Abstract:A new rotary unit-block diesel particulate filter (DPF) was developed. There were several unit blocks with fan-shaped cross-section in the filter. These blocks were arranged in a circle and axial rotation during regeneration with microwave. The mechanism of the rotary unit-block DPF on the filtration and regeneration were analyzed and the filtration efficiency, the pressure drop characteristic were compared with the traditional overall body filter. The experimental study shows that rotary unit-block DPF is a better solution to continuous regeneration and has better performance. It is able to break the power restriction when used for vehicle.

Abstract:Because of the poor oxidation stability and the high NOx emissions, biodiesel fuel was redesigned by adding anti-oxidants. The oxidation stability and viscosity of the biodiesel have been measured and analyzed. The engine experiment was conducted and it was fueled by biodiesel and BHA/biodiesel, NOx emission and smoke were measured. The mechanism of anti-oxidants to decrease the smoke, NOx emission was discussed. The results showed that BHA additive was a high effective antioxidant of biodiesel, the viscosity of biodiesel was decreased slightly; and the emission smoke and NOx was decreased significantly, especially at the high load condition. Anti-oxidants can restrain the high-temperature dissociation of long-chain fatty acid molecules during the combustion process, and it can promote the quenching effects of free radical. Also, it can change the “trade-off” tradition relationship between smoke and NOx emissions. 

Abstract:Experimental study focusing on the combustion and cyclic variation characteristics of a pure hydrogen-fueled engine at idle and lean conditions was introduced. The experiment was carried out on a modified four-cylinder spark-ignition engine equipped with an electronic controlled hydrogen injection system. The test results showed that when excess air ratio was varied within 2.08 to 3.20, the engine original electronic control unit could maintain idle speed of the pure hydrogen-fueled engine at its target value (790r/min) by automatic adjusting the spark timing and idle bypass valve opening. The engine cooling loss was decreased with the increase of excess air ratio. However, the cyclic variation in indicated mean effective pressure and combustion duration were slightly raised when the engine was gradually leaned out. When excess air ratio rose from 2.08 to 3.20, the engine fuel energy flow rate was reduced by about 15.4%. 

Abstract:Nonlinear Dynamic Characteristics Study on Combustion Process of Natural Gas Engine

Abstract:By an integrated numerical-experimental approach, the injection characteristics of a production high pressure common rail solenoid injector were investigated on kinds of control parameters include rail pressure and energizing time. The characteristics of injection quality, injection rate, needle opening and closure delays, injection temporal length were summarized via experiment carried out on a test bench. A model of high pressure common rail injection system based on AMESim was used to calculate simulation results, compare and approve the experimental injection data. The injector hydraulic process and lift process of needle were simulated and analyzed. The mechanism and rules of injection characteristics depending on rail pressure and energizing time were summarized.

Abstract:A precise model for the common rail fuel injector based on the Matlab/Simulink was built. Using the multi objective simulated annealing algorithm as the search strategy, the key injector parameters were optimized. The aim function of the multi objective optimization was the opening delay and the closing delay. The results showed that the delay of the opening was 0.25ms which reduced by 16.7%; while the delay of the closing was 0.78ms, which reduced by 15.2%. 

Abstract:Some hypotheses were proposed to analyze engine cooling system according to its structure and operating process. Lumped parameter method was used to build a mathematical model for engine electronic-control cooling system on those hypotheses. Then simulation of engine warming up and experimental verification were implemented, and the results showed that the model was reasonable. Furthermore, numerical simulation of engine coolant temperature control system was conducted. Finally, optimal design method of energy consumption in the case of heat transfer steady state was discussed.

Abstract:The methods of waste heat recovery from gas engine heat pump (GEHP) were analyzed theoretically. From the aspect of energy balance, the feasibility of the waste heat defrosting method was discussed, the results showed that the waste heat for defrosting was small, accounting for 6.5%~9.5% of the total waste heat, and the waste heat for refrigerant was less than 45% of the total waste heat, so the waste heat defrosting method was feasible. The waste heat can significantly improve the Cop and primary energy utilization rate of GEHP. 

