Abstract:Taking the piston pump and high speed on-off valve, the crucial parts of automotive electronic stability program (ESP). Their mathematical models were established. Besides, the co-simulation model of ESP hydraulic control unit (HCU) was built up by AMESim and Matlab, which was also verified by test. The simulation model described the motion intrinsic characteristic of the piston pump and high speed on-off valve. Consequently, the effect of those components’ parameters on the adjustment of braking pressure during active boosting was analyzed. The result can provide references for the design and development of ESP, especially for improving the efficiency of the pump and the linear control performance of the high speed on-off valve. 

Abstract:The obstacle climbing performance was discussed for variable diameter wheel all-terrain-vehicle (ATV) with two kinds of drive mode: rear wheel drive mode and four-wheel drive mode. In RecurdynV7R5 software models of the diameter-variable wheel and a normal tire were built to analyze the climbing obstacles characteristics. On this basis, the vehicle model which would be driven by rear wheel or four wheels mechanical was set up, and the calculation was executed. The results showed that the driving way and the variation of wheel diameter play an important role for obstacle climbing performance. In RecurdynV7R5 software the whole vehicle model with rear wheel drive mode or four wheel drive mode was built, and obstacle climbing performance was simulated in the condition of adjusting the wheel diameter size. Then, the calculation and the simulation were compared. In the end, experimental results verify the reliability between the theoretical calculation and the simulation analysis.

Abstract:Human driver exhibited excellent adaptive capability when perform steering. However, it is difficult to analyze this adaptive ability with traditional dynamics system, since the steering course concerns a complex course of driver-vehicle interaction. The investigating of driver-vehicle closed-loop stability was conducted. It can be found that drivers can utilize the linear dynamics characteristic to acquire the skill of controlling the driving direction. Besides, this skill can combine with physical limitations to form an internal reference model, which can be employed by drivers to adapt to the variable dynamics conditions. Based on above results, a adaptive steering control method was proposed. The lane change simulation experimental result indicated that the proposed method not only can realize the drivers’ steering task effectively, but also present good adaptability under the altered dynamics conditions.

Abstract:The 2-DOF dynamic model of these two joint was built by using Euler-Lagrange formulation. It was simplified to a linear-in-parameter mode. The relationship between joint torque and actuator force was deduced by differentiating the function of relationship between the joint angle and cylinder displacement, and friction was introduced into the actuator force. The recursive least square method (RLS) and recursive stochastic Newton algorithm (RSNA) were used to identify the unknown combination parameters respectively. Comparison experiments showed the predictive errors of joint torque of RSNA was reduced by 65% and 63% for the dipper joint and bucket joint respectively. The results demonstrated RSNA was more robust to the system noise. It can identify the dynamic parameters precisely. 

Abstract:Discrete particles often become the work objects or working medium of the modern agricultural equipment. Research work of particle collisions and fluid-solid coupling is always be involved in the study of particles movement. It is show that the methods and results of these researches are more and more important to the other research work in modern agricultural engineering field. The research methods of particle movement in agricultural engineering field were respectively illuminated from these aspects like theory analysis, numerical simulation and actual experiment. Then the status of particle movement research for a few typical agricultural equipments both in China and aboard was reviewed. Finally, the development tendency of particle motion research in agricultural engineering realm was proposed. 

Abstract:The Chinese grain crop mechanization production system structure was analyzed. A causal analysis diagram and flow chart of system dynamics were constructed. The results show that, the proportion of capital investment, land management scale and equipment level were the main factors effect of grain crop mechanization production system. Only by improving grain crop production scale of the degree of specialization and the law of industrial development, the mechanization production efficiency and production capacity would improve. 

Abstract:In order to determine the key parameters of the flattening component on combined cultivating implement, the field experiment was conducted by using the flattening device. The three factors and three levels orthogonal regressive tests were designed in the experiment with working velocity, diameter of the field-ditch filling disc, angle of the field-ditch filling disc as influence factors and the soil-breaking rate as response index. The regression mathematics models between response index and influence factors were established and the parameters were optimized through Design-Expert. The optimal combination was that working velocity of 10.63km/h, diameter of the field-ditch filling disc of 450 mm, angle of the field-ditch filling disc of 17.71°. At that time the soil-breaking rate was 91.92%, which could meet the needs of agricultural demands. 

