Abstract:With the analysis of vehicle longitudinal dynamic model, a modified recursive least squares for online estimation of vehicle mass and generalized slope was established. Compared with the recursive least squares of single forgetting factor, the modified algorithm had better performance in estimation of parameters with different change rates. On the base of that, the self-adaptive gearshift strategies of uphill and downhill slopes were developed. The vehicle road test results indicated that these strategies could improve the slope traveling performance of automatic transmission and overcome the problems encountered by traditional gearshift strategy travels on slopes. 

Abstract:Control method for traction control system of conventional internal combustion engine vehicle is not suitable for hybrid electric vehicle. The traction control system of hybrid electric vehicle should be redesigned. Hierarchical traction control system for ISG hybrid electric vehicle was proposed. In the top layer, desired traction total torque calculation strategy was used based on dynamical sliding mode control. In the middle layer, design algorithm of target engine torque based on low pass filtering and dynamic coordinate control strategy based on model matching 2-DOF control were developed. In the bottom layer, exit strategy based on dynamic compensation was proposed. At last, tests of simulation and hardware-in-loop were performed to verify the control system. Results of simulation and test showed that the proposed hierarchical traction control method for ISG hybrid electric vehicle could control the slipped wheels quickly and accurately to realize the traction control function of ISG hybrid electric vehicle effectively. 

Abstract:According to the testing requirements of tractor power shift transmission, a power shift transmission test bed for large-scale tractor was designed. The power shift transmission, drive motor, loading motor and energy feedback system were designed. The electronic control unit and electronic measurement system were developed. The overall scheme of tests for power shift transmission was determined and tested. The test results showed that the power of proposed test bed was up to 250 kW. A closed-loop feedback of energy was achieved thus energy-saving rate in overload operating conditions reached to 80%. The input speed and torque, output speed and torque, hydraulic system flow and pressure could be tested with the system. The test bed was operated steadily and could meet the design requirements.

Abstract:In order to avoid modifying vehicle body repeatedly in the later design stage, the multi-objective optimization module in vehicle concept design intelligent CAE system (VCD-ICAE) was developed. A multi-objective optimization algorithm was designed with the objectives of body structure stiffness and modal. The whole body structure performance could be improved on the premise that mass of body didn’t increase. The basis for realization of body lightweight in concept design stage was provided, so the time and cost were economized. Combining concept design process of a concrete body model, the multi-objective optimization was carried on. The bending stiffness, torsion stiffness, first bending frequency and first torsion frequency of body were increased. The validity and correctness of the proposed multi-objective optimization module was verified.

Abstract:There are many uncertain factors in the design of multi-disc wet brake. Considering of that, optimization design was applied with physical programming. Results of physical programming were compared with the traditional linear weighted-sum optimization. It is feasible to apply physical programming method to uncertainty optimization design of multi-disc wet brake. It meets the actual needs better than the linear weighted-sum method.

Abstract:In order to study the working characteristics of mining face-shovel hydraulic excavator with bucket capacity of 15m3 and machine weight of 260t, which is currently the largest tonnage of hydraulic excavator, co-simulation method of the dynamics of mechanical systems and hydraulic systems to the small excavator was authenticated. Then, by comparing the results of test and co-simulation, it was confirmed that co-simulation method could accurately simulate the practical working environment of excavator. On the base of before-mentioned research, mechanical devices and hydraulic systems of mining hydraulic excavator which bucket capacity is 15m3 were carried on with the help of ADAMS and AMESim software. Through simulation the rotation inertias of various parts of working mechanism to its rotation axis during working process were calculated. The displacement curves, velocity curves, force curves of each hydraulic cylinder and the excavating trajectory of bucket tooth crest could be obtained through co-simulation.

Abstract:In order to improve power density of vehicular hydrodynamic transmission components, with the aspect of structure design of cascade system, a blades design method for flat circular circle was put forward. Based on the analysis of constraint conditions and design streamline of traditional circular circle, the flatness ratio could be changed from 0.31 to 0.19 with only three parameters of effective diameter D, minimum diameter d0 and width limit Wlim. Besides, the program was rapid and convenient. Compared with traditional hydrodynamic components, the working volume obtained by flexible flat circular circle could be compressed to 40.9% with the same maximum diameter D and minimum diameter d0. The power density of hydrodynamic components was improved effectively and meanwhile traditional circular circle design method was simplified distinctly.

Abstract:Fractal characterization is an effective way to investigate the soil surface roughness. An appropriate fractal dimension computation method is critical to obtain the accurate results. Four methods commonly used for computing the fractal dimensions were evaluated by using the W—M fractal profile curves. The results showed that the mean-root-square method had the highest accuracy in describing the soil surface roughness with fractal dimension between 1.2 and 1.6, it had a good adaptability in characterizing the real measured soil surface roughness. Based on the fact that the mean-root-square difference of surface roughness was proportional to the section scale, the mean-root-square method was improved. Compared with the theoretical curves, the new method showed a higher accuracy and provided a new method for describing the complex characteristics of soil roughness.

