Abstract:A half-car model of semi-active suspension systems with 4-DOF was designed in Matlab, and a fuzzy hybrid controller was built. Then, the membership functions and rule of fuzzy hybrid control strategy were optimized by particle swarm optimization (PSO)．In order to verify the proposed control strategy, a series of experiments of PSO-fuzzy-hybrid control strategy on the platform of hardware-in-the-loop were carried out．It showed that compared with traditional fuzzy control strategy, PSO-fuzzy-hybrid control strategy enhanced the overall performance of the semi-active suspension system effectively, and obtained better control performance in all different road input excitations. 

Abstract:A kind of axial draft sensor was designed based on magnetostriction theory to improve the measuring accuracy of soil resistance. A mathematical model of sensor’s exciting circuit was established based on ferromagnetics theory, Ampere’s circulation and Ohm’s law for magnetic path. Then the performances of sensor’s output signal along with load were simulated by using Matlab/Simulink. 45-quenching steel and 40Cr-quenching steel were used as sensor’s shell separately. Load experiment showed that the performance of the sensor, of which shell was 45-quenching steel, was better than the other. The better sensor’s linearity determination coefficient of static characteristic curves was 0.9965. The output voltage was 0.55 V when the shearing force was 70 kN. 

Abstract:Based on fluctuating high frequency voltage signal injection sensorless control method, position sensor fault-tolerant control system for permanent magnet synchronous motor (PMSM) was designed. The phase delay, which existed between high frequency current signal and demodulated signal, was analyzed. The phase delay was caused by the inverter, the stator resistance and AD sampling time. The effect of the mutual inductance and the harmonic inductance on position estimation error were analyzed. And a compensation method was proposed. Simulation and experiment results showed that the position sensor fault-tolerant control system had the advantage of high tracking accuracy and certain disturbance-rejecting ability. It had also a good speed and position estimation performance at zero and low speed. 

Abstract:According to the working characteristic of hybrid electric vehicle (HEV) in different conditions, the multidisciplinary design optimization (MDO) method in parameter optimization of power system of HEV under uncertainty was studied. To estimate the impact of uncertain input parameters on objectives of drive power system by performing the Monte Carlo simulation. The aggregate preference function of objectives and corresponding constraint equation were constructed to satisfy the designers’ preference and engineering design. The power system parameters were optimized by using analytical target cascading (ATC) method which could hierarchically decompose and collaboratively optimize the system. The results showed that the values of vehicle’s performance and the power system design could be optimized currently.

Abstract:A method of high frequency current processing was proposed for inductance parameters identification. The d-axis and q-axis inductance parameters were identified. The effect of inverters nonlinear factors on identification accuracy of inductance parameters was analyzed and deduced. The base current and other high frequency clutter current were excluding by applying two delay filters and two synchronous axis filters on response current. The positive and negative phase’s amplitude were obtained. The d-axis and q-axis inductance were identified. The proposed method could identify inductance in the stationary state and operating state of the motor. The results showed that under the different loads and speeds of motor, the accuracy of inductance identification was high. It could give a help for improving the real driving control system. 

Abstract:A power system of electric vehicle driven by in-wheel motors was studied. First, force conditions of the running electric vehicle driven by in-wheel motors were analyzed. Then, the in-wheel motors and lead-acid batteries were selected with a certain type electric vehicle driven by in-wheel motors as a sample. A power system model of electric vehicle driven by in-wheel motors was built and simulated based on ADVISOR. The simulation result showed that the selected in-wheel motors and lead-acid batteries could meet the design requirement. Finally, the electric frame car designed was tested to prove the reasonableness of the simulation.

Abstract:Taking a self-developed articulated underground mining vehicle as prototype, the driving simulation scene model, 3-D vehicle model and tunnel model were established for the working environment of underground vehicles. A 3-DOF kinematics and dynamics nonlinear discrete model was built up to ensure the real-time driving simulator and reality. The models and the scene were driven by using an open-source graphics engine and an object-oriented graphics rendering engine. Ray casting method was used to virtualize the laser measurement sensors in simulator so that it could provide support for intelligent technique research of underground mining vehicle.

Abstract:The simulation models of electrical parking brake (EPB) actuator in Simulink software were built, including DC motor model, lead-screw model and inner friction analysis models. The inner friction concluded viscous friction, Coulomb-friction and etc. In order to save cost, a method for controlling EPB system by using on-off controller was proposed. The simulation results and experiment results were compared to verify the feasibility of the proposed simulation model and on-off controller used in EPB system. 