Abstract:Twelve kinds of sliding knife furrow openner with different thickness and sliding cutting angle were designed in view of this issue about the casualness in the design and manufacture and limited application. Mixed type orthogonal test was carried out through soil bin and press in the laboratory with test index of traction resistance and vertical pressure. The test results showed that the sliding cutting angle was the main factor effecting its working performance, and the furrow opener possessed better comprehensive performance when its sliding cutting angle in the edge curve terminal point was in the range of 35°～55°. 

Abstract:A control system for variable rate fertilization, which depends on deep-fertilization liquid fertilizer applicator, was introduced. The single chip microcomputer was used as core processor and electromagnetic proportion regulator valve was used as execution unit. Software was designed for selecting data and sending commands. The test results in the test-bed showed that the system can complete the control of variable rate fertilization and the error of the variable fertilizing was less than 0.5 mL in each time, which meets the liquid fertilizer variables requirement. 

Abstract:A kind of trapezoidal slot-type pneumatic wheat seed-metering device was designed. Through experiments, the sucking seed uniformity of the seed-metering device with trapezoidal, U-shape, V-shape slot-type and the straight slot-type was analyzed. The experimental data showed the variation coefficient of the seed metering device with trapezoidal slot-type was the smallest, which was 7.0%, and the seed breakage rate was lower than 0.30%. These data conformed to the requirement of wheat precise seeding. But in the actual operation because of undulation of negative pressure of the wind machine and difference of air current suction in each row slot-type, the consistency of each line seeding quantity of the seed-metering device was not improved. Its variation coefficient was not more than 4.4% in the different speed change situations. 

Abstract:Based on the technology of RFID and wireless transmission, a kind of dual-mode self-propelled precise feeding equipment for dairy cow was designed. The computer was used as the information management platform and MCU was used as control platform. Using this equipment, the dual-mode moving, the wireless transmission of individual dairy cow information and accurate feeding was realized. One-month feeding experiment in the dairy cow farm showed that the milk production was increased by 3.0kg per day, and the average fat content of the milk was 3.1%～3.3%. 

Abstract:The human-computer interaction optimization method was applied to solve the complicate multi-objective optimization design problem of vegetable seedling automatic pick-up mechanism. After the mechanism optimization mathematic model was established, the Visual Basic-based computer-aided analysis and optimization software was developed. The design variables’ impacts on the objectives and constraints were analyzed. The optimization combination of structural parameters meeting the seedling pick-up requirements was obtained. Then, the ADAMS software and high-speed digital video camera and image processing technique were used in simulation experiment and bench experiment for testing its kinematics characteristics. The basically consistency of experimental results and theoretical analysis results showed that the kinematics model and its optimization design theory and methods of the mechanism were correct and reliable. At last, it is proved through seedling pick-up experiment that the mechanism can successfully complete seedling pick-up operation with the success rate of 80%. 

Abstract:In order to solve the problem of scion seeding difficult to clamp in traditional vegetable grafting machine and easily be injured, an air-suction mechanism was developed with vacuum suction head adsorption for scion, which based on the analysis of structural parameters and mechanical properties of suction seeding. A computational fluid dynamic (CFD) simulation of a 3-D model was developed in the given boundary conditions to investigate the fluid flow features and the effect of adsorption ability caused by various factors. The orthogonal test was adopted in this experiment to optimize the design of the structure of the vacuum suction head. The result showed that the important sequence was determined as follows: shape of the suction head, vacuum degree and the depth of counterboring. Experiment results showed that the feature of the proposed air-suction mechanism was safe and reliable. The success rate of the proposed scion clamping mechanism reached to 97.8%, no scion wan injured, and the success rate of insert into stocks reached to 85.6%. Thus, it indicated that the proposed scion clamping mechanism could satisfy the requirements of location and clamping for vegetable grafting. 

