Abstract:On the basis of experiments on force-speed characteristics of solenoid valve damper, a slide model control strategy based on saturated input was put forward for a quarter vehicle semi-active suspension with solenoid valve damper, which considered the nonlinear properties of vehicle semi-active suspension and output saturation properties of solenoid valve damper with adjustable damping force. A quarter vehicle nonlinear model with semi-active suspension and a suspension reference model with simplified input were built. A slide model controller was designed for a quarter vehicle nonlinear model. Meanwhile, considering the damping force output saturation property of solenoid valve damper, an assistant analysis system was designed to generate control compensation signal in order to compensate the saturation of the slide model controller. The results of simulation under Matlab/Simulink and experiments showed that the slide model controller based on saturated input could effectively eliminate the influence of output saturation of solenoid valve damper, and make the performance indexes, such as vehicle body vertical acceleration and suspension working space, close to the corresponding ideal output of a suspension reference model. It could also optimize the semi-active suspension design and control so as to improve vehicle ride comfort.

Abstract:A hydraulic turbulent model was established based on the controllable vane damper structure analysis, and the hydro-structure of the vane was simulated. Based on the test data in the different temperature of damping force and velocity input, the parameters about the hydraulic turbulent model were identified. In the different temperature, comparison of the test data and results of calculation with the fitting parameters showed that the parameters were correct and the method was valid. From the fitting parameters and calculation result, controllable vane damp design and character analysis could be supported. The temperature could influence the damping force under the effect of high temperature and high speed, so that the damping characteristics should be obtained based on the principle of turbulence model integrated traffic parameters study finally through the simulation analysis. Parameter identified had the implications derived from the mathematical theory and clear physical meaning. It can be applied in characteristics analysis of other types of shock absorber.

Abstract:To improve the shifting quality of the automated manual transmission (AMT), a type of AMT gearshift system based on a 2-DOF electromagnetic actuator was developed. A coupling system model including electric, magnetic circuit and mechanics was built. The characteristics were investigated through tests. The output force was more than 1200N and the maximum output torque was 2.5N·m, which showed that the dynamic response was relatively fast. The gearshift process was divided into four phases. During the synchronization process, an optimal objective function of shift quality indexes was developed and the optimal control was adopted to achieve the optimal shift quality. The shift sequence coordinated control of shift out and gear selection was introduced, and the gearshift controller was designed and tested. When the equivalent inertia was 0.03kg·m2 and the speed difference was 620r/min, the results showed that the shift time was 135ms, the impact was 3.86m/s3, and the friction work per unit was 0.077J/mm2. The coordinated control method could be reduced to 11ms. The test results indicated that, combined with the designed control strategy, the novel gearshift system achieved good shift performance.

Abstract:To solve the problems of high idle speed and fuel consumption of wheeled electric drive vehicle on long downhill condition, an anti-drive energy feedback system was designed. The wheeled motors regenerative braking energy was feedback to DC bus and switched from rectifier to inverter module. The synchronous traction generator was driven by inverter as traction motor, which dragging the engine speed to the rated state, and at this time, the throttle was closed. Based on the hierarchical control idea, a three layers control algorithm of anti-drive feedback system, the up layer control algorithm of vehicle state estimation, middle layer of tracking generator rotor frequency and underlying layer of double fuzzy, was put forward. Bench test result showed the anti-drive energy feedback system could provide continuous braking force which equal to 20% of engine power, and save 15% of fuel. The control strategy has good robustness and strong driver intention recognition.

Abstract:The structure finite element model for the working device of hydraulic excavator was established, and each order modal frequency and modal characteristics of working device were gotten by analyzing the free mode of the finite element model. The key modal frequency was determined, which influenced the dynamic performance of the working device, and taking the key modal frequency as the optimization goal the sensitivity analysis was conducted for the main structural parameters to set up the dynamic optimum design variables of working device. Taking the geometric constraints and performance constraints of work device as constraint conditions, the dynamic optimization design was conducted by using augmented Lagrangian method. The instance analysis showed that the structure stiffness was improved, and the structure deformation was reduced. And the dynamic working performance and the structure stability reliability for the working device were improved.

Abstract:The characteristics of ethanol-air microscale laminar-flow diffusion combustion were investigated. Combined with experimental study and numerical simulation, the effects of surface heat loss on the flame stability in the confined space were systematically analyzed. The surface heat loss was controlled by electrical heating inside. According to the results, the electrical heating reduced the effects of heat loss and enhanced the stability effectively. Using the appropriate electrical heating power, it reached the widest stability limits of combustion. The flame feature size and temperature distribution were both changed by the electrical heating. The electrical heating raised the flame temperature. The chemical reaction rate became bigger, and the micro-flame shifed upstream. Within a certain range, the electrical heating increase was greater than the increase of the heat loss. The electrical heating inhibited the heat loss and enhanced the stability.

Abstract:With the improvement of power density of internal combustion engine, the coolant jacket structure is becoming more and more important. The design and optimization of coolant jacket depend heavily on the construction and position of the upper-nozzles, so that the flowrate measurement in the upper-nozzles will benefit those design and optimization. However, during the flowrate measurement, the construction parameters and installation parameters of the measurement rig will affect the measurement error significantly. This paper explored the relationship between these parameters and the measurement error by means of CFD numerical simulation based on orthogonal design method. In order to control the measurement error in 3%, the flow in many upper-nozzle schemes were simulate, and then the range analysis of the simulation results were achieved and the levels of each factor were optimized. After the optimization, the suitable levels of each factor were determined, and the maximum measurement error of the optimum schemes was reduced to 2.95%. At the end, the paper achieved a measurement experiment to correct the numerical simulation, and the difference between simulation error and experimental error was only 2.07% according to the experimental results, which verified the reliability of the numerical simulation and accuracy of the measurement technology.

