Abstract:In order to improve the field working performance, a kind of monitoring device for cleaning loss of combine harvester was proposed which primarily consisted of a monitoring sensor, signal conditioning circuit and an indicator. The results showed that the monitoring method and device for cleaning loss of combine harvester performed well. When the forward speed was 0.8 m/s, the error was 3.57%. Through the application of device during field work, the operator was informed of real time cleaning loss by using indicator light and alarm.

Abstract:To obtain the law and optimize factors of airflow field on the air and screen cleaning device, using the CFD software of Fluent, the numerical calculation and orthogonal experiment were implemented by changing three parameters: the obliquity of fan, the rotational velocity of fan, and the included angel of sieve. The influence law was analyzed and the airflow field was optimized by experiments results. The optimized results showed that the obliquity of fan had a great effect on the separation. The mixture of the grain and the blighted grain could be separated efficiently when the obliquity of fan was 25°, the rotational velocity of fan was 700 r/min , and the included angel of sieve was 20°.

Abstract:With the aim to deal the problems of the impurity cleaning materials and cleaning fan for D2 models of grain combine harvester, the special structure performance of cross-flow fan with double channels and herringbone variable inclined impeller was discussed from a point of view on cleaning system, including design of herringbone variable inclined impeller and the special structure of volute separation and cleaning air duct. The bench test shows that features and regulation of the orifice free jet meet flow distribution requirements of the pre-cleaning and wind screen cleaning. The matching test to the J4 models showed that the statistical average index were as follows: feed rate of 4.81kg/s, cleaning feed rate of 2.65kg/s, cleaning loss rate of 0.17%, grain impurity rate of 0.65%. The rethreshing thrower works properly.

Abstract:In order to reduce the consumption power and improve the working performance when corn snapping unit is working, the overall structure of corn snapping unit was designed, then the key structure and kinematic parameters were analyzed in theory. After that, the 3 D model of corn snapping unit was established by using Pro/E according to the design parameters. Finally, the power and noise level were tested at the different rotate speeds in testing bed. The results showed that the consumption power and noise level were too high when this corn snapping roll was working without load. After changing the finger rotor, the consumption power rose at low speed and dropped at high speed in contrast to before changing.

Abstract:The structure and motion parameters of corn header have clear influence on working performance of corn harvesting machine. The relationship between picking corn cob power and idling power of ejector roller and the influences of ejector roller speed, auger speed and picking board gap distance on broken rate of corn stalk were studied by field test. The results showed that idling power of ejector roller was larger than its picking corn cob power. The field test also showed that with the increase of ejector roller speed, the lose rate and damage rate of corn ear decreased. When the ejector roller worked in a high speed, the lose rate and damage rate were lower at a larger picking board gap distance. With the increase of ejector roller speed, both broken rate of corn ear and corn stalk decreased. The broken rate of corn ear was lower and broken rate of corn stalk was higher at a larger picking board gap distance.

Abstract:In order to research the factors that affect the corn stalk cutting force and cutting power consumption, field reciprocating cutting test bench for crop stalks was developed. The test bench could switch to a different shape of the blade. The cutting speed could be adjusted in a range of 0~2.5 m/s. The cutting angle could be adjusted in a range of 0°~35°. The curves of cutting force changed with time were obtained by the experiment. The cutting power consumption was calculated according to these curves. The effect of blade shape, blade opening angle, cutting speed and cutting angle on the cutting force and power consumption were analyzed. The experimental results showed that the error of test bench data was less than 1.12%. With the increasing of cutting speed and cutting angle, the maximum cutting force and cutting power consumption were both decreased gradually. The cutting force of zigzag blade was smaller than that of smooth blade. The cutting force of 20° cutting angle was smaller than that of the other angle.

Abstract:In order to study the cutting effects of corn stubble cutting and returning device, orthogonal experiment was conducted from three factors, including stubble cutting height, stubble cutting linear velocity and operating speed. Each factors performed three levels. The experimental data were analyzed in SPSS software. The results showed that the optimal operation combination was: stubble cutting height of 15 mm, stubble cutting linear velocity of 12.385 m/s and forward speed of 0.8 m/s in a given level. Single factor experiment was conducted on stubble cutting height. The drawing was plotted and the data was fitted by Origin software. The computation indicated the highest value of stubble cutting height for finishing stubble cutting work was 22 mm under fixed stubble cutting linear velocity of 12.385 m/s and forward speed of 0.8 m/s.

Abstract:A tangential-longitudinal axial combined threshing and separating device was designed in order to reduce the loss of the rape when harvested. Kinematic analysis and high speed photograph were carried out on the course of the material flowed into the entrance of longitudinal roller, and the simulation analysis on the movement characteristics of rape cane moved in the longitudinal roller was done also by using the software ADAMS. The result showed that the materials could be flowed smoothly when the installing angle of longitudinal roller was 20° and the initial phase angle of telescopic tooth mechanism was 0°. The trajectory of rape cane moved in the longitudinal roller was a spiral along the inner wall of the roller shell. The impact between rape cane and teeth occurred in the radial plane.