Abstract:An air-velocity distribution model of greenhouse air-assisted sprayer was built by means of CFD simulation technique. Experiments were designed for the evaluation of the simulation results. The research showed that the air velocity decreased as the distance increasing from spray nozzle in vertical and horizontal directions. The change of air flow rate at nozzle had no remarkable influence on the characteristic of air-velocity distribution, but enlarged the droplet distribution area significantly. By increasing the nozzle flow rate from 25 m/s to 50 m/s, the blowing distance could be increased from 2.4 m to 3.6 m, the range of air-velocity distribution expanded from 0.20 m to 0.25 m. The contrast of experiment results and simulation results showed that the simulation model built can be an accurate simulation of the air-velocity distribution of a greenhouse air-assisted sprayer.

Abstract:The hydraulic performance test of variable sprinkler were carried out for square and triangle spraying field, the wetted radius and water application rate of the sprinkler were measured and analyzed. The results showed that the maximum wetted radius of triangle spraying field was reduced than a square spraying field. The water distribution of triangle and square spraying fields were uniform relatively. Compared with the complete fluidic sprinkler, the difference of droplet size of variable sprinkler was smaller; the average application rate difference between the triangle and square spraying field was small. The maximum application rate was larger than the average application rate of triangle spraying field. The combination spacing increased, the overlap rate and number of variable sprinkler per acre were reduced. The uniformity was good for square spraying combination at the conditions of spacing factor was 1.25 and the wind speed of field was less than 1.2 m/s. The variable sprinkler operation was reliable and applied after the assessment of the natural environment. 

Abstract:A prediction and modeling method for dynamic contact angle of spraying agricultural drop on cucumber leaf surface based on image data collected was presented with combination of time series analysis and applying spatial trends theory. The dynamic contact angle θ of different mass fraction of glyphosate additives (EF8108-B) aqueous solution range from 16.08% to 82.14% on the cucumber leaf surface were measured by applying high-speed digital camera technology. Experimental results showed that the contact angle declined rapidly within the first 2 s, and then decreased slowly and gradually to reach its stabilized in the following 8 s. The contact angle didn’t show increase of a downward trend with increasing EF8108-B solution concentration. The self-relevant and self-regression model (AR(2)), the mobile average model (MA(3)) and exponential smoothing model (ES(6)) were established according to time series analysis, respectively. Moreover, the spatial distribution of spreading diameter, drop height, drop area and drop volume were simulated by applying trend surface theory, then the 3-D dynamic contact angle trend surface model were constructed. The numerical simulation and experimental verification results indicated that the goodness of fit was up to 94.72%.

Abstract:In order to study the application rate control characteristics of blended pulse variable rate application system, a blended pulse variable rate application system was constructed based on a commercial boom sprayer and by integration of high speed direct acting solenoid valves (type 6013), hollow cone nozzles (type TR80-05), pilot-operated proportional relief valve (type DBEE6-1X/50) and a self-designed PWM-based variable rate application controller. Influences of diaphragm pump’s input shaft rotating speed, nozzle positions, spray pressure, PWM signal frequency and duty cycle on nozzle’s spray flow rate were tested. Computational models of the nozzle’s spray flow rate under spray pressure of 0.2 MPa, 0.3 MPa and 0.4 MPa were fitted through monothetic linear regression, and corresponding control models of application rate were deduced. Application rate control characteristics testing experimentation of the blended pulse variable rate application system was performed too. Test results show that influences of nozzle positions and PWM signal frequency on the nozzle’s spray flow rate are very little, spray pressure and PWM signal duty cycle have crucial influences on the nozzle’s spray flow rate, the ratio of flow regulation is about 10∶1 with combine of the solenoid valve and the nozzle used in the system, the control error of spray flow rate is less than ±4% when objective spray flow rate is greater than 0.3 L/min, and the control error of application rate is less than ±6%.

