Abstract:In order to detect the ripe tomato in unstructured environment for robotic harvesting, a tomato recognition algorithm using noncolor coding approach was developed. The proposed algorithm was consist of offline training and online recognition. In the process of offline training, a strong classifier was obtained using AdaBoost algorithm with Haar-like features. The Haar-like feature is a kind of noncolor coding feature which can be extracted by integral figure calculation. In the online recognition process, the tomato object was detected by using the strong classifier which was obtained in the offline training process. Two couples of comparative tests were conducted to study the influence of the types of Haar-like features and training times on the performance of the proposed algorithm. The results showed that the Cstyle Haar-like features and 20000 training times were the optimal parameters for the size of training set. The results of online recognition tests indicated that about 93.3% ripe tomatoes existing in the testing samples set were successfully detected. The proposed tomato recognition approach was also successfully applied in the unstructured environment with various disturbances such as occluded, overlapping, and varying illumination, which indicated that the proposed tomato recognition algorithm was selfadaptive and robust. It was available to be applied in the vision recognition system for a harvesting robot.

Abstract:A design method for night lighting system of tomato picking robots based on experiments design was presented. In the design of experiments, an image segmentation evaluation index, which could determine the optimal night lighting system, was proposed. It was calculated as the ratio of F between intraclass and interclass variances of foreground and background of tomato images captured at night. Three factors, including light source type, light source layout and image acquisition distance, were considered. Moreover, orthogonal experiment table L18(6×36) was used to arrange experiments. Testing results showed that, the light source type and light source layout were two significant factors for night lighting system, while the image acquisition distance was not. So, it is focused on the influence of light source type and light source layout in the night lighting system. Meanwhile, the F value of fluorescent lamp was 2.159 which was the highest among those values of six types of light source type, and that of the diagonal layout was 2.234 which was the highest among the values of three types of light source layout. Therefore, in the current trial, the optimal light was fluorescent lamp, and the best light source layout was diagonal layout for the night lighting system of tomato picking robot. F values of tomato images captured at night were compared with image segmentation results using the OTSU algorithm based on normalized R-G color difference. Comparative results showed that the image segmentation results were better for images with higher F. The image segmentation evaluation index based on F and the design method for night lighting system are effective.

Abstract:Presently, teaplucking machine has a disadvantage that it cuts indiscriminately without identification of the tender tea. In order to solve this problem, a kind of teaplucking machine was designed based on machine vision. A method was put forward to cut intelligently fused with position servo, visual servo and levelness servo. The cutting line was kept consistently with tea ridge and the header of machine was consistent with horizontal plane by levelness servo. The initial height of the cutter was set by position servo. In order to make the cutting more precise, PID algorithm was used to obtain highly subtle measurements. In terms of visual servo inspection, firstly, tea images of picking surface were taken and the threshold of B component in RGB was used to eliminate background and segment the range of tea. Secondly, the thresholds of G and G-B components were analyzed to distinguish tender leaves from the image by improved OSTU (the algorithm of threshold automatically extracted according to the maximum deviation). Template matched method and threshold of R component were useful to identify cutter line. Finally, the proportion of tender leaves area above cutter line in the image was calculated and its height was adjusted to ensure the ratio above 70%. Experimental result shows that the proposed method solves present disadvantages of teaplucking machine effectively. Also, the efficiency of picking was improved with reduced labor cost.

Abstract:In order to improve the pesticide application efficiency and reduce the agricultural chemicals lost in orchard spraying, an automatic target spraying system based on the 3WGZ-500 selfpropelled sprayer was designed in view of excess spraying and ineffective spray at fruit trees clearances during traditional spray operation. Ten ultrasonic sensors were fixed on the two sides of the orchard sprayer at 15° intervals, which were used to measure the distance between the nozzles and sprayer targets. The sensor measure range was 0.35~2m and emission angle was 60°. Based on the sensor signals, three channel solenoid valves by side were used to control the switch of nozzles at the corresponding position. The experiment was worked at the five years old apple orchard, test spray pressure was 0.5MPa and operating speed was 1.3km/h, 1.7km/h, 4.5km/h and 7.2km/h respectively. The result showed that the operating speed had little effect on pesticide application efficiency at the condition of with target spraying system and without target spraying system. This target spraying system can reduce unnecessary spraying chemical pesticides. The pesticide application efficiency was 35.8% with target spraying system, which increased 29.7% compared to without target spraying system’s 27.6% and increased 91.4% compared with traditional spray’s 18.7%. The system can effectively reduce the pollution to the environment. Ground loss rate at different operating speeds was proximity. The ground loss rate was 13.3% with target spraying system, which reduced by 42% compared to without target spraying system’s18.86%.

Abstract:The type and content of the impurities in machineharvested cotton are important parts of the cotton parameters, and they determine the adjustment of the processing technique of cotton. A method based on color and shape features for recognition of machineharvested cotton impurities was presented. Different image processing methods were adopted for large impurities and small impurities, and the detailed algorithm flow chart was formulated. The window filtering, image segmentation, color feature statistics and shape feature extraction were adopted to process image. For the large impurities image, smooth filtering, clustering segmentation, binarization, hole filling were conducted sequentially, and then, shape features such as area, perimeter, eccentricity, rectangle degree and color pixel statistics of the target region were calculated. The impurities which include branches, boll shell, stiff flap and leaf were identified by using combination of color and shape features. For the small impurities image, large and yellow impurities were removed after image sharpening and clustering segmentation, and the area was calculated through color pixel statistics. In order to speed up the calculation and improve the recognition rate, watershed algorithm based on color gradient image and improved fuzzy Cmeans clustering algorithm with specified initial cluster centers were combined to split image. As a result, the recognition and classification of machineharvested cotton impurities can increase the efficiency of cotton processing equipment, reduce damage of cotton fiber, and provide improved guidance for cotton harvest equipment. For the investigated 100 sample images including five types of cotton impurities, a 89% successful recognition rate was achieved.

Abstract:It has great significance that using the machine vision technology to detect the quality of postharvest litchi fruit. Firstly, the camera and fluorescence spectrometer were used for the spectrum analysis of litchi image, the emission spectrum characteristics were analyzed under the fluorescence as excitation light, which determines the feasibility of the visual detection method of litchi fruits with different fluorescence exposures. Then, the machine vision system of different light switch controls were designed, the red, blue and green fluorescent lamp were selected, and the singlechip microcomputer system was used to control the switch of the LED lamps, of which the interval is 1s; meanwhile, the image acquisition system triggered the camera to take images, the frequency of the light switch in keeping with the number of taking image times. The grey level histogram of the fluorescence image for normal and microdamaged state of two kinds of litchi fruit was statistic analyzed, the image recognition method for the micro damaged litchi fruit was determined by using blue fluorescent as light source and the V component of HSV color space. Then the exploratory analysis was used for the statistics and analysis on test results of litchi fruit visual inspection. The grayscale image segmentation threshold of the normal and microdamaged litchi fruit was determined. The grayscale image threshold segmentation, the morphology processing and the optimized Hough circle fitting method were used to the litchi images, which realized the design of the machine vision intelligent classification system for litchi fruit. The test results show that: the recognition accuracy of the normal and microdamaged litchi fruit is 92%, which can provide technical support to intelligent detection technology for postharvest fruit and vegetable.

Abstract:Intelligent agricultural vehicle can significantly improve the production quality and efficiency, reduce environmental pollution, and take advantage of the agricultural resources efficiently. So an automatic guidance control system in agricultural vehicle was implemented by integrating the hardware and software.The hardware included sensors, actuators and CAN-Bus.The software was developed with multithread programming technology in Visual Studio 2005 platform based on Windows operating system. Openloop transfer function model of the heading control system and the lateral control system were established via the model of the vehicle motion and the steering system. Model of the vehicle motion was established according to the kinematic characteristics, and model of the steering system was identified according to the closedloop response curve. Then the heading controller and the lateral controller were designed via PID control theory. Tests results showed that the hardware and software system were running stability. With the initial heading deviations of -86° and 84°, the adjusting time were both in 2s, the turning precisions were both in 1°. With the initial lateral deviations of 0.7m and 1.2m, the maximum values of the lateral deviation were 10.4cm and 9.2cm respectively, the mean values of the lateral deviation were 6.4cm and 3.5cm respectively, and the standard deviations of the lateral deviation were 2.6cm and 1.7cm, respectively. So the proposed automatic guidance control system can make the vehicle track the desired path smoothly and steadily with a centimetrelevel tracking precision.

Abstract:An approach of robust feature recognition and precise path tracking based on two visual field windows was proposed for an AGV to identify multibranch paths and station point reliably, and to follow guide paths accurately. The whole visual field was used as a pattern recognition window, in which a recognition method based on kernel principal component analysis (KPCA) and BP neural network was developed. Path features were mapped to a highdimensional space by using the kernel function and then their dimensionalities were reduced by using PCA. After dimensionality reduction, the sample matrices were recognized by utilizing a BP neural network. Besides, a scaling window method based on a vertical view angle and a tilt installation angle of a camera was suggested for a guidance scanning window. In this window, guide paths were simplified according to a linear model and fitted by using the least square method. Path deviations with respect to the fitted straight line were estimated for AGV guidance. Experimental results show that the KPCA-BP approach improves the realtime performance and robustness of path feature recognition significantly, the average correct rate of which is 99.5% for six types of landmark feature, and that the guidance scanning window decreases the computing error resulted from linear fitting of guide paths effectively, the tracking error of which is no more than 3mm for linear path and 30mm for curvilinear path.