Abstract:The longitudinal axial threshing and separating unit and the tangential longitudinal axial combine harvester were used to conduct comparative experiment on spike tooth, combination of spike tooth and short rasp bar, short rasp bar and long rasp bar. The experimental results showed that the loss ratio before threshing and the threshing rate of short rasp bar were 4.58% and 95.38%, respectively. Comprehensive threshing and separating performance were better than other threshing units and could relieve cleaning load effectively.

Abstract:By using the self-designed threshing apparatus test- bed, single- factor tests of roller- speed and tooth- angle were carried out and the values of these two factors were obtained. On this basis, the three factors orthogonal test, including the speed of the roller, the mesh aperture and the thresh gap, was researched. The two factors regression experiment, including the roller speed and the thresh gap, was also studied. Optimum parameter combination of threshing apparatus was obtained. When the mesh aperture was 14 mm, tooth angle was 0°, thresh gap was 18.5 mm, roller speed was 927 r/min and roller length was 700 mm, the threshing loss rate was 2.71% and the trash content was 19.20%.

Abstract:In order to find the optimal combination of the structure and working parameters of comb type cotton picker harvesting device, the experiments were conducted. A central composite rotatable orthogonal experimental design of response surface methodology was employed to find the optimum combination effect on working properties. The three parameters, including working speed, comb space and vibration frequency of comb, were selected as input variables. Picking rate and loss rate were selected as response functions. Experimental results indicated that the most optimum combination region was: working speed of 0.45 m/s, comb space of 51 mm, and comb vibration frequency of 2.65 Hz, the picking rate was 96.5%, the loss rate was 2.8%.

Abstract:For agronomic requirements for cotton topping and unsatisfactory profiling effect of the existing machine, a kind of vertical lift type single profiling cotton topping machine was designed. Its structure and working principle were proposed. Central composite test was used on the factors which had effect on profiling effect and quality of topping of the proposed machine. The quadratic regression model of correlation coefficient and walking speed, profile plate and cutting distance, and pump flows were built respectively. The optimal structural and operated parameters were obtained by analyzing the response surface of model. The results showed that, when the travel speed was 0.86 m/s, distance profile plate with cutter was 0.543 m, and the pump flow 4.69 L/min, the best profiling effect and topping quality could be achieved with a correlation coefficient of 0.961. The field test showed that the optimized program was feasible, which provided theoretical basis for design of vertical lift type single profiling cotton topping machine.

Abstract:A type-L conveyor cleaning separation mechanism was designed. Virtual prototype model was established by using dynamics simulation software ADAMS. Based on the analysis of single fruit pods-screen surface, much fruit pods-screen surface and pod group-screen surface contact impact, the average impact load was obtained which affect the size of screen below. The movement rule of peanuts collision was analyzed. Results showed that the proposed mechanism could better complete conveyor cleaning separation operation under the given conditions.

Abstract:To reduce the inefficient of tomato harvester pickup mechanism and avoid the fruit injury and blockage, the movement trajectory of tomato harvester pickup mechanism was optimized. Firstly, the motion mathematical model of mechanism was established and parameterized in ADAMS. And then, the effect of main parameters on motion trajectory was analyzed. The jitter of pickup mechanism and tomato feeding stability in the process of harvesting were taken as optimization goal. The parameter optimization analysis was performed. Finally, a set of optimal parameter combination was obtained. In this combination, the mechanism had good movement characteristics, which could meet the agronomic requirements of tomato harvest.

Abstract:The cutter was simplified to a vertical over-hung rotor-bearing system. The slant crack was set near the junction of shaft and disk, only considering two nonlinear factors: the slant crack and the nonlinear cutting force. 3-DOF dynamic equations of the system were founded. Based on this model, a stiffness calculation model of opening slant crack was chosen and the dynamic characteristics of slant cracked cutter were investigated by numerical simulation. The results showed that, when the system was under the action of crack, the orbit of the shaft center and frequency components of the cutter were significantly different from that without the crack. When n was 800 r/min, as the crack depth increased, the shapes of orbit of the shaft center varied comparatively great and the corresponding displacement amplitudes tended to increase.

Abstract:In order to solve the problem of large loss in herbage dry and low retention of nutrition for dry harvesting technology process, theory analysis and equipment design was carried out. Wet harvesting technology process was proposed. The technology theory, process route and key equipment were described. Comparisons of dry harvesting technology process and wet harvesting technology process were performed. The results showed the advancement of wet harvesting technology process.