Abstract:Based on the linear instability theory, the dispersion equation of charged liquid jet was obtained. The charged liquid jet breakup length was measured by applying the high-speed photography technology to verify the theoretical results. The results of numerical calculation indicated that the growth rate of 0-order and 1-order surface wave grows with increasing of jet velocity and charged voltage. The maximum growth rate of 0-order surface wave was bigger than that of 1-order surface wave in the discussed range of jet velocity and charge voltage. The jet breakup length increased to maximum value and then decreased with increasing of jet velocity. Charge voltage always promoted the jet breakup and makes jet breakup length shorter. Higher liquid conductivity made jet breakup length longer. The experimental results showed that theoretical analysis gave a reasonable explanation to the influence of charge voltage，jet velocity and liquid conductivity on jet breakup length, but fails to be a good predictor of critical jet velocity corresponding to the maximum of jet breakup length.

Abstract:Effects of six planting patterns on cotton soil water-salt movement, seedling rate, leaf area index, yield and fiber quality under irrigation before sowing with 5g/L brackish water were studied by plot comparative trial. The planting patterns were respectively seeding raising and soil-substrate transplanting with plastic mulching, seeding raising in sand and root-naked transplanting with plastic mulching, seeding raising and soil-substrate transplanting without plastic mulching, seeding raising in sand and root-naked transplanting without plastic mulching, and bunch planting without plastic mulching. The results showed that salt stress towards cotton was reduced by applying plastic film mulching to decrease soil evaporation, improve soil temperature as well as inhibit salt accumulation in surface. Under the film mulching conditions, the cotton seedling rate, leaf area index before blossoming and boll forming stage, pre-frost yield and yield were higher than that without plastic mulching. Fiber quality was also improved. The techniques of seeding raising and soil-substrate transplanting and seeding raising in sand and root-naked transplanting showed a good yield-increasing potential. Especially during the successive overcast days in the middle-late stages of cotton (in 2011), the yield of seedling transplantation cotton was greatly improved. 

Abstract:Pot experiments were conducted to investigate the effect of low lead content (<300mg/kg dry soil) on winter wheat seedlings rhizosphere microorganisms. Compared to the control, the number of bacterial decreased significantly (p<0.01) by 16.25% at the third week and by 8.62% at the seventh week, and the number of fungi in low lead content decreased significantly (p<0.01) by an average of 34.08%, 39.89% and 17.49% at the third week, seventh week, and twelfth weeks, respectively. The actinomyces amount in low lead content decreased significantly (p<0.01) at the seventh and twelfth weeks. The correlation between the number of fungi and lead content was significant (p<0.01) at the third week and the number of actinomyces, the fungi and the total microbial had significant (p<0.05) correlation to the lead content at the seventh week. In the three growth stages, fungal/bacterial population ratio decreased evidently and the microbial functional diversity changed evidently in low lead content. In conclusion, soil microbial population and community in the rhizosphere of winter wheat seedlings were affected significantly by low lead content.

Abstract:基于时间序列遥感数据反演的条件植被温度指数（VTCI）干旱监测结果，应用季节性求和自回归移动平均模型（SARIMA）对关中平原进行了分区域干旱预测建模，得到了2009年4月上旬至5月下旬每旬1步、2步和3步共18旬的预测结果，并分析了预测精度。结果表明，SARIMA模型的预测精度随着预测步数的增加而降低，6旬1步预测结果的绝对误差频数分布基本是单峰分布，主要分布在-0.2到0.2之间；6旬2步预测结果的绝对误差频数分布出现双峰分布，3步预测结果绝对误差分布分散，且误差变大。通过分析干旱的时空分布规律，发现关中平原地区干旱具有较明显的区域特征，且1步预测和2步预测结果的干旱时空分布与监测结果较吻合，3步预测结果的不确定性较大，由此得出SARIMA模型适用于关中平原VTCI 1～2步预测研究的结论。

Abstract:Effect of mixing on dry thermophilic (55℃) anaerobic digestion of dairy manure was investigated. No significant difference in fermentation performance was observed between continuous mixing speeds of 8~32r/min. Compared to continuously mixing, although 10% less methane was produced with batch slightly mixing. It greatly decreased energy consumption for mixing, and more suitable for dry anaerobic digestion. No significant difference in pH value, concentrations of ammonia, volatile fatty acid and total alkalinity was observed among different mixing conditions during digestion. 