Abstract:The effect of no-till (NT) opening seedbed characteristics on soil moisture, crop growth, yield and water use efficiency (WUE) was studied in the field experiment at Daxing in Beijing in 2008～2010. The results indicated that no-till opening seedbeds could increase the capacity of water storage. Compared with traditional tillage seedbed, volumetric soil water content increased by 0.2%~2.7% in 0~30 cm soil layer and the crops growth were also promoted. The best results were achieved by the seedbed of NT with the opening depth of 20 cm. Compared with traditional tillage seedbed, NT with the opening depth of 20 cm increased winter wheat yield and WUE by 2.4% and 7.4%, and summer maize yield and WUE by 1.2% and 1.5%, respectively. The study showed that 20 cm could be the suitable opening depth for no-till seeding in northern China plain. 

Abstract:Plowing in rheological soil is a unique tillage practice in humid or water logged agricultural production regions in China. System optimization of moldboard plough for rheological soil condition is necessary for improving its performance and providing a reduced draft and minimized energy consumption. An orthogonal test using four factors with three levels was conducted to optimize plough body structural and working parameters. Significant influence of tillage depth on the plough’s performance was observed in the experiment. The optimum working condition occurred at a forwarding speed of 0.8 m/s and a tillage depth of 20 cm. This result was further evaluated and optimized with computer simulation, from which the structural parameters such as pushing angle, cutting angle, covering angle and height of plow were optimized. The simulation results proved that tilling rheological soil with a plow having a cutting angle of 35°, pushing angle of 90°and plow height of 200 mm provided the minimum specific draft of tillage, which was 0.69 N/cm2. 

Abstract:According to the problems of few test projects and test platforms in the existing rear suspension testing system, a tractive rear suspension multi-position rear suspension field experiment platform was designed on the basis of the relative design experience. Based on the statics principles, the suspension performance curves of hydraulic pressure three points were drawn. The steering operational, driving linearity and power output shaft with the highest speed under tractor, experiment platform, experiment suspending 2BDM-12 wheat specific row no-till dill and experiment suspending 2BMSF-12/6 no-till dill were tested in the field. The results showed that the steering operational, driving linearity and power output shaft with the highest speed had some changes but within allowed limits under four conditions. Therefore field experiment platform met the requirements of the rear suspension equipment tests in the field. 

Abstract:The equal-diameter cam seedling-pushing mechanism was proposed in order to solve the problem that the structure size of conjugate cam seedling-pushing mechanism was too big. In the proposed seedling-pushing mechanism, equal-diameter cam was used to control the motion of seedling-pushing rod. Ideal kinematic curves of seedling-pushing rod were constructed and reverse model of the proposed seedling-pushing mechanism was established according to requirements of planting agriculture as well as driving mechanism with planetary elliptic-gear trains. Then a reverse design and simulation software was compiled based on VB 6.0. A set of optimum parameters including structural parameters as well as pitch curve of equal-diameter cam were obtained through the software, which could meet the requirements of planting agriculture. The seedling-pushing mechanism was developed based on these parameters and testified by high-speed video. Analysis and results of the experiments showed that the proposed seedling-pushing mechanism could meet the requirements of planting agriculture and had a smaller outer dimension compared to conjugate cam seedling-pushing mechanism. 

Abstract:In order to achieve the automatically seedling pick-up of duck-billed transplanter, a geared five-bar linkage seedling pick-up device was introduced. The ideal pick-up trajectory was obtained by simulation and optimization of structural parameters. The dynamic characteristics of the proposed device were also optimized. On the basis of theoretical studies, a seedling pick-up bench was designed. Experiment results showed that geared five-bar linkage seedling pick-up device was feasible and rational. 

Abstract:A double offset disc air-suction seed metering device for soybean was designed. The key parts of seed metering device was designed and optimized based on the working principles of seed taking and seed metering. The single factor experiments and the quadratic general rotary unitized design were carried out with the rotational speed and air velocity as experimental factors and seed missing rate as experimental index. The regression surface was obtained and its mathematical model was built by using the Design-Expert software. The results showed that the air velocity of 220 m/s and rotational speed of 100 r/min were the best combination factors, which leaded to the seed missing rate of 2.72%.