Abstract:This paper focused on the special collision phenomenon of fruit gripping with its own characteristics of continuous energy input and restrained deformation. The gripping collision process was divided into three stages: constant-speed loading, collision decelerating and stress relaxation, and a three-stage gripping collision model was put forward under the conditions of constant static loading capacity and constant speed control mode, which was based on the stage dynamic characteristic of gripping collision process and viscoelastic Burger`s model of fruits. It was proved by test that the prediction of the peak collision force was feasible, and the predicton error under initial gripping speed of 19.2mm/s was 1.12%. By calculating with this model, it was found that time needed to grip fruit in different ripe period under initial speed of 6mm/s was 0.62~1.24s, and further raising the initial speed might have very limited effectiveness to improve the gripping efficiency. The peak collision force and fruit deformation were proportional and approximately proportional to initial gripping speed, respectively. Probability of skin rupture increased greatly with initial gripping speed. When initial gripping speed was under 20mm/s, probability of skin rupture of green ripening stage and early red ripening stage were the greatest and the least, respectively. This three-stage gripping collision model may provide helpful reference to discover the special law of gripping collision and to achieve high-speed safe gripping of fruits.

Abstract:n order to real-time achieve accurate sliding parameters between tracks of a agricultural tracked robot and ground and improve control accuracy, a dynamics equation and nonlinear measurement equation of agricultural tracked robot were deduced by analyzing working principle of an agricultural tracked robot and using dynamics principle. Then an estimation system based on the unscented Kalman filter(UKF) was designed to estimate the precision pose parameters of agricultural tracked robot. Through this estimation the system sliding parameters might be reconstructed relying on kinematics analysis, which couldn`t be directly measured before. The simulation and experimental results suggested that with careful modeling of agricultural tracked robot, the estimation system was able to provide reliable and high update rate sliding parameters, which were taken as the basis for accurate control.

Abstract:An object in the field environment usually contains two or more classes of color targets. Fast recognition of color target image is the key technology for robot positioning and operation, which is widely used in the field of military, natural disaster rescue, agricultural harvesting robot, etc. However the speed of multi-target recognition in the field environment is usually slow, which makes the visual positioning precision of robots lower at present. This paper proposed a double Otsu segmentation method based on the improved Otsu algorithm for the recognition of multiple targets. To prove the effectiveness of this method, it was used on mature litchi recognition in the field environment. First of all, in order to improve the efficiency, the traditional Otsu algorithm was improved. Then the background, stem and fruit of the target color image were respectively recognized by using the improved Otsu algorithm. Compared with the Kmeans clustering (K-means) algorithm, the fuzzy C-mean clustering (FCM) algorithm, the Otsu and K-means algorithm, and the Otsu and FCM algorithm, the double Otsu segmentation algorithm was superior to the other four algorithms on the segmentation quality and correctness rate, the running time and stability. The test results showed that the recognition time for the mature litchi by using the double Otsu segmentation algorithm was less than 0.2 s. The effectiveness of the algorithm was verified through the experiment.

Abstract:For automatically navigating and identifying branches obstacle in the picking process of agricultural harvesting robots，it is necessary to solve the defection of iterative threshold segmentation since the gray scale difference between target and background is not clear. The iterative threshold segmentation of apple branch images based on contrast limited adaptive histogram equalization (CLAHE) was proposed. Firstly，the RGB color space of the apple branch images were transformed to the XYZ andI1I2I3 color space by transformation, and the X-Y color difference factors and I2 color factor of the apple branch images were extracted to analyze their gray level difference. Then the CLAHE was applied to the image in which the gray level difference was not obvious before iterative threshold. Finally, the apple branch images were segmented from the original images. Results showed that the ratio of successful segmentation was 92%.

Abstract:A method based on color information and contour fragments was developed to identify citrus fruits in variable illumination conditions in the tree canopy, in order to guide the robots for harvesting citrus fruits. The color properties of target objects within natural citrus-grove scenes under various light conditions were analyzed, and a preliminary segmentation was put forward by fusing the Chromatic aberration information and normalized RGB model. The set of contour fragments was constructed via detecting the significant edge of Chromatic aberration map of R and B channels. The valid subset was selected by three parameters of the frament: length, bending degree and concavo-convex geometry characteristic. The ellipse fitting procedure was done to every frament, and the valid ones were chosen by the knowledge of fruit shape. The results showed that the occlusion contour were effectively recoveried under various light conditions using the proposed method, and the relative error of occlusion recovery was 5.34%.

Abstract:In order to construct colorful 3-D spatial structure of canopy accurately, apple tree canopies of maturation period were set for research object, and a PMD camera and a color camera were used to acquire multi-source organ images of apple tree canopies, which aimed at studying registration of multi-source images. SIFT algorithm was used to extract characteristic points from multi-source images and RANSAC algorithm optimized by objective function was adopted to purify feature vectors, which overcame scale change and effect of light. Bilinear mapping algorithm was employed as spatial mapping between multi-source images to avoide inaccuracy of using affine transformation to solve space mapping. The registration test in orchards with different natural environment showed that the method proposed was suitable for registration of multi source images of apple tree canopies, and the registration accuracy could be 88.2% in sunny day of light environment, 84.2% in sunny day of backlight environment, 72.7% in cloudy day. The research finding could provide maintenance assurance for picking and yielding links of apple orchard after 3-D reconstruction of canopies.

Abstract:An automatic detection method for external features of grafting seedlings based on mathematical modeling was studied. The detecting items included growth status (straight or curved, bending direction), cotyledons parameters (cotyledon flare angle, cotyledons flare spans), hypocotyls parameters (curvature, hypocotyl length, hypocotyl shaft), and other external parameters. First, image preprocessing was used to extract the binary image. Then, a reference point and its position were determined by statistic of horizontal pixels. Next, growth status was decided by a set inclination angle of the minimal bounding rectangle of the hypocotyl and its width. After that, the cotyledons span was calculated by the distance of the two cotyledons endpoint, and the cotyledons angle was computed by the angle between two lines that fitting with the bottom of flat cotyledons. Finally, the stem length and the coarse strains were obtained by doing slope compensations to two sections of stem separately which was divided at the point with maximum curvature. Results were compared with manually measured data, and shown that the coefficients of plant height, plant coarse, and cotyledon span were 0.9351, 0.8999 and 0.9034, respectively. And the relative errors of them were less than 7%, 5% and 7%, while the absolute errors of them were less than 4 mm, 0.2mm and 6mm, respectively.