Abstract:The pH value regulating control process has the characteristics of nonlinearity, pure hysteresis, time degeneration and uncertainty in the precision fertigation system. A model described the pH value regulating process was established. The cloud model is a model that can deal with the uncertain transition between qualitative concepts and quantitative description. Based on this, a control algorithm with cloud inference in the variable universe fuzzyPI controller (CVFPI) was proposed. In this algorithm, the normal cloud model was used to describe certain language concept corresponding to the system error and error rate. The inference of rule premise was realized by X conditional membership cloud while the inference of rule post was realized Y conditional membership cloud. A set of stretching factors with proportional exponential function was used to modify the universe of input and output variable real time, and a two dimensional inference engine based on cloud model was designed to adjust control parameters of PI controller on line. In order to verify the effectiveness and superiority of the proposed algorithm, the test platform of pH control process of the fertigation equipment was constructed. Two simulation experiments and two field experiments were carried out using CVFPI, VFPI and PI control algorithm respectively. The contrast testing results demonstrate that the proposed CVFPI control algorithm can meet the requirements of pH process control in the precision fertigation system, it has better characteristics both in dynamic process and steady state. Compared to PI and VFPI, CVFPI has smaller overshoot, shorter stable time and stronger ability of antiinterference.

Abstract:In order to improve the seeding performance of the airsuction seed metering device of notill planter, the optimal operating parameters of the seed metering device were found. With the discrete element method, the dispersion degree, the force among the seeds and seed velocity in seed metering device were simulated. The best suction metering parameter ranges are as follows: the stirring wheel speed is 14.8～18.5r/min, the vibration frequency is less than 10Hz, the amplitude selection is less than 5mm, and the capacity of seeders selection is 60%~80%. The results of metering test verification show that: the wheel speed is less than 18.5r/min, the average absorption rate is 94.7%, which is 7.1% higher than absorption rate of the seed stirring wheel speed greater than 18.5r/min. The vibration frequency is less than 10Hz and the amplitude is 2mm, the average absorption rate is 97.7%. Compared with the absorption rate of super 10Hz, the average increase of the absorption rate is 8.9%. The absorption rate is increased with the increase of the capacity of seeders. When the capacity of seeders is less than 60%, the average rate of absorption seed is only 85%; while the capacity of seeders is higher than 60%, the average rate of the absorption is 97%. Compared with the capacity of less than 60%, the average absorption rate was increased by 12 percentage points. This conclusion proves that working parameters of the simulation analysis and optimization are reliable. Therefore, the seeds of the airsuction seed metering device are in a loose absorption state in the ranges of those parameters, which could furthermore reduce collision and towing function of the seed, more conducive to the suction, and improve absorption performance.

Abstract:In order to discover the influence rules of paperbased passive micromixer’s parameters on mixing effect of pesticides, the Yshaped micromixer, Zshaped micromixer, squarewave micromixer were selected and the relationships among the parameters of each kind micromixer and mixing performance by experiments were researched. Then optimal parameters of each kind micromixer were chosen, and mixing performances of three micromixers were contrasted under the optimal parameters. The results of experiments show that Yshaped micromixer’s optimal parameters are inlet velocity of 0.010mL/min, inlet angle of 30°, Zshaped micromixer’s optimal parameters are inlet velocity of 0.010mL/min, peak separation of 3mm, corner angle of 30°, squarewave micromixer’s optimal parameters are inlet velocity of 0.010mL/min, wave height of 2mm, wave width of 5mm, and under their optimal parameters, Yshaped micromixer’s outlet mixing intensity is 0.6227, Zshaped micromixer’s outlet mixing intensity is 0.6902, squarewave micromixer’s outlet mixing intensity is 0.7326. The squarewave micromixer has the best mixing performance. Paperbased passive micromixer has some fibers in its channel, it can provide dynamic of flowing and enhance the diffusion of liquid pesticides. On the other hand, it can limit the convection to a certain degree. This article researched the mixing performance of paperbased passive micromixer for the first time internationally.

Abstract:The study on disturbance behavior of subsoiling is the basis to understand the subsoiler-soil interaction law deeply. A working model of subsoiling was established by using discrete element method. In addition, with the aid of highspeed photography technique and the indoor soilbin test, the micro movement and the macro disturbance behavior of the soil at different positions were compared and analyzed. The results showed that, the disturbance range of soil was decreased with the increasing distance between the soil and the subsoiler, and at different locations, the disturbance range from large to small was the shallow layer, the middle layer and the deep layer. In the subsoiling range, the movement speed of the soil was decreased with the increase of the distance between the soil and the subsoiler. The distribution curves of the samespeed soil particles were basically consistent with the curves of the subsoiler. The average velocities of soil particles in different depths and different directions were measured from large to small as follows: the shallow layer, the middle layer, the deep layer in x direction; the middle layer, the shallow layer, the deep layer in y direction; and the deep layer, the middle layer, the shallow layer in z direction. The discrete element simulation could accurately simulate the disturbance behavior of subsoiling, and the shape of soil disturbance section of simulation and obtained from experiment were basically matched. The relative error of the soil bulkiness and soil disturbance coefficient between simulation and experiment were 13.21% and 17.38%, respectively. The relative error between the simulated longitudinal accumulation angle of the surface soil and that of experiment was 9.42%.

Abstract:On the basis of studying both at home and abroad, not only the orientation of the corn harvester rear axle pivot had been considered, but also the track width differences between front axle and rear axle had been taken into account, thus a more accurate quasistatic lateral stability mathematical model was constructed. Then lateral stability experiment and simulation analysis were carried out in order to verify the validity of the model. Accordingly the lateral stability influence factors were obtained. Afterwards, each influence factor was firstly set at a certain range of values, then the value range of each influence factor was converted into an identical range \[-1,1\], taking advantage of encoding transform. Therefore the curve of lateral stability indicator λ changing with the varying of different influence factors could be drawn in the same picture which could directly show the impact extent each factor on the lateral stability. The analysis results showed that the main influence factors of corn harvester quasistatic lateral stability were wheel base x, the height of corn harvester center of gravity h, the distance between the center of gravity and front axle a, as well as front axle track width t1. In the end, this paper also put forward several measures to improve the lateral stability of the whole machine. When the center of gravity is lowered by 100mm, the load ratio of the front and rear axle is increased to 4, as well as the symmetric machine model is adopted. The result shows that the alteral critical angle of the corn harvester can be increased from 24.8° to 29.52° and the lateral stability can be raised by 19.03%. The establishment of corn harvester quasistatic lateral stability mathematical model can provide a foundation for corn harvester overall arrangement and structure design.

Abstract:A way of expelling straw sideways was adopted by the 2BMFJ type notill precision planter. The planter was able to complete seedbed preparing, precision seeding, fertilization, covering, rolling, pesticide spraying, straw mulching equably and so on. The planter has become an important technical mean to achieve conversation tillage. Cleaning device of the 2BMFJ type notill precision planter mainly completes preparing seedbed. However, there are some problems such as severe vibration, more power consuming and lower working speed on the cleaning device. So the optimization experiment was carried out. Wheat stubble fields were regarded as experiment objects. Orthogonal experiment with four factors and three levels was employed to find the optimal combination of the structure and working parameters for the cleaning device. The number of cutters per disk, cutter disks configuration, working speed and cutter disk speed were selected as factors. Passability, equivalent power dissipation, equivalent fuel consumption rate and vibration intensity were selected as indexes. The optimal combination of influencing factors was obtained by the experiment: the number of cutters per disk was 4, cutter disks configuration was 3-2-3, working speed was 5.4km/h and cutter disk speed was 300r/min. Under this condition, 〖JP2〗the cleaning device wasn’t blocked; the vibration intensity was decreased from 197m/s2 to 134.48m/s2, by 31.74%; the equivalent power dissipation was decreased from 5.88kW to 4.58kW, by 21.11%; and operation speed was increased from 4.5km/h to 5.4km/h, by 20%. The results can provide reference for the optimal design of the 2BMFJ type no-till precision planter.

