Abstract:A four-stroke free-piston engine was simulated and tested to achieve energy conversion from fuel to electricity. Simulation models were created based on the kinetic equation of free-piston, the equation of gas state, and an equivalent heat release rate of combustion process. Dynamic properties of the system were analyzed by using the model. Effects of the compression ratio and the expansion ratio were discussed. Based on the results of the simulation, an experimental prototype was fabricated. Testing results of the prototype were analyzed, and performance parameters were given out in detail. The generating efficiency 34% was obtained up to now, and the efficiency 45% was available after optimization. According to the simulated and tested results, the new generating system has distinct advantages to conventional gasoline generators.

Abstract:The control strategy, on the basis of features and demands of cold start conditions, was developed and illustrated thoroughly. The experimental platform was built up and the program of the cold start control strategy was written based on the preliminary work of electronic control system and test bench, and the research on cold start was made. The results show that the engine starts by three cycles successfully with the optimal control parameters for each stage to control cold start process. The engine speed fluctuated around 1023r/min and the speed fluctuation rate was only 6%. The light-off time of the catalyst was 38s and HC emission was at lower lever. The control strategy can meet the general demands for GDI engine cold start.

Abstract:The different carbonyl compounds emission from ethanol—biodiesel—diesel and diesel were investigated using high-performance liquid chromatography. The result showed that at rated speed, the overall specific emission of carbonyl compounds decreased by 2.98% at 10% load and 16.42% at 50% load, meanwhile, increased by 11.79% at full load. The C1~C3 pollutants of formaldehyde, acetaldehyde, acrolein-acetone are the main carbonyl compounds, and up to 91.9% among carbonyl compounds emission. In general, the emission of carbonay compounds decreased as load increasing or speed decreasing.

Abstract:Microstructure and size of particle emitted from the three-cylinder, direct injection diesel engine were investigated by using HRTEM under two fuel supply advance angles, two operating conditions and two kinds of proportions of biodiesel/diesel blends. The results indicated that under the research conditions, spherical primary particles consisted of the particles generated by the combustion of the fuels. The particles exhibited the different shapes and characteristics of fractal structure. The primary particles have multilayer graphite-like microcrystal structure. The diameters of primary particle for B0 and B20 are ranged between 25.6~31.3nm and 28.7~40.0nm, respectively. Mean diameter of primary particles of B20 is larger than that of B0.

Abstract:Fluid-solid coupled heat transfer simulation of cylinder head in CNG engine were carried out by using CFD software, the temperature field and the flow field of cylinder head were achieved and investigated. Calculating results were compared with the experimental results in order to validate the veracity of model. Improvements refer to gasket hole area have been presented according to the problems in calculation results. The cooling effect was improved by increasing water flow quantity in the vicinity of fifth cylinder and decreasing the water flow quantity near the first and second cylinders.

Abstract:An index system was constructed for accessing eco-environmental effect of water and soil loss comprehensive harness in meso-scale based on the DPSIR model. The eco-environmental effect of grain for green project was accessed. The results showed that comprehensive value of environmental effect of ecological restoration increased by 30% in test stage, 43% in formal implement stage, 56% in restoration stage, respectively compared with those in the initial stage of evaluation; whereas the values of environmental subentry decreased by 6%, 20% and 22%, respectively; values of social subentry increased by 43%, 114% and 143%, respectively; the values of economic subentry increased by 29%, 129% and 129%, respectively. Grain for green, farmland pressure, sediment transport modulus and erosive precipitation were sensitive indices which indicated that there was a hysteretic nature of eco-environmental changes compared with driving and pressure factors. Impacts of the project of grain for green for eco-environment to response usually need a period of time.