Abstract:In order to analyze the influence of flow field distribution of cupule type rice seeder on seeding performance, a 2BZQZ-300 seeder was investigated with Fluent software. Models of different nozzle diameters were built and both horizontal and vertical seed were considered in seed suction model. Then, planting experiment was conducted to confirm seed uniformity. The results showed that, the static pressure was well distributed whether above the nozzle or below it, and there was no significant coupling effect of airflow to adjacent nozzles. And when the considered seed was picked up, most airflow appeared at the area between nozzle and seed. The effective stress area of seed surface increased linearly with the increase of nozzle diameter. The negative pressure in the effective stress areas obviously rised with the aperture increasing during horizontal suction, while there were no obvious varieties during vertical suction. Therefore, the seed surface stress in horizontal suction was significantly higher than that of vertical adsorption, which would be helpful for improving the adsorption rate and the stability of seed carrying. The pickup performance was enhanced when diameter of nozzle increased. Because of the coupling effect of seed and airflow, the surface thrust of a horizontal seed was obviously larger than a vertical one, therefore a horizontal seed was much easier to suck up and more stable to carry. As the test showed, seeds were well distributed in trays, and total uniform coefficient reached 94.9%.

Abstract:In order to understand the airflow speed field and deposition distribution rules and characters of a designed hanging cold sprayer, several numerical spraying models for that based on CFD technology were established. Beside that, the verification experiments were conducted. The simulation results indicate that the effective blowing distance is positively related to the blowing speed of the cold sprayer. The cold sprayer gets the minimum blowing distance at the height of 1.5m. The model gets larger ground mass-flow rate under the blowing speed of 5m/s and 25m/s. The model gets better uniformity under blowing speed greater than 20m/s and height greater than 2.0m. The consequences of simulation and verification experiments show that, in the cold sprayer’s blowing area, the relative deviation of modeling air flow field is between 10%~35%, and the relative deviation of droplets’ deposition model is between 15%~35%. As the consequence, both of the models can forecast the cold sprayer’s air flow field and the droplets’ deposition distribution correctly.

Abstract:A model to solve the electrostatic field of multiple needle electrodes spraying blade was established. The distribution regularities of electric potential and electric intensity in the space out of multiple needle electrodes spraying blade were analyzed by Ansoft Maxwell software, and the influence of different gap of needle electrodes on electrostatic field was researched. Meanwhile, the particle sizes of the droplets atomized by the spraying blade with different gap needle electrodes were measured by laser particle size analyzer and the distribution law of the droplets was analyzed by computer. The results indicated that the highest electric intensity near the needles could be promoted to 2.7×106V/m by the multiple needle electrodes, and the amplitude variation of electric field near the needle electrodes was the maximum. A region with high electric intensity uniform distributed could be formed when the gaps of needle electrodes were 2mm which was the optimal gap, and the particle size of droplets atomized by the spraying blade decreased to 42μm. Furthermore, the distribution of particle size was more uniform, and the results of experimental were consistent with the characteristics of electrostatic field obtained by evaluation．

Abstract:In order to obtain grain moving laws in inertia separation chamber of combine harvester threshing prior to cutting, grains motion was simulated by using computational fluid dynamics and discrete element coupled methods. Simulation results showed that grain particles were separated from short straw through airflow and the performance of chamber separating and cleaning grain was improved with the increasing of airflow velocity, while the turbulence phenomenon in the rear of chamber got more serious and airflow pressure drop was increased. Not full grain particles also deposited in chamber. In order to verify the validity of simulation results, the experimental test was conducted. Experimental results and simulation results were basically accord, which showed that the simulation of grain motion in inertia separation chamber based on CFD-DEM was feasible. The results would be a better basis to improve the performance of inertia separation chamber to separate and clean grain.

Abstract:In order to meet the requirements of dryland pot seeding transplanting mechanism, which need to achieve ideal “olecranon shaped” track, a continuous transmission seedling pick-up mechanism of planetary gear train with second-order general non-circular gears was proposed so as to achieve the seedlings claw periodic secondary unequal amplitude swing. The curve fitting method was utilized to build free transmission function, and a mathematical model about non-constant velocity drive of mechanisms was established, The mechanism analysis software was compiled, and the transmission ratio functions and mechanism parameters were determined to manufacture the seedlings transplanting mechanism. The high speed video test was carried out, The results showed that the seedlings test trajectory could agree well with theoretical calculations. The depth of taking seedlings was deeper than 35mm, and the scoop of pot was less than 5mm. The posture of seedlings claw met the job requirements during plunging into pot and quitting pot process.

Abstract:A multi-line metering device was designed for drill seeding of wheat and rice with ring groove push movement. Working principle of the multi line metering device and force on dropping seed were analyzed, and the theoretical maximum speed of the metering plate was investigated. The Yannong-19 wheat was taken as the testing object, and the relationship among several parameters was studied, which were rotation speed with single-line delivery capacity, coefficient of variation of single-line flow rate, coefficient of variation of flow rate among all lines, coefficient of variation of total flow rate and damage rate through the captive test of seeding device. The experimental results showed that a linear increase was observed with increasing rotation speed. Coefficient of variation of single-line flow rate, flow rate among all lines and total flow rate firstly increased and then descended with increasing rotation speed, and the lowest coefficient of variation (28.5%,1.33% and 0.51%) were observed at 2.5r/min rotation speed. The damage rate increased with the increasing rotation speed, and increased obviously when rotation speed was higher than 2.5r/min.