Abstract:In order to solve the problems of transporting, such as complexity of the mechanism, high cost of the electrical control system, pot damage in the process of transplanting, a new automatic seedling transplanting device was designed, which consists of vertical movement mechanism, ejecting mechanism, horizontal movement mechanism, guiding mechanism and gripping mechanism. The specific form of each mechanism were determined by using F-P-A method. The cam’s maximum pressure angle was determined as 29.32° and the cam displacement was determined as 29mm according to agricultural requirements using virtual modeling, simulation and accuracy analysis. The sequence analysis model program was built with the Visual Studio software, and a group of optimal parameters was obtained with this program. The initial phase angle of vertical mechanism was 185°, initial phase angle of ejecting mechanism was 108°, the length of the crank was 78mm, the length of the connecting bar was 112mm, the eccentricity was 20mm, the initial phase angle of the gripping mechanism was 15° and the initial phase angle of the opening and closing mechanism was 135°. The experiment was done with three different moisture contents of the tomato seedlings aged 45 d. The experiment result showed that the moisture content and gripping speed both had impacts on the success rate of the seedlings, and both had negative correlation, the gripping speed had little impact on the damage of the seedling. This device had the performance that the maximum gripping speed was 140 plants per minute at which the success rate of gripping was above 95%, and the success rate of gripping was 98.44% and the damage rate of the seedling was 36.67% at the condition that the moisture content was 32.79%, which meets the agricultural requirements and was faster than the manual.

Abstract:The 3QXZ-6 seed corn detasseling machine was designed to improve the mechanical level during corn cultivation. The machine was consisted of profiling mechanism, hydraulic driving system and plantprofiling controlled system. The profiling mechanism was structured as a parallelogram. Roller was motivated by the loadsensing hydraulic system, and height adjustment was manipulated by cylinder, which was driven through proportional control hydraulic system. In a set distance, if the lower photoelectric signal is continuously lost, it indicates the plant is short, and if the upper photoelectric signal is continuously received, it indicates the plant is relatively tall. This is how the plant height profiling is fuzzily controlled. The test on synchronization performance of roller rotation speed, response time of controlling system, and hydraulic cylinder speed shows that when the engine rotation speed is around 2300r/min, the maximum deviation ratio of roller rotation speed is 4.4%, synchronization tolerance rate is less than 3%, responding time is 0.04s, cylinder liftingup speed is 0.21m/s, and droppingdown speed is 0.27m/s. Based on the data collected from experiment, a function was built by using control signal t as variable and vertical movement of tassel removal component. Field experiment proves that the 3QXZ-6 seed corn detasseling machine is reliable and highly efficient. It sufficiently meets the agronomy detassling requirement with a detasseling ratio 87.7% averagely.

Abstract:Aiming at the poor separation effect, the lower rate of tuber obvious and the high rate of tuber skindamage of the rodlink chains of small potato harvester, a poking roller shoving type potato harvester was designed, and the shoving type separate conveying device was studied. The structure and working parameters of the separate device were determined. The device adopts multistage roller to continuously push, and realizes the wave type backward separation and transportation of potatosoil. A specific cross mounting angle of the poking teeth on the adjacent poking roller, which ensures the movement track of the potato in the device, was a smooth curve. The quadratic orthogonal rotation combination experiment of three factors were carried out with the moving forward speed, the poking roller speed and hoisting height as experimental factors, the obvious rate and skindamage rate as experimental indexes. The regression equation was obtained and significance analysis was carried out by using the DPS software. The results showed that the influences on the obvious rate of the respective factors decrease in the order as below, poking roller speed, moving forward speed, and hoisting height, the influences on the skindamage rate of the respective factors decrease in the order as below, moving forward speed, poking roller speed, and hoisting height, and the moving forward speed of 1.0m/s, the poking roller speed of 60r/min and hoisting height of 150mm were the best combination factors, which leaded to the obvious rate of 99.01%, and the skindamage rate of 1.24%. The soil was broken in the process of poking tooth rotation. Potato was separated from the soil through picking and throwing of the poking tooth. Compared with the ordinary conveying device, the results show that poking roller shoving type potato harvester had good performance on improving the obvious rate, and had slightly improvement in decreasing the skindamage rate.

Abstract:In order to solve the shearing damage caused by the track combine harvester continuous steering in the field, increasing the steering flexibility of vehicle, and improving operation efficiency, the driving performance simulation test of a pivot steering mechanism at the flat hard pavement and heavy clay was conducted. In the test, the multibody dynamics model of the combine harvester was established in RecurDyn software, and the movement state was obtained, including steering angular velocity, steering angular acceleration, steering radius and output torque. On this basis, the new type pivot steering mechanism and the walking performance test harvester were trialproduced, and a large number of experiments were carried out. Test results show that, under the same steering mode condition, the differential steering output torque in paddy field is maximum, up to 5668.2N·m, much larger than that at the concrete floor, which is 2268.2N·m, at the same time, the differential steering output torque is the biggest of the three steering modes. As the rotate speed of the driving wheel is 75r/min, the angular velocity at the concrete floor is 0.610rad/s, and that of the paddy field is 0.592rad/s, which are improved by 87.7% and 88.5% separately; the minimum steering radius in the paddy field is 0.098m, and that of the concrete floor is 0.082m, which decrese the steering occupied area significately. The proposed differential steering mechanism improves the walking performance of the combine harvester greatly.

Abstract:The cleaning performance of cleaning device greatly affects the working performance of the machine. In order to overcome the shortcomings of the uneven airflow field in the longitudinal axial flow fullfeeding airandscreen cleaning device, the mixed flow field produced by the fan and the threshing roller was numerically simulated with computational fluid dynamics (CFD) software. A structure of fan with double airducts and six airoutlets was proposed based on the longitudinal axial flow fullfeeding cleaning device. By comparing and analyzing the improved structures, the air speed of the sieve has the influence on the distribution of the full airflow field. At the same time, the orthogonal simulation was carried out on a new type of cleaning device with the three factors (the fan speed, the incident angle of the fan, the included angle of the sieve) in Z section, and the influence of the three factors was analyzed. The optimal combinations are as follows: the incident angle of the fan is 30°, the included angle of sieve is 40°, the speed of fan is 1900r/min. With the best combination of these structural parameters, the speed of overall air flow in the front and the rear of sieve is uniform and efficient, and it is more beneficial to highload cleaning. Finally, field tests verified the accuracy of the improved structure and optimization program. The loss rate of the rice is 0.91% and the impurity rate is 0.87%. The loss rate of the wheat is 0.82% and impurity rate is 0.76%, it greatly improved the cleaning performance of the longitudinal axial flow.

Abstract:In order to solve the human cost, low efficiency, nonmechanization and other issues of picking, a Chrysanthemum morifolium combteeth picking machine was designed. The picking machine was mainly composed of combteeth, two chains with installation holes, four sprockets, a driven shaft, separating teeth, a box, a machine frame, four wheels, a stepping motor and control part. The gap between combteeth was larger than the diameter of bud and less than the diameter of tire chrysanthemum. The flowers were forced to take off by the impact. The test showed that Chrysanthemum morifolium combteeth picking machine can take off the Chrysanthemum morifolium flower reliably. The test was done when the flower moisture content was 82.5%. The single test of combteeth gap selected five levels (7.0mm, 7.5mm, 8.0mm, 8.5mm, 9.0mm). The Chrysanthemum morifolium combteeth picking machine worked well at the gap of 7.5~9.0mm. The drop rate was 0~4.06%, the broken rate was 0~100% and the removal rate was 92.43%~98.11%. The orthogonal tests showed the best combination of combteeth gap, separating teeth gap, feeding depth and rotational speed. Four levels were selected such as 7.5mm, 8.0mm, 8.5mm and 9.0mm for combteeth gap. Separating teeth gap included four levels such as 13mm, 15mm, 17mm and 19mm. Four levels (125mm, 150mm, 175mm, 200mm) were chosen for feeding depth. Rotational speed selected four levels such as 30r/min, 40r/min, 50r/min and 60r/min. The test showed that when the combteeth gap was 8.5mm, the separating teeth was 17mm, the feeding depth was 200mm and the rotational speed was 60r/min, Chrysanthemum morifolium combteeth picking machine would work better. The removal rate was 97.61%, the drop rate was 0.65% and the broken rate was 0.03% at this time.

Abstract:Pelleting is an effective way to store and utilize organic fertilizer. A key step is to dry after pelleting. At present, onezone rotary drying is often used for drying organic fertilizer pellets. But it has many problems, such as high energy consumption and etc. To guarantee the efficiency and high quality of the organic fertilizer in drying process, a triplepass rotary drum drying technology was introduced. Therefore, the problems of long overall length, large occupied area and low plant utilization factor can be solved. This study combines the advantages of triplepass rotary drum dryer. To explore the relationship among the residence time in the drum, the structure parameter of flight, and the drum installation angle, the EDEM software was used to simulate the movements of the pellets in the drum. The principle of the flight was analyzed, and a new type of combined flight was designed. The residence time in middle drum testing apparatus was set up, and the singlefactor experiment design was conducted. Then, the significant factors on residence time were obtained by using orthogonal experiments, which turned out to be the drum installation angles and flight angles. The results of the simulation and experiment were compared, and it’s verified a very highly prediction on the residence time and optimized parameters of the drum installation angle. Finally, the experiments showed that the installation angle should be less than 5° and flight angle should be higher than 40°.

