Abstract:Characteristics of regulated and unregulated emissions of biodiesel blends（derived from waste oil）in a common rail diesel engine without any modification were investigated. The results showed that NOx emissions increase significantly with a higher blend ratio and NO2 concentration increases after two diesel oxidation catalysts. A linear relationship between the reduction of smoke number and the blend concentration is found. For unregulated gas emissions, MECHO emission is reduced with a higher blend concentration of biodiesel at full load as combustion improvement. Due to low sulfur of biodiesel, the range of SO2 reduction is between 20%～60% for pure biodiesel compared with diesel. Particles in nucleation mode are dominated by the sulfur content of biodiesel blends. Concerning the pure biodiesel, total particle number concentration is reduced due to the lowest sulfur content.

Abstract:30.7%。The characteristics of particulate matter emission from the diesel engine burning diesel fuel(D), methanol-diesel fuel(M20) and biodiesel fuel(B) were tested respectively by using a two-stage dilution system and electrical low pressure impactor and the effects of the engine speed, load, as well as the different fuels on the particle size distribution were analyzed. The results indicated that the quantity of PM emission for methanol-diesel fuel(M20) and diesel fuels increases with rotation speed, but biodiesel doesn’t follow this rule on engine performance curve; the peak of PM emission for biodiesel and diesel fuels decreases with load rising at the speed of 2300r/min.On rated power mode, the total volume concentration of diesel is more than that of M20 and B. Compared with diesel, the quantity concentration of biodiesel increases by 30.7%, and the quantity concentration of M20 decreases by 62.8% in nuclear mode.

Abstract:Two cam phases were designed basing on original diesel engine which was refitted into spark ignition CNG engine. The influence of cam phase on combustion and exhaust was studied by experiment on indoor test. The conclusions are showed as follows. With the smaller valve overlap, the exhaust of HC and NOx reduces; but too small valve overlap at high speed is adverse to the exhaust of HC. The density of burning mixture reduces with smaller overlap and the growth of NOx is restricted.On the other hand，power of the engine also reduces. So, both the power and the exhaust should be considered at the same time. The crank angle of ignition advance should increase properly at high speed,in order to keep the power and avoid the post combustion and reduce the temperature of exhaust. 

Abstract:This study was focused on the impact of the changes of the EGR rate on combustion, emissions and the coefficient of variation of LPG engine at lean burn conditions. Test data showed that dual-spark plug-based rapid burning system increased the combustion heat release of LPG mixture, and improved the rapid burning process of LPG engine with EGR. Meanwhile, the excess air ratio limits of LPG leanburning was largely extended within the total effective range of EGR rate（REGR）. At the equivalent running conditions of LPG engine, largely extended REGR restrained the formation of NOx emission by high combustion temperature. The highest REGR of rapid combustion process was increased from 5% to 811% of normal combustion process. Additionally, the coefficient of variation of LPG combustion process got control effectively.

Abstract:The effects of bomb under equivalence ratios, initial pressures and CH4 concentrations on the premixed laminar flames propagation velocity and the laminar burning velocity of coal bed methane-air mixtures were studied in a constant volume combustion bomb by high speed video camera. The results showed as follows, when equivalence ratio is 1.1, laminar burning velocity has the largest value; in initial combustion stage, with the increase of initial pressure, maximum combustion pressure markedly increases, laminar flame spread velocity and laminar burning velocity decrease, and when the flame radius exceeds 40mm, laminar flame spread velocity and laminar burning velocity increase; with the increase of CH4 concentration, laminar burning velocity and maximum combustion pressure increase.

Abstract:The systems including an electronic control unit (ECU), liquefied petroleum gas (LPG) supply system and LPG electronic control injection system were developed, by which a 295T DI diesel engine was successfully refitted. Subsequently, taking respectively diesel oil and LPG / diesel as fuel, under the same condition, performance tests of the modified engine were carried out. Results indicated that the refitted engine’s power performance increased in a quite big range, economy performance became better, and Nox emission was lower; the CO level is closed to that of the prototype diesel engine; but the HC emission level was higher in low load stage and was lower in full load stage compared with prototype diesel engine. The research results also prove that our refitting scheme is feasible.