Abstract:The S-shaped region of complete characteristics on pump-turbine is caused by centrifugal force larger than common hydraulic turbine. The flow on that S-shaped region is very much unsteady. In order to obtain the flow on that region, the steady and unsteady simulations were analyzed on turbine, turbine runaway, turbine brake near no-discharge, anti-pump near no-discharge and anti-pump operation conditions which run on S-shaped curve. The results showed that much large eddy existed in vanes and runner. That eddy wasted much water energy and reduced turbine output. Through the unsteady simulation of S-shaped curve, it is found that the pressure pulsation frequency and amplitude in spiral casing and cone of draft tube are similar and the amplitude is small. The pressure pulsation amplitude on guide vanes and blade inlet are high, and those frequencies are also high. Those simulations are always used to know the essence of S-shaped region and reduce the unsteady characteristics. 

Abstract:In order to study the vortex pump flow field characteristics of its external, it is necessary to carry out unsteady flow numerical simulation by using RNG k—ε turbulence model and structured grid inside the vortex pump. The results showed that the pressure changes within the linear distribution, with flow rate increasing, longitudinal vortex flow decreased, while the radial vortex flow periodically was removed from the leaves and increased with time. The pressure fluctuation at the different monitoring points was changed periodically at design condition. The pressure pulse amplitude increased from the entrance to the exit gradually. The blade passing frequency was dominative in the pressure fluctuation. With the flow rate increasing, pressure fluctuation was more obvious under the blade passing frequency.

Abstract:A simplified mathematic model was formed to estimate the soil infiltrability from the total water supply, the initial and saturated soil water content and the linear assumption of the soil water distribution based on the study of modified Green-Ampt model and the mass/water balance principle. The soil infiltrability estimated with this new simplified method is very close to the values calculated with the other methods. Comparisons were made between the predicted and measured soil water distribution. The average relative error was 4.18% which verified that the predicted one was very close to the measured values. The results showed that the newly suggested model could predict the soil water distribution along the horizontal soil column as a function of time very accurately. This new model is readily applicable to the related studies and applications. It has great importance for the study of hydrologic circulation studies.

Abstract:Aiming at farmland wind erosion sand calamity, in situ testing was adopted to make test for oat stubble, grave covering and traditional drought farmland by using movable wind erosion tunnel and its matching equipment. In order to provide technical basis, blown sand movement law was researched for the three kinds of farmland, and the mechanism and protection effect of soil erosion were explored for the oat stubble and grave covering affecting drought farmland. It is showed that near surface blown sand movement of oat stubble and grave covering are obviously different from autumn-ploughed farmland, the blown sand movement layer was lifted, near surface wind speed was weakened at different degrees, sediment discharge is less than autumn-ploughed farmland’s and would have maximum value in certain height, because of barrier and evacuation effects of oat stubble and grave covering. By anti-erosion efficiency analyzing, it is showed that oat stubble and grave covering have important effect on drought farmland for wind erosion controlling, and the effect of the latter is less than the former.

Abstract:In order to do the research on the influences of the parameters on spray drift, measurements of the drift potential under different wind tunnel conditions were made for different typical nozzles. The results showed that smaller type nozzle, larger spray pressure and wind speed could enhance the drift sensitivity along with the change of spray height, and the sensitivity of LU nozzles was more obvious than ID nozzles. Relative to the wind speed and nozzle type, the spray orientation has an inapparent influence on spray drift.

Abstract:Passive stubble-cutting disc with oblique ripple was taken as the object. Based on the method of velocity instantaneous centre, seeder advance speed and in-soil depth of cutting disc were chosen as the main factors affecting stubble-cutting speed. Stubble-cutting depth and draught resistance were the indicators of cutting disc performance experiment, while seeder advance speed and weight assigned to the cutting disc were the experimental factors. Two-indicator and two-factor orthogonal field experiment was carried out for passive stubble-cutting disc with oblique ripples. The results showed that both stubble-cutting depth and draught resistance increased with the two factors, and pullback weight was the principal factor to stubble-cutting depth. When pullback weight on cutting disc reached a certain degree, influence of seeder advance speed on stubble-cutting depth was more prominent than that on draught resistance. 