Abstract:The biomass continuous pyrolysis reaction device with a variable pitch spiral conveyor was developed. To be more specific, the special screw conveyer was designed and optimized. Cold experiments showed that pyrolysis volatiles could be smoother to the end by way of combining the variable pitch with pros and cons screw. For general biomass, the productivity of the device was about 30kg/h, and stay time was 5~10min, which can meet the needs of pyrolysis reaction stably and continuously. Experimental research for various agriculture and forestry biomass could be carried out.

Abstract:Taking intermittent high-pressure transesterification reactor as object, the influence of background pressure and temperature on thermal equilibrium state of the water were discussed. Through establishing 3-D temperature-pressure field analysis model, the high-pressure hydrothermal state control equation was determined and supercritical state reaction condition was optimized. On this basis, the experimental study on biodiesel prepared with large-scale aquaculture microalgae as raw materials was carried out and the oil quality was analyzed. The results indicated that the output rate of biodiesel prepared with chlorella was evidently higher than that of other types of algae. The introduction of supercritical state reaction condition almost doubled the output rate of biodiesel and the oil quality had nearly the same carbon/hydrogen mass ratio, calorific value and density with the 0# diesel.

Abstract:Comprehensively considering the construction features of the multi-temperature refrigerated truck and the externalsol-air temperature, vehicle speed, compartment seal and air flow characteristics between the frozen and refrigerated zone of the multi-temperature refrigerated compartment, the cooling mathematical models in the every temperature zones of the multi-temperature refrigerated truck was built up. A testing was conducted to verify the correctness of the mathematical model, and further the impact factors of the cooling performance were analyzed. The study results showed that: during the cooling process in refrigerated trucks, temperatures both in two temperature zones were decreased exponentially with time. Cooling time in both the two zones was increased when the cooling capacity was reduced or the respiratory heat of goods and the vehicle speed and thermal conductivity of the compartment insulation material were increased. Besides, the cooling time will increase in the frozen zone while the cooling time in the refrigerated zone would decrease if we enlarge the fan wind speed between the two zones or increase the wind outlet areas. If volume in the frozen zone was enlarged and volume in the refrigerated zone was decreased with the total volume unchanged, cooling time in the frozen zone would increase while the refrigerated zone keeps unchanged. The two cooling characteristics remained the same when the thickness of the insulation panels between the two temperature zones was changed.

Abstract:The design of wireless sensor node in cold chain logistics was introduced, which solved the problem as high power consumption, channel collision and network complexity in cold chain logistics monitoring applications. Choosing MSP430F149 as the core processor and SHT11, PT1000 as temperature and humidity sensors, it can precisely collect data of temperature and humidity in different accuracy requirement. The wireless transmission was realized by SX1212. A kind of self-organized wireless protocol of star-shape was designed，in which physical layer was designed to fit the characteristics of cold chain logistics and the fusion of synergetic integration of binary tree and dynamic framed slotted ALOHA algorithm was used to avoid collision. Tests showed that the node had the advantage on ultra low power consumption and the rapid organizing of networks and it works well in cold chain logistic. The wireless sensor node can meet the requirement of cold chain logistics.

Abstract:To detect bruised kiwifruits from intact kiwifruit early and effectively, near infrared diffused reflectance spectroscopy technology combined with Fisher discriminant function, BP neural network and least square support vector machine(LSSVM) were applied to discriminate collided kiwifruit, pressed kiwifruit and intact kiwifruit after storage of 1d, respectively. Effectiveness of the discriminant model using full spectrum(FS), feature variables based on principal component analysis(PCA) and characteristic wavelength by successive projection algorithm(SPA) was compared and evaluated. The results showed that SPA gave the best advantage compared with methods of FS and PCA. Three models all had an acceptable accuracy, especially LSSVM model had the optimal recognition performance. SPA-LSSVM had an accuracy rate of 100%, 95% and 100% for identifying collided samples, pressed fruits and intact ones respectively, and the discriminant accuracy rate for total samples was 98.2%. 