Abstract:Daxing distict of Beijing was selected as the study area, the effect of agricultural water-saving measures on the quantity of groundwater extraction and recharge was studied by rejusting irrigation water supply rates and irrigation water supply rates based on the calibrated water balance model. The main results were as follows: when irrigation water supply rates decreased and water use efficiency increased, groundwater extraction was decreased significantly in different hydrological years. When irrigation water supply rates decreased, the net groundwater extraction was decreased much more than when irrigation water use efficiency increased. The sensitivity analysis showed that irrigation water supply rate is much more sensitive variable to the groundwater extraction. On the other hand, irrigation water use efficiency is much more sensitive to groundwater recharge. Within the value of index level selection, the variation of irrigation water supply rate is much more sensitive to groundwater extraction and exchange. With the increace of irrigation water use efficiency, the sensitivity to groundwater extraction and exchange is decreased. Therefore, compared with the increase of irrigation water use efficiency, the decrease of regional irrigation water supply rates is much better to promote regional water resource continuously and effectively as well as to reduce groundwater extraction for water shortage region under any water-saving condition.

Abstract:Based on practicability analysis of SWMM model parameters in the calibration process, four parameters of subcatchment slope, subcatchment width, Manning coefficient and depression depth on pervious area and three infiltration parameters were selected. Two popular infiltration models of Horton and Green—Ampt were examined respectively. Global sensitivity analysis method of Morris was used. Flow metrics of total rainfall depth and peak discharge were simulated for single rainfall events with different rainfall types and return periods while runoff coefficient was examined for the long-term rainfall data. Main results were: sensitivity analysis results for T1 and T2 rainfall events indicated great differences and T2 rainfall event with small return period was not suitable for parameters calibration; for Horton model, peak discharge of large T1 rainfall can be used for calibrating subcatchment width and slope while total runoff of large T2 can be used for calibrating infiltration parameters; for Green—Ampt model, peak discharge of small T1 rainfall can be used to calibrate subcatchement width and that of large T2 rainfall can be used to calibrate minimum infiltration rate and water deficiency; for the runoff coefficient, sensitivity analysis results of the two methods are similar.

Abstract:In order to provide scientific and theoretical basis for control of water and soil loss of slope, soil anti-scourability for different land uses (shrub land, waste grassland, cultivated land and bare land) in Longbagou basin, the dry valley of upper Minjiang River was studied by the flume experiment, and soil erosion and sediment yield characteristic and its influencing factors were discussed. The results showed that the anti-scourability of surface soil under different land use patterns increased and assumed wavy variation along with scouring time; the anti-scourability followed the order of waste grassland, wheat land, shrub land, corn land, bare land; soil anti-scourability values and silt content has a significant negative correlation (r=-0.992, P<0.01), and sand content has a significant positive correlation (r=0.925, P<0.01).

Abstract:A contrast study on effect of powdered, aminated straw with or without inorganic soil conditioner（calcium sulfate）on soil structure and water-holding capacity in low suction section was made through soil column incubation test. The results showed that the pretreated straw significantly improved soil structure stability, decreased soil structure fractal dimension. Therein the soil with comminuted and aminated straw had a slow acting to improve soil stability. Different pretreatment of straw mixed with soil could make soil porosity connectivity poor in the early stages, and then better with the straw decomposition later. Therein the soil with long straw always kept worse soil porosity than soils with the powdered straw. Furthermore there was a significantly linear correlation between soil aggregate fractal dimension and soil porosity fractal dimension in low suction section. That quantitively explained the effect of the pretreated straw on soil structure and water-holding capacity in low suction section of soil.

Abstract:Based on the experiments of the sandy soil penetration, a semi-cylindrical sandy soil bed in 3D was established, and the simulation with discrete element method for the penetration was investigated. According to the studies on the experiments and simulations, the analysis of influencing factors to the cone index of soil was discussed. And the result showed that the vertical resistance of the penetrometer, cone index and the normal force on the semi-cylindrical wall all increased as the increasing of the penetration depth. And the cone indexes of the narrow and big particle soil bed are much larger than the wide and small particle beds. Besides, the normal force on the semi-cylindrical wall of the big particle bed after penetration is larger than the small particle one. Only after the penetration velocity exceeded 0.2m/s would cone index increase obviously because of impact force from the penetrometer on the particle bed. Finally, according to the displacement of particles, the particle bed after penetration was divided into four zones, and the influencing area could be defined easily, which provided theoretical foundation for determination of distance between measurement points in situ test of soil compaction.