Abstract:A bond graph model was established for the air-flow calculation of the diesel engine's heat dissipation system, to find out the relations between the design parameters and system's heat dissipation performance, especially when there was a lack of supportive data. By overall consideration of influences of the fan's parameters and the aerodynamics on the system's final performance, the bond graph was applied to calculate the power-loss during the process. Then a mathematic model of power flow with the design parameters of geometric parameters and air characteristics, where the flow-rate of the radiator's air duck could be calculated according to the fan's rotational speed. Formula of air speed distribution was also proposed that matched the data from field test. The bond graph model of the fan-channel is proved to be an effective estimation method of flow rate.

Abstract:11%～46%。3-D finite element models and meshes of the cylinder in a certain vehicle diesel engine were established. With the combination of finite element analysis and submodel technology, ABAQUS software was used to carry out finite element strength analysis on engine block. Then the stress concentration position was determined and structural improvement of cylinder block was proposed. Based on this, MSC.Fatigue software was adopted to calculate fatigue strength of the water jacket basement submodel before and after modification, and stress test was done to validate the effect. The experiment results indicated that the stress of water jacket basement reduces from 11% to 46% after adding stiffening rib to the cylinder.

Abstract:The application of inverse system theory to vehicle handling dynamics was proposed to study steering angle input by driver for vehicle accurately achieving the given lateral acceleration. Based on the state equation of vehicle steering angle input, with the stable, invertible, controllable and observable inverse system meeting, steering angle was identified with the lateral acceleration of closed-loop simulation and actual test respectively as the inverse system input. Steering angle of identification was compared to that of actual test. The results showed that steering angle trend of identification conforms to that of actual test, with the small absolute error of lateral acceleration.

Abstract:3.0%。In order to define the optimum performance parameters of pneumatic precision metering device for rapeseed, single factor and orthogonal experiments were carried out, with the experimental factors of rotational speed of metering disc, speed of seed belt, pressure and vacuity, employing eligible index, multiple index, miss index, seed damage rate as judging indexes. Single factor experiment showed that the damage rate of seed is zero in every group of experiments，and the other three indexes were remarkably influenced by rotational speed of metering disc, pressure and vacuity. Furthermore，orthogonal experiment indicates that when the pressure is 440Pa, the vacuity is -834Pa and the rotational speed of metering disc is 15r/min, the eligible index reaches as high as 94.2%, both of the multiple index and the miss index are lower than 3.0%.

Abstract:10°。A finger-chain type sugarcane-lifter was studied. The orthogonal and single experiments were conducted to study the following factors: advancing velocity vm, rotational speed of driven sprocket n, lateral-angle βof slideway and oblique-angle αof slideway. The mathematical models for the two evaluations index which contained lodging angle after lifting and different factors were constructed by using the method of mathematical statistics. And the parameters of the sugarcane-lifter were optimized. The results of experiments showed that these four factors had significant impact on lodging angle after lifting. The optimal parameters were as following: the function between rotational speed of driven sprocket n and advancing velocity vm was n=-1599.618v2m+1609.678vm, the obliqueangle equaled to 60° and the lateral-angle equaled to 10°. 

Abstract:Impact damage is the main form of rice threshing and one of the significant causes of rice injury. Based on the contact mechanics, models of the compressed displacement and the largest pressure distribution were established, as the threshing component centrally collided with a rice kernel. Due to the difference of moisture content, rice kernels plastic mechanics and brittle mechanics were different. The critical speed formula about impact damage was obtained as the rice kernel collided with the threshing element. Furthermore, the critical speed was calculated for the impact damage as to the spike tooth and the rice of zhendao10, wuxiangjing14, huaidao9, zhennuo653 and xieyou084. Besides, experimental study was performed on the test platform which proved that the experimental mean value was by and large in according with the theoretical calculation.