Abstract:Aiming at the problems of small amount but large varieties in peanut, low efficiency of artificial shells, high damage rate and low shelling rate of mechanical shelling in peanut breeding research, a shelling scheme which has threelevel rotary and singlerow threeroll parallel shelling was proposed based on physical and mechanical properties of typical peanut research. The critical components of shelling drum, rotation rod, transmission system were designed, and the peanut sheller prototype was developed. Shelling drum was composed of three subrollers which are sidebyside on the same axis, it was able to adjust the distance from the concave screen, and increase or decrease the number of rods. Pneumatic cleaning device was composed of centrifugal fans. Three parameters, including drum rotating speed, hulling interval and hitting times of rods, were selected as experimental factors, the peanut shelling rate and peanut broken injury rate were selected as experimental indexes. Experimental results indicated that drum rotating speed, hulling interval and hitting times of rods all had influence on peanut shelling rate and peanut broken injure rate. The optimum combination indexes were: drum rotating speed of 350r/min, hulling interval of 20mm and hitting times of rods of 3. The peanut shelling rate was 99.15% and the peanut broken injury rate was 2.3%. The research results can provide a reference for the development of peanut seed sheller.

Abstract:The control system of a smart pig porridge feeder was designed based on MCU whose kernel was the ARM CortexM3. The control system could well solve the problems of pig porridge feeder which include both the weight proportion between water and dry feeding, and the dry feeding weight delivered for every day. The ways of dynamical adjustment for the weight proportion of water and dry feed were shown as follows. Firstly, the least square support vector regression (LS-SVR) model between the delivered speed of the dry feeding and the motor’s rotary speed was founded. Then referred to the LS-SVR model, the abnormal realtime sampling weight value during continuous delivering feed was removed by using some data process methods, such as the threshold value judgment and the Grubbs criterion. At last, the value of feeding at certain times was predicted via the line regression model attained by least squares fitting the rest of sampling data. Because the water flow could be truly detected by a flow sensor, the weight proportion of water and dry feed was well adjusted. Using recursive weight compensation combined the LS-SVR model and static measurement means, the delivered dry feeding weight for one day was accurately controlled by the control system. After being mixed with stirred fully by the feeder using the control system, the water and the dry feed were turned to porridge whose nutrients should be better absorbed by pigs. The weight proportion of water and dry feed error was below 4%. The weight error of feeding for a pig per day was less than 1g.

Abstract:Microporous concrete irrigation emitters were prepared with dry pressing method and then cured by an atomizing humidifying means. The effect of particle size of sand and cement content in raw material on the flexural strength, open porosity, pore size and hydraulic performance of the irrigation emitters was studied. By testing the hydraulic performance of the irrigation emitters, the variation of the water flow rate of irrigation emitters with time was analyzed, and the reason causing the variation was investigated. The particle size of sand has little effect on the flexural strength, open porosity and mean pore size of microporous concrete. As cement increases, the microporous concrete increases gradually in flexural strength, decreases obviously in open porosity and gradually in mean pore size. The water flow rate of irrigation emitters decreases obviously with the increase of cement in raw material, and decreases slightly as the particle size of sand decreases. When the cement content of raw material was 12%, the irrigation emitters are of high water flow rate but easy to be destroyed because of low strength. When the cement content of raw material was 21%, the irrigation emitters have good reliability due to their high strengths but are hardly to be used in practice because of very low water flow rate. When the cement content of raw material was 15%~18%, the irrigation emitters possess both good reliability and relative high water flow rate due to their suitable strengths, open porosities and mean pore sizes. During hydraulic performance testing, the soluble alkali in microporous concrete was dissolved and taken out by water, which makes the water flow rate with time of the irrigation emitters increase slightly because of the gradual increase of open porosity and mean pore size. Nevertheless, the slight increase of water flow rate has little impact on irrigation in practice. The microporous concrete irrigation emitters are promising good subirrigation emitters.

Abstract:Differences in the water quality can affect the water infiltration process of layered soil. Four kinds of water, deionized water, natural water, natural precipitation and tap water were used to act on three soil configurations (homogeneous loess soil, loess soil with gravel and sand with loess soil), and the influences of these four kinds of water on the infiltration characteristics of the layered soil structures were studied. The results showed that the infiltration descending time order of these four kinds of water in the three soil configurations was: deionized water, natural water, tap water, and natural precipitation. The changing trends of cumulative infiltration amount in the four kinds of water qualities were basically the same, and the descending order of cumulative infiltration amount was: natural water, tap water, deionized water, natural precipitation; sand with loess soil, loess soil with gravel, and homogeneous loess soil. The ascending sort order of advancing distances of wetting front in the same period was: homogeneous loess soil, loess soil with gravel, and sand with loess soil. The influence degree of water quality on infiltration rate, cumulative infiltration amount and the wetting front’s advancing distance of layered soil was determined by the layered combination mode of the soil.

Abstract:Overland flow is one of the important factors inducing soil nutrients loss into runoff. In order to simulate and study the effects of overland flow on soil nutrients loss, a mathematical model describing soil nutrients transport with overland flow was developed based on the concept of effective mixing depth and Kostiakvo equation. In addition, the model also makes the corresponding assumptions to simplify the infiltration process. The obtained model was denoted as the incompletemixing model. Field water scouring experimental data was adopted to test the applicability of the proposed model. The experiment was performed on a natural, fallowed loessial slope (38°46′~38°51′N, 110°21′~110°23′E), in 14km west of the Shenmu Erosion and Environment Research Station of the Institute of Soil and Water Conservation, Chinese Academy of Sciences, in the Liudaogou watershed, Shaanxi Province. Field plots were established on a slope that had been fallowed for seven years. Vegetation types cover were adopted (herbaceous and crops), including caragana and soybean. The characteristics of the transport of runoff, nutrients (nitrogen and phosphorus) under different vegetation cover were discussed in this study. Results indicated that the incompletemixing model performed pretty well in predicting the process of nutrients transport into runoff. The correlation coefficients were larger than 0.9 for all the treatments. Moreover, little bias was observed between the measured cumulative mass and the simulated data obtained from the incompletemixing model. Taking nitrate nitrogen for example, the relative errors between the measured data and simulated results were 6.6% (caragana) and 5.9% (soybean). When the nutrient was soluble phosphorus, the relative errors were 1.1% (caragana) and 2.3% (soybean). For better simulation results, the calculation accuracy and simplicity in obtaining parameters should be taken into consideration during model selection. The results in this study will provide significant references for more analysis on nutrients transport into runoff with overland flow in future.

Abstract:To effectively improve the enzymatic hydrolysis rate of carbohydrates in lignocelluloses, the liquid ammonia treatment (LAT) was employed as pretreatment for Miscanthus floridulus. The pretreatment temperature T, Miscanthus floridulus moisture M, residence time t and the ratio of ammonia to biomass (dry basis) k were chosen as variable factors. In the experimental ranges of T (70~170 ℃), M (20%~200%), t (5~30min) and k (0.5~5.0), the influences of different variable factors on enzymatic hydrolysis of Miscanthus floridulus were investigated. The chemical composition analysis showed that the chemical constitution of Miscanthus floridulus was close to Saccharum arundinaceum and Miscanthus sinensis, and it could be a prior species of plant energy. The pretreatment methods and effects of these biomasses could be used as reference for each other. The parameter optimization results show that the optimal LAT pretreatment conditions for Miscanthus floridulus were 130℃, 80% moisture content, 10min residence time and 2.0 ammonia to biomass ratio. Enzymatic hydrolysis using cocktail enzymes including cellulase, βglucosidase and xylanase for 72h after pretreatment under optimal conditions, the glucan and xylan hydrolysis rates of LATtreated Miscanthus floridulus achieved 72.1% and 82.5%, which were 3.3fold and 4.3fold than those of untreated biomass respectively. The total fermentable monosaccharides after pretreatment under optimal conditions following enzymatic hydrolysis was 55.8g per 100g of dry raw material. Compared with untreated substrates, it was about 3.65fold in sugar yield for LATtreated substrates. As a result, the LAT process significantly reduced the recalcitrance of Miscanthus floridulus and facilitated biomass conversion to fermentable sugars.

Abstract:For an anaerobic fermentation system, the temperature is one of key factors which affect the efficiency of biogas production. A parabolic trough concentrator (PTC) was used as the heat source for an 8m3 underground anaerobic digester. To improve the efficiency of concentrating solar collectors and the biogas productivity of traditional anaerobic fermentation system, the sizes of important components in the digester were determined, and the energy balance was also calculated. Moreover, the angle change of solar concentrator in Yangling was counted, the angle of the collector during one year was optimized, and the inclination angle and installation method of the concentrator bracket were also designed. It was found that feed heat loss (16077.31kJ/d) and wall heat loss (23180.01kJ/d) were the two main heat loads in this system. The key parameters of PTC were determined: the size of aperture was 2.4m, the focal distance was 0.6m, the area of collector was 4.16m2, and the diameter of collector pipe was 0.0168m. In addition, the heat transfer of anaerobic reactor was simulated through Fluent software. The simulation results revealed that interior temperature in the digester could be maintained at 35℃. A PTCbased anaerobic digester with similar parameters of simulation model was designed to verify the simulation effect. The experiment results indicated that the temperature range of material liquid in the reactor could be kept at 33.6~35.8℃, approximately consistent with the Fluent simulation. The results in this study provide a new solution for efficient and lowcost biogas fermentation device.