Abstract:The phenomenon of soil adhesion occurred widely when conventional press roller worked. To solve the problem, nine biomimetic press rollers with bionically ridged structures were designed learning from the geometric structure of the ventral surface of dung beetle (Copris ochus Motschulsky). Bionically ridged structures using ultra high molecular weight polyethylene material, which possessed good hydrophobic properties, were modeled on the surfaces of press rollers. Orthogonal tests of L9(34) were performed in an indoor soil bin with a moisture content (dry basis) of 20%. The effects of the bottom width of ridge section (W), ridge height to width ratio (R), roller loads (F) and the area ratio (K) on soil adhesion and traction resistance were determined. The results showed that under the identical conditions, all bionic rollers exhibited lower adhesion than a conventional roller against soil in a suitable compaction for corn, and the maximal adhesion reduction rate was 41.08%. The bionic roller with ridged structure with reasonable dimensions could reduce the traction force by 11.75%~39.40% than conventional roller. The order and optimal levels of the experiment factors influencing soil adhesion and resistance were determined by range method. The impact of the different factors on the soil adhesion and resistance of press roller was discussed.

Abstract:Efficient soil digging property of claw toe of Mus musculus was applied to the structure design of anti-drag subsoiler. The anti drag subsoiler had exponential curve shape of soil-cutting edge of shaft. To compare tillage resistance, the subsoiling experiments were conducted using bionic anti-drag subsoiler and traditional subsoiler. The results showed that both tillage depth and forward velocity could affect on subsoiling resistance significantly and the tillage resistance increased with the tillage depth and forward velocity. The tillage resistances of bionic anti-drag subsoiler were reduced by 8.5% to 39.5% respectively compared with traditional subsoiler under the same experimental conditions and the effect of reducing resistance was obvious.

Abstract:A 1PJ-4.0 laser leveler installed on a wheeled tractor through the hydraulically driven 3-point linkage is developed. The harrow of the laser leveler can move up and move down by a cylinder and a planar four bar linkage. Hydraulic systems of the laser leveler are designed, including height position control hydraulic system, leveling control hydraulic system and folding hydraulic system. Experiments are carried out to investigate the dynamic response characteristics of the height position control system and leveling control system, respectively. The response time of leveling harrow moving up is almost twice as much as moving down. The moving up velocity of leveling harrow increases with the rate of accelerator pedal deepness, while the moving down velocity of leveling harrow is stable because a one-way throttle valve has been applied in the height position control hydraulic system. The average moving up time is about 3.31~4.23s and the move down time is 1.7s in testing space of 400mm. It is bilateral symmetry of rotate angular velocity in the clockwise and reverse to control plow leveling. The results of the paddy field experiment show that the laser leveler installed on wheeled tractor for paddy field can work steadily, and the surface smoothness of paddy field can be obviously improved. The maximum height variation of paddy field surface decreases from 32cm before leveling work to 4.9cm, and the relative standard deviation reduces from 12.28cm to 2.64cm. The cumulative percentage of the sampling points, which have smaller than or equal to 3cm of absolute difference value, is more than 69.4%.

Abstract:In order to meet the reqirements of sprinkler irrigation uniformity and tower travelling capacity of a single-span center pivot irrigation system, the dynamics and hydraulic characteristics of the centrifugal water motor with a lower injector port were investigated. Relevant formulas were established for computing driving torque, speed and operating flow rate. The key factors affecting the driving torque and rotation speed of centrifugal water motor were analyzed. The results showed that the irrigated water depth could be adjusted more effectively by changing the working pressure of the water motor to control the rotation speed than by increasing the diameter of sprinkler nozzle to increase the work flow of water motor or by extending the length of the rotating arm. It is necessary to consider the structural and hydraulic designs of centrifugal water motor, travelling capacity and sprinkler irrigation uniformity of center pivot irrigation system simultaneously and optimize their combinations. In this way the demands of system traveling capacity and agricultural irrigation uniformity could be met at the same time.

Abstract:In order to realize column clamping of fresh tea in tea leaf and stalk separation, a self-locking gripper consisted of slider-crank mechanism and RRR assur group was designed. Analysis showed that, retraction phenomenon might happen if parameters were not suitably selected, which make it difficult to grip small diameter objects. However, it could be avoided by the constraining of retraction height. Secondly, relations between parameters were deduced, based on which an appropriate method was proposed on the determination of design parameters. The design problem was attributed to a transcendental equation, which was solved by particle swarm optimization method. Experimental results showed that grippers designed with this method can realize clamping and self-locking successfully, and a clamping length of 5~15mm was suitable.

Abstract:n order to explore the impact of mineralization degrees on infiltration character of soil under moistubeirrigation, an indoor soil box simulation experiment method was used to investigate the infiltration character of soil water under five different mineralization degrees selectively. Results indicated that the degree of mineralization had small impact on the shapes of soil wetted zone, and the wetting front shape were similar to circle. Degree of mineralization had a relatively bigger influence on the volume of wetted soil.The volume of wetted soil in mineralized water was bigger than that in pure water. When the degree of mineralization was 3g/L, the wetting front (horizontal, vertical up and down) migration distance was the farthest, which had a power function relationship with time. The mineralized water could increase cumulative infiltration.However the relationship between cumulative infiltration and degree of mineralization was not linear relationship.The cumulative infiltration and average soil moisture content was the biggest when the degree of mineralization was 3g/L.The results of this study provided reference for the utilization of moistubeirrigation with mineralized water.