Abstract:In order to investigate the adaptability of the developed taped type rice direct seeding machine for field surface roughness, dynamic simulated experiments were carried out. A field surface roughness measuring system composed of two angular displacement sensors, an A/D converter, a computer etc. was designed according to the structure and working principle of the seeding machine. The two types of field surface roughness, one known as original field surface roughness formed by the working of rotavator and the other known as rolled field surface roughness formed by the roller of the seeding -machine,were detected. The signals were analyzed in timedomain and frequency-domain by using Matlab software. Transfer functions were established by the method of identification, and the dynamic characteristics of the system were analyzed. The results showed that the “soil-machine” system is linear with the first order typical feature. The dynamic characteristics of the systems such as rapidity, bandwidth and soil covering thickness are able to satisfy the requirements of rice seeding technology. 

Abstract:A multifunctional machine with functions of harvest, ditch and stalk-disposing was developed， by using which, the working procedure of harvest, ditch and stalk disposing can be implemented in one work operation. Test results showed that the power transmission system is reasonable, firm ditch device works well, trapezoid ditch (193?mm mean depth, 220mm top and 160mm bottom width) can be obtained and meets the agricultural requirement.

Abstract:Based on the theory for water movement in non-saturated soil, the mathematical model of film hole irrigation was developed to describe soil water movement, and the simulation was performed by using SWMS—3D software. According to the simulated results, the characteristics and infecting factors of infiltration of film hole irrigation was analyzed, and the simplified film hole infiltration model including the opening hole ratio and the film hole diameter was presented. The model was verified by infiltration experiments at several typical soils condition and other researcher’s experiment results. It was showed that the model is simple and credible with less parameters, which can been using for deciding reasonable technological elements of film hole irrigation water to improve irrigation water quality.

Abstract:In order to study the relationship between the atomization properties and dynamic surface tension(DST) of pesticide surfactants aqueous solutions, the median volume diameter （D50） of agriculture flat-fan nozzle were measured, with the particular emphasis on the effects of different nozzles and pressures. The results showed that the D50 was correlated linearly with　γ0.023; the D50 increased resulted from DST with the increase of the nozzle type under the same pressure; with the increase of the pressure, the D50 decreased for the same nozzle.

Abstract:The hybrid genetic algorithm combined with Levenberg-Marquardt optimization algorithm was established to estimate root water uptake model parameters. A series of numerical experiments and root water uptake were conducted to verify the model. The results indicated that the optimized value of the root water uptake model parameter optimized model with the hybrid genetic algorithm has a higher precision. The time and space interval of soil water content had a great influence on the root water uptake model parameter's optimized precision. In practice, it is recommended to choose 5～10d for time interval and 5～10cm for space interval. Furthermore, the inverse method was applied to simulate the average root water uptake rate distributions of cotton. The simulated results showed that the optimized model solving the root water uptake model can simulate the root water uptake of cotton, to solve the root water uptake parameter.

Abstract:Based on the models of charged liquid jets and Lagrange equation under the generalized coordinate, the dispersion equations of inviscid liquid jets in an electrostatic field were established and solved by using the numerical methods. According to analyzing the calculated values, the effects of different factors on axisymmetric models and non-axisymmetric models of charged liquid jets were studied. The results showed as follows. The maximum value of the disturbed growth rate of charged liquid jets is increased with the stronger electric field intensity. When the voltage is lower, the electrostatic field has a significant effect on the axisymmetric instability models. The non-axisymmetric instability models exert a dominant influence since the voltage is enhanced gradually in an electrostatic field and it leads the droplets to break up finally. Instability of charged liquid jets is increased as the jet radius reduces. The changes of the jet radius in the non-axisymmetric modles have more effects on the instability of charged liquid jets than in the axisymmetric models. The effects of different liquid dielectrics on the non-axisymmetric charged liquid jets instability become very obvious.