Abstract:To seek for the optimal forming parameters of the roller briquetting machine with plungers and explore the influence law of the forming parameters on the forming results, sawdust was used as the raw material, the moisture content, the length to diameter ratio of the forming mold and the spindle speed were taken as the experimental factors, while the density of the forming particle and the productivity of the briquetting machine as the experimental indexes, the experimental data was processed and analyzed by the experiment design method of Design-Expert BBD (Box-Behnken Design), and the regression equations of the experimental factors on the experimental indexes were established. The results showed that the optimal results of the moisture content of sawdust, the length to diameter ratio of the forming mold and the spindle speed were 15.5%， 5.3， 47.25r/min，respectively. On this condition，the density of the forming particle and the productivity of the briquetting machine can reach 1.17g/cm3, 75kg/h, respectively. The contribution rate of the experimental factors on the forming particle density in the order from large to small: the length to diameter ratio of the forming mold, the spindle speed, the moisture content, while on the density of the forming particle: the moisture content, the length to diameter ratio of the forming mold, the spindle speed. The maximum relative error is 0.426% between the experimental value and the predicted value of the density of the forming particle，while it’s 2.733% on the productivity of the briquetting machine, so theres high consistency.

Abstract:Corn stover contains abundant nutrients for animals and it is the main source of roughage for large domestic animals. To guarantee the quality of feed, the online measurement of the nutrient content of corn stover is essential when it is being used as a roughage feed or a raw material for silage. In the present study, the online determination of moisture, crude protein (CP), acid detergent fiber (ADF) and watersoluble carbohydrate (WSC) of corn stover was investigated using near infrared spectroscopy (NIRS) operating over a conveyor belt moving at 20cm/s. The distance between the sample surface and the scanning window was 100mm. The 217 corn stover samples, collected from three provinces of China, were crushed to not more than 5cm for spectral analysis. The relative standard deviation (RSD) and ratio of standard error of performance to standard deviation (RPD) of the models developed for moisture, CP, ADF and WSC were 9.03% and 1.97, 11.36% and 2.31, 3.75% and 2.02 and 16.18% and 3.61, respectively. The results showed that it was feasible to determine the moisture, CP, ADF and WSC contents of corn stover using on-line NIRS, which would help raise the efficiency of nutrient measurement and thus guarantee the quality of feed. The sensitive bands of the models were investigated, which could help to simplify the models and thus reduce the cost of the specific spectrometers for practical application.

Abstract:Aiming at the problem of rope-biting hook under heavier load and serious abrasion of its roller in ropebiting mechanism of knotter, a calculation model of curved surface of cylindrical cam was built up by analyzing the kinematics of ropebiting mechanism in order to make the roller and cylindrical cam keep linecontact as well as ropebiting hook open and close according to sin acceleration law. By carrying out dynamic analysis of ropebiting mechanism and combining with the test of compression amount of compressing spring and tensile test of the rope, the statics model of ropebiting hook on the position of holding on to the rope was solved analytically, and optimum range of holdingon force of ropebiting hook was obtained which value is between 300.64N and 329.89N. The dynamic model of ropebiting hook was also solved analytically, and the contact force of cylindrical cam was between 240N and 330N when holdingon force of ropebiting hook is within optimum range. The peak value of contact force of cylindrical cam may be used to check contact fatigue strength of the roller, and guide material choice of the ropebiting hook and its roller. The field tests showed the roller installed on the rear of ropebiting hook didn’t have obvious abrasion after the kontter prototype finished 5000 bundles of rice and wheat straws according to predetermined preload force of compressing spring and initial pulling force of the rope. The result showed that the holdingon force of ropebiting hook was controlled suitably and linecontact cam improved contact load of the roller, which met the design requirement of impact resistance and antifriction.

Abstract:An online weighing method for poultry was proposed to meet the demand for online weight grading and weighting of poultry which were carried out on a suspension transportation device. The mechanical model of drawing tension was developed by a force analysis to suspension chain conveyors which was used for butchering the poultry. The method of different weighing heights was proposed to estimate the draw tension of chain and the weight of objects was calculated according to the estimated drawing tension. A weighting test device for the poultry weighting was established. At first, a simulation experiment was carried out and the Matlab and SimMechanics were used to simulate the procedure of online weighting. The results showed that correlation coefficient was 0.99914 between Dvalue and drawing tension, and the object weight deviation from simulating estimation to drawing tension was within 15.7g. Then the experiments were conducted on the same test device and the results showed that correlation coefficient was 0.76 and the correlativity between Dvalue and drawing tension was significant at a significant level of 0.10. The maximum error was 125.03g when the object weight was calculated according to Dvalue. The study suggested that it was realistic to get the object weight on the basis of drawing tension, and the online weighing for poultry carcass could be realized through further improving the measurement accuracy.

Abstract:To explore a method for detecting solids content of soybean milk, network analyzer and openended coaxialline probe were applied to study the influence of frequency (20~4500MHz), temperature (20~80℃) and solid content (2.00~7.01g/（100mL）) on dielectric parameters (relative dielectric constant ε′ and dielectric loss factor ε″) of soybean milk. The models describing the permittivities as functions of temperature and solid content were built, and its feasibility to predict solid content using obtained permittivities were verified. The results showed that over the frequency range of 20~4500MHz, ε′ was decreased with an increase of frequency, and ε″ was increased after decrease with increasing frequency. The minimum ε″ was observed at 600~2000MHz. ε′ was decreased with an increase of temperature, and ε″ was increased with increasing temperature at low frequency end and decreased at high frequency end. The frequency where minimum ε″ was increased with increasing temperature. ε′ was decreased but ε″ was increased with increasing solid content. At a given frequency, quadratic polynomial could be used to describe the relationship among permittivities (ε′ and ε″) and temperature and solid content. The determination coefficient of the built model was 0.989 for ε′ (100MHz) and 0.990 for ε″ (20MHz). The model verification results showed that the determination coefficient was 0.978 between the calculated solid content using obtained ε″ at 20MHz and the measured ones. This study indicated that permittivities could be used to detect the solid contents of soybean milk.

Abstract:Infrared drying experiments were carried out under different drying conditions. The apparent density, porosity, volume ratio variation and volume shrinkage of the dehydrated samples were researched. The experimental results showed that changes of apparent density were proportional to sample thickness in the initial drying process, and the apparent density was inversely proportional to radiation distance and radiation power. The final apparent density of dehydrated carrot was between 1.01×103~1.71×103kg/m3. The apparent density of fresh carrot slices was 1.05×103kg/m3. With the decrease of water content, the apparent density increased, and the maximum value was 1.71×103kg/m3. The porosity increased with the decrease of moisture content. Sample thickness was proportional to porosity inversely, and the radiation distance was proportional to porosity, but when the radiation power exceeded a certain range the porosity would decrease. In the whole drying process, the range of the carrot’s porosity was between 0.24 and 0.62. The sample thickness and radiation power had a significant effect on volume ratio variation and volume shrinkage. The two order polynomial was fitted with the test data by the linear least square method, and the exponential equation was fitted by the nonlinear least square method based on Matlab 7.0. The maximum determination coefficient R2 of two order polynomial was 0.9966, the minimum value was 0.9762. But the maximum determination coefficient R2 of exponential equation was 0.9601，the minimum value was 0.9017. The fitting results showed that two order polynomial model was a good fit to predict the relationship between shrinkage and the dry basis ratio of carrot more accurately.

Abstract:In order to decrease the damage and slippage of packaging material during the operation of conveying mechanism of freshcut fruit and vegetable packaging machine, a study was conducted. In this work, the compression deformation principle of the packaging boxes compressed by the conveying mechanism was analyzed. Through compression test of PET packaging boxes, the force of the conveying mechanism should be between 5N and 15N, and the compression displacement should be less than 10mm, which could avoid mechanical damage of packaging boxes and fruitvegetable products. Then, based on parametric modeling, the process and mechanism of the compression deformation of the packaging boxes were analyzed by the finite element simulation. The easy damage position of the packaging boxes and the reason were analyzed. According to the above experiment and analysis, the quality of packaging boxes, the compression displacement and the speed of the vertical belt conveyors were selected as the orthogonal test factors. When the quality of packaging boxes was 19g, the compression displacement between the vertical belt conveyors and the packaging boxes was 8mm and the speed of the vertical belt conveyors was 0.25m/s, the results showed that the slip rate was 0.043%. Under this condition, there was no compressed damage on packaging boxes and freshcut fruits and vegetables. Meanwhile, good transport synchronization was occurred between PET packaging boxes and conveying mechanism.

