Abstract:The control system of boost CNG Engine based on electronic pressure regulator was studied. The structure and working principle of universal exhaust gas oxygen sensor were analyzed. Based on the main chip MPC561 and integrated CJ125, universal exhaust oxygen sensor control circuit and heater circuit were designed. Based on adaptive algorithm, the A/F ratio closed controller was designed and its control strategy of air-fuel closed loop was discussed. The CNG engine experiments of air-fuel ratio closed loop on bench test showed that the dynamic response of UEGO control system was rapid and accurate. Based on UEGO control system, the intelligent control of engine’s air-fuel ratio could be achieved, and the performance of economy and emission could be improved.

Abstract:A motion controller was designed to achieve stable running of a four-stroke free-piston linear generator. Simulation model of the free-piston motion controller was built based on the control theory of hybrid system. Motion control process was analyzed by using the proposed model and the model of a free-piston linear generator. Effects of circulation burning fluctuations and misfires were discussed. Based on the results of the simulation, an electronic control system was designed by using a high-performance digital signal processor. Testing results of the electronic control system were analyzed in detail. According to the simulated and tested results, the designed motion controller has the advantages of simplicity and reliability. It satisfies the requirement of four-stroke free-piston linear generator for piston motion control.

Abstract:A free-piston linear alternator with an axial uniflow-scavenged using passive charge valve was designed. The structure and principle of the alternator were introduced. A simulation model of the working process which was validated with the test was established based on dynamics and thermodynamics equation. The motion characteristics and the performance effective factors of the alternator which was beneficial for performance optimization and prototype design were analyzed. The simulation results show that the alternator possesses a longer ventilation time and the duration accounts for about 58% of the whole cycle, which provides sufficient fresh mixture entering the cylinder. The motion curve of piston is non-symmetrical, the acceleration of the free-piston at TDC changes violently and it needs accelerate the combustion heat release rate to adapt to the changes. It should appropriately increase the piston mass and the opening-closing position of the exhaust valve, and reasonably reduce the ignition advanced position and the working pressure of the inlet valve to reach higher output power.

Abstract:The indicator diagram was collected to study the effect of injector parameters and low pressure fuel supply system on cyclical combustion variation of DME as engine. The experimental results showed that the cyclical combustion variation of the DME engine decreased when the nozzle diameter hole diameter was increased. The influence of the nozzle hole on the cyclical combustion variation for the DME engine at high speed was more significant than that of low speed. The cyclical combustion variation increased when the opening pressure of the oil injector was increased at low speed, however it showed the opposite changing trend at high speed. The cyclical combustion variation decreased when the load of the engine was increased. The cyclical combustion variation coefficient showed a trend of first increase and then decrease when the fuel supply advance angle was advanced from BTDC 6°CA to BTDC 13°CA. The cyclical combustion variation could be controlled effectively by adding the volume of the accumulator of the low pressure fuel supply system.

Abstract:Based on the theory of permanent magnet latching, an electromagnetic linear actuator (EMLA) for a fuel injector of engine was presented. Using method of equivalent magnetic circuit, the dynamic model of the EMLA was established. Eddy current, dimensions of components, and fringing effect were taken into account in modeling. Using PWM method and H-bridge driver circuit, the prototype of the EMLA was tested on the test bed. The experimental and simulated data agreed well and the model was validated. The results show that under 0.5MPa supply pressure, the transition time of the EMLA was 1.57ms over 0.25mm stroke. The EMLA had good transient characteristics and met the working requirement of the fuel injector. Furthermore, because of no holding current, the fuel economy of engine was improved.

Abstract:Aiming at solving the difficulties in hydrogen on-board storage and carriage, a self-designed system was designed in an SI gasoline engine to recover the exhaust heat and produce hydrogen by the ethanol steam reforming. The engine intake manifolds were specially modified so that the produced syngas could be injected and mixed with gasoline simultaneously. During the experiment, the engine was kept at 1800r/min and a manifolds absolute pressure of 61.5kPa. The combustion and emissions performance of the 2.5% syngas-enriched gasoline engine was compared with that of the original engine under various excess air ratios. The experimental results demonstrated that the enhancement of excess air ratio could improve the hydrogen volume fraction whereas reduce the CO concentration in the syngas. The blending of syngas was beneficial for accelerating the flame development and propagation, elevating the indicated thermal efficiency and reducing the HC emissions. Meanwhile, the CO and Nox emissions were slightly increased after the syngas addition.

Abstract:TGA, SEM and TEM were used to investigate the variation of PM properties before and after the treatment of direct nonthermal plasma, including the content of elemental carbon and volatile fractions, the surface morphology and the accumulation form of primary particles. The results showed that with the increasing of load, the content of elemental carbon grew and the morphology changed from accumulated clusters to folium piles and then to porous sponge, and the accumulation of primary particles changed from simple fractal block with high thickness into complex fractal stripes. After the treatment of DNTP, the content of elemental carbon grew and the morphology variation versus diesel load was similar to that of before treatment but presented dendrite structure at full load. Accumulation form of primary particles was similar with that of untreated PM obtained at full load, indicating the volatile fractions with high viscosity can be decomposed effectively by DNTP.