Abstract:Using 4 different types of soil samples, the saturated hydraulic conductivity of soil was tested with falling head method by filling 0.25~5mm soil aggregate dry screened in indoor and set with 1.40g/cm3 bulk density in earth columns. The soil samples were immersed in five ammonium chloride solutions of different concentrations for 24, 48 and 72h later respectively, which was used to discuss the reaction characteristics of different types of soil structural stabilities with saline solution as well as resistances to chemicals damage. The result indicated that the soil saturated hydraulic conductivity were not constant, and the saturated hydraulic conductivity of all 4 types of testing soil decreased significantly with the increasing of ammonium chloride concentration and soaking time. But different types of soil in response to salt solution were significantly different. The main conclusion was that not all water-stable soil aggregates owned stronger chemical stability, and the chemical stability of aggregates had relation with the type, quantity and quality of different cementing agents, especially had significant response to chemical substances in the soil solution.

Abstract:This article attempts to analyze the impacts of sampling extent and sampling spacing on soil air permeability’s spatial variability, and preliminary discuss the scale-dependency. The spatial variation of parameters in Linze County, an agricultural area in the middle reaches of Heihe River Basin, was examined. A study in a 21m ×21m of wheat zone was carried out, and the spatial variation of soil air permeability was analyzed with all the data measured under 3m×3m sampling grid. Then, re-sampling technique was employed with including coefficient of variation, correlation length and Moran’s I index were applied to each scenario to characterize the degree of spatial variability of soil air permeability. The results showed that all measured indices increased with various degrees with increasing extent. However, the spacing did not affect coefficient of variation and Moran’s I index, while correlation length decreased with the increase of the spacing.

Abstract:Precise irrigation of agro forestry is imminent with the shortage of water resources in the world and the development of modern agro forestry and information science. One of the effective means to realize precise irrigation is to improve the control method and control accuracy. In order to study the effective control strategy for the irrigation of urban green land, an irrigation control model with optimal control theory was built. To testify the model, a dual-layer sensor was used to obtain the soil moisture in depth of two layers (20cm and 40cm) simultaneously. The experiment was conducted in an urban green land of Beijing. With the same climatic environment, the traditional irrigation control model with Bang-Bang control method and the optimal irrigation control model were compared. After comparative study in two months of 2011, the experiment result indicated that, comparing with Bang-Bang control, the optimal control saved water remarkably (approx. 25%) in the same weather ,soil and grass management conditions and ensured the lawn grass meeting the landscape requirements.

Abstract:Three indexes, gross irrigation water productivity (Pg), canal irrigation water productivity (Pc), and net irrigation water productivity (Pn), were built. The data from 443 major irrigation areas throughout China were collected in 1998, 2005 and 2010, and the spatial and temporal variation of irrigation water production and the relationship between the indexes were analyzed. The results showed that the national average value of the three indexes were 1.361, 2.532 and 2.989kg/m3. and the indexes in each province showed a trend of increasing with time. The municipalities directly under the central government increased large while grain producing areas in Yangtze River Basin were small. The irrigation water productivity indexes in representative years aggregated obviously in the area of Huang-Huai-Hai plain as a high value area while the low value areas were in south, northwest and northeast of China. There were significant linear correlations among Pg, Pc and Pn, respectively. The determination coefficients were greater than 0.90. Any index can be used as the representative of regional irrigation water productivity in the country.

Abstract:This paper describes a new method for determining the amount of earthquake-added soil erosion in Wenchuan earthquake area. To study on the method, typical landslides were chosen in Wenchuan County, and the information of typical landslide surface and its surrounding terrain were obtained by on-site measurement. The rill/gulley on the landslides were identified by image analysis, and the amounts of slope erosion from landslides were estimated by numerical calculation. The on-site measurement was carried out by using a 3-D laser scanner (HDS3000, Leica Company). The scanning distance reached as far as 300m, with a distance measurement accuracy of ±4mm at 50m. The scanner was set up in front of the slope of the landslide to be measured. The distances from the scanner to near end and the far end of the landslide were 58.32m and 136.81m respectively. The scan grid was set to 20.0cm horizontal and 20.0cm vertical at 200 m from the scanner. The actual scan grid of the measured landslide was 5.8cm×5.8cm at the near end and 13.7cm×13.7cm at the far end, respectively. Landslides surfaces sections prior to erosion were specified by using least squares curve fitting method, and fitting it with curve of the second degree. The gully volume was estimated by comparing the result of surfaces prior to erosion and on-site data collected with laser scanner. The erosion volume of a typical landslide surface gully from 2008 to 2012 was estimated to be 355m3. The method was verified with the data calculated by traditional cross section area method. The cross sections area and length of gully were calculated by the built in method of the 3-D laser scanner. The result showed that the values calculated by the method suggested were a little bigger than that by the traditional cross section area method. The relative error of the method was 15.6% for the whole gully, with the lowest being 7.9% and the highest being 27.1% for the segmentations. The reasonable accuracy of the method showed that the rill/gully volume of landslide could be estimated reliably by using it in engineering application.

Abstract:Effect of independently developed microbial inoculum on cattle manure enhanced composting was studied, which was named CC-1 with high lignocellulose degradation ability. CC-1 was a mixture with Geotrichum candidum-BD1, Streptomyces thermocarboxydus-SM, Bacillus subtilis-KC and Coriolus versicolor, in which the first three kinds of microbial were selected from cattle manure in Beijing areas. The orthogonal composting test was conducted in simulated fermentation tanks to study the effects of different parameters such as C/N ratio(26, 28, 32), initial water content(55%, 60%, 65%), aeration rate (10min, 20 min, 30min ventilation every day, with 1.63m3/min ventilation pump power), and inoculation amount of microbial agents on cattle manure composting. And composting effect was evaluated from temperature changes, C/N, sensory effect (including material particle size and stench) and total nutrients contents. The results showed that the optimum control parameters were as follows: C/N was 28, water content of compost materials was 55%, microbial inoculation amount was 0.8%(volume ratio) and 20 minutes ventilation every day (ventilation volume was 5.09m3/(min·m3)). Then, with the optimum conditions, another composting was carried out to prove the effect of CC-1 on cattle manure composting, and the composting inoculated by EM and composting with non inoculum were taking as the controls. In this test, temperature changes and lignocellulose degradation during composting were measured. Besides, pH value, GI (germination index), TC, TN, TP, TK, and humic acid were determined when composting finished. The results showed that the composting period was shortened. The period of temperature rising to 50℃was 2 or 3 days earlier and the period of temperature decreasing to 40℃ below was 8 days earlier, compared to that inoculated by EM and non inoculated. When composting finished, pH value and GI of compost inoculated by CC-1 were 7.9 and 106.5%. Compared to compost that inoculated by EM and non-inoculated, the TN was 19.33% and 27.35% higher, total nutrient was 7.91% and 23.95% higher, and the humic acid was 16.38% and 47.53% higher in compost that inoculated by CC-1. Degradation ratios of hemi-cellulose and cellulose in compost inoculated by CC-1 was 1.2 and 1.8 times, and 1.8 and 2.1 times that in compost inoculated by EM and non-inoculated, respectively.