Abstract:Bioimpedance properties of Fuji apple fruit with different freshness were investigated. Fruit with weight loss of 0, 5%, 10%, 15% and core-browning under room temperature were chosen as samples corresponding to descending freshness grades of 1,2,3,4,5, respectively. 126 observations of 14 bio-impedance parameters under nine frequencies of total 424 fruit from each grade were measured fruit by fruit with LCR impedance meter. Data were computed by using the sparse principal component analysis-linear classifier (SPCA-LDC) model. Results indicated that classification accuracy reached to maximum stably when the ratio of training sample to test sample of 9∶1 and former 39～45 principal component (PC) were adopted. The least 39 PCs were consisted of 44 from the 126 observations. Average rate of classification accuracy reached to 87.90% within 50 test repeats. 

Abstract:Influences of antioxidant on Antarctic krill during storage at 2℃ and 25℃ were investigated after pretreatment by different wine extracted solutions (0.1, 0.5, 1.0 and 2.0 g/L) in the research by testing the indexes of PPO activity, TBARS, color changes and sensory evaluation. The results exhibited that the optimal solutions of wine extracted for antioxidant effectiveness at 2℃ and 25℃ were 0.1 g/L and 0.5 g/L, respectively. Under the situation, PPO activity, TBARS value and effects of blackening protection of Antarctic krill were better than any other solutions and control group, which could maintain the quality and extend shelf life for Antarctic krill effectively. Changes of A450 value and RGB value have significant correlation with storage time, therefore, those could be considered as the right indexes to reflect the degree of antioxidant. 

Abstract:A pulse Doppler radar based real-time speed measurement system was designed by using CAN bus communication technology and multithreading technology according to the low speed characteristic of intelligent agricultural vehicle. In order to obtain a high precision result with the least system resource consumption, the multiresolution adaptive policy was designed by dividing speed level and variable sliding-window gray prediction. Experiments showed that the average error was 1.45% and the working frequency of resolution generator was reduced by 76.7% after adaptive policy started when the speed of vehicle was 0.2 m/s. The average error was 0.61% and the working frequency of resolution generator was reduced by 90.0% after policy started when the speed of vehicle was 0.8 m/s. The output frequency of system was steady 9.6 Hz and the frequency of resolution generator was dramatically reduced during variable speed movement. 

Abstract:The two-parameter optimal control method based on the speed and steering angle was designed with the optimal control theory. The automatic transmission system and the automatic steering system were developed for the automatic navigation tractor on the purpose of improving the work efficiency and the work quality. The straight path tracking controller and the turnrow turning path tracking controller were designed and simulated by the harrowing operation with the Matlab. The field test was carried out to validate the designed controller, and the results indicated that the control accuracy of the lateral deviation and the orientation deviation were less than 0.12 m and 1.1°, respectively. The speed control accuracy was less than 0.2m/s. 

Abstract:A kind of sensitive slippage sensor was developed by using piezoresistor, and a slippage observation system was constructed. The technique of STFT was applied to analyze the spectral information of slippage signal. Then slippage signal was distinguished with the signal resulted from different normal griping forces by using the result of DWT. The experimental results showed that the slippage signal was able to be effectively extracted regardless of different normal gripping force. At last, the experiment of gripping force adjustment was carried out by using two parallel fingers hand equipped with the designed slippage sensor. The experimental results of grasping actual fruits and vegetables demonstrated the promise of this slippage sensor in the agricultural picking robot. 

Abstract:To improve the accuracy of machine vision based maize leaf disease segmentation under the background of farmland, a graph theory based approach to maize leaf disease segmentation in multi-color space was proposed. The graph theory was used in different color spaces and the maize leaf disease segmentation was then formulated as a graph segmentation problem in different color spaces. Furthermore, an effective fusion method was applied to update the initial segment result. Experiments on the maize leaf disease showed that the segmentation results were good. The results revealed that the proposed approach was feasible and effective.