Abstract:In order to analyze the effect of fluid-structure interaction (FSI) on flow field in screw centrifugal pump, a ZJ200—25 screw type centrifugal pump with double screw blades was chosen as the study subject. The two-way coupling method was established to study the effect of FSI of impeller on flow field in screw centrifugal pump. CFX12.1 and ANSYS Workbench were used to the combined calculation for turbulent flow and structure response of impeller. And the unsteady flow field of the pump was simulated numerically under several operating conditions without effect of FSI. Compared the result of the two calculation methods, it’s found that, with the effect of FSI, pressure fluctuations in pump inlet intensified. The dominant frequency of pressure in inlet and outlet do not change but the phase position was different after FSI. The inner velocity distributions satisfy the common characteristic, but the largest differences were appeared under the condition of small flow rate. The flow field near volute tongue was affected by FSI most obviously when blades passing by the tongue. Magnitude of radial trust changing with time has similar regularities, but the fluctuation range with FSI method was reduced. Flow filed in impeller was more dissymmetrical under the effect of fluid-structure interaction. The conclusion obtained in this investigation will provide an essential guide to analyze the inner flow filed and master characteristics of rotor vibration characters and inducing factors of the pressure fluctuation in the screw type centrifugal pump.

Abstract:A type of diffuser which had two asymmetrical exits and a separating flow board was placed at the inlet of the impeller of flow-ejecting self-priming centrifugal pump. The gap between the separating flow board and the impeller was 1.0mm. Based on Mixture multiphase flow model, the standard k—ε turbulence model and SIMPLE algorithm, unsteady numerical simulation of the self-priming process was carried out by using Fluent software. The distributions of pressure, velocity and gas-liquid phases field inside the pump, and also the changing regularity of pressure, gas phase volume flow rate and liquid mass flow rate on the two exits of the diffuser with the change of timestep were obtained. The results show that the pressure in the diffuser gradually increases along the direction of flow and appears larger change gradient, the pressure inside the each runner of the impeller approximate symmetric distribution.The flow parameters appear periodic change on the two asymmetrical exits of the diffuser. The gap between the separating flow board and impeller have not only prevented the formation of circulation of the fluid, reducing hydraulic loss and improving the efficiency of the pump, but also quicken the mixing of the gas-liquid near the gap, shortening the self-priming time of the pump.

Abstract:Sediment deposition in the pumping station has a huge negative impact on unit operation. 3-D CFD method was used to simulate pumping station inlet structure flow based on Eulerian solid-liquid two-phase flow model. Numerical results of preliminary scheme show that sediment deposition occurs in the forebay of pumping station because of poor flow pattern therein. In order to improve hydraulic configuration in the forebay, one modified measure was reconstructing water diversion weir shape, and another measure was setting a water retaining sill in the approach channel. The simulation results of modified scheme prove that back flow in the forebay was eliminated and sediment deposition region was also reduced greatly.

Abstract:3-D unsteady turbulent flow simulation with RNG k—ε turbulence model of complete flow passage on Francis turbine at partial load condition was performed. The simulation results were compared with the test data. The simulation predicted the pressure fluctuation magnitude and frequency characteristic in the draft tube successfully. A method injecting water from the crown tip to the turbine draft tube to weaken the pressure fluctuation was introduced. Simulation of the flow with water jet was performed, showing that the water jet weakened the pressure fluctuation in the turbine draft tube effectively. With the increase of the jet flow rate, a greater reduction of pressure fluctuation magnitude was detected, but a decrease of efficiency was found. To keep a balance between pressure fluctuation mitigation and efficiency requirement, 0.03~0.05 times of flow rate at the calculated operating condition was suggested.

Abstract:The nonlinear circulation mathematical model of axial flow pump impeller was established based on the independence assumption of the cylindrical layer, the velocity gradient equation and meridional velocity equation in axial-flow impeller outlet. Miniature five-hole spherical probe was used to measure circulation and meridional velocity of South-to-North Water Diversion Project axial flow pump model (TJ04—ZL—06) in the blade outlet at the optimal condition. The experimental results show that the nonlinear circulation distribution appears in the axial flow impeller outlet. The circulation curve is relatively flat in the central of blade, while it reduces to about 0.8 times near hub and increases to about 1.2 times near tip. The meridional velocity distribution shows parabolic flow pattern and the maximum velocity appears in the middle of blade. The meridional velocity in blade outlet was calculated based on nonlinear circulation mathematical model. The results show that the calculated values show agreement with the experimental results, and the calculation errors of different radius points are less than 5%.