Abstract:Type 9HS-170 yellow corn forage harvester was designed and the overall structure and working principle of the machine was elaborated. The roller device and toss blower which were the core components of machine was analyzed. Trajectory of any point in circular arc section of work of moving blade was trochoidal, through the analysis of the theory of roller device. According to the mechanical properties of corn stalk, the corn stalk could be cut off to be suitable for livestock to chew in cases with fixed blade to cooperate and linear velocity of moving blade of 38.6 m/s. Moreover, peripheral speed of blade terminal was 35.7～42.8 m/s and there was secondary flow in toss tube, through numerical simulation and analysis of the air flow field of toss device by using the software of Fluent. Overall, the design of toss device was reasonable. The field experiment was conducted. The results showed that safety performance and operation performance of type 9HS-170 yellow corn forage harvester were good. The average productivity of machine was 0.7 hm2/h. The average loss rate was 2.8%. The stubble height was 87 mm. The bearing temperature rise was 7℃.

Abstract:According to the harvest characteristics of low yield per unit and grass ratio of gramineous herbage seeds, high moisture content of plant stem and leaf when the seeds matured, and not suitable for all feed gain, the harvest principle of threshing prior to cutting was proposed. The main working parts, such as collector, brush roller and whole structure were designed. Also the parameters were selected. Test results listed as follows: the working speed of 9.0~9.7 km/h. When it was used to harvest elymus dahuricus, elymus sibiricus and Chinese wildrye, the harvest ability were 2.8 hm2/h, 2.8 hm2/h and 2.6 hm2/h, respectively. The comb brush loss rate were 1.41%~1.43%, 1.33%~1.51% and 1.54%~1.70% respectively. The fuel consumption of harvesting elymus dahuricus was 24.6~25.6 L/hm2. The imports of wind speed, leakage of wind speed and the exhaust wind speed of harvesting machine were 19.0 m/s, 14.9 m/s and 3.9 m/s, respectively.

Abstract:Aiming at poor stubble quality, high loss cutting rate and winding leakage for cutting young and small diameter caragana microphylla of rotary cutter, a kind of reciprocating double knife shrub harvester was designed, which using double crank and rocker mechanism with no fast returning characteristic to drive two sets of knives move and cut in opposite direction. The relation between the displacement, velocity and acceleration of the cutter with crank rotation angle was analyzed. And the double-acting blade cutting speed ratio was analyzed and tested. The results showed that it was best to harvest 2 years old caragana microphylla by the machine when the machine forward velocity was 1.0 m/s and cutting speed ratio was 1.6. The fraction defective of stubble height was 2.3%, the broken stubble rate was 3.3%, the miss cutting rate was 2.3%, the recutting rate was 2.7%, and the productivity was 0.38 hm2/h.

Abstract:The structure and working principle of the self-propelled Salix psammophila stumping machine were described. And aiming at the saw blade rotation speed and walking speed matching problem of the machine, the design and experiment on the working parameters were carried out, such as cutting saw blade linear velocity and machine walking speed, and the structure of the drive chassis. Results of the trial were summarized as follows. The proper linear cutting velocity for Salix psammophila stumping was 50 m/s. And the machine walking speed was determined by the brush size and plants density. The effective uphill angle of the machine walking on sand was less than 10°.

Abstract:The driving performance of single track rubber roller driving device was studied. The test was carried on a test-bed with floating vertical pressure clamping and 2-DOF of opposite torque. The curves of compression, friction and positive pressure were figured out. In order to further analyze the deformation micro status of rubber roller, Mooney-Rivlin model in nonlinear finite element and augmented Lagrangian contact algorithm were utilized in numerical analysis. The relationship among positive pressure, adhesion area and compression was analyzed. The contact stress distribution, friction stress distribution and contact state distribution were also obtained. The simulation results of relationship between positive pressure and compression were found to be accordance with the experimental results, which verified the correctness of driving performance relationship between positive pressure and friction. The results showed that, when the positive press was 2 750 N, the maximum single static friction was 1 167 N, the macroscopic friction coefficient was 0.85, the adhesion area was 1 909 mm2, and the compression was 4.6 mm, which met the static technology demand for orchard transportation.

Abstract:A mathematical model for dynamic simulation of anaerobic digestion of dairy manure was conducted. The model included an enzymatic hydrolytic step and four bacterial steps, also focused volatile fatty acid, pH value, free ammonia inhibition, plus gas liquid equilibrium and ions equilibrium. The model was applied for the simulation of batch and continuous dry thermophilic digestion of dairy manure, and the result compared favorably with experimental data.

Abstract:The microbial pretreatment of yellow corn stover and corn stover silage was achieved via the solid state cultivation of white rot fungi. Pretreatment effects on the biodegradability and subsequent anaerobic production of methane were investigated. The white rot fungi pretreatment of yellow corn stover was accompanied by 38.3% cellulose, 42.2% hemicellulose, and 39.1% lignin degradation, while the degradation of corn stover silage was 9.9% cellulose, 23.2% hemicellulose, and 15.2% lignin. The reducing sugar yield of pretreatment yellow corn stover and corn stover silage after enzymatic hydrolysis was 195.8 mg/g and 67.7 mg/g respectively. These indicated much more composition of yellow corn stover was degradated, and more available composition retained in the corn stover silage after pretreated.The results showed that the total VS methane production of pretreated corn stover silage was 215.5 mL/g after 21 d anaerobic digestion,which increased by 29.2% more than the untreated ones and accounting 73.1% for 60 d total methane production. The biogas production of pretreated yellow corn stover was not increased. So microbial pretreatment of corn stover silage by white rot fungi could increase substrate biodegradability, and further stimulate methane production.

