cutting performance of cotton stalk for giving technical support and theoretical basis of the development of cotton stalk harvester, a crank-connecting rod cotton stalk cutting test bench was designed which could simulate the cutting harvest of cotton stalk with regardless of row. The feed conveying speed and the cutting speed of cotton stalk were regulated from 0 to 2m/s and the cutting angle was adjusted from 0° to 15°. The working performance of prototype and the cutting properties of cotton stalk were investigated. The results indicated that the peak of cutter resistance increased with the increase of the average cutting speed and the change of average cutting speed had no effect on the power consumption of cutter resistance in a working cycle when the cutting test bench was under no load running. In addition, the peak of cotton stalk cutting force and the power consumption that the unit cotton stalk was cut decreased with the increase of average cutting speed in the process of cutting cotton stalk.

Abstract:Nine sieve matrixes with different sizes and spacing of bionic micro surface-rebuild was fabricated by YAG—M50 laser-marking machine. Surface profile of the samples was analyzed by NT1100 optical profiling system. Double-distilled water and rapeseed oil were chosen as liquid component, with which contact angle of the nine sieve matrixes was obtained by CAM101 contact angle meter. Wettability of the bionic sieve matrix was analyzed with factors of figure size and spacing. The results showed that the spacing between two figures had significant influence on wettability when the figure size was small, while the influence of figure size on wettability was related to the liquid component with the same spacing condition.

Abstract:In order to realize the recognition and harvesting of the similar-color fruits, a spectrum selected method was developed to analyze and verify sensitive bands of cucumber based on statistical variance analysis and artificial neural network. Then the selected spectrum composition was used as reference basis for spectral image acquisition in greenhouse cucumber recognition, and the results of image processing indicated that the images within sensitive bands were captured to cope with the similar-color segmentation problem under complex environment effectively. By comparing the spectral reflectance difference of cucumber plant (fruit，leaf and flower) from visible to infrared region (350~1200nm), sensitive bands of fruit information were obtained by statistical variance analysis. After that, principal component analysis compressed the sensitive bands into several new variables that were the linear combination of original spectral data. In order to set up the three layer verifying model of back propagation artificial neural network (BP—ANN), the first four PCs (principle components) were applied as inputs of BP—ANN, and the values of type of cucumber organs were applied as outputs. In this model, the trained network arrives at a 100% identification rate for 120 training samples as well as a 95% identification rate for 40 test samples. It proved that the selected spectrum composition could better reflect the characteristic difference of cucumber organs.

Abstract:In order to promote the practicality and utilization of harvesting robot, a general clamping mechanism was designed. With the virtual prototype built in ADAMS and ANSYS, the clamping mechanism of the harvesting robot for avoiding fruit injury was discussed. Through the deformation stress analysis of citrus, the impact analysis of picked stress was examined and the structure was optimized. Therefore, the parameters of the structure and the minimum amount of clamping （below 2mm in diameter direction) were validated.

Abstract:A handy harvester for berry was designed, and equations of motion of harvesting device and branches were established. Through simplified and analysis equations, at last, fruit branches movement equation and harvest device horizontal movement equations were obtained. It could locate the best position of operating handle. Excitation frequency was slightly higher than the natural frequency in the harvesting operations. It had smaller vibration intensity on the appropriate excitation frequency, and chose the appropriate operating position which could reduce the operator’s labor intensity.

Abstract:The key technology to improve accuracy and uniformity of variable fertilization lies in reducing the response time and choosing the best control parameters. A bivariate control fertilization sequence decision-making method based on relevance vector machine was presented. The method took into account the interaction among the before-current-after, three adjacent fertilizing rates, the response time and working dead features of active roller length and speed control. An optimal control parameters decision-making was carried out using non-linear programming method. Finally, the problem of small fertilizing rate under big active roller length with small rotational speed was avoided. The impact of the fluted metering roller’s pulsation was reduced. In order to coordinate the limited computation power of the vehicle mounted computer and respond time of bivariate control, relevant vector machine was utilized to achieve a near-optimal real-time computing for fertilization control sequences. Laboratory test results showed that the average error was 4%, which was smaller than the original method, while this method was effective to avoid the extreme case that the motor could not drive the roller shaft with improper parameters. The field test showed this kind of applicator could response to the instruction in time, and it had good accuracy and consistency, which proved its practicality.

Abstract:In order to match the requirements of MQ—600 type air-assisted boom sprayer, the axial fan for air-assisted duct was designed. According to final velocity principle of air-assisted duct on crop canopy, the fan’s air flow, air pressure and the flow velocity and other parameters were determined. The key parameters, such as ratio of axial fan speed, wheel hub ratio, diameter, blade pressure distribution of the whole flow cross-section were calculated. Then, the selection of fan blades, blade chord length of each section was calculated. According to the designed parameters, the physical prototype was built and its performance was studied. The results showed that when the fan speed was under 1473r/min, the outlet wind velocity of the duct was 32.1m/s, and the wind velocity was 8.6m/s at the 0.5m blow the duct, which means the fans met performance requirements. 

Abstract:A comparative puffing experiment on blackcurrant slice between the microwave and microwave-vacuum method was performed. During microwave puffing process, microwave intensity was 20W/g and initial moisture content of blackcurrant slice was 35%. While the initial conditions were the same with that for microwave puffing method except for 30kPa vacuum pressure during the microwave-vacuum puffing process. The conclusion was obtained that for microwave-vacuum puffing technology, the expansion ratio was first increasing and then almost in constant. The puffing process was in the accelerating dehydration period in first 10s, and subsequently kept the constant dehydration phase. While during microwave puffing process, the expansion ratio and dehydration rate were first increasing and then decreasing. The anthocyanin content of blackcurrant slice obtained by the microwave-vacuum method was higher than the microwave method. Therefore, the microwave puffing characteristics combining with vacuum technology were superior to that produced at the atmosphere pressure.