Abstract:Taking HP multistage pump as example, physical model and mathematical model of its bearing-rotor system were established though appropriate simplified process. Four stiffness coefficients and four damp coefficients which express its dynamic characteristic of the water membrane bearing were deduced and calculated. Rigid support Campbell drawing by multi-load modal analysis on ANSYS considering inertial effect was generated. The fore four natural frequency considering inertial effect and critical speed on the load of 3000r/min were also obtained. Unbalance response curves of the shafting on working speed and unworking speed were obtained by analysis. This water lubricated bearing-rotor system was certified to be a steady rigid system by transient state characteristic analysis which driving force was feed in a sudden and the rotational speed was considered. Though rather large vibration may appear in the beginning of this period, oscillating amplitude will be reduced gradually and return to stabilization soon.

Abstract:Considering the complicated relation of triangle labyrinth channel parameters to hydraulic performance, the explicit analytical model was not figured out. Moving least squares response surface methodology was introduced to build parameter sensitivity model corresponding to reliability of hydraulic performance. The analysis of parameter sensitivity shows that the length and the width of triangle labyrinth channel parameters have great influence on the reliability of flux coefficient. Meanwhile, the width, and the angle of triangle labyrinth channel parameters have great influence on the reliability of flow index. Standard deviation increasing in the parameters of triangle labyrinth channel will reduce the reliability of flux coefficient and flow index. The reliability sensitivity analysis for hydraulic performance demonstrates that the result of presented method is accord with the qualitative analysis. Thus the proposed method is efficient and accurate.

Abstract:Two kinds of tee pipes DN75×75 and DN75×50 were discussed by test methods and numerical simulation. The results showed that local resistance coefficient of main branch to side branch ζ01 and main branch to straight branch ζ02 decreased with increasing Reynolds number and stabilized after the Reynolds number was greater than 1.5×105. The local resistance coefficient ζ01 and ζ02 was correlated with the flow ratio by second order parabolic equations. The numerical simulation results were in good with the experimental data. Through those variables other five kinds of tee pipes were simulated numerically. It showed that the local resistance coefficient ζ01 and ζ02 decreased with increasing diameter ratio, and the variable extent of ζ01 was greater than ζ02. Also the expression equation of local resistance coefficient variation with the flow ratio was given simultaneously. Flow characteristics analysis showed that the main reason caused the local resistance coefficient ζ01 due to the loss of direction changes and velocity distribution caused by centrifugal force, and changes ζ02 was due to the vortex motion and velocity gradient in the straight branch caused by water shearing and transverse circulation in the large flow ratio. 

Abstract:With the aim to preclude the effect of penetration friction component (PFC) between the penetration shaft and surrounding material during a penetration process, an improved cone penetrometer with a mini force transducer embedded in the cone tip was developed. This kind of cone penetrometer could measure the density of soil and silage correctly. The results showed that the effect of PFC could be negligible in the two kinds of soil samples. But during the density measurement of the two different density chopped maize samples, PFC accounted for 32.56% and 34.05% respectively in the measurement value of force sensor. When there was no resistance on the cone, the measurement value of embedded force sensor was zero, whereas the measurement value of force sensor were about 110N and 280N. Appreciable error was found in the original test results for chopped maize.

Abstract:The earthworm’s surface was selected as the object to study the mechanism of resistance reduction of wavy surface, and discrete element method (DEM) was used to simulate the dynamic response of the contact soil particle with wavy surface. The results of simulation showed that the contact time was shorter when the particle contacted with wavy surface, and the particle separated at 1.0s. Macroscopic showed that the porosity was formed between the wavy sample and soil particle. X direction displacement of the contact particle was increased linearly and in the same direction, the average displacement was 60.33mm.Y direction velocity was changed with the concave-convex of the wavy surface like sinusoidal variation, and generated microseism, the amplitude of the wavy surface was bigger than the smooth surface. Contact position directly determined the size and direction of the contact force. Analysis showed that the amplitude and frequency of the contact particle with wavy surface was greater than smooth surface. The results can supply the reference to design the bionic wavy surface.

Abstract:Non-standard Proctor compaction as a soil remolding technique was compared with hand-rolling method. Non-standard Proctor compaction modified soil physical states in a large, stable and controlled manner, allowing the investigation of the co-relationship among soil density, water content, compacting work and specific soil fragmentation energy possible. It was found that density alone did not reflect cohesive soil compaction precisely; in contrary the specific fragmentation energy was more sensitive to inter-aggregate cohesion force. Therefore there is a need to refine the habit of using soil density or relative compaction as a proxy for modeling the specific traction in soil tillage research. The combined procedure of non-standard Proctor compaction and fragmentation test provided an increased exponential trend of specific fragmentation energy with respect to soil water content, while the fractal dimension of soil fragments decreased.