Abstract:In order to improve the utilization efficiency of mushroom cultivation waste, mushroom residue was used as raw material for fermentation to conduct anaerobic digestion experiments with wet fermentation of 7% TS mass fraction and dry fermentation of 16.5%～23.6% TS mass fraction. The results showed that the experimental groups at the ratio of 1∶0 and 2∶1 could gain better effect of gas production in wet fermentation, and the gas production rate were 301.25 mL/g and 300.60 mL/g respectively. The dry fermentation reaction could not be started at medium temperature of 35℃, the rate of inoculation less than 30% and the TS mass fraction higher than 19.1%. Under the TS mass fraction of 19.1% condition, the reaction could be started successfully and the highest gas production rate of 328.90 mL/g was got with high temperature of 55℃. The gas production rate was 112.40 mL/g at temperature of 45℃. The experimental results showed that mushroom residue had a high potential. The high temperature fermentation of 55℃ could avoid the acidification at dry fermentation, and the gas production rate was better than the rate of wet fermentation.

Abstract:In order to explore the biogas production characteristics of lignocellulosic feedstock, some typical materials including maize straw, rice straw, cotton straw, rape straw, herbal residue, bagasse and papermaking residue were chosen as substrates to analyze the effect of retting time, initial pH value and inoculation rate on their biogas productions. And the biogas production potential difference between mesophilic (（35±2）℃) and thermophilic fermentation (（53±2）℃) was compared as well. The results indicated that cotton straw and bagasse could not be started successfully to produce biogas without retting, but could obtain the highest biogas production after 7 d retting operation. And rape straw could be fermented successfully and even gain the highest biogas production without any retting. Among all the raw materials, rice straw could gain the largest biogas production under the mesophilic fermentation condition (352.56 mL/g). And its biogas yield could only be increased by 20.92% when the fermentation status was changed from mesophilic to thermophilic condition, which meant that mesophilic fermentation might be suitable for rice straw. Under the thermophilic fermentation condition, the silage maize straw could gain the highest biogas yield (480.00 mL/g), which was 82.49% higher than the mesophilic fermentation. So the thermophilic fermentation might be perfect for silage maize straw. In addition, the biogas production could also be increased gigantically for herbal and papermaking residues when the thermophilic fermentation condition was adopted.

Abstract:In order to obtain the engineering control measures helpful to improve the dry fermentation efficiency, taking fresh cow dung and rice straws as raw materials, the effect of gas guide measurement and leachate-recirculation on gas production from dry fermentation was analyzed under the conditions of room temperature (ambient temperature of 22～36℃)and the total solid concentration of 16%. The results indicated that biogas efficiency was improved through regulation measures including laying vertical and horizontal vent tubes. The average volume of biogas yield was up to 0.36 m3/(m3·d) (the gas yield with raw materials was 155 m3/t of total solid), higher than the comparison garage(0.28 m3/(m3·d), the gas yield with raw materials was 120 m3/t of TS) in the whole fermentation cycle(86 d). From the effect of leached with fermentation materials, it was concluded that the garage by returning spray digestive liquid every day was more effective. Furthermore, the equal flow distribution with spray device, matching of the pump selection and layout of return pipe should be in-depth researched.

Abstract:With the aim of isolating a high biomass accumulation strain and optimize environmental factors to enhance its biomass production, an unicellular green algae was isolated from fresh water samples, the morphological and genomic characterization identification of this strain was carried out by using 18s rRNA and ITS1 analysis. This newly isolated strain named EJ12-3 was identified as Desmodesmus sp. The environmental factors for biomass production of Desmodesmus sp. EJ12-3 was optimized by using response surface methodology (RSM). The experimental and the predicted values were very close which reflected the accuracy and the applicability of RSM (R2＝0.950). According to the results, the optimal condition for biomass production within the experimental range of the variables studied was: temperature of 28℃, light intensity of 131 μmol/(m2·s), light/dark cycle of 15∶9 and pH value of 6.0. Under this condition, the predicted biomass production value was up to (0.648±0.015) g/L.

Abstract:Taking liquid nitrogen filling in fresh-keeping transportation truck with controlled atmosphere for fruits and vegetables as design platform, a kind of control system regarded ARM11 series of S3C6410 microprocessor as the core was developed. In the Linux operating system environment, the system used C language and Qt interface designing language to the temperature, relative humidity, oxygen concentration sensor and actuator signal, such as refrigeration equipment, humidifying equipment, the gas adjustment equipment, ventilation equipment and so on. In the proposed system, a kind of variable air volume ventilation system was designed and a type of fruits and vegetables’ fresh-keeping parameters database was established, meanwhile, the collected data in the process of running would be stored in NAND Flash, so that user could read it in real-time and export it after the test. Test showed that the system could correctly collect the fresh-keeping parameters of fruits and vegetables in the truck, and according to the processing results, it could accurately control the corresponding actuators in time. The design and experiment provided a reference for the design of fresh-keeping transportation truck with controlled atmosphere for fruits and vegetables.