Abstract:A total of 156 soil samples with different textures（sand soil(51), clay soil(54) and land soil(51) were collected, and the spectra of all soil samples were scanned with spectrophotometer (ASD FieldSpec3) from 325 to 2500nm. Orthogonal signal correction (OSC) was applied to eliminate the influence of the textures. Soil organic matter (SOM) prediction models of different textural soil samples were then obtained by using partial least square analysis (PLS) and OSC〖CD*2〗PLS. The result showed that when the calibration sample was clay and land soil, the correlation coefficients of PLS and OSC—PLS model were 0.809 and 0.823; when the calibration sample was sand and land soil, the correlation coefficients were 0.837 and 0.734; and when the calibration sample was clay and sand soil, the correlation coefficients were 0.887 and 0.823, respectively. SOM content of another textural soil samples were predicted by using above models, the result showed that the predictive correlation coefficients of PLS and OSC—PLS to sand soil were 0.572 and 0.864; to clay soil were 0.555 and 0.540; and to land soil were 0.643 and 0.721, respectively. The results indicate that OSC can eliminate the influence of texture and improve the prediction precision and solidity of the model.

Abstract:Over the course of two rape growing cycles, fertilization types and application rates affected plant growth and groundwater pollution from solar vegetable greenhouses in Beijing agricultural region were studied. Seven fertilization patterns were selected, and in each treatment, the NH+4N and NO-3N migration and accumulation in 0～200cm solar greenhouse soil and the affect on rape yield were studied. The results showed that the different fertilization patterns mainly affected the average NH+4N accumulation and content in the 0～40cm soil layer. Average soil NH+4N accumulation and content was larger in the treatment of only chemical fertilizer than that of only organic manure. When N application rate was less than 383kg/hm2, the average soil NO-3N accumulation and content in the 0～40cm soil layer were found to be in the following descending order: use of only chemical fertilizer, use of only organic manure, use of both organic manure and chemical fertilizer. The different fertilization patterns also affected the migration and accumulation of NO-3N in 40～160cm soil. It is concluded that organic manure (N application 150kg/hm2) mixed with chemical fertilizer (191kg/hm2) is the best fertilization pattern for planting rape in solar greenhouses in Beijing agricultural region.

Abstract:Control volume finite element method to solve incompressible flow problems was investigated. The streamline FCBI method was built and compared with the original FCBI and general FCBI method. Lid-driven cavity flow and S-channel flow were chosen as the test cases. The similarities and differences among the three interpolation functions were discussed according to the analysis. The results showed that for convection-dominated flow, especially with complex performances, the Streamline FCBI method could better describe the velocity distributions in the element and achieve more stable converged results. For convection-diffusion problems, the precision of all the methods were low when element Re was high. From the analysis that for convection-diffusion problems, it is concluded that good results can be achieved by using FCBI methods when element Re is less than 5.

Abstract:The test by changing different diameters of balanced hole in the 3BA—6 single grade single suction pump was made. The pressure of outlet of impeller rear sealing and the pressure of inlet in pump were measured. The test curves of the liquid pressure in balance cavum and the pump head, and the pressure of import of the pump and the pump head were both obtained. Thus the fluid leakage characteristic curves of balance cavum were obtained. The theoretical curves and the test curves of fluid leakage in balance cavum at the different diameters were compared and analyzed in design condition. After measured the axial force curves of pump, the result showed that axial force curves which obtained by calculating based on the fluid leakage characteristic curves of balance cavum could meet the engineering calculation need.