Abstract:By using explicit dynamic simulation software ANSYS/LS-DYNA, the sugarcane-cutter system dynamics simulation model was established. The precision of the simulation model was verified by physical experiment. By using four-factor of second order general rotation composite design and the sugarcane-cutter system dynamics simulation model, the dynamics simulation of one-blade cutting sugarcane was carried out. The mathematical model of the influencing factors, cutting forces and shear stresses was established. The influence law of the factors and their interaction were analyzed, and the respective optimization of the factors was gained. The optimal cutting force interval with 95% reliability was obtained. The results showed that when knife-edge angle of blade is 17.5°, cutting angle of blade is 27.73°, obliquity of disc cutter is 28° and cutting velocity is 16m/s, the optimal cutting force interval with 95% reliability is from 235.82N to 297.98N.

Abstract:In order to lower power consumption, speed up the axial conveying of materials in threshing cylinder and improve the efficiency of machine cleaning of wheat breeding plot seed combine harvester, a longitudinal axial conical cylinder threshing unit with conical short-rasp-bar tooth structure was designed. The experimental results showed that the new device could speed up the conveying of materials in threshing cylinder and lower power consumption while threshing wheat, and the amount of wheat seed residued in the shell internal was little and there was no need to do manual clearing. The threshing unit can be applied to half-feeding breeding plot wheat seed combine harvester with cyclone air cleaning devices. 

Abstract:Driving force, driving resistance and operating resistance of wheeled combine harvester during operating process was analyzed, tire model, road model as well as force model was built, numerical simulation of motion for whole wheeled combine harvester was finished and attitude curve was obtained. Lifelike virtual scene including terrestrial surface environment, such as farm field, roads, trees, grassland, etc. was created. Visual model of wheeled combine harvester after reasonable simplified was imported to visual simulation driving platform, and interacting control of whole machine attitude in visual scene was put forward, which made visual simulation more realistic. This study laid the foundation of building interacting control integrated virtual testing platform for combine harvester. 

Abstract:For the sake of achieving uniform drying and separation of alfalfa leaves and stems in one process, a quad-pass rotary drum dryer-separator was designed, which mainly comprised the pre-drying, quick-drying, tempering and separating zones. The air flow in the dryer-separator was simulated by using CFD method with applying the standard k—ε model, and the effect of different opening areas of the adjusting gate on the velocity in the separating chamber was analyzed emphatically. It was found that the desired velocity for leaf-stem separation in the separating chamber was gained, when the opening area of the adjusting gate was (150×150)~(200×150)mm2. 

Abstract:Based on rectangle circulating chart method, a seed melon pulp-excavated machine was designed. Improved swinging cam was used for feeding melon mechanism, a 2-round pin and 4-grooved wheel mechanism were chosen to realize precise indexing motion of a plug melon saddle, and flat-bottom tappet disc cam mechanism with improved rod gear mechanism was used for lifting tool saddle. The orthogonal experiment was done and the optimum parameters of digging was discovered as follows: the type of digging tool is hemicycle, the speed of digging tool is 240r/min and the installation angle of digging tool is 15°. Replicated tests showed the cleaning rate is more than 98%, grain seedless rate is more than 98%, loss rate is less than 2% and broken rate is less than 1%, respectively.

Abstract:In view of the special structure of bamboo, bamboo OSB flaker was developed. Development concept, mechanical and hydraulic design were presented. Then bamboo OSB flaker was tested run. Bamboo flake processed by bamboo OSB flaker was pressed into bamboo OSB, and the main physical and mechanical properties were tested and researched. The results indicated that bamboo flake with high quality shape could be sliced, which made the even distribution of outer of bamboo in the bamboo flake. Moreover, the bamboo OSB flaker has the characteristics of high efficiency, minor impact vibration and etc. The tests show that the key performance indicators of bamboo OSB are higher than the standards of LY / T 1580-2000 (OSB/4). Therefore, the research and design of bamboo OSB flaker is reasonable and effective. 

Abstract:Based on the technology of MCU, one kind of dairy cow precise feeding equipment was designed. This kind of equipment used computer as information management platform, MCU as data processing and control platform, and used the RFID technology to identify dairy cows. The working parameters of the equipment were established and the feeding accuracy of the equipment was verified. By using the equipment, one-month feeding experiment in the dairy cow farm was conducted. The results showed that the milk production per day was increased by 3.9kg, and the average fat content of milk was 3.74g/(100g), the average protein content of milk was 2.98g/(100g).