Abstract:On the basis of analysis on processing technology of tea, the fuzzy algorithm was applied to realize the intelligent control of traditional tea cylinder waterremoving machine. By detecting the weight and grade of fresh tea leaves in the tea cylinder waterremoving machine, the fuzzy control rule of decisionmaking was used to adjust time and temperature of tea waterremoving realtimely; at the same time, fuzzy proportionintegrationdifferentiation (PID) controller was used to adjust temperature of tea waterremoving to realize the accurate control. Data acquisition and double fuzzy control system hardware were made up with NI USB-6215 data acquisition card and Siemens programmable logic controller (PLC), etc. In addition, output effect of double fuzzy control system model was tested by laboratory virtual instrument engineering workbench (LabVIEW). Finally, the possibility of the double fuzzy control system was proved by the substantial evidence and the result of tea waterremoving was tested. Experiment result show that this control system output parameters are ideal for the waterremoving of tea, the temperature departure of waterremoving is less than 1℃ and the time deviation of waterremoving of tea is less than 5s. This control system can reduce the human factors in the process of teamaking. Whats more, it will improve the intelligent level of the machine for teamaking.

Abstract:The rigid components are always used in traditional walnut shellbroken kerneltaken device. During working process, the walnut kernel is easy to be excessively broken. The shellbroken rate and kernelunbroken rate are also low and the adaptability for different kinds of walnut is poor. In order to improve the walnut shellbroken and kernelunbroken effect, combining with the current research situation of walnut shell breaking by mechanical approaches, a walnut shearingextrusion flexible shell crushing, kernel taking and shellkernel separating device was designed. Stiffness at different positions of walnut shell was analyzed by theory of elastic mechanics, which contributed critical force of unstability of different positions. Critical force of cracking and breakage at different positions of walnut shell was disclosed. Conditions for crack extension after walnut shell breakage were analyzed and calculated by fracture mechanics theory. The results demonstrated that when the mean crack length is 20mm, the critical external force for crack extension is 191N. The singlefactor experiment was carried out to analyze the impact of the top and low section belt spacing (A), top and low section velocity difference (B) and extrusion included angle (C) on walnut crushing force. In this way, the optimal combination of three factors (A, B, C) can be identified through the orthogonal experiment. The experimental results indicated that with A of 23mm, B of 0.19m/s and C of 45°, the most satisfactory shellbroken effects were obtained, which generated the first grade kernel rate of 75%, the second grade kernel rate of 18%, the kernel cracking rate of 5% and the kernelunseen rate of 2%. In other words, under this condition, the shellbroken rate reached 98% and the kernelunbroken rate reached 93%.

Abstract:Considering the sensitive factor of each parameter differences, in order to analyze the effect of influence parameters of multitemperature refrigerator truck on the cooling process, sensitivity analysis method was used to analyze the cooling influence parameters sensitivity of freezing and refrigerated zone for multitemperature refrigerated trucks. The result shows that: for refrigerated zone, when δi is 100mm, λi is 0.0338W/(m·K) to 0.0438W/(m·K), the weights shows an inverse trend which decreases from 0.564 to 0.477; when δi is 20~200mm, the corresponding weight is 0.448~0.126; when Ff is 0.01~0.02m2, the corresponding weights is 0.28~0.113, the heavy weights of other parameters are negligibly small; when δg,vw, Q0, vf,Ff,λi, δi, β1 and H increased by 30%, the corresponding changing rates of weight are -32%,-36%,-30%,-37%,-34%,-17%,-30%,1% and 0.5% respectively. Whereas, when δg, vw, Q0 , vf, Ff, λi, δi, β1 and H decreased by 30%, the corresponding weight changing rates are 90%, 58%, 42%, 78%, 56%, 17%, 44%, -1% and 0.5% respectively. The weight changing rates of the freezing and refrigerated zone are almost the same. When vw, Q0, vf, Ff, δg, λi, δi and β2 increased by 30%, the corresponding weight change rates of all the sensitive factors gradually increases in the negative direction except β2, which increases in the positive direction, the corresponding weight changing rates are -23%,-39%,-35%,-29%,-46%,-19%,-20%,-5%. When vw, Q0, vf, Ff,δg, λi, δi and β2 decreased by 30%, the corresponding weight change rates of all the sensitive factors gradually increases in the positive direction except β2, which increases in the negative direction, the corresponding weight changing rates are 104%, 50%, 66%, 54%, 138%, 20%, 25%, 5%, respectively.

Abstract:Solar withering is the first and essential processing during Oolong tea manufacturing, which can improve and develop a pleasant scent, especially for the floral fruity scent. The traditional technology employed hot air withering in rainy days, which lacks of light radiation, the quality of Oolong tea has no fruit floral odour and the taste is niffy green and astringency. In order to make up the light waves in rainy days or instability sunlight, an artificial light source could be considered for quality improvement during withering process in Oolong tea. In this study, solar, LED (red, yellow, blue) and dark treatments were projected for the test of physiological response, physicochemical, aroma, sensory evaluation and efficiency. Firstly, the constant temperature and humidity containing LED resource withering device for Oolong tea was developed, mainly including LED panel, air circulation channel, temperature/humidity transducer and uniform plate. The temperature/humidity transducer was applied to control the fixed conditions; Air circulation channel was projected as a medium to dehumidify and ensure the circulation of air in the box. Secondly, the test of physiological response indicated that fresh tea leaves plucking from tea plants had a limited capacity to absorb light, the net photosynthetic and transpiration rate of tea leaves increased at first and then decreased, reached peak at 10~15min; However, the dark treatment remained negative value(-2.5μmol/(m2·s)), mainly conduct respiration action, and when photo synthetically active radiation was 300μmol/(m2·s), the time of withering by 30min could be well. Thirdly, the test of biochemical component indicated that treatments exposed to different light significances increased the content of water extracts, amino acid, soluble sugar and flavones, boosted the conversion of polyphenol and decreased content of caffeine. Then, the volatile components of different treatments were assayed by chromatography-mass spectrometry detection (GC-MS). Principal component analysis method was used to evaluate the results. In contrast to dark treatment, the relative content of alphafarnesene and nerolidol increased by 11.42% and 30.65%, respectively. The score of aroma quality exposed to solar was the highest, yellow and blue light had a bit better than red light, and dark treatment ranked the last. The sensory evaluation of quality in raw tea showed a similar trend to the results of principal component analysis. Moreover, based on light withering ,the productive efficiency can be improved by 2.6 times, the grade of tea quality increased 1~2 levels, and the economic benefit enhanced by approximately 63%. In conclusion, light can regulate and improve the taste and volatiles of Oolong tea, selecting LED as an artificial light to substitute for solar withering could be a promising technology, especially for the standardization during Oolong tea manufacturing.

Abstract:The degree of water stress is an important life index for characterizing plant health. In addition, water stress is a reliable foundation of plant precise tending technology system. Therefore, to study the realtime detecting method of water stress for plants has important theoretical significance and practical application value. The research progress of detecting methods of water stress was discussed from two aspects of physiological indexes(stem flow, water potential, transpiration rate, stem water content) and morphology(2D image, 3D image, stem diameter, spectral feature). The detecting theory of each method was also expounded. Compared with each other, advantages and disadvantages of each method were analyzed from the point of practical application. Detecting methods based on physiological indexes had higher measuring precision. But it had complex operation progress and varying degree of destruction to plants. Detecting methods based on morphology had advantages of nondestructive, quick and simple operation. But it had relatively larger measuring error. Some international production organizations and its relative products which had been widely recognized for detecting water stress were also recommended to researchers. Eventually, two research focuses were proposed based on each methods advantages and disadvantages.

Abstract:As an emerging technology, internet of things (IOT) has been widely used in the greenhouse environment monitoring. Because of complexities of greenhouse environment, unreasonable system design can lead to data incorrectness and system unstability. Hierarchical model based on the architecture is instructive to the implementation of IOT. However, the architecture model does not provide a system architecture modeling tool and a model validation method. In comparison, modeling and model validation method based on timed automata theory are effective means for IOT modeling. It could improve the stability of the system and ensure the correctness of the system during system design. Based on the analysis on the intelligent greenhouse monitoring IOT system, from the perspective of system implementation, the hierarchical redivision was made based on the greenhouse environment monitoring IOT system. Continuously, the corresponding components of different layers were modeled by using timed automata theory modeling. On the basis of subsystem model, the timed automata network model was formed. Ultimately, the system logic correctness verification and system implementation timing verification were made based on the established formalized model by use of UPPAAL, the timed automata modeling tool. The results show that UPPAAL and timed automata theory can realize modeling and model validation of the intelligent greenhouse IOT system. Moreover, the correct model analysis in system design can avoid design errors, reduce the design defects and avoid risk in system operation. Thus, it can enhance system stability and reliability to ensure the correctness of the system.