Abstract:To solve the problem of rotor-stator flow coupling, the FVM was adopted to discretize the incompressible rotating flow equations. The time and spatial discretization schemes of the convective, diffusive, and the source term of the equations were investigated. For the rotor, the non-inertial reference frame was adopted to solve the relative flow equations, and for the stator, the inertial reference frame was adopted to solve the absolute flow equations. To keep flux conservation, the Neuman condition was prescribed on the rotor-stator interface. To realize the rotor-stator flow coupling, the relative velocity at rotor outlet was transformed to the absolute velocity, which used as the stator inlet condition. Then a switch mode was adopted to run the algorithm. To validate this algorithm, the flow coupling between the ERCOFTAC centrifugal impeller and the diffuser was conducted, and the steady and unsteady results were obtained and compared with the literature. And good consistency was observed by comparison. It shows that the algorithm is capable of forcasting the rotor-stator flow coupling. The algorithm can be used to forecast and investigate the centrifugal pump flows.

Abstract:Combined with the technological features of stamping pump, numerical simulation based on Fluent was made for 100XQJ8—43/9 stamping well pump. In order to improve the accuracy of numerical calculation, numerical calculation of stamping well pump model of different blade thicknesses was carried out by using different grid numbers and different stage models. The relationship between the blade thickness and the overall performance of pump was analyzed from the external characteristics and internal flow field. In conclusion, with the increase of blade thickness, the best efficiency point of pump shifts to the small flow direction and the internal turbulence losses of pump were increasing gradually. Through the experiment of the mode pump, the numerical simulation values under the whole flow field are much closed to the experimental values and the error is less than 1%, which verified the feasibility of numerical simulation. The text would be instructive to the optimization of new-type well pump which is designed by the impeller diameter maximum approach.

Abstract:The forecast and balance of axial force is the key and difficult aspect in the design of multistage pump.150QJ20 type deep-well centrifugal pump was chosen as an example; the whole flow field of two-stage deep-well centrifugal pump was simulated in Fluent by the standard k—εturbulence model, SIMPLEC algorithm and second-order upwind scheme. The pump efficiency, single-stage head and single-stage axial force at different operating points were obtained by numerical simulations. The external performance and axial force of the prototype pump were tested by the experiments. The difference between numerical results and the experimental result were compared and analyzed. The results indicated that the numerical methods could accurately forecast the pump performance and axial force.

Abstract:In order to find out the effects of splitter blades on the performance of pump as turbine, a pump as turbine and an open pump as turbine test rig were built. Research results showed that the addition of splitter blades could improve its efficiency, increase its flow rate at the best efficiency point and decrease its required pressure head. Internal flow field analysis showed that the flow field was improved and the area and intensity of vortex region was decreased with the increase of splitter blades. Power loss distribution analysis within pump as turbine showed that power loss within impeller took up the majority of the total power loss. The power loss within impeller was decreased when splitter blades were added to the impeller. With the increase of blade number, the interaction of impeller and volute was enhanced, so the power loss within volute was increased.

Abstract:After hydrothermal pretreatment of corn stover, solid fraction and hydrolysate were collected separately. To find out the appropriate process for ethanol production from corn stover, ethanol production was evaluated from dried solid fraction and the hydrolysate employed as liquid fraction by baker’ yeast. The effects of different pH value and detoxification on ethanol production were investigated. Firstly, prehydrolysis was performed at 50℃ for 24h. When 100% hydrolysate was added, ethanol content of 0.31g/L (9.48% of theoretical ethanol yield) was obtained based on the cellulose available in the pretreated corn stover due to the existence of acetic acid and furans which are important inhibitors of the fermentation to microorganisms. After prehydrolysis, the initial pH value was adjusted to 5.5, 6.0 and 6.5, respectively. The best value obtained was ethanol content of 10.67g/L with addition of 100% hydrolysate at pH value of 5.5. The hydrolysate was overlimed, then prehydrolysized for 24h at 50℃. After prehydrolysis, the initial pH value was adjusted again to 5.5. Ethanol content of 10.96g/L (57.9% of theoretical ethanol yield) was obtained. Ethanol yield increased almost 6 times compared to that at pH value of 4.8.