Abstract:Supply cost of crop residues for power plants was analysed. The supply chain includes five sub-processes, i.e. field collection, transportation, handling, pretreatment and storage. Five supply patterns were set up based on the differences in sub-processes, including bulk material pattern, centralized-storage chopping pattern, distributed-storage chopping pattern, baling pattern and pelleting pattern. The results show that, under specific conditions, the cost of the pelleting pattern is always the highest due to its high pelleting cost, followed by the baling pattern, the distributed-storage chopping pattern, and the centralized-storage chopping pattern in sequence. The bulk material pattern takes priority over the other three patterns when transportation distance is smaller than 69km, 28km and 16km respectively. The baling pattern needs improving since the cost reduction in transportation process can not effectively offset the cost increase in baling and handling processes. For all patterns except pelleting, purchase cost accounted for the largest proportion, followed by transportation cost and field collection cost.

Abstract:In order to investigate the effects of reaction temperature and reaction distance on the pyrolysis volatilization characteristics of biomass in a down-flow tube reactor, a ceramic ball heated down-flow tube reactor was designed and fabricated, and biomass pyrolysis experiments were conducted in the reactor. The experimental apparatus could control the reaction temperature precisely, feed the biomass and heat carrier evenly and continuously. Pulverized corn stalk powder was used as the feed stock. Reaction temperatures were 450℃，500℃ and 550℃. The falling distances, which was the indirect measure of the residence time, were 150mm，550mm，850mm and 1150mm. Ash tracer method was used to calculate the volatilized fractions of the pyrolyzed biomass at different experimental conditions. The experimental results showed that the volatilized fraction of corn stalk powder increased nonlinearly with the increase of reaction temperature and residence time.

Abstract:Different air distribution craft should impact the temperature of biomass gasifier in the gasification process. After temperature compared test, the bed temperature in the condition of double-layer air distribution is lower than the center tube air distribution. Using the fluid analysis software Fluent to simulate the pressure field under those two crafts, the result displayed that the pressure of pyrolysis layer of biomass gasifier bed in center tube air distribution was reduced, and the pressure field became more regular. The conclusion is the volatile in pyrolysis would be more precipitated if the pressure of this field was prompted based on the combustion theory, and the reaction rate and temperature would speed up and improve. That explained the result of gasification test by the perspective of bed pressure. Finally the accuracy of simulation result was tested by the method of error analysis.

Abstract:To address the problem of heating biogas project and compensating the lost ground temperature of ground source heat pump system, the integrated solar and ground source heat pump system (ISGSHPS) was presented for heating biogas digester, and the economic and environmental performance of ISGSHPS with that of ground source heat pump and electricity heat membrane system were compared to obtain the optimal solar collector area. The results show that the optimal solar collector area is related to annual total running hours and electricity price. The most economic running period is from October to the next May; ground source heat pump system is more economical than ISGSHPS when electricity price is lower than 0.5 Yuan per kW·h; when the electricity price is between 0.5 and 1.0 Yuan per kW·h or higher than 1.0 Yuan per kW·h, the optimal solar collector area of ISGSHPS is 24m2 and 32m2 respectively. At present, the optimum collector area is 24m2, under which total cost saving in 20 years is 10830 Yuan and 59244 Yuan, and carbon dioxide emissions could be reduced about 74t and 266t by comparison ISGSHPS with ground source heat pump and electricity heat membrane system. Therefore, this system has potential to develop.

Abstract:Although pulse combustion drying would exhibit high rate of mass transfer when used in a drying process, there is no numerical research about the mass transfer between materials and unsteady flow generated by pulse combustor. The results of an investigation of the moisture diffusivity in refractory clay and the convection process of moisture between refractory clay and outflow was reported. A Helmholtz type pulse combustion was used to generate an oscillating airflow. The moisture diffusivity in refractory clay was determined by the simplified method of drying methods. The mass transfer coefficient between refractory clay and outflow was evaluated by the results of experiment and Fick’s second law with reasonable initial conditions and boundary conditions. The effect of airflow oscillating frequency on mass transfer coefficient was investigated and the correlation was established.