Abstract:As irrigation water for irrigation area, irrigation return water supply from surface water was prone to soil secondary salinization. Four evaluating elements and seventeen evaluating factors, including the natural condition, water environment, soil environment and socio-economic environment, were chosen to constitute the index system of groundwater environment for irrigation district in western Jilin province. The catastrophe theory was used in analyzing the groundwater environment. The analysis results show that Wujiazi irrigation district, Daan irrigation district and Songyuan irrigation district belong to the slight risks. The risk values were 0.9206, 0.9303 and 0.9196, respectively. Groundwater environment for irrigation district in western Jilin had some risk.

Abstract:Using rice straw and cow manure (volatile solid ration 1∶1) as materials, continuous anaerobic co-digestions were carried out to investigate the effects of organic loading rate (OLR) and temperature on stability and performance. The experimental results showed that, for thermophilic digestion, volumetric biogas production rate (VBPR) increased with increasing of OLR and the maximum VBPR was 5.26m3/(m3?d). The maximum average specific biogas production (SBP) of 489.6L/kg was obtained at OLR of 3.6kg/(m3?d).For mesophilic digestion, biogas production was seriously inhibited by volatile fatty acids (VFAs) at OLR of 12kg/(m3?d). During the OLR of 3~8kg/(m3?d),VBPR gradually increased with the maximum of 2.57m3/(m3?d). The maximum average SBP of 440.0L/kg was obtained at OLR of 3.6kg/(m3?d). When the OLR increased to 8kg/(m3?d), serious sludge expanding was observed both in thermophilic and mesophilic system.

Abstract:For the purpose to improve the conversion rate of reducing sugar of rice straw,the cellulose was used in the enzymatic hydrolysis of rice straw. The content of reducing sugar was detected by 3,5-dinitrosalicylic acid method. The enzyme concentration, hydrolysis time and temperature were selected as inspecting factors. Meantime, comparisons of the enzymatic hydrolysis of rural rice straw with that of steam explosion pretreatment rice straw were made. The results showed when the cellulose weight content taking 10% of the dry rice straw, enzymatic hydrolysis time of 48h and reaction temperature of 50℃ were ideal reaction conditions. The maximum reducing sugar yield of enzymatic hydrolysis original rice straw was 9.7%. The highest reducing sugar yield of enzymatic hydrolysis steam explosion rice straw was approximately 34.3%. Steam explosion pretreatment can obviously improve the production of reducing sugar of enzymatic hydrolysis rice straw, and at the same time accelerate the reaction rate. 

Abstract:The conversion between qualitative descriptive language and corresponding quantitative values was achieved in corn juices sensory evaluation process based on cloud model. Backward cloud model was used to transform and analyze the scores of sensory evaluation of corn juices. The qualitative concept of corn juices was obtained. Forward cloud normal model transformed the qualitative concept of corn juices to quantitative values, and restored to different test points retaining the data characteristics. The cloud model was extended to multidimensional space based on the assessment for corn juices. Integrated qualitative characterization described general character of corn juices in 4-D space.

Abstract:A system of determining acrylamide contents in fried potato chips based on computer vision technology was developed. For each 60s, the image acquisition device collected double-sided images of potato chips removed from the fryer. The acrylamide contents of the corresponding potato chips were determined by gas chromatography-mass spectrometry (GC—MS) method, meanwhile, the target potato chips of the double-sided images were extracted and L*,a*,b* average of the overall target was measured by proposed image filtering algorithm, the color image segmentation algorithm and the color measurement algorithm, respectively. The obtained data was analyzed and a strong correlation between the average of double-sided a* average and acrylamide contents of potato chips was found (R2=0.971) and a linear regression equation was established. Potato chips double-sided images of 10 different brands sold on the market was collected and the average of double-sided a* average was put into the equation. The maximum relative error between the acrylamide contents calculated and standard chemical method was 4.94%, which indicated that the method was feasible and accurate.

Abstract:A real-time monitoring system for grain moisture content in grain storage was developed based on equilibrium moisture model, wireless sensor network and embedded technology. The error and precision which forecast by the equilibrium moisture model of modified Henderson, modified Chung—Pfost and modified Owin were verified in this experiment. The results showed that there was high precision in the modified Chung—Pfost model. Moreover, the prediction result was with higher accuracy when A was 363.06, B was 0 .1804, and C was 26.674. It was indicated that the system was able to realize stable data transmission by testing the transmission quality of sensor nod. This study presented a new method for real-time monitoring rough moisture content in grain storage, which was important significance for ensuring grain safety in storage.