Abstract:Carr-evaluation method for evaluating flow characterization of biomass particle straw has been studied to resolve the problem of testing flow characterization of crop straw. And the flow characterization of 8 types of crop straw came from North China was measured by the two methods of Carr-evaluation method and inner-friction angle method. The results showed that Carr-evaluation method can reflect the variation of particle straw flow characterization, the more score it had, the better flow characterization it was, and the 8 types of crop straws were divided into three categories, easy flow (such as the score of corn cob was 81), the general flow (such as corn stalks) and difficult flow (such as soybean), the results of Carr-evaluation method is similar to the results of inner-friction angle method.

Abstract:According to the actual operation data from a mixed waste fired power plant in Shanxi province, the model of pollutant emission process of boiler burning waste, coal and straw was established. Validation showed the model can better simulate the process of mixed fuel boiler pollutants emissions. The multi-objective optimization function of flue-gas pollutants emission was designed and the Pareto optimal solution set was found. According to the engineering condition of dioxins could be broken down when the mixed fired temperature was in the range of 850~900℃，the efficient solution subset of boiler mixed burning operating condition that emission values could satisfy the engineering requirements was further selected from Pareto optimal solution set. The subset showed that when the temperature was higher than 850℃,with appropriate increase of the blending amount of coal and temperature, the formation of dioxins of boiler side exit has been significantly reduced, the minimum was 0.0128ngTEQ/m3, far better than the national standard value of 1.0ngTEQ/m3 of eventually allowed emissions gas and test value 0.026ngTEQ/m3 of the on-site gas after purification. Moreover, the other pollutant emission value is also much lower than the actual test value of side exit of on-site boiler.

Abstract:Aiming at the poor portability of devices, high cost of the existing traceability methods for agricultural products quality and safety, an agricultural products quality and safety traceability system based on two-dimension barcode recognition of mobile phones was developed. The architecture and main function design of the system were illustrated in detail. Through the tests of the best recognition distance, recognition time, recognition rate and accuracy rate on the system using three types of mobile phones from Nokia in the case of the mobile phone cameras various distances away from the barcodes, the average identification time for barcodes of food wrappers and tagboards was 7.3s and 5.1s respectively, average recognition rate was 67.8% and 75.6% respectively，and accuracy rate were to 100%. The best recognition distance was about 10cm，identification time for barcodes of food wrappers and tagboards was only 6.4s and 3.4s respectively. The test results show that users can recognize two-dimension barcode labels attached on products quickly and conveniently through the system, and it will provide a new traceability means.

Abstract:Acinetobacter lwoffi was studied by impedance and plate count method throughout rotational combination design to define the effects of temperature and pH value on maximal specific growth rate (μm) of A. lwoffi, conductance and admittance. Polynomial models were established (Pr<0.05) and validated. The results showed that the established model with viable count method was better than the other two (R2=0.9455), which fit well when μm was less than 0.06. The correlation equation between μm of conductance/admittance and μm of A. lwoffi were established and the R2 were 0.859 and 0.806, respectively.

Abstract:Near-infrared spectroscopy (NIRS) quantitative detection models of sesame oil adulterated respectively with soybean oil, corn oil and peanut oil were established by interval partial least squares (iPLS). Mixed samples of sesame and adulterated oils with different proportions were scanned by using a FT-NIR spectrometer and the near infrared transmission spectra were collected in 4000 ~12000cm-1 region which divided into calibration and prediction set. The spectra in 4420~12000cm-1 region was pretreated with different ways and the best was Savitzky—Golay moving. The characteristic wavelength bands were selected by iPLS and the quantitative models were established by PLS finally. The results showed that predicted correlation coefficients of the models built with PLS for three kinds of vegetable oil reached to 0.998，0.999，0.999 respectively, while the root mean square error of prediction were 0.24%，0.24%，0.19%, which have high accuracy. The experiments proved that NIRS technique used for rapid detection of adulterated oil in sesame oil possesses certain feasibility.