Abstract:Pressure boundary condition was used to investigate the unsteady 3-D flow characteristics in a single-stage single-suction centrifugal pump with vaneless volute. For the calculation, the total pressure and the static pressure were specified for inlet and outlet respectively, and the sliding mesh technique was used. The results show the capability of this numerical method in capturing the unsteady flow characteristics due to the impeller-volute interaction. The flow is characterized by periodic pulsation, blade passing frequency in volute and impeller rotating frequency in impeller. To a large extent, the asymmetric shape of the volute affects the propagation of impeller-volute interaction and results in the circumferential non-uniformity flow distribution in the pump. 

Abstract:This experimental study on plasma pyrolysis of corn stalk and the feature of bio-oil was carried out in a self manufactured small fluidized bed reactor with corn stalk. Results showed that the temperature in the fluidized bed was steady under the condition of adopting the plasma body to heat the reactor, and the preheat time is 1.5h. The heating value of pyrolysis liquid—bio-oil was analyzed. The heating value of crude bio-oil obtained is 18066.62kJ/kg. Heating value after taking off carbons is lower by 3446.71kJ/kg than that of before taking off carbons. Thus, there is some certain solid charcoal in the bio-oil. The bio-oil after taking off the carbon was get rid of the water, which heating value is one time higher than that of the bio-oil after only taking off the carbon, with the difference of 14345.95kJ/kg.

Abstract:65.417%。Taking particles of rice straw as material, using straw treated by alkali as binder, adopting the quadratic orthogonal rotation design, the effects of various pressure, the additive proportion of binder, the moisture content and the grain size of raw materials on the loose density and the dropping intensity of briquette fuels was studied. A mathematical model of experiment with four factors was established and analyzed by regress method in SPSS 13.0 and response method in Matlab 7.1. The results showed that the regression equation was significant. The optimum factors were as follows, the pressure was 32MPa,the additive proportion of bonder was 4∶1, the moisture content was 10%, and the grain size of raw materials was 4mm. Under this condition, the loose density reaches 1188g/cm3, and the dropping intensity reaches 65.417%.

Abstract:In order to improve the functional properties of wheat germ globulin, the ultrasound treatment method is adopted. Effect of ultrasound treatment on physicochemical and functional properties of wheat germ globulin is studied. Results show that free sulfhydryl and disulfide bond contents, ultraviolet spectrum, and fluorescence spectra of wheat germ globulin are changed significantly after ultrasound treatment. The hydrophobicity, foaming capacity, foaming stability, emulsifying activity and emulsifying stability of wheat germ globulin decrease with the increase of ultrasonic power. When the ultrasonic power is more than 900W, the hydrophobicity, foaming capacity, foaming stability, emulsifying activity and emulsifying stability of wheat germ globulin are improved due to wheat germ globulin unfolding and exposed hydrophobic group increasing. Moreover, ultrasonic power has significant influence on the solubility of wheat germ globulin, which is gradually increased with the increase of ultrasonic power. Thus, ultrasound treatment could be used to modify the physicochemical and functional properties of wheat germ globulin by appropriate selection of ultrasonic power level. 

Abstract:The effects of different heat-shock treatments on biochemical properties and microstructure of Lactobacillus helveticus were determined. The strain was subjected to heat-shock treatment at 67℃ and 70℃, holding time was 10s, 15s and 20s, respectively. The biochemical properties related to cheese ripening such as cell residual viability, lactic acid productivity, and proteolysis activity were monitored. The results suggested that the modified cells using heat-shock parameter of 10s at 70℃, gave the best results upon inhibiting lactic acid productivity and the remaining proteolysis activity. Moreover, SEM photographs showed the changes of surface structure on cell membranes, and elucidated the relationship with heat-shock treatment.

Abstract:Taking the corn material in bin as the study object, a pore network model for the corn drying was developed by applying the theories of drainage and percolation through porous media and transport-process. Various factors for the drying process, such as the heat and mass transfer in grain itself, vapor-phase convection, temperature gradient, as well as physical structure characteristic were considered into this model. Five independent variables were involved in this model, which was able to describe the drying process of corn material more effectively than the traditional drying model. Moreover, the physical structure characteristic parameters of corn material, such as porosity, pore size distribution and so on, as the model parameters, were input the model directly to predict the drying characteristic of corn material.