Abstract:With the aim to investigate the influence of spermine (SPM) treatment by vacuum pulse infiltration on postharvest quality of common beans (Phaseolus vulgaris L.), common beans were immersed in SPM solutions (0, 0.02, 0.2, 0.5 or 1.0mmol/L) under vacuum (-20kPa) for 2min and then stored at 20℃, 80%~85% relative humidity for 8 days. The results indicated that exogenous SPM treatments could significantly inhibit water loss and cutting-force increasing, and reduce the rust spots forming and decay of bean pod. Exogenous SPM treatments could also remarkably prevent decrease in levels of the soluble protein in the bean seed and the total soluble solids in the bean pod. The treatment with 0.5mmol/L SPM was more effective than the other treatments. The decay or rust spots index of the bean pod treated with 0.5mmol/L SPM was about 68% or 23% lower than that of control in the 8th day of storage, respectively. The results could be applicable to improve quality of common bean for commercial purpose. 

Abstract:Sweet cherry fruit (Prunus avium L. cv. Sunburst) were held into auto-modified atmosphere box (MAB). The postharvest qualities and antioxidative enzymes of sweet cherry fruit were investigated at interval. Results showed that CO2 and O2 concentration in MAB were kept at about 11%~12% and 9%~10% after 30d of storage of sweet cherry fruit. Firmness in fruit stored in MAB was higher than those in control during storage. MAB treatment maintained the higher Vitamin C content, and was effective in inhibition of the declining of soluble solids content in contrast to control, and increased peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) activity in the early storage. But MAB treatment delayed the increase of pH value, anthocyanin and total phenol content of sweet cherry fruit. MAB treatment inhibited significantly the decay incidence of sweet cherry fruit during storage. The sweet cherry fruit treated by MAB still had good sensory quality significantly after 60d of storage.

Abstract:By using whey protein isolate as the target, some treating conditions affecting the hardness, elasticity and water holding capacity of the whey protein gels were investigated by the single-factor experiments, among which the electric field strength, pulse numbers and heating temperature varied from 15 to 55kV/cm, 2 to 8 and 50 to 90℃, respectively. The research found that properties of the formed gel have shown significant change after being treated by the high intensity pulsed electric field. Compared with whey protein without effect from the high intensity pulsed electric field, the hardness, elasticity and water holding capacity of gel decreased when the electric field strength varied from 15 to 25kV/cm, increased significantly when the electric field strength was 35kV/cm, but decreased again when the electric field strength was 45kV/cm. When the electric field strength was 35kV/cm, the hardness, elasticity and water holding capacity of gel strengthened with the increase of pulse number, but the later amplification was not remarkable. When heating temperature was 80℃, the hardness and elasticity of gel reached their best. The water holding capacity showed optimal performance when heating temperature was 70℃.

Abstract:Visible/near infrared (Vis—NIR) spectroscopy was investigated to determine the dry weight of the cocoons layer of mulberry silkworm fresh cocoons. Optimal partial least squares (PLS) models were developed with different preprocessing, and the data preprocessed by Savitzky—Golay (SG) smoothing was chosen for the effective wavelengths selection. The selection was operated based on regression coefficients in PLS models, and reduced the original 601 varieties into 7. Then multiple linear regression (MLR) was used for calibration and prediction based on the seven effective wavelengths, compared with the PLS model built on full-spectrum data. The results showed that MLR model was the optimum model for the dry weight of the cocoons layer detection in the process of production and marketing, because of its simple arithmetic and accurate detection. The correlation coefficient and residual predictive deviation were 0.7587 and 2.0464.

Abstract:The glucose, fructose, ethanol and glycerol were predicted by using NIR spectroscopy and multivariate calibration methods. And the reference values were analyzed by HPLC to evaluate four components above. The principle component analysis regression (PCR) and partial least squares regression (PLSR) were compared. The correlation coefficient of calibration (R2), the root mean square error of calibration (RMSEC) and the root mean square error of prediction (RMSEP) were used to evaluate the models. Results from the application of PCR and PLSR were presented, showing there were no significant differences between PCR and PLSR to predict glucose, fructose and ethanol. While for the glycerol, it was better to use the PLSR. PLSR almost always required fewer latent variables than PCR, but this did not appear to influence predictive ability.

Abstract:The total sugar, starch and reducing sugar, yield and pH value change were thoroughly studied in solid state fermentation for protein feed production from Panax notoginseng residues. The related degradation kinetic model of total sugar and starch was established as well. The results showed a four-parameter model matched well the degradation kinetics of total sugar and starch and predicted the change of total sugar and starch contents relatively accurately. The half-life of total sugar and starch were determined as 58.32h and 42.47h, respectively. The peaks of degradation rate were observed at 46.1h and 29.1h, respectively. The average degradation rates of both total sugar and starch in the fast degradation stage were twice more than those in the slow degradation stage. It was found that the average degradation rate of starch was greater than that of total sugar in the fast degradation stage, but oppositely less in the slow degradation stage.