Abstract:A solar-air drier which was applied to dry many kinds of agro-products was studied in order to take advantage of ample solar energy in Xinjiang and improve productivity of solar drying equipment and improve quality of dried fruits and vegetables. Solar energy was the main energy sources and electricity was auxiliary. Azimuth angle and elevation of solar collector could be adjusted manually when sun light changed. The experiment result showed that solar collector could provide 11964kJ/h heat energy which was sufficient for the drier, but there was 1.5~4.0℃ difference in fore and back parts of the drier. The time of drying entire apricot was 79h which was 52％ shorter than convention, the percentage of first-class dried apricot was 85％. 

Abstract:Thin layer drying experiments of apricot in low temperature were carried out on rotation design. The drying characteristics and the drying model of apricot were studied based on temperature and velocity of drying medium. The experiments showed that temperature was the main influencing factor in the drying process. The mathematical model was set as Wang—Singh equation at low temperature and the coefficients of the model were related to temperature and velocity. The established mathematical model could be used to describe the change regulation of moisture ratio well during the drying process of apricot according to the comparison of experimental values and calculated values.

Abstract:A semiconductor laser generator with 650nm wavelength and power of 13.25mW was used to irradiate the surface of “Jiro” persimmon during the storage and the characteristic laser refractive image was collected by a CCD camera. Through the midpoint subdivision method, the image region segmentation threshold was determined. Then, the image segmentation of the pixel size parameters, regional information entropy of the gray value as well as the standard deviation of gray value was calculated. The system parameters above were chosen as the parameters set. In order to get more compact model, the principal component analysis (PCA) was taken on the parameters set in the forecasting course of “Jiro” persimmon’s soluble solids. Through the analysis, the most important laser image parameters were obtained for the contribution in forecasting the soluble solids content of “Jiro” persimmon. An improved SVM regression model was designed to forecast the “Jiro” persimmons soluble solids content with the laser image parameters obtained by PCA. Both model performance parameters and verification experiments showed that the model had good stability and accuracy with the SVM related index R of 0.9905 and the average prediction accuracy was 94.1%.

Abstract:The composition and quality of domestic and imported sesames and their oil processing properties were compared. The results showed that the kernels of imported sesames were larger and more plump than the domestic varieties. The fat content of domestic and imported sesames had no significant difference, but the protein content of domestic sesames was higher than the imported ones. The imported sesames were rich in ash and oxalic acid. The phospholipid, acid value, saponification value, peroxide value of domestic sesames was lower than imported sesames. Antioxidant components content and oxidative stability of domestic sesame oils were higher than imported kind. Fatty acids composition of sesame oil from different cultivated areas had no significant difference. The favor of domestic sesame oil was better than the imported variety.

Abstract:To identify the wilted plant morphology, based on the 3-D images obtained from a laser-scanner, four types of wilt-index were defined, including statistical index of wilt-induced leaf (SIWL), Gaussian curvature at the physical center of leave, projecting distance from leaf-tip or leaf-edge to a referenced plane being tangent at the physical center of leaf. For the experimental methodology, the wilted-leaf statuses were divided into five levels, which were used for verifying whether each defined index had monotone property from earlier to serious degree of wilt status. The experimental results demonstrated that the indices in terms of the projecting distance method could meet the requirement for this purpose. In particular, the index relating the leaf-edge to the referenced plane could provide more robust results. 

Abstract:A fast segmentation method for high-resolution color images of cotton foreign fibers was proposed. It detected the edge of color image by using edge detection method based on improved mathematical morphology. A color image was converted into a gradient map in the first step, and the best threshold of the gradient map was chosen by selecting the best experience value iteratively. The experimental results indicated that the proposed method could segment the high-resolution color images of cotton foreign fibers directly and precisely, and the speed of image processing increased more than two times than the traditional methods.

Abstract:To segment the complex target image, an algorithm based on integrated technology was proposed. First, the image was preprocessed to find the target area and have the image enhanced. Second, the target area was segmented by threshold and Canny operator, some raw results were acquired. Finally, in order to get the precise and complete target image, the optimizing process of the algorithm was made with morphological methods and logical calculation. Experimental results of field jujube leaf image showed that this algorithm was feasible and effective. This algorithm had a great advantage in complex leaf image which contains overlap leaves and uneven gray scale. The clear, smooth, precise edge image could be obtained.