Abstract:A new strategy was demonstrated to establish typical spectra database. For the study, bone fragments of three different species MBM were analyzed on near-infrared microscopic imaging system, and both visible and near-infrared images were acquired at the same size. To extract and mark the position of every single bone fragment in visible image, a graphical user-friendly interface, based on marker-controlled watershed segmentation method, written in Matlab for extracting and marking bone fragments has been developed. The recognition ratio was 96.4%. By the position information in visible image, near-infrared microscopic imaging data was decompounded to spectrum of each bone fragment. Next, typical spectra were selected by the multivariate ‘distances’—Global Hood (GH) & Neighbor Hood (NH) statistics.

Abstract:The manufactured method of fortified vitamin B1 and vitamin B2 rice by using extrusion technology was introduced, and the HPLC (high performance liquid chromatography) result showed that retention ratios of vitamin B1 and vitamin B2 in the fortified rice were 62.8% and 81.0%, respectively. The physicochemical properties of fortified rice had great changes compared to the raw rice, the degree of starch gelatinization and water soluble carbohydrates obviously increased from 8.86%, 0.58% to 86.21% and 2.98% respectively, and the apparent density decreased from 0.91g/cm3 to 0.80g/cm3. The SEM (scanning electron microscope) result indicated that the surface of fortified rice presented in smooth and even micro-porous structure. The edible qualities of fortified rice accessed high-grade japonica rice analyzed by the TA—XT2i type instrument compared to the hybrid rice (raw rice for fortified rice) and japonica rice.

Abstract:The antioxidants of clove were extracted by water bath shaking, ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE) and ultrasonic and microwave-assisted extraction (UMAE), the effective fraction of clove were immersed in the artificial gastrointestinal juice. The results showed that the total polyphenols and flavonoids recoveries were highest, and the antioxidant capacities were strongest for the extracted liquids by MAE and UMAE. However, the extraction time of UMAE was only half of that of MAE. The extraction efficiency of UMAE was the highest. The antioxidant capacities of the effective fraction of clove were significantly improved after immersed by the artificial gastric juice (P<0.001), while its antioxidant capacities were significantly reduced after immersed by the artificial intestinal juice (P<0.001).

Abstract:The winter wheat PVC estimation models based on canopy spectral characteristic parameters were established in different growth periods. The results showed that the winter wheat canopy hyperspectral reflectance in the visible light decreased from reviving to heading stages, then increased from heading to maturing stages, while in the near infrared band, it increased from reviving to heading stages, decreased from heading to maturing stages. Under different crop densities, hyperspectral reflectance of winter wheat canopy with suitable for water supply in the visible light was less than that of slight water deficit and severely water deficit in order, but in the near infrared band, it had opposite conditions. There were good relationships between winter wheat PVC and the spectral characteristic parameters of traditional and new spectral characteristic parameters in different growth periods. Compared with the models of winter wheat PVC which used the parameters of traditional spectrum characteristic as the independent variables, the models based on the kurtosis of green peak can improve the estimation accuracy of winter wheat PVC.

Abstract:Taking winter wheat in China as an example, large-scale crop planting areas automatic identification methods were researched based on time-series of MODIS—NDVI datasets. The characteristics of NDVI time series of winter wheat in China were firstly analyzed, and then the threshold values of extracting crop planting area were set and the extraction models of winter wheat were established, finally spatial distribution of winter wheat of 2010—2011 was obtained, the results showed that the extraction accuracy of winter wheat planting area was more than 81% compared with the average statistical data obtained in years. MODIS data of China in 2011 were used to monitor the growth condition of winter wheat, and the growth condition was compared with the average crop growth of the last five years. Results show that winter wheat growth condition has different characteristics both in spatial and temporal.

Abstract:The existing image processing systems were always designed for certain items. One system can not deal with different types of items. In order to solve this problem, a designed method of parametric agricultural image processing system was proposed. Different parameters were set according to the different characteristics of items at first, and then different algorithms were chosen. The design and simulation results of the top-level controller of the system were presented. At last, the description of how to set parameters in the system was also provided. The system has strong flexibility and robustness.