Abstract:In order to make bag pick and send accurately, reposefully and fleetly in automatic bag-delivering packaging machine, based on the mathematical model of mechanism for bag-picking, the kinematics characteristics of end actuator were analyzed. The calculation formulas of displacement, velocity and acceleration of end actuator for bag-picking were deduced. Based on the above calculation, the motions and defects of mechanism for bag-picking were summarized and improved. The kinematics curves of bag-picking mechanism were obtained with Matlab and the original results were compared with the improved one. The contrasting result showed that the curves of displacement, velocity and acceleration of modified mechanism for bag-picking were improved. The better kinematic characteristics were gotten and the expected goals were achieved.

Abstract:Effect of UV-C treatment on rice ageing, especially fatty acid oxidation and antimicrobial activities during storage was investigated. The rice was irradiated at ultraviolet of 4 W/m2 exposure intensity for 0, 10, 30 and 60 min, and then exposed or unexposed. The control rice was 0 min exposure. The changes of activities lipoxygenase-3 (LOX-3), which was the key enzyme of resulting in the rice aging, and malondialdehyde (MDA）of fatty acid oxidation metabolism products, the amount of microorganisms, respiration rate and the permeability of membrane, were researched for illuminating effect of UV-C treatment on rice ageing and obtaining optimal processing parameter. The results showed that UV-C could inhibit LOX-3 activity, and reduce the content of MDA. Among the samples, content of MDA of 30 min irradiating time and unexposed to air was shaved up the most to 62.78%, but the content of MDA of 60 min irradiating time and unexposed to air was slightly increased. In addition, exposed to air immediately could delay effect of UV-C treatment. The content of MDA of exposed to air immediately was steadily reducing and the rate of change was lesser. Similar change rule was found out including the change of the total number of microorganisms, breathing intensity, cell membrane permeability. The result indicated that treatment of 4 W/m2 exposure intensity for 30 min and unexposed to air could effectively inhibit fatty acid oxidation and antimicrobial activities of rice, delay rice aging and improve rice quality and effect of preservation.

Abstract:The starch damaging, gelatinization properties and electrical conductivity were investigated during ohmic heating for soft wheat starch suspension (5%) after a homogenization treatment at a series of pressures ranging from 20 to 60 MPa. DSC analysis indicated that gelatinization properties varied insignificantly (gelatinization degree was 1.80% at 60 MPa), and microscopy showed that most treated starch granules stayed originally. As a result, the amount of damaged starch of homogenized starch suspensions ascended from 6.56% to 7.96%. The electrical conductivity of native starch suspension increased linearly during ohmic heating. Slopes of electrical conductivity temperature curve of homogenized starch suspensions during ohmic heating highly correlated to the amount of damaged starches in the suspensions.

Abstract:Taking apples as experimental materials, effect of pretreatment of high voltage pulsed electric field on dielectric properties was studied. The effect of pulse voltage, frequency on dielectric properties was analyzed. The theory of electromagnetic field was used to analyze the influence mechanism. The results showed that equivalent capacitance and equivalent impedance of apple were both decreased when the pulse voltage and the pulse frequency increased. The parameters of high voltage pulsed electric field had a certain effect on dielectric properties. The obtained conclusion could provide reference for further research on the effect of electrical parameters on dielectric properties for different fruits and vegetables, and also parameters optimization of high voltage pulse electric field pretreatment.

Abstract:Potato was chosen as the subject of the compression experiment, and the microstructure deformation, microscopic mechanical properties, deformation and failure process were gained by the system of microscopic image and mechanical test. The fitting equation and the optimal parameters of yield strength and PEF parameter were analyzed and further optimized by SAS software. The result could provide a theoretical basis for optimizing the technologic parameter of freeze drying and the design of processing equipment.

Abstract:In order to improve the drying quality of apple slices and shorten the drying time, medium and short wave infrared was applied to drying apple slices. The drying experiments were investigated under different drying temperatures, slice thicknesses and radiation distances. Experimental results showed that the drying temperature had a significant influence on the drying processing, while the slices thickness was less significant and the radiation distance was the last. The whole drying procedure appeared a falling rate period. According to Fick’s Second Law, the water effective diffusion coefficient (Deff) was worked out. In medium and short wave infrared drying condition, the Deff ranged from 2.85×10-10 m2/s to 7.24×10-10 m2/s. The activation energy determined from Arrhenius equation was 36.58 kJ/mol. On the other hand, drying temperature had a marked impact on the color changing, while the slices thickness and radiation distance had a little influence on color value. Both high L* value and drying efficiency were ensured when the drying temperatures was 70℃，slice thickness was 5 mm and the radiation distance was 80 mm.