Abstract:Taking the 11% glutamic acid fermented liquid as testing samples, the effects of vacuum membrane distillation technology on the VMD of glutamic acid, decolorization and reuse of waste water were explored. The effects of heating temperature and concentration multiple on VMD enrich were also examined. The research results indicated that in the VMD process, with the membrane distillation technology, the glutamic acid concentrate in the glutamic acid filtrate liquid and the decolorization liquid was increased from 11% to 63.2% and 11% to 65.17%, respectively. Decolorizing process by using active carbon was able to reduce membrane fouling and improve membrane flux. After L9(34) orthogonal decolorizing test, variance analysis result showed that active carbon was the priority factor to decolorization. The level of activated carbon was 30g/L. The decolorization time was 0.5h and the revolving speed was 120r/min. The results of water product on membrane distillation and GC testing indicated that the peak time of seven volatile substances in water product were similar to the glutamic acid filtrate and they were inferred the same materials. Therefore, the water product by filtrate membrane distillation can be reused to original fermentation liquid and improve water utilization efficiency.

Abstract:The current field monitoring is mainly physical data and lack of multimedia data. A remote monitoring system of crop environment and growing was designed based on WMSN. Firstly, the advantages of the proposed system were analyzed. Then, the key parts of the hardware circuit of Hi3512 and CC2430 and software systems were designed. The key issues of fusion of the crop physical environment and multimedia growing information were resolved. Finally, the temperature and humidity, light intensity, and four channel video signal in different monitoring points in the four greenhouses were monitored dynamically. The results show that the environment of the crop growing remote monitoring system is stable and accurate. Multimedia data acquisition, H.264 compression, 3G transmission, display on PC could be achieved, together with ZigBee networking including temperature, humidity and light intensity sensor nodes.

Abstract:Currently, most existing multi-angular earth observation equipments are inflexible, have long operation time and light pay-load capacities. To overcome the limitations mentioned above, the ground-based agriculture-oriented multi-angle observation device (GAMOD), oriented to fast acquire crop multi-angular data, was designed. The GAMOD was tested in a soybean field with visible/near-infrared imaging hyperspectral spectrometer (VNIHS) mounted on. It takes 10min to acquire multi-angular data at four view zenith angles of 0°, 20°, 40° and 60°, under azimuth angles of 0°, 90°, 180° and 270°, respectively. As a result, 3-D structure information of soybean group can be effectively captured by supporting of multi-angular observation.

Abstract:In order to construct a fast measurement system for leaf area index (LAI) based on near-infrared reflection, an innovative way was explored to accurately detect the LAI of overlapping leaves. Research methods were concluded as follows: overlapping leaves were put under the direct parallel light generated by the near-infrared laser, and the photoelectric sensors were used to measure the reflected light energy. The output voltage signal of the sensors was sent into the computer through the data acquisition card. The amount of overlapping layers was determined by software programming. The amount of overlapping layers was multiplied by the area of direct beam’s light spot was the area of the leaves. The total area of the leaves was the cumulative leaf area in the whole testing process and LAI could be calculated. Based on the result of spectral reflection test, near-infrared was used as direct light source to demarcate the system to get the index fitting model between overlapping leaves’number and measuring voltage, which is notable in 0.05 statistic level. The result of data collection experiment shows that under the method in manual scanning and timing collection, the value of LAI was calculated by the system with 11.01% of the error compared with the true value of LAI calculated by square method.

Abstract:In order to develop a method for rapid detection of total potassium content in leaf of maize, electrical impedance measuring method was used to collect the electrical impedance parameter of the leaf tissue juice under different potassium levels, and the relationship between impedance value and total potassium content of the leaf were investigated. Using stepwise regression method to choose the sensitive frequency for the total potassium content, every regression model included two sensitive frequencies based on which the linear regression equation was the best with the correlation coefficient of 0.83 at least and root mean squared error of 0.16 at most for four growth periods respectively. Therefore, it was demonstrated that impedance value could be a predictor for maize leaf potassium content. Electrical impedance measuring technology could be an available method for potassium fertilizer recommendation in crop.

Abstract:Real-time infield weed detection is the most important technique of the precision infield weeds control. The real-time weed detection equipment is a key of the site specific weed management. Currently research is being carried out relating to weed sensor based on the spectroscopic, imaging and spectral imaging techniques. Theses advance technologies and equipments were reviewed for application them in China. The weed detection technique based on spectroscopic is suitable for classifying weeds from soil background without crop seedlings, such as the WeedSeeker and Weed-IT. The weed detection technique based on imaging is appropriate for discriminating inter-row weeds, including the Robocrop InRow mechanical weed control machine and the vision navigation product of the Autopilot, Cam Pilot and Robocrop, etc. The weed detection technique based on spectral imaging is more appropriate for distinguishing intra-row weeds, and a joint research on microphotonic plant discrimination and weed control sensor has been done by China and Australia. It is still a continuous project that how to detect infield weeds in real-time and specific under the complex and open field environment.