Abstract:A method for parameterized geometric modeling of cucumber leaf based on data constrains was presented. Firstly, the data of leaf was collected and measured, the statistics law was analyzed. Secondly, vein distribution and morphological characteristic parameters of two types of leaf margin were refined based on the law, which constrained the overall shape of leaves and described the details of leaf margin in the partition. According to the parameter values, the 3-D coordinates of contour feature points were calculated, and the 3-D grid was generated by Silhouette-axis skeleton modeling method. Finally, texture mapping was used for increasing the realism. The experimental results showed that the method could construct the 3-D model of cucumber leaf quickly and flexibly, and with good realism effect.

Abstract:A precision agrochemical application robot installed on elevated guide rails for cucumber disease management in greenhouse was developed. This robot integrated a disease diagnosing and early warning system, a variable agrochemical application system and control system. Diseases were acquired by using machine vision, and quantitative effects were analyzed according to the color and texture for cucumber plants. Relations between environment information cycle data, including illumination, soil temperature, air temperature and moisture, and plant disease valid characteristic were established to realize the early-warning of arising and growing trend of the disease. The environmental elements comparison and lesions on cucumber distribution offered the basis of decision for trajectory planning and target spray. The spray task was performed by a PLC controlled three-degree of freedom Cartesian coordinate manipulator and each individual nozzle. The robot which worked stably and availably was tested in laboratory.

Abstract:A yield monitor system for corn ear was designed and applied in field. It is consisted of a monitor, a ground speed sensor, a yield sensor, a DGPS, a header sensor, an elevator speed sensor and the guiding device. The data of grain-ear ratio and moisture content of corn grains were sampled before harvest. The header sensor was used as a logic switch of the system while harvesting corn ears. All the corns were forced to impact the yield sensor at the same speed with the help of the guiding device. The monitor received signals coming from the yield sensor, the ground speed sensor, the elevator speed sensor and the DGPS worked out the yield in the plot and saved it in the file with extension of “.vld”. The yield map would be drawn by means of the self-developed DCAS (data collecting and application system).This system was applied in field in the autumn of 2009. The data of the experiment showed that the average relative error of the yield monitor system was 18.11%.

Abstract:A highly accurate model for crop yield estimation was developed by using the entropy combination forecasting method. Firstly, the single-temporal remotely sensed Landsat TM/ETM+ images at main growth and development stages of spring maize in 2007 and 2008 were used to construct the single-temporal yield estimation models. Secondly, the weights of the single-temporal estimation models were calculated by applying the entropy methods. And then, a combination forecasting model was developed. Finally, the two models were compared. The results showed that the yield estimation model based on combination forecasting and multi-temporal remote images could increase the precision of the yield estimation model based on single-temporal remote images, and the correlation coefficient was remarkably improved in comparison with those of the single-temporal models. They were increased by 0.137 and 0.121 respectively. The values of weights in the combined forecasting showed that the sensitive degree was displayed between main growing stages and maize yield, and that was of great importance for some key aspects: (1) looking for the main limiting factor of maize growth; (2) raising maize yield. Therefore, it is feasible and effective to estimate spring maize yield based on the combined forecasting of entropy method and multi-temporal remotely sensed data. 

Abstract:The temperatures, electrical conductivities, capacitances and somatic cell counts of cow fresh milk were measured accurately, and a four-layer BP neural networks regression model was established. The temperatures, electrical conductivities and capacitances were used as the model input data, and somatic cell was counted as output data. The model results were compared with those of the model without the capacitances parameters. It showed that the detection accuracy had been significantly improved with the capacitances parameters, the correct cow mastitis detection rate for validation sample set was 100%.

Abstract:In the process of using BP-neural network in fault diagnosis, there will be “dimension tragedy” as the input variable increases, which causes the lower training effective. Besides, traditional BP algorithm tends to fall in local optimization. The reduction based on the rough set (RS) is the conventional “reduce dimension” method, but it is NP-hard problem, whose computing will gradually augment as the information increases. Therefore, a heuristic algorithm was used for attribute reduction based on the importance of attribute value to reduce attribute, a fault diagnosis approach was formed combining the fuzzy information system knowledge method with BP-neural network of the particle swarm optimization (PSO) algorithm to diagnose the fault of engine. The experiments show that comparing with the conventional method, it can not only require fault diagnosis rule, but also reduce net input dimensions effectively, avoid falling in local optimization and increase the efficiency of fault diagnosis.