Abstract:125.73mL。In order to improve extract efficiency of apple polyphenols, the dynamic law of apple polyphenols (AP) adsorption and desorption to NKA—9 macroporous resin was researched to establish a mathematic model. The Response Surface Methodology(RSM) was used to investigate the effects of feeding rate, sample concentration and pH on the adsorption properties of macroporous resin and the effects of flow rate, eluent concentration and elution volume on the desorption properties of macroporous resin for apple polyphenols. The results showed that the optimum adsorption conditions were the feeding rate of 1.10mL/min, sample concentration of 2.50mg/mL, pH 4.83. The optimum desorption parameters were the flow rate 0.61mL/min, eluent concentration 59.48%, elution volume 125.73mL. In conclusion, the NKA—9 macroporous resin can be used as the best material to extract the apple polyphenols.

Abstract:The dielectric properties of rap oil, soybean oil, peanut oil, corn oil and well-distributed oil were studied by the open-ended coaxial probe technology over the frequency range from 200 to 4500MHz and temperature from 20 to 90℃. The reasons why relative dielectric constant and dielectric loss factor changed with frequency and temperature were analyzed. The results indicate that the relative dielectric constant of rap oil was maximal and the dielectric loss factor of which was minimal among five oils at the same frequency. However, the corn oil had minimal relative dielectric constant and maximal dielectric loss factor. The good linear relationships between permittivity and saturated fatty acid and unsaturated fatty acid were found over the frequency from 500 to 4000MHz. The relative dielectric constant decreased linearly with increasing temperature, but the loss factor increased linearly. The permittivity of rap oil was affected obviously by the temperature, while the influence was very small to corn oil. The penetration depths of electromagnetic energy in edible oils decreased with the increase of frequency and temperature. This study was useful to understand the microwave dielectric properties of vegetable oils and to further study the effect of edible oil quality based on the dielectric property. 

Abstract:With the aim to solve the drawback on the traditional fructose production from inulin hydrolysis in acidic aqueous solution, the high pressure CO2—water system for the inulin hydrolysis was studied instead of the traditional acidic aqueous solution. The effects of CO2 pressure, reaction temperature and reaction time on fructose production from inulin hydrolysis were investigated. The results showed that the hydrolysis degree of inulin was positively related with CO2 pressure and reaction time, and increased at first followed by decreasing with reaction temperature rise. Under an optimum reaction condition of CO2 pressure 20MPa, reaction temperature 70℃ and reaction time 3h, the hydrolysis degree of inulin reached 94.9%, which implies that the inulin is efficiently hydrolyzed to produce fructose in the high pressure CO2—water system, and the complicated operations and pollution of the traditional acid hydrolysis process were avoided. 

Abstract:Microwave processing technology and equipment were developed to solve the problem of wheat germ’s easily acidification and deterioration, aiming at improving the storage stability of wheat germ and better prepare for its further processing. With this developed equipment, microwaves of different power and processing time were selected to test their respective influence on the wheat germ stabilization. The result showed that processed with microwave of 2.8kW for 4 minutes, wheat germ relative lipase activity is 17.63％, peroxide value is 3.81mmol/kg, acid value is 14.65mg/g，VE loss is 5.29％，NSI is 51.10％，moisture content is 3.72%, and no distinct change in its fatty acid composition and relative content. Furthermore, the equipment developed was tested to be collocated with wheat flour product line with the daily capacity of producing 300t. This equipment effectively passivates lipase in wheat germ, preserves various nutrition, and lengthens quality guaranteed time at the cost of lower power.

Abstract:The antioxidant activity in vitro of onion flavonoids was investigated by measuring its scavenging activity on DPPH, nitrite, its chelating activity on Fe2+, its inhibitory effect on peroxidation of yolk lipoprotein and oil. The results show that onion flavonoids posses strong chelating activity, good DPPH radical scavenging activity and nitrite scavenging activity, significant inhibitory effect on peroxidation of yolk lipoprotein and oil, namely onion flavonoids have good antioxidant activity in vitro. 