Abstract:To study the cone-jet shape forming process and its impact factors by electrostatic spraying, combining with electrostatic spraying blade, the 2-D axisymmetric cone-jet physical model was proposed. Based on continuity equation and momentum equation in fluid dynamics, electric potential field equation and boundary conditions, the control equation of mathematical model was calculated by using Matlab and finite difference methods. The cone-jet shape, the electric field distribution for both internal and external of cone-jet and the electric field strength of the cone-jet surface were obtained. The calculated results showed the larger fluid flow and fluid surface tension, the larger the diameter and the top of cone-jet were. In the internal of cone-jet, the radial potential and electric field strength were gradually decreased, but the axial potential was increased slowly and the axial electric field strength kept invariant. In the external of cone-jet, the radial potential was stable and the axial potential uniformly changed. Fluid surface tension and fluid flow were inversely proportional to the normal electric field strength along the con-jet surface, but had no effect on the tangential electric field strength. 

Abstract:A pesticide mixing ratio detection unit based on light permeability of pesticides, a pesticide injection device controlled by PWM duty cycleand a low power consumption control unit based on single chip microcomputer MSP430F149 were designed. A performance test and a calibrating experiment were conducted for each unit. An online pesticide mixer with mixing ratio feedback was constructed and a fixed-point tracking experiment on the Paraquat SL mixing pesticide and water by 1∶200 was conducted. The result showed that the online pesticide mixer developed by the method of online mixing pesticide with mixing ratio feedback based on light permeability of pesticides could acquire mixing ratio information in time, automatically adjust injection volume of pesticides, accurately track the set of mixing ratio, and effectively meet the requirement of online mixing pesticides. 

Abstract:The harvesting flow chart and overall design of 4LQZ-6 tangential-longitudinal axial combine harvester was put forward and the design parameters of major working parts such as tangential axial threshing and separating unit, positive feeding unit, longitudinal axial threshing and separating unit and air-and-screen cleaning unit were discussed. The test in fields showed that when the wheat yield was 6605 kg/hm2, the total loss rate was 0.2%, breakage rate and rate of impurity were both 0.1%, productivity was 1.47hm2/h. When the rice yield was 8021kg/hm2, the total loss rate was 1.7%, breakage rate and rate of impurity were 0.9% and 0.8% respectively, productivity was 2.27hm2/h. The technical indexes could meet the demands of design.

Abstract:Spatial structure of the D-type knotter was studied based on its working sequence. Key spatial parameter relationships were confirmed to ensure the eight knotting processes going well through analyzing the knotter working principle, and the parameter model of knotter was build. Key spatial axes parameters were also designed by using mathematica 8.0 software, and two knotter frames were finally determined with different spatial parameters. The knotting experiments were carried out by using the two different knotter frames which were both assembled with the homogeneous New Holland parts, the results showed that, in the indoor experiment, the knotting rate of knotter frame Ⅰ (KFI) was 1.0% lower than knotter frame Ⅱ (KFII), while the average breaking force of the knot formed by the KFI was 13.9% higher than KFII at the same preload. In the field experiment, the knotting rate of KFI was decreased 4.0% in compared with KFII while its average breaking force was 2.5% higher than KFII. The average breaking force of the knot formed in the field was 94.2%~115.9% higher than indoor due to the different preloads and the additional extend force of the compressed straw baler. 

Abstract:The measurement accuracy of T-TDR sensor was improved via studying the heat conduction process and optimizing the embedded point of the thermocouple nodes. Using 2-D heat transfer equation in the soil, the initial boundary value of the Heat Transfer of the T-TDR probe was analyzed numerically. Then the relationship between the thermal field of T-TDR with time, thermal conductivity and capacity of soil was established. Furthermore, the dynamic process of heat transfer and spatial thermal distribution of T-TDR at different environment temperature, conductivity and volumetric heat capacity were simulated. The results showed that the optimal positions of the thermocouple node on both sides were on the probe midpoint at 2 mm thermocouple junction of the sensor terminal direction distance. This was the most sensitive point to the radiant heat of the intermediate probe. 

Abstract:To investigate the effects of different packing modes, inoculation quantites and hydraulic retention time on nitrate removal, permeable reactive barriers (PRBs) packed with sawdust, zero-valent iron (Fe0) and active carbon were tested in laboratory. The PRB filled with completely mixed sawdust and Fe0 showed higher nitrate removal efficiencies than those filled with sawdust and Fe0 in layer modes. Nitrate removal efficiencies and dissolved organic carbon (DOC) in effluent increased with hydraulic retention time increased. Within limits, increasing the amount of inoculum quantity of PRB could increase nitrate removal rate. Nitrate removal efficiency, DOC concentration and the number of bacterial colonies in effluent decreased with the initial nitrate concentration increasing, whereas the accumulation of ammonium showed an opposite trend. Addition of active carbon not only could promote the reduction of nitrate, decrease ammonium concentration but also could improve outlet water chroma. Furthermore, the nitrite could be nearly detected in the effluent, while the number of bacrteria colonies changed from 103 CFU/mL to 106 CFU/mL. 