Abstract:In order to improve the utilization of CO2 fertilizer, the photosynthetic rate of tomato plants in the flowering stage was studied. A wireless sensor network system was used to real time monitor greenhouse environmental parameters. A LI-6400XT portable photosynthesis analyzer was used to measure the photosynthetic rate of tomato plants, and the environmental parameters of leaves were controlled according to the presetting rule. The photosynthetic rate prediction models of single leaves were established based on the back-propagation (BP) neural network. The environmental parameters were used as input neurons after processed by principal component analysis (PCA), and the photosynthetic rate was taken as the output neuron. The performance of the prediction model was evaluated. The prediction results of the models showed that the correlation coefficient between the simulated and observed data sets was 0.99, RMSE was 0.288. Furthermore, when different CO2 concentrations were selected as the input to predict the photosynthetic rate, the simulated and observed data showed the same trend. According to the above analysis, it was concluded that the model could be used as the basis of the quantitative regulation of CO2 fertilization to tomato plants in greenhouse.

Abstract:An intelligent control system for micro plant factory was designed based on embedded technology, which took the STM32 microprocessor as its core control part and programmed in the μC/OS-Ⅱenvironment. Furthermore, the real-time display and accurate control of environmental factors (temperature, humidity, light, etc) in the micro plant factory were achieved by the control system. In order to control the temperature and humidity, a fuzzy control and fuzzy decoupling method for the control of the temperature and humidity was proposed which could solve the problem of long time delay and strong coupling between them. It had high practicability.

Abstract:In order to measure and monitor the yield of solar greenhouse crops, a solar greenhouse yield monitoring system was developed. The system was consisted of three parts: a pressure sensor terminal, wireless data transmission network and software of monitoring yield. The wireless data transmission network was built and the communication among wireless network, pressure sensor output terminals and PC monitoring software was realized. The yield related information was got and the data was stored in the database to facilitate statistical analysis. The results of the analysis could help to adjust the greenhouse environment, crop growth environment and the greenhouse management. Meanwhile, the RFID tags were added on the measured vegetables to achieve traceability of the vegetable origin and other information. Experimental results showed that the system design was reasonable, reliable, easy to operate and convenient to use. The system could improve the efficiency of the greenhouse yield measurement, and it was able to effectively enhance the degree of automation in greenhouse yield. Meanwhile, this system facilitated the adjustment of greenhouse management.

Abstract:In order to measure the morphological characteristics of crop non destructively, the stem angle of tomato plant was measured by using digital image processing. The image of tomato plant was acquired in greenhouse and the image processing algorithm was discussed based on the geometric correction algorithm. The linear and bilinear model was applied and the results showed that the correlation coefficient (R2) between measurement of original image and plant was 0.50 with absence of geometric correction; when the linear and bilinear model was applied, the R2 was 0.625 and 0.723 separately. The corrected image was processed following the color space transformation, image segmentation, binary image filtering, straight line fitting and the angle calculation. The saturation image was selected and segmented by Otsu method. A good result was gained by combination the median filtering and close-open morphological method. After image thinning, the stems of the plant were simulated by straight lines based on least squares method. The angle between main stem and branch was calculated. The experiment result showed that there was linear relationship between the calculated by image processing technology and manual measurement with R2 of 0.703. The manual and automatic measurement result also showed good correlation with R2 of 0.985. It provided a method for the automatic measurement and analysis of tomato growth.

Abstract:In order to real-time detect crop nutrition content, a smart apparatus for detecting crop nutrition was developed based on NIR spectroscopy, electronics and ZigBee wireless communication technology. It was designed to work as a wireless sensor network with one control unit and several optical sensor nodes. The incident sunlight and reflective light from crop canopy were measured at the wavebands of 550 nm, 650 nm, 766 nm and 850 nm respectively, and then the canopy reflectance and some vegetative indices were calculated. The field experiments and analyses on crop growth monitoring in wheat fields were conducted. Results showed that the correlation coefficient between NDVI and chlorophyll content was higher than RVI. The chlorophyll content and the vegetation index which was calculated with the reflectance at 550 nm and 766 nm had the highest correlation coefficients (r was 0.693 9), and the prediction model of chlorophyll content was built. The r2 of the calibration model reached to 0.494, and r2 of the predicted model reached to 0.478.