Abstract:A series of drying experiments on municipal solid waste(MSW) in Guangzhou were conducted in air dry oven，simulating the drying process in incineration. The influence of temperature on drying characteristics of MSW was analyzed. Seven different drying models were fitted to the experimental data as comparing the correlation coefficient and chi-squared value. The optimal drying models were obtained to predict experimental drying process. The results showed that drying time was shorter and the maximum drying rate was higher with the higher drying temperature. The drying time decreased from 322min to 102min and the maximum drying rate increased from 0.009g/(g·min) to 0.027g/(g·min) as the drying temperature rising from 100℃ to 160℃. The experimental drying process could be described accurately by page, Modified page and Weibull distribution models. The effective diffusivity of MSW changed from 2.212×10-9m2/s to 8.044×10-9m2/s with fick’s diffusivity model. The MSW activation energy of 27.035kJ/mol was determined through Arrhenius equation.

Abstract:A Kalina cycle power system was developed. The net power output, net power output per ton of geofluid, energy efficiency, and heat exchanger area of per net power were determined as the performance criteria of the power system. The influences of ammonia water mass fraction, solution circulation ratio, geofluid temperature, cooling water temperature, and the heat exchanger end temperature difference on performance criteria were analyzed. Results showed that the performance could be changed by adjusting ammonia water mass fraction. The optimal solution circulation ratio value was about 4 and the corresponding ammonia water mass fraction difference was about 12%~13%. The net power output per ton of geofluid increases and energy efficiency decreased by increasing the heat exchanger end temperature difference.

Abstract:In order to improve the accuracy of online detecting soluble solids content (SSC) of apples by the method of near infrared spectroscopy, the combination of moving window partial least squares (MWPLS) and genetic algorithm (GA), successive projections algorithm (SPA) was used to select the characteristic variables, and then the partial least squares regression model was developed. The MW-GA model with the 36 selected characteristic variables obtained the best result with correlation coefficient of prediction (Rp) of 0.90 and root mean square error of prediction (RMSEP) of 0.70°Brix, which indicated that the combination of MWPLS and GA could select the characteristic variables of near infrared spectroscopy effectively.

Abstract:In terms of spherical fruits, the lighting was usually uneven distribution on the surface of fruits due to the larger change of curvature from fruit surface. Therefore, some drawbacks such as large error and low accuracy were still existed in the grading and assessing for fruit peel color. In order to solve this problem, B-spline lighting correction method was proposed in this study. Using the proposed algorithm, R, G and B channel images abstracted from original RGB image were firstly corrected respectively. Then, the corrected RGB image was changed into HIS color space image and hue H and illumination I component images were abstracted. Finally, the correction performance was assessed by computing the standard deviation of pixels in H and I component images before and after correction. For the investigated 160 orange sample images, the result showed that the corrected images were more uniform in terms of hue and illumination. Only 21.57% and 33.94% of mean standard deviations of original hue and illumination component were obtained. The uniformity of hue and illumination was effectively improved.

Abstract:In order to solve the problem of excessive energy consumption of high moisture grain drying, a high moisture grain dryer was designed, and the state parameters in high moisture grain drying and the change characteristics of moisture binding energy were analyzed. From the theoretical and experimental evidences, the utilization effects of drying potential energy and the changing process for the temperature and moisture of high moisture grain dryer were illustrated and observed. The experimental result showed that the temperature of grain could be reduced and was lower than environment temperature nearly 10℃ when temperature was 30℃, relative humidity was 40% and drying rate was more than 0.76%/h. The result also pointed out the design method of grain drying process for saving energy and provided energy efficiency of pre-drying equipment for large-scale grain drying companies.

Abstract:In recent years, with the rapid development of greenhouse agriculture and information technology, more and more modern information technologies were applied in greenhouse environment management. And those technologies promote the development of intelligent management technology for greenhouse environment. Aiming at the demands of intelligent management for greenhouse environment information oriented to internet of things（IOT）， this paper analyzed the research progress of intelligent management for greenhouse environment information from three aspects, information acquisition, information processing and decision-making service of greenhouse environment, and the future studies about intelligent management of greenhouse environment were proposed.

Abstract:Light incident upon a leaf surface will be partially reflected, partially absorbed and partially transmitted. Green plant tissues show an auto fluorescence in the visible spectral range that is excited by UV or visible light. Key pigments in plants, including chlorophyll, carotenoid and other compounds, such as flavonol and anthocyanin, generally have the property of emitting fluorescence after excitation. Fluorescence imaging is a kind of advance techniques based on computer vision. The health information of plant can be acquired by analyzing its fluorescence image without influencing its growth condition. This paper reviewed the researches of applying fluorescence imaging technology to detect plant diseases and compared this technology with RGB imaging, hyperspectral imaging, multispectral imaging and thermal infrared imaging techniques.