Abstract:Wheat starch stearate was synthesized by esterification of wheat starch with stearic acid, and hydrochloric acid was added as catalyzer. The effects of temperature，homogenizing rate and pH value on emulsion capacity and the effects of temperature and shearing rate on viscosity were investigated. Furthermore, the product properties, such as color, transparency percentage, retrogradation, freeze-thaw stability were also determined. The results showed that the emulsion capacity of starch stearate is superior to that of arabic gum, with the similar change trend resulting from pH value. Therewith, the chromatism value of starch stearate was similar to that of arabic gum. As DS (degree of sustitution) increased, the color changed into yellow, transparency percentage enhanced, retrogradation weakened, and freeze-thaw stability fell.

Abstract:0.015m和0.079m。In order to increase the work efficiency, an automatic control system of tractors platooning was developed. A tractors platooning model was established and a platooning control method was designed. Firstly, a reference route for the following tractor was dynamically created from the position points of the leading tractor, and subsequently processed by the least squares fitting method to filter out some noise. Secondly, a feedback path-tracking controller was designed to guide the following tractor along the reference route. Field tests were conducted on a flat meadow. The results indicated that the following tractor followed up the leading one successfully with the mean and RMS lateral deviations of less than 0.015 m and 0.079m, respectively.

Abstract:95％。A new tractor navigation line detection arithmetic, named rotation and projection arithmetic, was put forward. At first, the image ROI rotates a series of given angles and for each rotation the ROI’s column average values were computed. And then the column average values and the enumeration angles compose the rotation and projection matrix R. Through all row vectors difference operation in R the difference rotation and projection matrix Rd was attained by whose extremum values the image navigation line parameters can be found out (including heading angle and lateral position). Finally the world coordinate guidance line parameters were attained by those parameters. By using the same principle the field end line can also be detected. In order to make the arithmetic more efficient, there are four measures to be used: setting appropriate ROI, utilizing linear reducing, starting as rough-divisiory rotation angle and then elaborate-divisiory rotation angle, using the former frame information. Those measures make one frame processing time in 6.2ms or so. Using various mature wheat images testing indicates that the precision rate of recognizing navigation line is up to 95%. 

Abstract:An apple recognition method with color difference R-G and color difference ratio (R-G)/(G-B) was presented.The apples in the images taken under frontlighting and backlighting conditions were recognized. The contour images were gained through the pretreatments such as noise removal, area filling etc. Shape features were extracted from the contour images based on genetic algorithm (GA). For the clustered or overlapped apples, the method of multiple running GA and converting the contour points of every apple into background in turn was applied. The experiment results showed that the proposed recognition method, to a certain extent, eliminated the influence of shade, backlighting and soil. The recognition rate reached 97%. The features extraction method based on GA segmented the clustered or overlapped apples successfully. Meanwhile, the center points and radiuses were quickly and accurately extracted.

Abstract:In order to solve the disadvantage of image segmentation by K-means clustering to extra-green character used to be adopted in agricultural images, an image segmentation method based on the particle swarm optimization and the K means clustering was proposed. Firstly, image pixels value was fast clustered with the K-means clustering. Regarding the results as the position of a particle, PSO can be used and the new class centers also can be re-calculated with the K means clustering. Subsequently,the position of all particles got updated and the optimal threshold was obtained. Experimental results proved that the improved algorithm was an effective method for segmenting the object accurately from images, and applicable for various kinds of agricultural images with extra-green character.

Abstract:96.7%、93.1%。A machine vision approach for the detection of greenhouse cucumbers with near-infrared spectral imaging was presented. Firstly, a spectral image using certain near-infrared wavelength was applied to resolve the fruit information representation within the similar-color background. Secondly, fruit was recognized based on the following steps: region partition according to gray distribution of vertical histogram, optimized threshold of invariable intensity moment on divided local image, noise elimination using specified morphological template. Thirdly, the region for robotic grasping of cucumber fruit was determined by texture feature analysis and the cutting point was located with inertia axis principle. The experimental results showed that the correct recognition rate of fruit is 93.3%, as well as the rates of the grasping point and cutting point within the effective range are 96.7% and 93.1% respectively.