Abstract:To avoid the harms caused by the peak ammonia and nitrite produced during the ammonia release period, and increase the productivity and reduce the cost, operations under variable flow rates were investigated. To obtain the proper parameters for variable flow rates, the characteristics of tilapia ammonia release were firstly studied. After then, the effects of different flow rates on the nitrification rates and water qualities of recirculating aquaculture system (RAS) were studied. The results showed that during feeding interval, the highest ammonia release rate (0.21~0.23g/h) was found in 4~8h, 〖JP2〗while in other stages the ammonia releasing rate was 0.08~0.09g/h. Moreover, no obvious effects of flow rates on nitrification abilities were observed and the maximum ammonia oxidizing rate (7.72g/(m3·h)) 〖JP〗was higher than the maximum nitrite oxidizing rate (7.21g/(m3·h)) in nitrifying biofilm, indicating that mass transfer did not greatly affect the nitrification process. Besides, high flow rate (750L/h) in RAS produced lower ammonia and nitrite than those of low flow rate (375L/h), which also exhibited peak values of ammonia (3.26~3.37.mg/L) and nitrite (1.32~1.45mg/L) exceeding the permissive concentrations for tilapia in 12h. Therefore, the RAS was operated at 750L/h in 4~8h and 375L/h in other time during feeding interval. Lower ammonia and nitrite concentrations (2.03~2.24mg/L and 0.56~0.62mg/L) were obtained during the peak stage of ammonia release under variable flow rates. This operation could be achieved just by providing additional pumping for 4h under 375L/h during the peak stage of ammonia release, and it could be a reference for economical RAS technique.

Abstract:To provide reliable data on the indoor environment in livestock buildings, continuous measurements were conducted in two commercial naturallyventilated pig weaner barns in eastern China. The barn floors were partiallyslatted and pig manure was removed daily. Indoor temperature and relative humidity (T and RH), and concentrations of carbon dioxide (CO2), ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4) were continuously measured with multipoints monitoring for one year. Hourly means of barn T and RH were ranged from 0.9℃ to 42.0℃ and 31.1% to 97.7%, respectively. Hourly mean CO2, NH3, H2S, and CH4 concentrations were ranged from 423mg/m3 to 3534mg/m3, 0.11mg/m3 to 49.7mg/m3, 0.9μg/m3 to 41.7μg/m3, and 0.1mg/m3 to 17.7mg/m3, respectively. The yearly average barn T and RH were (25.6±8.6)℃ (yearly mean ± standard deviation) and (71.4±11.7)%, respectively. The yearly average CO2, NH3, H2S, and CH4 concentrations were (1.982±744)mg/m3, (10.9±8.4)mg/m3, (8.2±5.2)μg/m3, and (2.9±1.9)mg/m3, respectively. Diurnal and seasonal variations of T, RH, and gas concentrations were clearly shown. The minimum and maximum hourly mean T and RH, and the maximum hourly mean CO2 and NH3 concentrations exceeded the relevant China National Standards for commercial pig weaner barns. However, the maximum H2S and CH4 concentrations were at safe levels for animal health and barn safety. The longterm highfrequency monitoring system has been approved as an appropriate technique for assessing air quality and environmental condition in animal building, the results also indicated that piggery housing system design and ventilation system optimizing still need further exploration in eastern China.

Abstract:The high temperature in summer causes heat stress in dairy cows, spray cooling system is one of the most effective physical cooling technologies that is widely used in practice. The laser precipitation monitor (LPM ) was used to measure droplet size ,droplet velocity and intensity. Six kinds of standard fanshaped nozzles (9010, 9030, 9060, 9080, 90100, 90120) were measured with LPM under 0.15MPa, 0.20MPa, 0.25MPa pressures, the droplet distribution, the relationship of droplet diameter and spray flow, single droplet kinetic energy, spray intensity was analyzed. The results show that: the droplet distribution normally distributed model and average droplet diameter are ranged from 0.475mm to 1.210mm under 0.15MPa, 0.20MPa, 0.25MPa pressures of six different nozzles. Droplet diameter has a linear relation with spray flow (R2>0.96). 15%~20% of droplet diameters within 0.125~0.250mm were sprayed by nozzles of 9010 and 9030 type, which make it easy to drift but not suitable for cows evaporative cooling. The single droplet kinetic energy along with the water droplets was increased with the increase of droplet diameter under three different working pressures, showing a power relationship (R2>096). The mean nozzle spray intensity and mean droplet diameter show an exponential relationship (R2>096). The average intensities of spray were all greater than 72mm/h, which satisfied the purpose of cows spray cooling system. The experiment concluded that the average drop particle diameter are 0.801mm (9060), 0.914mm (9080), 1.047mm (90100) and 1.210mm (90120), which could cool cow from 39.3℃to 37℃, using 85s, 75s, 48s and 30s, respectively.

Abstract:In order to improve the classification accuracy and reduce computation complexity, a hyperspectral remote sensing data classification method based on sparse nonnegative leastsquares coding was proposed. By adopting nonnegative leastsquares, the test samples were expressed as a linear combination of training samples, and the obtained coefficients were used as its feature vector. As a result of the nonnegative constraint, the feature vectors were sparse, which can not only improve the efficiency of the proposed algorithm, but also enhance the discrimination performance of algorithm. At last, the minimizing residual was used to classify the test samples. The experimental verifications of the proposed method were carried out on AVIRIS Indian Pines and Salinas Valley hyperspectral remote sensing data, the classification accuracies of the proposed method were 85.31% and 99.56%, and the Kappa coefficients were 0.8163 and 0.9867, respectively. The proposed method was compared with PCA, SVM and SRC in terms of classification accuracy and Kappa coefficients on two databases, experiment results showed that the proposed method was superior to PCA, SVM and SRC. The proposed approach was valuable for hyperspectral data classification with low computational cost and high classification accuracy, it was a better method of hyperspectral remote sensing data classification.

Abstract:This article proposed a new method for fast measurement of the volume and surface area (VSA) of spheroid agricultural products based on 3D wire frame model via image processing using an Android device (AD). The spheroid product counting algorithm software was developed in Java combined with OpenCV library that uses AD to measure the VSA of spheroid agricultural products. The target photos were taken in normal conditions by AD. The image processing was used to get image, segment image, generate binarization image, filter noise, and calculate the VSA according to the coordinate of threedimensional wireframe model. Using this method to measure the ball with different diameters at six distances that between 100mm and 350mm, and the segment spacing was 50mm, which verified that the camera distortion was less than 0.3%, and the contour size of the measured object had scarcely effect on the measurement accuracy. The proposed method was applied to measure the VSA of 10 different citrus, apple and pear, and then all the fruits were measured by drainage method to get their volume and scanning method to attain their surface area. The test result shows that the correlation coefficient among proposed method, drainage method and scanning method was more than 0.98. The results indicated that the introduced method could be utilized as a rapid and nondestructive method for the AD measurement of different spheroid produces of agricultural products.

Abstract:Leaf area index (LAI) is one of important parameters of quantitative description of leaf growth situation. Compared with effective LAI which is influenced by gathering condition among leaves greatly, actual LAI can reflect the real crop growth status more accurately. Terrestrial laser scanning (TLS) can obtain high precision crop structure information quickly such as height and biomass. But in terms of leaf area information, the major part is effective LAI. Reference to the idea of voxelization, the method was put forward for estimating actual leaf area of maize according to the leaf and its projective plane’s mathematical relationship in voxel, which makes full use of TLS’s advantage of gathering vertical information. The point data which can perform maize actual growth state as the data source directly. And the maize point cloud was divided into a series of leaf unit by voxel. The leaf unit area based on the leaf and its projective plane’s mathematical relationship in voxel were calculated. Then the maize actual leaf area was calculated. The different TLS was used to obtain four sample’s maize point clouds which were different in varieties and scales in both Beijing City and Hebei Province, respectively. The point obtained from sample points (No. 1, 2, 3) is individual maize point, and the actual LAI was calculated in different voxel sizes. The main conclusions are as follow: calculated LAI has a good correlation with measured LAI as all of decision coefficients are greater than 0.8, it proved that this method is credibly. The optimal voxel size is 0.17cm, 0.15cm and 0.15cm, respectively. Relevant with the optimal voxel size, RMSE is 61898cm2,44058cm2 and 42844cm2 respectively, the relative error between the plant total leaf area is -2.678%, 0.619% and -0.474% accordingly. The result means that this method has a high accuracy. In the sample point No.4, the relative error between calculated LAI and measured LAI is -14.663%, the calculated LAI is smaller than measured LAI. All in all, the method about estimating actual leaf area of maize according to the leaf and its projective plane’s mathematical relationship in voxel is feasible with high precision.

Abstract:As the important transmission part of the vehicle vibration, the suspension bushing has a significant effect on weakening the vehicle vibration. In the wheel drive electric vehicle, the broadband frequency longitudinal vibration of the vehicle body will be caused by the torque ripple of the hub motor. The traditional rubber bushing has small changes of damping characteristics in broadband frequency ranges and it will not generate high damping to weaken the vibration rapidly on specific frequency band as well. So the hydraulic bushings were used to attenuate the excitation of torque ripple in particular frequency band. Firstly, the accurate finite element model was established and applied to analyze the sensitive factors of mechanical properties of the hydraulic bushing. Then, the design of the hydraulic bushing was performed according to the results of the analyzed sensitive factors. The results illustrated that the hydraulic bushing could substantially decrease the influence on the vehicle body longitudinal vibration by 13.4% whining the range of 0~120Hz through the reasonable parameters design of rubber shear modulus of the hydraulic bushing, the cross section area of the channel and the numbers of channels, which also supplies the reference of the suspension structure design of the distributed driving electric vehicle.