Abstract:In order to determine the electric parameters of pulsed electric field(PEF) biological effects, we researched the response of the equivalent circuit model in the PEF based on multi shelled dielectric model of spherical cell. The simulation of the transfer function revealed that the cell outer membrane had low pass filter characteristic and the inner membrane had band-pass filter characteristic. Time domain characteristic of transmembrane potentials on cell outer membrane showed that the pulsed electric field, which had less than 2.83Hz of PEF frequency, more than 69.7kV/m of PEF electric field intensity, and ms/μs class of pulse width, could produce reversible electroporation on cell outer membrane. Extremely low frequency pulsed electric field of 100kV/m, 1Hz and 80ms was used to treat germinating mung beans seedling. It was found that the seed germination process was significantly promoted: on the 4th day of germination, and the shoot length and root length of germinating mung beans seed increased by 65.8% and 80.2% respectively compared with those of the control group.

Abstract:Optimization of feature space and improvement of the segmentation algorithm are the keys of accurately obtaining seedling information using object-oriented technology. An improved edge segmentation algorithm was used to segment image based on dealing with the noise of multispectral images. The algorithm developed the simulated balloon expansion method, and could control the direction of the force field, so that the curves were made to split and collapse inwards. And the feature space made up of texture, shape, spectral features was built to accomplish seedling information extraction. The results showed that the total accuracy of seedling information extraction was 86% by the method of this paper, 12% higher than that of traditional methods, and the KAPPA coefficient was 0.8145, 0.1159 higher than that of traditional methods. The method of this paper could accomplish seedling information extraction quickly and accurately, and provide a reference for the accurately monitoring and decision making to management departmen. It has important meaning to forecast and evaluation for the future afforestation situation.

Abstract:Nuclear magnetic resonance (NMR) technique has been broadly used in probing plant water relations. However, the relationship between NMR parameters and photosynthetic traits is still not clear. An NMR system was constructed to perform non-imaging relaxation measurement or magnetic resonance imaging on wheat non-invasively and non-destructively. It was found that from the onset of leaf senescence to the degradation stage, the average T2 relaxation time (T2,mean) increased gradually and the chlorophyll content decreased, while the amplitude (A) of T2 relaxation spectrum and water content kept stable. When wheat leaves approached cell death, all of the above mentioned NMR and physiological parameters decreased to its minimum value. It was deduced that A and the water content of wheat leaves were linearly correlated. On the other hand, T2,mean was related with leaf senescence status. Therefore, non-imaging T2 relaxation technique was thought a fast and powerful method to estimate the senescence status of wheat leaf. In addition, T1 weighted imaging and T2 weighted imaging could represent leaf physiological status directly based on the relaxation property. T1 weighted imaging was comparatively time-saving, whereas T2 weighted imaging was much more sensitive to leaf aging.

Abstract:During the simulation of bamboo rhizomes, there are some faced difficulties caused by high strength of calculation and large amount of data. Therefore, it is hard to satisfy the simulation performance requirements by using traditional architecture based on single processor and serial computing. In order to solve this problem, a multi-nodes parallel simulation mechanism was proposed based on network compute cluster, and the parallel simulation platform was built for uniaxial scattered bamboo rhizomes. The parallel simulation platform was composed of modeling node, task managing node, graphics node and network switch in hardware. The growth model of uniaxial scattered bamboo rhizomes was constructed on the basis of SimRoot model, whose geometric architecture parameters and growth parameters can be obtained through experimental observation. Function decomposition method was used for dividing integral task of growth modeling into fragments, and the corresponding task scheduling mode was established. Then, multi-nodes parallel growth modeling mechanism was designed. Finally, as an example, multi-nodes parallel simulation experiments for Phyllostachys parvifolia were executed. The experimental results show that multi-nodes parallel simulation based on network computer cluster appears to have obvious efficiency in reducing memory demand and simulation time, which has good adaptability to the large-scale simulation of scattered bamboo rhizomes.

Abstract:In order to evaluate pearl color and luster, a monocular multi-view imaging device was designed by placing a HD camera in front of a symmetric bucket cavity body which constituted by the multiple pieces of plane mirror. The device could achieve the pearl’s surface images taken from five different perspectives. Then image processing was used to fuse the five pearl images and achieve a new image which contained the pearl’s whole surface. After that, a pearl’s region was divided into highlight areas and bright area, then the characteristic parameter of color was picked-up from bright area and the characteristic parameter of luster from highlight area. Finally, the feature fusion was used to determine the quality of the pearl. The experimental results showed that the monocular multi-view machine vision device could obtain the entire surface of the pearl in the same color system, and accomplish the real-time detection and grading for pearl’s color, luster and uniformity.

Abstract:To find out the effect of cultivation methods on vegetable root, the lettuce root length, root depth and root width radius were studied in four cultivation substrates under drip and micro-sprinkler irrigation. The result indicated that root characters of lettuce cultivated in different substrates were no significantly different at 0.05 among different irrigation methods. Based on the experimental data of lettuce root, the simulation models for lettuce root length and root depth were established using the scale of effective cumulative temperatures (DD). The root depth in different layers and DD were used as the dependent variables to establish the root width radius model. The repeat test data were employed to verify the establishing models. The root mean square error and relative error between simulated and observed values were only 290cm, 0.81cm, 0.63cm and 15%, 12%, 13% for lettuce root length, root depth and root width radius under drip irrigation and micro-sprinkler irrigation.

Abstract:This paper adopts a line based wavelet transform method with the Le Gall 5/3 filter, in which the image lines are read to SRAM line by line from the SD card and write to the SD card after the multi-level transform operation. The wavelet transform method requires low SRAM memory and involves fixed point integer multiplication, addition, shift operation only. Appling the method to a 256 pixels ×256 pixels gray image of piglets. experimental results show that the SRAM cost of the method is 3.968KB and the time cost is 8.718s with a reasonable cost of the arithmetic operation. This study establishes the foundation for the wavelet transform image compression on the image sensor nodes, and makes it possible to transmit the images of agriculture over the low bandwidth WMSN efficiently.