Abstract:0.003。Computer vision analysis and impact excitation frequency analysis were used to construct the duck egg’s intensity model. By the analysis in the CV (coefficient of variation) of the duck egg’s impact excitation frequency and the analysis of the crack egg’s intensity, the threshold value (λ=0.02) which can be applied to distinguish the duck egg intensity at the level of 1MPa (confidence at the level of 95%) was obtained. Then the characteristic variables were entered into the model. The backward elimination procedure was used to perform multi-dimensional linear regression in order to establish the forecast model of the non-crack duck eggs’ shell intensity. Combined with the threshold value which had been obtained, the system model of duck egg’s shell intensity based on the multi-sensor fusion can be obtained. The confirmation experiment indicates that the model had good adaptability on duckeggs with different color and mass, the model shows high accuracy (the mean of forecast error is 3.1%) as well as good stability (the standard deviation of forecast error is 0.003). 

Abstract:Fourier descriptors(FDs) which didn’t change with changes of translation, rotation and scale, and were also independent of the location of the beginning point of the image edge were analyzed. The FDs and Euclidean distance were applied to the recognition of the rice hopper shape. Average discrete degree of sogatella furcifera and rice hopper was calculated to test stability of FDs and coefficients reference value of shape feature was determined. Through 191 sample images tested, it was found that when similarity difference was less 0.0123,error rate of rice hopper was 7.85%. The experiment results indicated that this approach had a good recognition performance.

Abstract:Nonlinearity between exciting current and output displacement spoils magnetostrictive actuators’ performance. Chaotic nonlinearity is an important aspect of nonlinear character for magnetostrictive actuators. To explore the erratic behaviors of the actuators, a nonlinear dynamic model was established. The bifurcation diagrams, Lyapunov exponent, phase portrait, Poincaré mapping diagrams, amplitude spectrum, etc., which demonstrate dynamical characteristics of the system were obtained by numerical integration. Analysis indicates that under the condition of low frequency range, chaos would appear when exciting current is high and stiffness of the system is relatively low. 

Abstract:With the study object of tooth shaped chain board, a precise measurement technology for small parts was proposed using image processing technologies combined with least square support vector for regression (LSSVR). Electric coupling apparatus（CCD）was adopted as the sensor to collect images, single pixel edge information of the undeterminate part was obtained after image preprocessing such as image denoising and image binaryzation, etc. Afterwards, on the basis of structure feature analysis of the part, candidate regions were searched automatically where the coordinates of the points were taken out as training point set to train LSSVR. Then the candidate geometry parameters, such as the included angle between every two lines, diameters of the round holes as well as errors of the two round holes were gained through experiment results. The last two geometry parameters with millimeter unit were obtained through unit transmitting from pixel to millimeter by camera calibration, and the precision can attain the micron level. The experiment showed that the proposed solution has a high convergence speed as along with the high precision and excellent stability.

Abstract:The minimal energy dissipation of ideal velocity profile and the velocity function of general acc/dec algorithms were deduced. Subsequently, according to the relation between the velocity curve and the power dissipation in the motor, the energy dissipation function per step under the S curve velocity was derived, and its minimum was solved with Matlab. It is a new discovery that the optimal velocity can be gained when t1 of trapezoidal algorithm and quadric spline curve is T/3 and T/6 respectively; t1 and t2 of S curve algorithm is 0.01T and 0.32T respectively; t1 and t2 of AS curve algorithm is 0.01T and 0.35T respectively, and R2 is 0.98. At last, the energy dissipation of acc/dec algorithms were calculated under the conditions of different time parameter settings, and were compared with the ideal velocity, more, there were obvious differences in energy dissipations of different algorithms. It is very useful to set the time parameters of acc/dec algorithms and improve the efficient of motor in acc/dec motion control. 