Abstract:To address the low accuracy and low stability of a single feature for weed recognition, a multi-feature fusion method based on support vector machine (SVM) and DS (Shafer-Dempster) evidence theory was proposed. Firstly, three types of plant leaf features such as shape, texture and fractal dimension were extracted from the plant leaves after a series of image processing. Then the SVM classification results of each single feature were used as evidences to construct the basic probability assigned (BPA), and the method of DS fusion based on matrix analysis was used for decision fusion. Finally, recognition results were given based on fusion results and classification thresholds. The experimental results showed that the accuracy of multi-feature fusion method was 96。11% which has good performance on accuracy and stability compared with the single feature method in weed recognition．

Abstract:A fast feature selection for cotton foreign fiber objects based on binary particle swarm optimization was presented, for the current feature selection of cotton foreign fiber having more iteration times and slow speed. Binary particle swarm optimization (BPSO) was used to select feature in the method, and the support vector machine algorithm was used to verify the optimal feature set. Experimental results showed that the running time could reduce by 26%, when the classification accuracy was almost with other algorithms.

Abstract:Crown structure is complex and has huge amount of point cloud data. In order to achieve more accurate and more efficient measurement of crown surface area and volume, the characteristics of existing algorithms were analyzed and an improved triangular mesh surface reconstruction algorithm which is based on spatial division block priority mechanism was proposed for the reconfiguration of the crown surface. A precise and efficient factor extraction method for crown surface area and volume was formed. Crown point cloud data obtained through ground 3-D laser scanning system was used. Through the traditional artificial method, cloud point measurement method, the classics digital elevation model algorithm and the proposed algorithm, the crown surface and volume of the experimental subjects was calculated respectively. The inter comparison of the algorithm results fully meets the calculation accuracy. The time consumption of the proposed algorithm only accounts for 41% of the traditional way and 62% of digital elevation model method, which appears to greatly improve the operation efficiency. 

Abstract:Leaf area is an essential indicator of photosynthesis for the study of crop and forest productivity. The Levenberg-Marquardt back-propagation optimization algorithm was coupled with Bayesian regulation to train the artificial neural network (ANN), and the predictive model was developed to determinate rapidly and accurately Moso bamboo leaf area. The results showed that the best input variables were the combination of leaf width and leaf length for ANN model, whereas the leaf shape index did not significantly affect the variability of leaf area. The optimization ANN model possessed with excellent performance and predictable accuracy, with the high determination coefficient of 0.992 and mean relative prediction error of 4.28%. The ANN model would be allowed for estimating accuracy the leaf area of Moso bamboo.

Abstract:Hyperspectral images of soybean at different growth stages were collected by using multi-angular observation system in the field. Reflectance spectra of different objectives including soil, soybean plants, and illuminated leaves were extracted and they were used to retrieve the chlorophyll density of soybean canopy by using reflectance spectra at different observation angles, and furthermore explored detailed model inversion effects of soybean group for ground soil, shadow leaves, and angle changes. Studies have been showed that when the angles combination was 0°, 20°, 40° and 60°, there were the highest determination coefficient of 0.834, and the lowest root mean square error of 6.13 for prediction model of chlorophyll density. Meanwhile, the zenith angle and azimuth angle was 40° and 0°, respectively, which had the best inversion model. The changes of zenith angles were the most key factor to affect assessment accuracy of chlorophyll density for soybean canopy.

Abstract:For analyzing the spatial variability and correlation of corn yield, the combined method of traditional statistical methods and geostatistics methods were compared. Firstly, the reasonable sampling number was sampled and its statistical characteristics were analyzed. The crop yield information was obtained by traditional statistical methods. Then, the spatial variability and correlation of crop yield at county-scale were studied by geostatistics methods. The regional spatial distribution map of crop yield was made by kringing interpolation methods. The results showed that the corn yield and its components had intermediate variability and the coefficient of variability was 10%～100% by traditional statistics. However, the spatial distribution of corn yield was found that it had relatively strong spatial correlation by geostatistics analysis. Further analysis showed that the spatial variability of corn yield was depended on its consistent factors rather than random factors and the spatial heterogeneity scales was about 3400 m.

Abstract:Using the axiomatic design theory and the method of Z-type mapping, difference characteristics of mapping process between design the reconfigurable product system (RPS) and common product system was analyzed. The C-F-D-P mapping process of RPS was analyzed by the defined rule of and transformed domain. Taking the reconfigurable small agricultural machinery as an example, the implementation process of RPS by Acclaro DFSS software was verified.