Abstract:A complex curved surface was divided into several patches and trajectory planning for each patch was performed. The trajectory integration problem can be modeled as the tool trajectory optimal integration problem (TTOI), and an ant colony algorithm was advanced to solve the TTOI. Simulations were carried out on the automotive body parts and the results validated the proposed algorithm. And a workpiece with a complex curved surface was used to test the scheme. The results of the experiments showed that the trajectory optimization algorithm achieved satisfactory performance, and the time of robotic spray painting saved 20%.

Abstract:A high pressure electronic pneumatic pressure reducing valve, consisted of a two-position three-port pilot valve controlled by electromagnet and a piston type main valve, was proposed. The valve used a pressure sensor and a controller to constitute the closed-loop feedback. By consuming a little gas in the pilot valve, rapidity and stability of pressure regulation were preserved, the influences of pilot leakage on the valve and unexpected icing in pilot valve could be avoided. Then the characteristics were analyzed based on the structure and working principle of the valve, finally the simulation model including the vibration of gas supply pressure and load flow rate was built up with AMESim. Simulation results showed that steady pressure reduction could be achieved under the condition of gas supply pressure slowly reducing and load flow rate fluctuating in a big range. When gas supply pressure is 31.5MPa, the output pressure could be steady in 1~30MPa without adjusting the controller parameters; the influences of machining errors on the valve were also simulated, the results showed that under-lap of pilot spool should be avoided to reduce gas consuming and 10μm is a suitable choice for the height of annular clearance.

Abstract:In order to explore the strength of the structures with unsymmetric lap-joints, the adhesively bonded single-lap joints whose adherends were steel sheets, aluminum sheets and steel-aluminum were separately tested in tension loading which created shear across the bondline. The tests were conducted under different temperatures to provide the experimental tension loads for the three kinds of dissimilar lap-joints. According to the method which Wu Z J proposed, the equations of edge-loads were given based on G—R’s theory. The stress of adhesive was obtained through finite element analysis. In addition, the effects of the unsymmetric structure on the strength of joints were discussed.

Abstract:New tool wear state recognition method based on hyper-sphere support vector machines was proposed. The correlation between the tool wear loss and the features acquired from cutting force and vibration signals of different wear states was analyzed. The mean value, mean square root, the energy and approximate entropy of wavelet coefficient were calculated and integrated as the feature vectors. Ultimately, in order to realize recognition of different wear states, hyper-sphere support vector machines (SVMs) algorithm was adopted as classifier. The results show that hyper-sphere SVMs are with excellent study ability, generalization ability and of high recognized precision with small training samples.

Abstract:As one kind of high strength and thermal resistant nickel-based alloys, Inconel 718 has been used extensively in aerospace industries. To satisfy the instant requirements of higher material removal rate and good surface integrity from engineering practice, high speed machining of Inconel 718 is an inevitable trend. The influences of cutting speed on surface integrity were investigated through the experimental study with high-speed milling Inconel 718 using Sialon ceramic tool. The results showed that higher cutting speed could exploit to give excellent surface integrity. The best surface integrity was obtained in the investigation at the highest cutting speed of 1400m/min in the applied cutting speed range.

Abstract:The reciprocating sliding tribological behavior of the micro wire electrical discharge machining (micro-WEDM) surface was investigated under dry friction and wear conditions by using the ball-on-flat contact model with 0.6mm amplitude. The influences of different loads and frequencies on the friction coefficient were analyzed and the wear mechanism was also studied. The results showed that the friction coefficient decreased with the load increasing because of the third body friction, friction coefficient decreased with the frequency increasing because the oxide film formed with temperature rising led to the decrease of shear strength of microtip contact surface. The wear-loss volume of the micro-WEDM surface increased with load and frequency increasing, and the wear scars appeared adhesion and oxidation wear mechanism.

Abstract:The slippery zone of inner pitchers in Nepenthes bears specialized structures to serve the functions of trapping insects. The surface microstructures of slippery zone and its geometrical dimensions were acquired with scanning electron microscope (SEM) and scanning white-light interferometer (SWLI). The slippery zone consists of plenty of downward-directed lunate cells, as well as relatively dense and irregular wax crystals. Based on the microstructures and the geometrical dimensions, surface structures of slippery trapping plates used in controlling plague locust was designed with 3DSMAX software, and this design provided theoretical foundations for manufacturing slippery trapping plates.