Abstract:In order to improve the efficiency of permanent magnet brushless D.C. motor (BLDCM) driving air compressor, genetic algorithm embed BLDCM module which optimizes the air compressor was put forward. Optimized target of genetic algorithm is the efficiency of BLDCM. Optimized variables are the diameter of low pressure cylinder, the diameter of high pressure cylinder, the journey of low pressure piston, the journey of high pressure piston and the rotate speed of BLDCM. The values of variables were passed to BLDCM module by sim function. Simulation time was controlled by sim function. The efficiency value was passed to genetic algorithm program. Simulated result shows that the efficiency of BLDCM is higher than that before optimized. The experimental result shows that the specific power of air compressor is almost the same as that before optimized at 0.7MPa, but is much less than that before optimized at 2.5MPa. The result also shows that genetic algorithm embed BLDCM module which optimized the air compressor is available and practical. 

Abstract:Aiming at the decision-making problem of process route in a CAPP system, an algorithm based on the genetic algorithm for optimization of process route was illustrated by an example. A machined part was divided into some feature cells machining chains of that were generated by reverse design. Then the preference sequence of feature cells was determined and the objective function was built. A checking program was designed to ensure the validity of chromosomes. The fitness function was built based on the objective function. The operator algorithms of replication, crossover and mutation were designed and the process route were optimized using the genetic algorithm. At last, the feasibility and effectiveness were verified by an example.

Abstract:Two steps are involved to determine transmission ratios of serial robot, i.e. relative proportion of transmission ratios determination and absolute transmission ratios determination, and the former is stressed from viewpoint of manipulability. Based on analyzing the essence of manipulability index related with condition number, the determination of relative proportion of transmission ratios was formulated as optimization of manipulability related to driving space. An optimization model on the basis of global manipulability related to driving space was given to determinate relative proportion of transmission ratios. A method to obtain Jacobi matrix in the optimization model was proposed with consideration of the difference of power elements’ velocity driving capability and endeffecter’ pose velocity of job requirement. At last, an optimization process was conducted to determine relative proportion of transmission ratios of a 6-DOF serial robot, and its global manipulability related to driving space was increased.

Abstract:以前馈型BP神经网络进行双目立体视觉系统的摄像机标定研究，基于Harris角点提取，提出了增加约束的改进方法，从而提高网络训练样本集的数据精度；探讨了神经网络的欠泛化、过泛化问题，综合运用归一化、提前终止等多种策略，进一步提高网络泛化能力，并与经典标定方法进行对比。试验结果表明，该方法能够获得较高的摄像机标定精度。

Abstract:As a driver of piezoelectric pump, the vibration performance of piezoelectric actuator influences the performance of piezoelectric pump. There are a number of factors which influence the vibration performance of piezoelectric actuator. Therefore, in order to improve the vibration performance of piezoelectric actuator, it is essential to optimize the structural parameters and materials. Based on the finite element simulation analysis method, an orthogonal scheme of four factors and three levels was designed. Through the range analysis for the result, the influencing order of each influencing factor on two important indexes that are the oscillation amplitude and resonance frequency of piezoelectric actuator were acquired. Simultaneously, the superior schemes were obtained. Because the superior schemes were not in the original design schemes, additional designs were made and contrasted. Finally, the optimal scheme was obtained. 

Abstract:In order to keep drill out of breaking in the micro-drilling process, a real time monitoring and controlling system for micro-drilling was built based on virtual instrument technology. The system took IPC as main controller and used the Holl current sensor to monitor the spindle motor currents. The sampled data were processed by software written in LabVIEW language, which the functions such as the virtual oscillograph, the virtual spectrum analyzer, the digital filter etc. were implemented. In the experiment taking the spindle motor currents as monitoring objective, the monitoring and controlling threshold was determined according to the relationship between the failure distribution function and the reliability function of the drills. When the monitoring value exceeds the threshold given, the feed motion is forced to backward and a warning is given to indicate tool changing. The experimental result shows that the system together with monitoring and controlling method is able to effectively avoid drill breaking and increases the usage of the micro-drill.