Abstract:The method for measuring the sensitivity of the bottleneck degree to the bottleneck shifting factors was proposed. According to the material-flow bottleneck defining, the production capability and load were described from the perspectives of process speed and quality level, then the bottleneck index was constructed to characterize the degree of manufacturing unit blocking the material-flow (that is bottleneck degree). Based on the measurement of the sensitivity of the bottleneck index to the single bottleneck shifting factor and DEMATEL method for analyzing the relationship of the factors, bottleneck shifting sensitivity index was built to measure the sensitive degree of bottleneck index to the uncertain environment. At the end of this thesis, an example for monitoring the bottleneck and measuring sensitive degree to the uncertain environment in job shop was given to prove the validation and practicability of bottleneck index and bottleneck shifting sensitivity index.

Abstract:A research concerning active residual vibration control of planar 3-RRR flexible parallel robots was presented. First, based on the finite element method and the Lagrange’s equation, the equations of motion of the smart beam bonded lead zirconate titanate (PZT) actuators and sensors were modeled. Considering constraint equations of rigid motion and elastic motion, the general motion equations of planar 3-RRR flexible parallel robots were determined by the compatibility. The high-order equations of the system in physical space were transformed into modal space through the modal theory. According to the low-order modal equations, both the strain rate feedback controler and the optimal state feedback controler were designed for suppressing residual vibration of the system. The numerical simulation results revealed that two kinds of controllers could effectively suppress residual vibration of the system. Moreover, comparing the strain rate feedback control, the optimal state feedback control could obtain better control results in a lower control voltage.

Abstract: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s torque and the number of sliders were obtained. Meanwhile, the results show that lag angle could influence torque pulsation when outer motor and inner motor work at the same time and differential connections. This research work laid a theoretical foundation for the design of double-stator single-acting multi-motors. 

Abstract:A type of double-pitch silent chain for conveyors was proposed. Its structure was designed and the relative parameters and designed formula were given. And wear test for 200 h was done. The results showed that the ratio of wear elongation of double-pitch silent chain for conveyors was 0.149%, which was shorter than the double-pitch roller chain’s, and the design could improve the conveying conditions distinctly. Therefore, the design of double-pitch silent chain for conveyors showed the feasibility of application.

Abstract:In order to research load sharing characteristics of the dual power-split gear train, the mechanical structure model was established. With the method of the tooth contact analysis and loaded tooth contact analysis, the actual meshing process of gear pair was simulated and the time-varying mesh stiffness was obtained, which can enhance the precision of the computation. According to the closed-loop characteristic of the power flow of the system, the reverse angle deformation coordination conditions were deduced, which were combined with the mechanical equilibrium equations and elastic support conditions to calculate the transfer torque and load sharing coefficient of system. The influences of errors on the power split characteristics were analyzed. It provided an important role in the reference for the design of the dual power-split transmission system. 

Abstract:Based on the relationship between the rough surface statistics parameters and surface profile fractal parameters, a method for calculating equivalent rough surface fractal parameters was proposed. Furthermore, tangential contact stiffness model was modified. The FEM and modal of the dumb-bell could be obtained when the joint interface was equivalent to the spring elements whose stiffnesses were obtained from the contact stiffness model and evident the effectiveness of the contact model, then the major factors of the modeling accuracy from the stiffness and the numbers of the equivalent spring element was discussed. In addition, the FEM of another dumb-bell was obtained similarly. The frequency response functions (FRFs) of the flexible connection FEM model and the rigid connection FEM model could be obtained from the result of the harmonic response analysis. Through the comparison of the FRFs, the necessity of the research on contact stiffness model was confirmed. 

Abstract:A three-point bending test of hot forming high strength steel specimens with different thickness was designed. The related mechanical parameters were obtained. The results indicated that the bending mechanical properties of hot forming specimens were strengthened with the increase of the thickness. The specimens which were based on different thickness had higher center hardness and lower surface hardness. Meanwhile, a multi-layer composite material was proposed with hardness gradient distribution in the direction of the thickness. Based on the hardness gradient and the hardness-strength corresponding to the relationship, a multi-layer gradient numerical simulation model of three-point bending was established, explored that the gradient material model was more rational for numerical simulation. 