Abstract:This paper comprehensively summarized the research results from domestic and foreign studies of the effect of biogas slurry farmland application on plants yield and quality, and the effect on water and soil environment. It showed that biogas slurry played a positive role in improving the quality and yield of crops, improving plant seed germination, prevention and treatment of plant diseases and insect pests, and improving soil quality. However, an excess amount of biogas slurry application could lead to the pollution risks of water and soil environment. It should fully consider the land carrying capacity for biogas slurry and choose appropriate dosage which had no pollution on soil and groundwater, so that the demand of fertilizer could be saved and the production cost of farmers could be reduced. It could provide scientific guidance for biogas project handling biogas slurry. 

Abstract:Taking natural root-soil composite of corn Shennong 46 as test material, cutting mechanical tests were carried out in the universal test machine and homemade pressure system around specimen. The results showed that moisture content was the key natural factor influencing ultimate shear stress, which increased with moisture content. The ultimate shear stress in vertical profile 20 mm away from root center was the largest, and the secondary was in vertical profile through root center. For vertical profiles more than 20 mm away from root center, the longer distance, the smaller ultimate shear stress. Combining with ridge-till specifications, reasonable cutting section for stubble-cutting disc was 40 cm away from ridge center. In the vertical section, the greatest shear stress existed at a depth of 20~60 mm from the surface of earth, was about 5.20~7.15 MPa. The maximum power was consumed in this depth range for rootstalk cutting mechanism.

Abstract:For theoretical analysis effect of self-adjustment flow on the adaptive drip irrigation emitter, the original size and pre-deformation deflection after fixed of the elastic adjustment diaphragm on the control volume were designed, and the total force to the elastic adjustment diaphragm based on description of its structure and working mechanism were analyzed. The theory and calculation method of mechanics to calculate the stress, the stiffness, the effective area of diaphragm and the sealing pressure ratio at interface of rubber adjustment diaphragm and energy dissipation hole were used. Then the actual sealing pressure ratio of the together control force was obtained. Results indicated that the minimum of actual sealing pressure ratio was 0.61 MPa at the combined action of the force produced from the pre-deflection and soil negative pressure of 20 kPa, but the computational theoretical sealing pressure ratio was 0.61 MPa too. The former was equal to the latter in both of them and met the condition of the actual sealing pressure ratio which was equal to or greater than the theoretical sealing pressure ratio. So the minimum of actual sealing pressure ratio was enough to maintain the drip emitter at the mode of initial shutoff water, and in a critical state of shutoff water and supply water. As long as soil negative pressure was bigger slightly when soil was drought little by little and it was equal to 21 kPa only or more than it, the actual sealing pressure ratio reduced to 0.54 MPa and far less than the theoretical sealing pressure ratio. Then the adaptive drip irrigation emitter began to drip water, and entered the mode of automatic regulation. So it had realized the effective of self-adjustment drip flow really at the same time. 

Abstract:A total of 71 wheat straw samples of different varieties were collected from different locations of China. 54 samples were selected as calibration set, and the rest 17 samples were taken as validation set. Static and simulated online quantitative analysis models of net calorific value of wheat straw were established in laboratory by two different near-infrared spectrometers—Spectrum 400 and Antaris Target, respectively. Spectrum 400 was used for rapid detection in a static mode. The determination coefficient and the relative analysis error of calibration set were 0.90 and 2.75. Antaris Target was used to simulate on-line detection. The determination coefficient and the relative analysis error of calibration set were 0.93 and 3.26. Moreover, the static and simulated online models were compared and discussed.

Abstract:In China, there are great difference in temperature and humidity in different regions. During the storage time, the characteristic of biomass pellet fuel will change, so the application of the fuel will also change. The corn stalks and wood pellet were tested with different storage method, temperature and humidity. The results showed that during the storage time, the temperature, humidity and storage method were the main factors which affected the total moisture of pellet fuel. When the humidity was larger than 70%, the corn stalks will appear mildew. The wood pellet will crack and mildew under the condition of high temperature and humidity.