Abstract:In order to realize the recognition and localization of the mini-watermelon with stereoscopic cultivation in greenhouse, a machine vision method for acquiring harvesting information of watermelon based on the near-infrared spectral image was presented. By comparing the spectral reflectance of fruit, leaf and stem, a wavelength of about 850nm was chosen as the best wavelength, of which the images taken at different illumination conditions were tested for fruit recognition. At first, the Otsu threshold algorithm was adopted to eliminate most background information. Then, a template liked circle was used to detect fruit region and reduce the noises. Thirdly, according to the morphological feature, the centroid of fruit was considered as the optimum point for picking and the cutting point was judged by “block-location method”. 50 images including fruits and 20 images without fruits were tested by the recognition algorithm, which can satisfactorily detect fruit with a recognition rate of 86% and 95%, respectively, and the accuracy rate of locating algorithm for picking point and cutting point detection was 93.0% and 88.4%, respectively, which met the demand of robotic vision system.

Abstract:In order to change the lane of a weeding robot to the navigation line, a visual navigation system and two reference frames were established, some relative navigation and measure algorithms were put forward. According to the condition whether robot’s moving direction were parallel with the navigation line or not, two different paths for lane changing were put forward and proved to be the optimal lane changing paths after the minimal turning radius was restricted. The corresponding control process and some calculation formulae about pivotal points and indispensable data related to the optimal paths were given. The two optimal paths planning methods for lane changing can be applied to any vehicle and robot with front wheel steering.

Abstract:An algorithm based on image processing technology was proposed for generating navigation directrix in orchard of complex circumstance. Image of R—B component was binarized by 2-D maximum between-cluster variance. A region of interest was detected by horizontal projection method to extract tree trunks. Crossing points between tree and ground were obtained by scanning the trunks and classified into different clusters in terms of their neighboring relation. Least square method was used for detecting two border lines, center points of crossing points between two border lines were extracted to generate navigation directrix for agricultural robot. The experimental results under various scene conditions showed that the algorithm could generate navigation directrix accurately, the accuracy was more than 90.7% which showed a good noise robust；the average processing time of a 640×480 pixels image was less than 119ms and met the need of real-time.

Abstract:The research object is a force bilateral servo system in which the master side is a hydraulic manipulator and the slave side is a hydraulic cylinder actuated robot. Facing the concussion problem occurred when the slave hand contact rigidity object, a strategy-switching algorithm was proposed. A four-channel slave driving strategy was used to the flexible load and a three-channel strategy without slave force was used to the rigidity load. The switch was judged by the ratio of slave force and velocity. It is proved by the experiments that the strategy is valid and the concussion problem of the former strategy when catching rigidity object could be avoided.

Abstract:In order to improve the safety of the wind tunnel test, the flexible dynamics of a 6—PSS parallel mechanism for the wind tunnel was analyzed. At first, inverse kinematics of the parallel mechanism was received based on the analysis of its kinematics, and Jacobian matrix was calculated by using the first-order influence coefficient method. Then, the dynamics equation was solved by using the Lagrange equations and a simplified rational dynamics method. A simple and practical method of flexible dynamic simulation was put forward. The flexible dynamic simulation of the parallel was obtained with ADAMS software. The correctness of flexible dynamics simulation was verified by comparing the kinetics and dynamics date form rigid and flexible analysis. At last, the character of flexible kinetics was summed up by analyzing the driven force and flexible deformation data.

Abstract:A novel translational parallel mechanism with three degrees of freedom was presented, which consisted of a moving platform connecting with a fixed base by three identical limbs. Mobility of the moving platform was analyzed and calculated according to the units of single-open-chain. Kinematic problems were discussed by means of different actuated joints inputs, i.e., rotational angle displacements and linear displacements, respectively. The analytical solutions of position, velocity and acceleration were derived. The kinematic simulation of this mechanism was carried out by Matlab and Pro/E software. Position, velocity and acceleration curves were described based on the analytical solutions and virtual prototype. Simulation results showed that the theoretic analysis was correct and feasible．When the linear displacements are selected as the actuated inputs, the Jacobian matrix of the mechanism is an identity one and its condition number is always equal to 1. The parallel mechanism, therefore, is full-isotropic throughout the entire workspace in this case.