Abstract:In order to detect soil nitrate nitrogrn content rapidly with low cost, an automatic multi-channel detection platform for soil nitrate nitrogrn was developed. The self-designed PPy(NO-3) ion selective electrode (ISE) was used to sense the nitrate ion in solutions. The platform response time, effects of rinsing time on platform calibration and soil nitrate-nitrogen detection were discussed with a series of standard nitrate solutions, nitrate-nitrogen contents of which were ranging from 1~250 mg/L. Testing results showed that response time of the platform was 40 s when it was used in soil nitrate-nitrogrn detection. During system calibration and soil nitrate extracts determination, rinsing operation for the system could be carried out directly with the next sample solution. And rinsing 2 times could achieve a desirable effectiveness. No significant differences were got between the results detected separately by the platform and manual operation. Also, different channels of the platform possessed similar detection performances and good consistency. The system validation results conducted with 20 soils indicated that satisfied correlation was obtained between the soil nitrate-nitrogen results detected with the platform and ultraviolet spectrophotometric method. The determination coefficient (R2) was 0.91.

Abstract:Forecast system for origin environment quality of agricultural product was proposed based on the database technology, ArcGIS Server, Flex and model theory. Taking VS 2008 and Flash builder 4.6 as the development environment, the proposed system could be used for the query of agricultural environmental information, the spatial analysis of pollutant information, and the forecasting of farmland environmental pollution. Based on the time series characteristics of heavy metal pollution in origin environment, exponential smoothing forecasting model was built to predict the heavy metal pollution. According to the monitoring data of heavy metals from January 2010 to April 2013, six kinds of heavy metals concentration prediction models were established. The analysis results showed that the prediction accuracy of models were around 90%, which meant that the exponential smoothing model could better fit the variation of heavy metal pollution.

Abstract:In order to make up for the deficiency of traditional method of 5 d for dilution and seeding method (BOD5), the on line biochemical oxygen demand(BOD) measuring instrument based on microbial sensor was designed. BOD biosensor was the combination of dissolved oxygen electrode and microbial film. Measurement of BOD using microbial membrane sensor was a fast and effective way for measuring biodegradable organic compounds in water. The principle of BOD biosensor was discussed. Whole structure of on-line BOD measuring instrument was given. The continuous sampling system and sensor signal process circuit were designed. The methods of automatic calibration, temperature control, and data process and concentration calculation of organic compounds were expounded. The relative errors of designed BOD on-line instrument with standard samples were less than 5%, and had a better correlation with the method of dilution and seeding. The designed instrument could be used for rapid determination and evaluation of biodegradable organic compounds in wastewater.

Abstract:Turbidity of water was a very important parameter in aquaculture. An integrated portable turbidimeter was developed to measure turbidity of water body based on the comprehensive measurement method combined scattering light and transmission light. It used AT89S52 microcontroller as control chip and consisted of the light emission unit, detection unit and control unit. The light emission unit comprised two sets of 860 nm LED light source and the corresponding collimating lens. The detection unit comprised two photoelectric sensors. And the control unit included the light source driving circuit, the two-stage amplification circuit and the A/D conversion circuit. The integrated detector was calibrated in laboratory and carried out field experiments. The results showed that the turbidimeter achieved a high accuracy, the calibration R2c was 0.994 and the validation R2v was 0.999, with the resolution of 0.01 NTU and the error of ± 2%. It was concluded that the turbidimeter reached the practical level.

Abstract:In order to improve the efficiency of water utilization in mountain orchards, an automatic irrigation control system based on soil moisture was designed. The system was composed of an S3C2440 ZigBee gateway, several CC2530 soil moisture sensing nodes and irrigation controlling nodes. In addition, solar batteries were applied to provide extra power and recharge lithium batteries. Using the self organized ZigBee network, the gateway collected and updated soil moisture data to internet server for decision support. Therefore, irrigation process was handled according to soil moisture. The system test in a mountain orchard showed that the wireless network had a low packet loss rate(less than 15%), and maintained soil moisture in a suitable range (above 18%) for plant growth.

Abstract:The “Golden Triangle” of MSGN (Inner Mongolia, Shaanxi, Gansu, Ningxia), a region with abundant energy resources, is a new energy base of China. To get the vegetation coverage status and its dynamic change, the 2000～2009 SPOT VEGTATION NDVI (normalized difference vegetation index) of Golden Triangle energy in MSGN region was used to calculate the maximum vegetation coverage in one-year of every pixel, and the variation between ten years was analyzed. Result showed that the FVC (fractional vegetation cover) in Golden Triangle area was increased generally from 2000 to 2009. The highest average value was 45.45% in 2008, and the lowest average value was 33.74% in 2000. The vegetation coverage was declined slightly in 2005 and 2009, and the main reasons were attributed to city expansion and regional resources development.

Abstract:The non-ionizing radiation processing with 20 s was treated on wheat seeds by using low-temperature plasma (LTP). The effect of the proposed technology on seed germination and seedling growth was analyzed. The effects of different intensities of LTP on wheat seeds (45 d after treated by LTP) were investigated to determine the optimal conditions. The germination energy and germination rate were obtained. Also, the samples were sowed in field to investigate the characteristics of seeds. The results showed that the germination energy and germination rate increased by 11.25% and 5.56% respectively for the treatment intensity of 80 W. The green weight, dry weight, root length and maximum tillers of seeds in double ridge stage were increased by 13.02%, 6.00%, 15.20%, and 38.46% compared with contrast.