Abstract:Aiming at the evolution problem of core module in product family design, the module evolution law and process evaluation were analyzed. A method for law analysis and evaluation in the module evolution was proposed. The relationship between customer demand and module design was also studied. The core module standardization and universal indicators based on existing products were analyzed. An analytical model for core module evolution was established in the process of needs analysis, and the model was trained by the history data. The changing law of design and craft was obtained by demand evidence reasoning in core module. Based on the evolution law analysis, the design parameter and reuse degree were also analyzed for core parts. Comprehensive evaluation value for core module evolution was gained. Finally, the effectiveness and feasibility of the method was tested by core module design of small wheel loaders.

Abstract:A method for constructing rotation surfaces with local shape parameters was proposed to solve the problems in adjusting and controlling shapes of rotation surfaces. Based on the transfinite vectored rational interpolating function, the quartic λ-Bézier rotation surfaces with multiple shape parameters were constructed using a quartic λ-Bézier curve. Then, the explicit function expression of the quartic λ-Bézier rotation surfaces was presented. The proposed quartic λ-Bézier rotation surfaces inherited the outstanding properties of the Bézier rotation surfaces, and had a good performance on adjusting their local shapes by changing the value of shape parameters. Finally, some properties of the quartic λ-Bézier rotation surfaces and applications in rotation surfaces design were discussed. The modeling examples showed that the proposed method was simple and effective, and easy to control the shape of rotation surfaces, which provided a valuable way for the design of rotation surfaces.

Abstract:This paper took the constant-breadth cam mechanism with floating flat faced pushrod as research object. The concepts of rise and return travel, radius-making line, and width mapping interval set were introduced. The intrinsic regularity relationship of the angles of rise/return and farthest/nearest dwell angle, and the characteristic relationship of kinematic sizes, amplitude of rise travel, and the beginning parameters were discussed in detail. Then, the displacement function of the rocker was solved. The selected interval of the flat and the range of base circle radius, pressure angle, and width were presented. They reveal that the design of this mechanism contained a special, complex and profound content. The comparison of constant-breadth cam and conjugate cam were presented, which deepen the understanding of similarities and differences of the two kinds of shape lock mechanism. A mechanism synthesis example of this mechanism was displaced.

Abstract:To reuse 3-D CAD models more efficiently, a 3-D CAD model retrieval algorithm based on distance and angle distributions was proposed. Firstly, a large number of random points on the model surface were taken to calculate the length of the directed line constructed between two random points and the angle between the normal of the point and the directed line. Then, a distance-angle planar grid was constructed to express the distance-angle distribution by obtaining a statistic data of the sampled points. At last, the Manhattan distance metric method was used to compute the similarity between the two distance-angle matrices, which can give the similarity coefficient for two compared 3-D CAD models. Experiments results show that the algorithm can effectively support 3-D CAD model retrieval, and the efficiency meets the requirements of engineering application.

Abstract:针对复杂曲面中较为常见的双曲面进行了研究，建立了加工双曲面的数学模型，通过对双曲面参数特征的分析，发现了双曲面上任意点的切线斜率极限值以及刀具轴线斜率极限值的变化规律，据此推导出双曲面参数、刀具参数与偏心率平方之间的函数关系，推演了加工双曲面不发生干涉的参数准则，同时明确了切削角与偏心率平方满足不同函数关系对应的干涉区域。通过仿真实验，验证了理论分析的正确性，为加工双曲面的参数选取提供依据。

Abstract:It exits large computational error that the computational formula derived from the untrucated poppet valve is adopted for the cross section area of the truncated popper valve. The flow pattern of the truncated poppet valve was studied with CFD visual algorithm. The position of cross section was confirmed based on the flow filed characteristics and the concept of the turn opening position was proposed. It was concluded that the cross section area of valve had a key turning point when the stroke of truncated poppet valve was large. The established technique and computational formula of the cross section was differed from the stroke and the converging/diverging flow. The result of the cross section area and the flow rate was more exactitude by adopting the new computational formula for the truncated poppet valve than by adopting the traditional formula. Comparing the flow filed characteristics of diverging flow with that of the converging flow, it was pointed out that the channel flow in the truncated poppet valve should consider the throttling pressure loss and the local pressure loss. It was summarized that the difference of the flow filed characteristics was induced by the local pressure loss.

Abstract:Aiming at a kind of new 6-DOF wind tunnel support parallel robot, using the method of D-H single-chain, and together with the method of parameters-perturbation, the motion error model of this support parallel robot used in wind tunnel was established, and simulation program based on this motion error model was made. According to six kinds of typical motion mode of wind tunnel test, six kinds of posture errors of different motion mode of this parallel support system was analyzed and error curves of typical motion mode were also get by simulation. Using the motion error models obtained from the simulation, the corresponding error controlling methods was carried during this parallel support robot components designing and assembling, and ensuring the design and manufacture accuracy of the parallel support robot reached the requirement of wind tunnel tests, and error estimation program which was similar to that of the motion error simulation was embedded in the wind tunnel test to compensate the motion errors of posture and location of tested aircraft model, and it was proved in practice that the precision of wind tunnel test data was improved.

Abstract:To meet the needs of different working conditions, a double-stator multi-motors was designed. Double-stator single-acting multi-motors was one of double-stator multi-motors. In order to realize the performance of motor, the influence of torque pulsation by different number of slider was studied based on the analysis of the theoretical displacement and theoretical torque of double-stator single-acting multi-motors. Through the analysis, mathematical expressions of the motor torque and the number of sliders were obtained. Meanwhile, the results show that the lag angle can influence torque pulsation when outer motor and inner motor work at the same time and differential connection. It turns out that the uniformity of angular velocity is smaller when the number of alien slider is odd, while the amplitude of angular velocity is a little larger than the motor whose number of sliders is even. This research work lays a theoretical foundation for the design of double-stator single-acting multi-motors.