Abstract:The defects, size, color of fruit and the lighting influence the accuracy of segmentation. In order to improve the segmentation accuracy, a combinational method was presented based on apple images processing. The R, G, B components were calculated by arithmetic operations at first. Then the arithmetic result was processed for noise cancellation by morphological opening and for smooth boundary by linear spatial filtering. After these operations, the automatic threshold method was used for background segmentation. This combinational method shows good performance to process 280 images of apples with different attitudes, size, color and defects. And these images were gained in 4 types of illumination conditions. The segmentation deviations of 203 images which are 72.5% of total images are less than 1%. The segmentation deviations of 70 images which are 25% of total images are larger than 1% but less than 2%. Only 7 images’ deviations are larger than 2%, and the maximum segmentation deviation is 2.83%.

Abstract:In order to meet the demands of intelligent agriculture and realize the automatic operation of rice transplanter in the field, the intelligent operation control system based on GPS navigation technique was developed. This system functionality includes automatic operation of rice transplant and automatic control of the traveling speed according to the prescription map. The YANMAR VP6 rice transplanter’s manual operation was transformed into electric control. The road experiment with GPS navigation system was accomplished on this platform. The results indicated that the electric control of the transplant operation performed accurately, the maximum average error of speed control was 0.0113m/s, and the speed control precision reached the requirement of the rice transplanter.

Abstract:In order to improve the precision of a navigation control system for agricultural machines, the research on the path tracking method that is the core of an agricultural machine navigation system was carried out. An agricultural machine path tracking method based on fuzzy adaptive pure pursuit model was proposed. The method utilized pure pursuit method to conduct the path tracking control and determined the desired steering angle by combining with the agricultural machine kinematic model. The method made use of fuzzy adaptive control to find out the look-ahead distance online and adaptively, thus the path tracking precision gets enhanced. The results of the path tracking experiment for the agricultural machine show that the max tracking error is within 10cm and the mean error is no more than 5cm, so the proposed method can completely satisfy the operation requirement of agricultural machines and the feasibility and effectiveness of the method was verified.

Abstract:The electric pulley cableway system in banana plantation was studied. With the selection of the pulley location, pulley speed, swing angle and swing angular velocity of banana bunch as generalized coordinate variables, the mathematical model was derived with Lagrange equations. The dynamic characteristics were analyzed theoretically and experimentally. The results of virtual test showed that the conveying system with multiple moving mass in series was similar to the hoist system with a single moving mass if the distances between each hook point and banana bunch centroid were equal. The test results illustrated that the proposed dynamic analytical model and virtual prototype model were similar to actual system for analyzing the frequency and amplitude of swing angular velocity. The analytical results of virtual prototype model were basically consistent with the actual data. It is evident that the dynamics analytical model is correct and the virtual prototype model gives the realistic reflection to the system dynamics, which provide theoretical reference for the design and modification of the actual system. 

Abstract:For the complex product design knowledge with a large number catalogs and data volumes, the multi-classification problem was solved by using linear approach based on the margin and probability information of MPM. The true mean and covariance were replaced by the sample ones. The weight voting matrix was established, the coding matrix varied with the difference algorithm and training data. The classifier with max value was selected by using the amplitude value. Linear classifier was used as binary one for high speed. The angle difference measurement of subspace was proposed to characterize the difference of every class conception. The feasibility and practicality of the above mentioned method were approved by forklift product design knowledge.

Abstract:The problems of the existed acquisition method and representation method for patent technical solution were discussed. A new knowledge acquisition method for mechanical patent’s principle solution including the acquisition task of technical object and technical relationship was proposed. Based on extensible markup language schema definition (XSD) and unified modeling language (UML), the representation model of patent technical solution was built up. According to the characteristics of mechanical patent’s text, technical object with the method of maximum entropy principle and patent term dictionary was acquired. The composition verb database was established and technical relationship was acquired. This method has some advantages such as the intuitionistic representation of the patent knowledge and the feature that the knowledge was automatically processed by computer. A whole process involved the steps like acquiring the principle knowledge from patent documents, writing the knowledge into XSD and transforming XSD to the representation model was illustrated with a US patent in detail. The model and process laid the foundation for the efficient utilization of patent knowledge.

Abstract:The principle, the algorithm, and the applicable scope of the Monte Carlo method were analyzed. The non-uniform feature of the distribution of random points in workspace was analyzed, as well as the different signification between the points within the workspace and the points on the boundary. The error resulted from spatial workspace slicing was summarized. In order to optimize the boundary accuracy, based on the continuity of the mapping from joint space to workspace, by generating new random joint values in a sufficiently small neighborhood of the existed random joint values corresponding to the boundary points extracted before, new random points in workspace were generated, which distributed around the corresponding old boundary points. Then, from the newly generated points, more accurate boundary points could be extracted. The approach demonstrated to be effective to improve the boundary precision. To reduce the error caused by the slice thickness, in each slice interval, only a thin layer of points were used. A large number of tests illustrate that the algorithm works well.