Abstract:This review mainly focused on researches and applications of visible/near infrared (Vis/NIR) spectroscopy and Raman spectroscopy for quality and safety inspection of fruits and vegetables. Vis/NIR spectroscopy was widely and successfully applied in fruits and vegetables for quantitative quality analysis (including internal components like sugar content and acidity, and tissue properties like firmness, etc.), qualitative quality analysis (including defects detection, maturity classification, storage time/on-shelf life discrimination, etc.), growing or processing monitoring, growing condition analysis, safety inspection, variety and geographical origin tracing, and so on. Raman spectroscopy was used for internal components analysis (especially for carotenoids), quality classification, maturity discrimination and defects detection of fruits and vegetables. It is even a more potential way for detecting pesticide residues and microbiological contaminations in fruits and vegetables. At the end of this review, advantages and disadvantages of spectroscopy techniques for quality and safety inspection of fruits and vegetables were summarized, and also the future trends. 

Abstract:In order to explore a rapid and non-destructive method for identifying storable quality of indica paddy, experiments were conducted on 80 samples of severely unstorable indica paddy and 80 samples of other indica paddy. Support vector machine (SVM) method was selected to build qualitative model according to training samples’ characteristics. A combined kernel function was defined after analyzing and studying different kernel function. The proposed combined kernel function was the linear combination of polynomial function and radial basis function, and it combined each advantage of these two functions to acquire both interpolation and extrapolation properties of kernel function. The experiments showed that the model had the best comprehensive performance when the linear combination polynomial function and radial basis function was taken as the kernel function of SVM, and the control factor was 0.7. The training identification rate was 97.21%，and the test identification rate was 93.25%.

Abstract:The classified feasibility of Malus asiatica fruit by using near-infrared spectroscopy (VIS/NIR spectrometer) and softening index during different shelf life was analyzed. A mathematical model was established by combining partial least square (PLS) and standard normalized variate (SNV) which was regarded as the best pre-processing technology. The determination coefficients (R2) of calibration set and prediction set were 0.847 and 0.813 respectively, which illustrated that there was a high correlation between spectrum and the softening index. It showed that the softening index could be used to classify Malus asiatica samples during different shelf life. The LS-SVM and PLS-LDA were applied to build classification models, respectively. The results indicated that non-linear LS-SVM model was more suitable for classification of Malus asiatica samples than linear PLS-LDA model. The average correct recognition rate and average correct rejection rate were above 94%.

Abstract:To determine the moisture content in de-enzyming green tea leaves rapidly and nondestructively, prediction models were established based on visible-near infrared spectroscopy. Diffuse reflection spectra of 192 samples were collected with a portable field spectrometer (FieldSpec 3, ASD), among which 144 samples were partitioned to a calibration set and 48 samples to a prediction set using the sample set partitioning method based on joint X-Y distance. 11 sensitive bands were selected with correlation coefficient method, and then moisture content models of partial least squares and principal component regression, artificial neural network and their combination were established with the preprocessing methods of the first derivative and moving average filter. The model comparison showed that the prediction model of partial least squares regression was the best when 5 principal components were adopted. The calibration and prediction correlation coefficients were 0.990 and 0.819 respectively, and the root mean square errors of calibration and prediction were 0.011 and 0.037 respectively, and the mean error of predicted moisture content was 3.30%. 

Abstract:The variation of color and texture during banana storage was studied based on computer vision. The images of green banana in first mature stage were acquired everyday during storage. After the binary operation, RGB and gray images were masked by the binary images to eliminate the background. Then, R, G and B average values were extracted from pre-processed color images as color indexes. The gray-level co-occurrence matrix generating rule of the irregular image was used to obtain these matrixes of pre-processed gray images. Three texture descriptors were extracted as texture indexes from these matrixes, namely energy, contrast and homogeneity, respectively. Results showed that the change curve of R average values in combination with that of G could describe banana surface condition before the sixth mature stage, and the curve of contrast and homogeneity could do that after the sixth mature stage.

Abstract:Effect of treatment with 1-MCP or its structural analogues on ethylene synthesis and senescence of ‘Hanfu’ apple during cold storage was investigated. After being fumigated for 20 h with 0.75 μL/L 1-MCP (1-methylcylopropene), 2μL/L 1-PentCP (1-pentylcyclopropene) or 0.5μL/L 1-OCP (1-octylcyclopropene) respectively, the apple fruits were packed with 0.02 mm thick plastic bags and then stored at (0±0.5)℃. The results showed that treatment with 1-MCP or its structural analogues reduced ethylene production and respiration rate, delayed the respiration and ethylene peak by 30 d compared with control fruits. The content of ACC(1-aminocyclopropane 1-carboxylic acid) in treated fruits exhibited higher level than untreated control fruits throughout the whole cold storage, because treatment with 1-MCP or its structural analogues promoted the activity of ACS (ACC synthetase). All the treatments inhibited the activity of ACO (ACC oxidase), therefore, ethylene production of the treated fruits was suppressed during the cold storage. In addition, 1-MCP and its structural analogue also deferred the increase in MDA content and membrane permeability, decreased respiration rate and ethylene production, and delayed senescence of ‘Hanfu’ apple. However, there existed no significant differences between treatments with 1-MCP or its structural analogues. 