Abstract:Aiming at the compound fertilizer particle inspection for strong corrosive and high dust environment, a kind of inspection system based on binocular vision was proposed. Firstly, using demand of the inspection system was analyzed, and the design requirements which can realize the continuous large sample testing, and result online showing and granulator closed-loop controlling were put forward. Then three binocular visual inspection plans were proposed and compared. Binocular linear CCD inspection was sure for the feasible plan. Hardware configuration, anti-corrosion and dust removal were designed. In order to improve the precision, electromagnetic vibration feeder was servo controlled, which was feedback by robot vision. Also, double cameras parallel image processing program was used. Finally, particle size distribution experiment was executed. The results show that the system error is within ±3%, facilitative for practical application.

Abstract:3D part contour curves matching algorithm is an important content in panel die-face design based on template. By researching on the existed 3D curves matching algorithm, according to the feature of complex part contour curve, 3D part contour curves matching algorithm was advanced. This algorithm was based on the skills of multiscale filter, feature calculation, partition equivalent class by Hausdorff distance, and the ISODATA cluster analysis method of calculating the best matching switch matrix was put forward. The corresponding programs were developed. The algorithm was demonstrated to be efficient, robust and fault tolerant by three typical examples of actual parts which are the selfsame, different in size and little change in shape.

Abstract:The principle of initial parameter method to establish the initial parameter matrix equation for force and displacement of ball screw was explored. The structural characters, including boundary condition, force balance and displacement compatibility in support point were used to achieve initial parameter values. As a result, force and displacement of every point on ball screw could be obtained. Meanwhile, an identification method of the radial rigidity of support point was put forward. The identification models of radial rigidity were built by analyzing the amplitude changes of ball screw under some load affection employing the knowledge of mechanical vibration and material mechanics. The results are in good agreement with the results obtained by the available experiments.

Abstract:In order to narrow the margin between the predetermined symmetrical parabola transmission error curve (TEC) and that of tooth contact analysis (TCA), a dual-layer method was proposed for the TEC optimization of spiral bevel gears. The method consisted of inner and outer layer optimizations which were conducted in turn. In inner layer optimization, pinion machine-tool settings were obtained based on local synthesis and TCA was carried out which gave TEC and contact pattern. An agreement objective was set up. The difference between TCA TEC and that of the theoretical one was diminished in least square sense to ensure agreement by tuning the four higher order modified roll coefficients in the relative motion formula linking the pinion and its cradle. In outer layer optimization, a symmetrical optimization objective was set up. The number of meshing points on the left and right branches of TCA TEC has been regulated until equal to each other to ensure symmetry by adjusting the displacement of the mean contact point along tooth depth. The method brought up is validated for a pair of spiral bevel gears. The results show that the method corresponding to the symmetry and agreement is indeed effective for TEC optimization of spiral bevel gears.

Abstract:Elliptical micro-textures were made by using laser on the rake face of the tungsten carbide cutting inserts. Molybdenum disulfide (MoS2) solid lubricants were embedded into the micro-textures to form self-lubricating textured tools. Finite element analysis was conducted to assess the effect of micro-texture on the stress distribution of the cutting inserts. Dry cutting tests were carried out with these self-lubricated cutting tools and conventional cemented carbide tools. As the results, there is no conspicuous adverse effect on the stress distribution of the tool nose with micro-textures on the rake face. The cutting forces and the cutting temperatures with the self-lubricating textured tools were greatly reduced compared with that of conventional cemented carbide tools. Meanwhile, the rake wear and the chip deformation were reduced, and the chip coiling was improved with micro texturing lubrication.