Abstract:A 4—UPS—UPU spatial 5-DOF parallel robot mechanism was introduced. A dynamics model of 4—UPS—UPU was presented. The kinematics of the UPS and UPU chain of leg was analyzed and the velocity mapping relationships between the parts and the driving axis were established. The exterior force load and the equivalent driving force were educed. The dynamics model of 4—UPS—UPU parallel robot mechanism was educed by the virtual work principle approach, which was the foundation of the dynamic analysis. Combined with engineering application examples, numerical verification and virtual simulation verification of the results of driving force and constraining torque was carried out.

Abstract:In order to improve the safety and manipulation performance for telerobotic system, a kinesthesis teaching control strategy for telerobotics was presented. Utilizing the characteristics of human’s sensitivity to force information as well as the specific feature of vision’s forecast and guidance, the control force of the operator with the virtual forces was merged, including the attraction force from objectives, and the rejection force from obstacles, which were generated from the recognition results of working fields based on vision techniques. Furthermore, it combined the advantages of machine intelligence with human’s high-level decision, which could improve effectively the working efficiency as well as local autonomy of tele-robot, and reduce the proficiency requirements of operator. Especially, in a teleoperation system with large time delay, the method could avoid the blinded manipulation of robot caused by lagging transmission of image. The system structure, extraction of the operating environment spatial information and control methods were introduced in detail. The superiority of the proposed control strategy in improving the operating efficiency and security of the telerobotic system were verified by relative experiments.

Abstract:A fractal model of joint interfaces was established based on fractal contact theory. The elastic-plastic deformation of asperities was taken into account in the model. By numerical simulation, the nonlinear relationship between the contact force and the real contact area was obtained，as well as the effects of elastic-plastic deformation on the contact of joint interfaces. The result showed that the contact force increased nearly linearly with the real contact area. The contact force decreased due to the increase of fractal roughness parameter G with the same contact area, but complicatedly varies with the fractal dimension D. The share of elastic-plastic contact area decreased with the increase of real contact area, increased with the increase of G, and complicatedly varies with D. The share of elastic-plastic was large enough and can not be ignored. It decreased with the increase of D.When the elastic-plastic deformation was overlooked, the contact fore was slightly larger than the results involved the elastic-plastic deformation. The error percentage lied within the range 5%～60%, which decreased with the increase of D.

Abstract:The temperature distribution of parts and mould was simulated by ANSYS/LS—DYNA. The shortcomings of the uniform waterway were analyzed. APDL was applied over the thermal field simulation. Zero-order search and fist-order search was combined as the optimization algorithm. In this program, the radius of holes, the distances of adjacent holes and the distances of holes and the profile were chosen as optimization variables. The well-distributed temperature of parts and the needed critical cooling rate were chosen as the optimization objectives to create the objective function. Objective function value was 26.553 after the optimization which was 64.404 before the optimization. By comparing the temperature distribution of the optimized cooling water channel with original, it can be seen that the maximum temperature was decreased by 44.5% and the lowest temperature was decreased by 14.5%, to realize the optimization design of parameters of the cooling water channel. Finally the experiment had been designed to verify the correctness of the optimization result.

Abstract:A bionic excavator tooth was developed, which is bio-inspired and based on the morphology of the toe of mole cricket foreleg claw. The profile line of the mole cricket’s toe was fitted by using polynomial fitting method. The bionic tooth specimens were fabricated by a rapid prototyping machine. The cutting resistances of the bionic tooth and JL80 tooth specimens were measured during soil cutting. The experimental results show that the cutting resistances of bionic tooth is about 11% lower than that of JL80 tooth. The force analysis indicates that the bionic tooth is more likely to form self-sharpening blade so that the cutting performance of the tooth can be maintained. Besides, the bionic tooth is convenient for reducing the cutting angle, which can help for the reduction of cutting resistance, without changing the design and working condition of the excavator.

Abstract:In order to find the interpretation of the incomplete closure of piezoelectric pump check valve in high frequency, the characteristic of the pump in that working conditions was analyzed, together with the judgment basis and theoretical demonstration of the existence for the phenomenon. The incomplete closure of piezoelectric pump check valve phenomenon was found, and frequency response of the check valve in water was obtained from its dynamic model. The mean force and displacement of valve was calculated in hydrodynamics. Relative reaction of the frequency response and mean displacement were analyzed. Sufficient condition for the check valve incomplete closure was obtained which was amplitude amplification less than 0.25. The results show that check valve can close completely operating at 80Hz. When the amplitude amplification less than 0.25,the check valve incomplete closure phenomenon was observed at 140Hz. With further increasing of the frequency, amplitude amplification factor decreases, the phenomenon is more obvious under the condition of low amplitude amplification factor, the minimum clearance between the check valve and valve seat more than 30μm at 260Hz.