Abstract:Effects of various 1-methylcyclopropene(1-MCP) treatment durationon fruit quality, respiration intensity, ethylene release rate, cell membrane permeability, MDA content and fruit texture (including pericarp break force, pericarp break distance, pericarp toughness, pericarp brittleness and mean flesh firmness) of Fuji apple were studied. The results showed that 1-MCP treatment significantly reduced respiration intensity and ethylene release rate, and maintained storage quality of fruit, but the beneficial effect of 1-MCP treatment decreased with prolonged treatment period. The storage effect of 1-MCP treatment on 0, 7 and 14 days after harvest were obviously better than 21 days. Thus, 1-MCP treatment should be applied within two weeks to maintain the good storage quality of apple fruit. 

Abstract:Numerical simulation on the inner flow, heat transfer, mass transfer and cracking reaction in vortex reactors was carried out with gas-solid two-phase flow-reaction model. The detailed information of flow field, temperature field and concentration field of vortex reactor was obtained.Results showed that the motion of particles was cork screw path. The temperature in vortex reactors had certain rule and temperature gradient in axial and radial direction. The distributions of velocity had relations with different angles of rotor blade and no relations with hot oil temperature. The entrance velocity of vortex reactors was bigger and later flattens.

Abstract:The probiotic function and structural properties of recrystallised sweet potato starch before and after in vitro digestion were studied. The results demonstrated that the annealed, temperature-cycled and heat-moisture treated sweet potato starches before and after in vitro digestion could resist the degradation of tract enzymes and selectively promoted the proliferation of Lactobacillus, Bifidobacterium, Fecal streptococci and Clostridium septicum in human feces. Compared with the annealed, temperature-cycled and heat-moisture treated sweet potato starches, the digested annealed, temperature-cycled and heat-moisture treated sweet potato starches possessed the more stable structure as well as the higher selective proliferation of probiotics. Therefore, the recrystallised sweet potato starches could accord with the conditions of prebiotic, and be further studied as the new prebiotic product.

Abstract:In order to confirm the soybean protein solution properties and rheological behavior after combined with lecithin, the surface charge, particle size, fluid type and the solution viscosity of lecithin-soybean protein complex were investigated. The results showed that the enhanced negative charge of protein particle, greater particle size and improvement of soluble protein were occurred with the increasing of combined lecithin content. The rheological characterization data displayed that the corresponding protein concentration reduced gradually when the n value, which indicated the fluid type, began to less than 1 with the increasing of lecithin combined content. This change explained that the complex of lecithin on soybean protein could lower the inflection point of protein concentration which indicated the change of fluid type. And then the protein viscosity was reduced by the effect of moderate lecithin content. 

Abstract:Effect of three factors (microwave anode current source, microwave process time and potato thickness) on comprehensive quality of potato slices was studied. Quadratic regression orthogonal rotary combination design method and response surface methodology were used to obtain the optimum technological parameters, which were as follows: microwave anode current source of 161.78mA, microwave process time of 10.19s, and potato thickness of 2.88mm. Verification results showed good fitting degree of the regression model. Results showed that with the optimum technological parameters, microwave enzyme inactivation technology could reduce the activity of polyphenol oxidase and maintain good sensory quality of potato slices. 

Abstract:In order to further improve overall heating efficiency of the greenhouse heating system, a hot air heating system which used the biomass boiler as a heat source and the fan coil as the end of the cooling device was presented. Combined with experiment greenhouse, a CFD model about this greenhouse without plants was set up. After that, a CFD simulation was carried out by using this CFD model. After compared with the simulation results and experimental data, it was found that the overall trend of the temperature in the greenhouse was consistent. Error of each point was less than 3℃, and the root mean square error was 0.66℃. The results indicated that the CFD model was effective. The results showed that the forced-air heating system could effectively improve the indoor temperature. The temperature range of plant growth area was 12～17℃. The plant canopy temperature was evenly distributed without larger gradient.