Abstract:In order to seek for the effect factors on turbocharger efficiency, and explore effective methods to improve turbocharger performance, the turbine of a turbocharger was taken as the study object. The improvement of isentropic efficiency, which is a key parameter to evaluate the performance of a turbine, is treated as the main optimization target based on the design of experiment (DoE) method. The characteristic blade curve of turbine, which is a mathematical method to describe the shape of blade and includes 50 parameters, was reasonably selected and adjusted to fit the turbine. According to the original turbocharger, a computational fluid dynamics (CFD) model was established, and it was verified through a turbine hot gas experiment. The calculation values were in good agreement with the experiment values, and the maximum errors were 512% in mass flow rate and 2.18% in isentropic efficiency. 14 parameters describing turbine blade shape were selected out as design variables from the 50 controlling parameters of characteristic blade curves, and then the orthogonal matrix method was carried out on the design space. According to the results of simulation calculation, five parameters of high sensitivity were selected. Combined with CFD simulation, the optimal Latin hypercube design method was employed to acquire the distribution scheme of characteristic sample points and the simulation data within the sample space, through which a response surface approximation model was established accordingly. Based on the response surface approximation model, a kind of combinatorial optimization method combined with multiisland genetic algorithm (MIGA) and sequential quadratic programming (SQP) was employed in the process of optimization simulation calculation. The results of optimization simulation showed that the decreasing of the optimized circumferential bending degree of the turbine blade and the inclination angle of turbine blade at the entrance leaded to the decreasing of vortex intensity in the flow tunnel, therefore flow field distribution was more uniform and the flow losses was reduced. The isentropic efficiency of the turbine was 74.04%, which enhanced by 2.16 percentage points compared with the original turbine. This study can improve the design efficiency of the turbocharger and could be a reference for the design and optimization method of turbocharger turbine blade shape to some extent.

Abstract:Although Landweber method is a classical algorithm for image reconstruction in electrical capacitance tomography (ECT) system, the application of Landweber method in multiphase flow detection is limited due to its semiconvergence. To solve this problem, this paper analyzed and proved the semiconvergence of Landweber method mathematically so as to explore its physical properties. Based on this, an improved Landweber method with full and stable convergence was proposed by structuring a compression operator for Landweber. Then the “soft field” characteristic of sensitivity field in ECT sensor and its effect on sensitivity distribution, which is an important basis for image reconstruction, were analyzed. The sensitivity distributions for each typical electrode pair under different flow patterns were given in threedimensional graphics. As ignoring “soft field” characteristic leads to inconsistency of the best iteration times of Landweber for different flow regimes, an adaptive iteration stopping criterion was proposed. The criterion is based on a priori condition obtained by training a number of image samples with least square support vector machine. With this criterion, iteration can be stopped when the image reconstructed is the closest to the actual distribution of multiphase flow. Meanwhile, the effect of “soft field” characteristic on image reconstruction could be compensated. The experimental results prove that the method not only has a stable convergence, but also can improve the image accuracy by 16%~50%. Therefore, the fullconvergence Landweber method can be widely used in none realtime multiphase flow measurement and detection system for its high detection precision.

Abstract:In order to enhance the motion precision and reduce the initial error of the pitching mechanism which is used in the wind tunnel experiment, a novel error optimizing method was proposed. This new error optimizing approach is based on an improved ant colony algorithm. Firstly, three independent error sources which have influences on the motion precision of pitching mechanism were found and the mathematical models of three error sources including the radius of arc guide rail R, the length of connecting rod L and the installation position of linear guide rail yOa were established, respectively. The effect of each error source with the method of controlling variables was analyzed. Secondly, according to mathematical models of each error source, the mathematical model of three combined errors in the pitching mechanism was established. Based on the derived ant colony algorithm which is used in the error analyzing, the error optimizing problem could be converted to an optimizing problem of multiplied objectives. Finally, compared with results which utilize traditional Newton-Raphson iterative method, the motion accuracy of improved ant colony algorithm was higher, and the accuracy can reach a level of 10-5 mm. The compared results could also prove that the improved algorithm has a better global optimizing ability and it could avoid undesired effects of initial error in the structures when adopting the improved algorithm. The correctness and effectiveness of this method were confirmed by simulation with Matlab. In conclusion, the proposed approach was certificated to be effective and applicable in the engineering field.

Abstract:In order to reveal the efficiency characteristics of axial piston pump and improve the accuracy of efficiency characteristics mechanism model under the whole working conditions, a semiempirical parametric modeling method based on mechanical forward and backward inference for piston pump efficiency characteristics was proposed. Considering the volume loss caused by oil compressibility and the piston pair coulombs friction formed by overturning moment, the flow and torque loss mechanism models were established. Then the nonlinear changing regularity of system parameters contained in the composite parameters of mechanism models was analyzed and the composite parameters empirical formulas were fitted based on measurement data. The piston pump efficiency characteristics semiempirical parametric model was obtained. The results show that average flow and torque loss estimation error are respectively within 3% and 1% over wide operating ranges of speed 500~3000r/min and pressure 2~24MPa. Composite parameters and corresponding loss energy proportion reflect the efficiency characteristics of piston pump directly. The rapid changes of system parameters, such as oil effective volume elastic modulus and coulombs friction coefficient, are the fundamental reasons of volumetric efficiency and mechanical efficiency unable to upgrade again and the piston pump efficiency decreased under extreme conditions. The models established in this paper can be used to investigate energysaving optimization design, performance evaluation, performance degradation and failure mechanism analysis of piston pump deeply and realistically.

Abstract:Surrogate models are often used to replace expensive simulation models in complicated engineering problems. The common practice is to construct multiple metamodels based on a common training data set, evaluate the accuracy, and then use only a single model perceived as the best while discarding the rest. This practice has some shortcomings as it does not take full advantage of the resources devoted to constructing different metamodels and increases the risk of adopting an inappropriate model. However, ensemble technique is an effective way to make up for the shortfalls of traditional strategy. In order to improve the efficiency, accuracy and robustness of the surrogate model, an optimal iterative weight factors method for constructing ensemble of surrogate model was proposed. At first, the leaveoneout cross validation strategy and PRESS criterion were presented to calculate initial weight factors. Then, an iterative process for the weight factors was conducted and at the same time the weight factors were updated until an ideal prediction accuracy of the ultimate ensemble of surrogate model was reached. To evaluate the effectiveness of the proposed method, three metamodels and five ensembles of surrogate model for three benchmark problems and an engineering problem were constructed to compare their performances of efficiency, accuracy and robustness. Results show that the proposed method can not only get a higher accuracy and robustness surrogate, but also shorten the time of constructing surrogate model evidently.

Abstract:In order to realize kinetostatics analysis of spatial 4-UPS-RPS 5DOF parallel mechanism, the expression of kinetostatics was derived by d Alembert principle, and the force state of mechanism was analyzed. Firstly, the model of inverse displacement, inverse velocity and inverse acceleration of 4-UPS-RPS parallel mechanism were educed. And then, the kinetostatics model of 4-UPS-RPS 5DOF parallel mechanism was established by the d’ Alembert principle, the expression of driving force and constraining force were deduced. Finally, combined with examples, the driving force of driving limbs and constraining force of spherical hinge on moving platform were carried out by numerical calculation and virtual simulation, separately. The results of force analysis shows that the driving force of driving limbs and constraining force of spherical hinge on moving platform are varied with the position and posture of 4-UPS-RPS 5DOF parallel mechanism, and the force value obtained by numerical calculation and by virtual simulation are basically the same. So far the numerical verification and virtual simulation verification of the kinetostatics analysis results are realized. The research can not only provide theoretical basis for solution of driving force, constraining force and structure design of 4-UPS-RPS parallel mechanism, but also suggest a way of thinking about force analysis for other spatial parallel mechanism.

Abstract:In order to reduce the misdetection ratio and false detection ratio of small casting defects in X radiographic testing，a dynamic defects tracking and detection method based on selective attention mechanism and deep learning feature matching was proposed. The misdetection of image sequences was eliminated with attention region detection of individual images and the false detection was also eliminated with feature matching among the image sequence. In the phase of individual images detection, a search method based on central-peripheral gradient was proposed to simulate the central-peripheral difference operation of biological vision. And the gradient threshold was defined. Then by comparing each regional gradient with threshold, the suspicious defect area was directly detected according to the gradient threshold. The defects did not need to be segmented from the suspicious image area. So the method avoided the great influence of the defects segmentation accuracy rate to defects tracking. In the phase of tracking among the image sequence，referencing to the deep learning hierarchy of human visual perception system, a deep learning network based on convolution neural was established. The gray level signal of the suspicious defect area was directly used as input. The network could automatically extract the essential feature which made up the deep learning feature vector. The similarity of feature vector was defined based on Euclidean distance. Defect tracking was achieved by similarity matching of suspicious defect regions in continuous frames. Then the noise and other false defects were eliminated. The experiments show that the false detection rate and the misdetection rate are less than 3%. The detection accuracy rate is more than 97%，which proved the method is advanced and effective.