Abstract:The design of tea production line was considered in a 3-D level, and it was transformed into an assembly modeling problem. At first, a position irrelevant plane layout method was introduced which made the frequent adjustment of devices’ positions unnecessary, thus the workload of designers were relieved dramatically. Then, with the orientation coding of devices and their connection relations, absolute and relative orientation of devices were determined. Finally, datum constraints were exerted to devices which realize the assemblying or positioning of devices automatically, rather than manual. According to this idea, by secondary development of SolidWorks, a program called TPLLayout was written by VB 6.0. The example showed that the system was user-friendly, and easy to operate, which improved the design efficiency dramatically, and the cost was reduced as well.

Abstract:The technologies of virtual assembly for combine harvester chassis parts were studied and the virtual reality assembly was realized. The 3-D models of the combine harvester chassis parts were created by Pro/E, and then were converted into the virtual reality models with the model conversion interface between the CAD system and the virtual assembly system. The assembly model composed of assembly object information, assembly hierarchy information and assembly constraint information was built in the virtual reality system. By using virtual reality system and the ART tracking system together, the interactive assembly of combine harvester chassis was achieved. At the same time, the interchangeability assembly method, the usage of assembly tool, and the records and optimization of assembling path were studied. With the EON software and its secondary development tool, the virtual assembly experiment of the combine harvester chassis parts were carried out. The result indicated the methods mentioned above could work availably.

Abstract:The design process and features of design knowledge of crawler harvester transmission were analyzed comprehensively. Then, the reasoning process suitable for the rapid design of crawler harvester transmission was researched. Taking the instance similarity matching algorithm as the core, the case based reasoning (CBR) was designed. And taking the constructed design knowledge base of crawler harvester transmission as a core, the rule based reasoning (RBR) method was studied. Also the CBR and RBR hybrid reasoning method was designed. On the basis of all these, the inference mechanism of crawler harvester transmission rapid design system was established. Practical applications showed that this reasoning method could better achieve the crawler harvester transmission rapid design and shorten the design cycle.

Abstract:A specific mathematical model to obtain the parameters of steering wheel alignment for large wheeled harvesters was proposed in light of multi-body dynamics technique. A comparison between the proposed model and the traditional ones was made in terms of the optimization design of steering geometry and the performance of steady-state cornering response. Results showed that both models could reach a similar computing value in the small range of steering angles. However, for large steering angles, the proposed one was more appropriate to express the steering characteristics. Through theoretical analysis and experiment validation, it was limited to adapt traditional simplified bicycle model to depict handling stability of large wheeled harvesters. Therefore, the proposed model demonstrated its unique accuracy in the calculation of parameters of steering wheel alignment for large wheeled harvesters.

Abstract:In order to solve the problem of low efficiency of transmission design and long development cycle in the traditional design process, the parametric design method was proposed. Based on the typical harvester gearbox design knowledge, the reasoning mechanism for gearbox parametric design was studied. In the environment of VC++ 2008, secondary development Pro/TOOLKIT of Pro/E 5.0 was used. A platform of parametric design of large harvesting machinery transmission based on reasoning was developed. Compared with the traditional parametric design, the proposed method did not need to consider the complex relationship among parameters of parts, components and products in the parameterized software.

Abstract:Three typical work conditions were chosen to analyze the forces of steering axle housing of wheeled combine harvester. The effect of different section forms of wheeled combine harvester on strength and rigidity of steering axle housing were studied. Then, the optimized design method of steering axle housing was put forward. The strength and rigidity of steering axle housing for a certain type wheeled combine harvester were analyzed in ANSYS. Meanwhile, its section forms and dimensions were optimized. The improved steer axle housing not only satisfied the demand of strength and rigidity, but also reduced its weight by 17.8%, and enhanced its manufacturability at the same time. The reasons for stress concentration were studied and the optimization processes were proposed.

Abstract:The VII-HPC power platform with the balance rocker suspension, variable ground clearance and variable wheel track was designed to meet special needs in the hilly regions. Variations of ground clearance, wheel track, and attitude of the VII-HPC power platform were studied by employing traditional approaches. The formula, boundary conditions and the corresponding curves on centroid height changing trends, sideslip and rollover, longitudinal slip and turning were summarized. Its stability was verified better than the ordinary tractor by simulation analysis.

Abstract:Fuzzy-PID self-adaptive control method was used in tractor’s electro-hydraulic hitch system. Firstly, the fuzzy-PID self-adaptive controller was designed, and the model of the system was built. Secondly, the performance of draft control and position control was simulated and analyzed compared with PID control. At last, a field-test bed of electro hydraulic hitch system was built. The test result showed that fuzzy-PID adaptive control had a better performance than PID control in electro-hydraulic hitch system. When the preset position stepped from 0.1 m to 0.3 m, the response time was 4 s, and overshoot was 0. When preset draft stepped from 3 kN to 7 kN, the system’s response time was 5 s, and the overshoot was 25%.