Abstract:Fruit tree canopy volume is an important factor for precision management in fruit orchards such as pesticide variable spraying, precision fertilizing and yield estimation. In order to overcome the problems of uneven hilly environment and irregular planting on fruit tree canopy volume, a platform for measuring fruit tree canopy volume by laser was set up. Based on AHRS and DGPS sensors, 3-D data of laser scanned point of fruit tree canopy in geodetic coordinate system was deduced through spatial coordinates transforming. The area and line information of point cloud of fruit tree canopy were extracted by using slicing technology, and the canopy volume was calculated with an accumulation method. The test showed that the shape of fruit tree canopy could be represented by the canopy point cloud of litchi fruit tree in the geodetic coordinate system. Taking three artificial pruning cylindrical hedgerow trees as experimental object, the relative measuring errors between artificial measurement and laser measurement was about 5%.

Abstract:A method applying 3-D laser scanning to estimate tridimensional green biomass of individual trees was proposed. For each objective tree, some tree parameters were obtained such as height, diameter at breast and crown width of an individual tree from cloud points, which were gotten from 3-D laser scanning. Then, through dividing crown into a plurality of irregular bodies, the volume of crown was regarded as the summation of volume of each body. Finally, the product of tridimensional green biomass and weighted average green looking rate from different perspectives and volume of tree crown was obtained. The method was tested on 13 trees, 6 species, and the results showed that the average tridimensional green biomass of broadleaf trees was 253.02 m3 and 146.75m3 for coniferous trees. It was obvious that the average tridimensional green biomass of broadleaf trees was bigger than coniferous ones, which was contrary to results from traditional method. 

Abstract:Aimed at the image of the simple grapevine taken in the pergola trellis, a grape recognition algorithm combined with color and texture feature of color image was suggested in order to get the center line and the length of the grape. Firstly, Sobel operation was used to get the edge of the |G-R|+|G-B| chromatic aberration image. Then, berries of the grape were detected by Hough transform according to the mathematical model of the outline of the grape berries. The circles detected by the Hough transform were judged by the feature of the color and texture of grape berries and the concentrated berries. At last, the shape parameters of the grape bunch were determined by the information of the berries after judged, which was needed by bagging automation of grape. The experimental results showed that the method of grape recognition was effective in segmenting the comparison of grapes. There were totally 78 images used in test, and 70 of them were correctly recognized. The correct recognition of grapes reached to 90%.

Abstract:In order to solve the low utilization and unsuitable ratio of N, P and K in traditional fertilization, soil sample strategy and distribution maps of available nitrogen, phosphorus and potassium were studied. The variable rate fertilization decision support system was developed based on distribution maps. Combined with GPS information, the motor speed of independent fertilizer for N, P and K were controlled to make urea, diammonium phosphate and potassium sulfate be used as needed. The comparative experiment of traditional fertilization and ratio fertilization for corn and soybean in No.5-2 plots of Heilongjiang Hongxing Farm was carried out. Results showed that, with ratio fertilization method, the yield of soybean and corn increased by 2.33% and 9.32% respectively in case of saving fertilizer of 15%.

Abstract:There is a certain correlation among the growth parameters of pigs, and some parameters have non-linear relationship with pig weights. When using the simple linear regression model to predict the pig weight, the collinearity among independent variables and low fit goodness were found. For these problems, based on the nearest neighbor clustering algorithm for RBF neural network, a pig weight prediction RBF neural network model was constructed with the growth parameters of 52 Landrace sows. The predicted value and measured value of the pig weight were compared by linear regression test. The regression analysis showed that the goodness of fit (R2) of RBF neural network prediction model for Landrace pig weight was 0.998, while R2 of the linear regression model was only 0.891. The results indicated that the RBF neural network-based modeling method was an effective way to build the prediction model of pig weight. It eliminated the collinearity of the independent variables in linear regression analysis, and forecasted better than linear regression model. 

Abstract:Based on the concept of hybrid mechanism and reciprocal screw theory, a method of structural synthesis of fully-decoupled two-translational and two-rotational (2T2R) parallel mechanisms was proposed and 106 parallel mechanisms were obtained. All mechanisms synthesyzed in this paper consisted of two limbs which were connected with the moving platform and the fixed base. One limb was a single open kinematic chain and another was a hybrid chain. Jacobian matrix of each mechanism was diagonal and there existed a one-to-one mapping relationship between the output velocity of platform and input of actuated joints. Therefore, these parallel mechanisms were fully-decoupled on kinematic solutions, which could avoid some drawbacks of the general paprallel mechanisms in terms of high coupling and complicated control design.

Abstract:A 4-UPS-RPS spatial 5-DOF parallel mechanism, which could achieve three rotational DOF and two translational DOF, was introduced, and its kinematics analysis was carried out. 4-UPS-RPS parallel mechanism included five limbs, where four limbs were types of universal joint-prismatical joint-spherical joint, and the other was type of revolution-prismatical joint-spherical joint. The reverse solution of position analysis for the parallel mechanism was presented. On this basis, the Jacobian matrix and acceleration equation were derived, and the inverse position, velocity and acceleration of this parallel mechanism were obtained. Then the virtual simulation of mechanism kinematics was implemented by using ADAMS software. The simulation results showed that the numerical calculation results were correct. The research could provide a theoretical basis to promote application of 4-UPS-RPS parallel mechanism. 

Abstract:A method of position analysis for spherical mechanisms with four-bar closed-loop chains was proposed. The mechanism was divided into a four-bar closed-loop mechanism and a single-opened-chain (SOC) unit. The constraint equation of the four-bar closed-loop was established with spherical loop equation. The constraint equation of SOC was set up with coordinate transformation and direction cosine matrix. The coupled constraint equation of whole mechanism was built up based on spherical trigonometry. The proposed method was simple to set up constraint, easy for elimination and less extraneous root, which was helpful to obtain symbolic solutions or figure-symbolic solutions. 

Abstract:In order to overcome the nonlinear influence of electromagnet material on control system, a new method of nonlinear power amplifier was put forward. By this special amplifier, the differential electromagnet load system became a linear system. For the controller of active suspension, the control object was transformed into a linear control system, which facilitated the real-time calculation of the controls variable. The experiment result showed that the nonlinear amplifier had expanded the dynamic range of the controller and improved the stability of the active magnetic levitation control system.

Abstract:Static property of a type of speed compensation valve was analyzed. It was found that the load capacity was in proportion to main valve spool spring stiffness K, throttling flow rate q, inverse of throttling coefficient C-1q, inverse of hydraulic perimeter of throttling port w-1, square root of oil densityρ0.5, throttling differential pressure Δp, ratio of rod diameter and piston diameter of load hydraulic cylinder R. The model used to study the dynamic property of the speed compensation valve was built by AMESim dynamic simulation code. By the results with the dynamic simulations of the model, it was observed that increasing control pressure pc could improve the steady speed magnitude of load, but had no effect on the transition time to reach steady speed. Decreasing spring stiffness K of main spool could improve the speed of load and increase the transition time. Increasing the mass of load would lengthen the transition time correspondingly, but had no effect on the final steady speed magnitude. The variation of taper spool diameter D almost had no influence on load dynamic property. Decreasing the ratio of rod diameter and piston diameter R would increase the final steady speed magnitude of load, but had no influence on the transition time of load speed.

Abstract:To meet the requirement of smooth convey for light, thin and small product in modern industrial, an inertial piezoelectric vibratory feeder was designed. Its working principle was analyzed and the dynamic model of bimorph vibrator was established. The effect of vibrator length, vibrator mass and impact force on deformation was analyzed in Matlab software. The force of parts in the hopper was analyzed. The prototype of inertial piezoelectric vibration feeder was developed and tested. The relationship among voltage, amplitude, frequency and feeding speed were obtained. The experimental results showed that the proposed vibratory feeder had good performance at resonance. The amplitude and feeding speed increased linearly with the increase of voltage. The proposed vibratory feeder had better driving ability and smaller space compared with the cantilever bimorph piezoelectric vibratory feeder, and had wide prospects.

Abstract:Eccentric error of planetary gear was transformed into equivalent mesh error on meshing line by geometry method. Then coupling error of every equivalent mesh error was calculated and deduced when angular frequency was 0, same and different. The best compensational effect was obtained with the first two cases. The value range of the difference among initial phase errors were concluded when the coupling error could be effectively compensated and the relationship of initial phase with the best compensation. Furthermore, assembling method by allocating initial phase error was proposed, which could improve transmission accuracy of planetary gear. The transmission errors of planetary gear were calculated with allocating assembly, random assembly and machining precision improvement, respectively. The comparison and analysis proved that the proposed method was effective and economical through. 

Abstract:A measurement method was proposed for rotation axes of five axis machine tool based on machine vision. Firstly, the vision technology was adopted to obtain sign images by using CCD camera. Then, the digital image processing techniques were used to analyze these images. At last, the positioning errors of rotary axes were identified by calculating the relative rotary errors at different positions of rotation axes of machine tool. Comparing to traditional method, the experimental results showed that the proposed method with a simply, high efficiency and application value provided a computation basis for the error compensation of a machine tool.