Abstract:Aiming at the seed-dropping problems of clamping cotton-seeds precision dibbler due to vibration in operating, the seeding devices of the dibbler were improved. A seed retaining equipment was designed and installed on the dibbler. Mathematical models that described relationship between the performance indexes and influence factors of the seeding devices were established by applying quadrate regression experiment with general rotary design method. The tendency and regularity of the performance indexes influenced by the factors were analyzed. For the Xinluzao—26 cotton seed, with a goal of maximum single seed index and a given range of multi-seed and missing seed index, length of the clamping boards of the seeding device’s jaw were 4.50mm, width of the jaw were 5.70mm, and opening of the jaw was 7.50mm by parameter optimization. The experiment results showed that the effect of operating vibration was reduced on the improved dibbler.

Abstract:With the transmission characteristics of non-uniform velocity transmission and the wide range of transmission ratio for deformable elliptical gears, a new type of rotary transplanting mechanism was designed. It was used as the main transmission part of the transplanting mechanism. The new transplanting mechanism could develop the narrower plant hole so that upright growth of rice seedlings could be ensured. Secondly, the work principle of the proposed mechanism was analyzed and the kinematic model was established. Dynamic simulation and parameter optimization software were developed with VB language. The optimized parameters, optimized objections and main structure parameters were displayed in this software. Meanwhile, the optimized results were digitized. By the interaction in human-computer, the best structural parameters were obtained to satisfy the work requirement of the rice transplanter.

Abstract:A rotary transplanting mechanism with planetary elliptic gears used to transplant seedlings for automatic vegetable transplanter was described. Work principle and structural features of the mechanism were analyzed. The kinematics model was established. Based on Visual Basic 6.0, the software of aided analysis and parameters optimization for rotary transplanting mechanism were developed. Kinematics property was analyzed and simulated. Though conversations in human-computer, structural parameters of the transplanting mechanism were optimized and meet the demands of transplanting seedlings. Finally, 3-D mechanism model and simulation analysis were carried out, and the results of simulation accorded with theoretical analysis.

Abstract:A finite element analysis model of the clod crushing rake tooth in field cleaning machine was built by the non-linear finite element analysis method. Based on the analysis of strength and rigidity, the bearing forces and distortion of the rake tooth in work were predicted. Compared with the simulation results, the prediction results calculated by finite element analysis model showed confident with the simulation results and reliable in the design and assessment of rake tooth.

Abstract:Aimed to the problems revealed in latest grassland tests of the 9ST—460 vibration spacing scarifier, optimizations were carried out on the transmission mode of the parts, vibrating and loosening components. The results of comparing test indicated that the improved device ran steadily and showed good performance. The bulk density of soil decreased but water content increased after scarifying. The yearly average economic benefit increased by 155RMB/hm2 in next 3 years after scarifying, which well fulfilled the requirements of grassland improvement procedure.

Abstract:The droplets velocity in spraying fan of flat fan nozzle LU120—03 was tested by phase Doppler particle analyzer (PDPA). The initial velocity was liquid-sheet velocity and the velocity distribution in spraying fan was confirmed. The results showed that the velocity of minimum droplets in spraying fan edge was lower than that in central position near the nozzle, so it was more likely to drift; the fine droplets velocity decreased rapidly far away from the nozzle so that the droplets were very easy to result in drift influenced by airflow. 

Abstract:To improve the drawbacks of original designed air-assisted duct of boom sprayer, such as huge wind consumption, low efficiency, large coefficient variation (CV) of wind velocity, 3-D flow field of interior duct and exterior free flow region was simulated by using computational fluid dynamics (CFD). Flow field analysis of the simulation results showed that there were strong swirling and narrow flow channel in the flow field of prototype air-assisted duct. It also resulted in large CV in exterior free flow field. In response to these shortcomings, two kinds of improvement designs were proposed. Firstly, the outlet size and outlets spacing was decreased to greatly reduce the CV of wind velocity, but could not fundamentally change the flow structure. Secondly, on the basis of above optimization, a flow deflector was added to overcome the strong swirling flow and narrow flow channel. Prototype testing indicated that final scheme achieved high efficiency and small wind speed variations.

Abstract:Flour method is extensively used in the sprinkler droplet size measurement. The traditional calibration equation only considered the relationship between dried pellet mass and droplet diameter. The effects of droplet diameter, droplet impact angle and impact velocity on dried pellet mass were discussed through the orthogonal test. The results showed that droplet size and impact angle had significant influences on dried pellet mass while droplet impact velocity had little influence. A modified calibration equation considering two factors of droplet size and impact angle was established. The modified calibration equation had high calculation accuracy compared with the traditional one. The method of measuring sprinkler droplet using the modified calibration equation was presented with the application of the droplet dynamics-evaporation model.

Abstract:Aiming at exiting problems of flowers and leaves as well as the nutrition loss by using the dry harvesting technology process in field for forage grass, the introduction for the wet harvesting technology process innovation and its advantages of forage grass in different views was gave, such as technological theory and technological process. And in order to provide technical support for forage grass dimension mechanization desiccation by using solar energy, one type of solar energy bale drying machinery was developed. It could work in solar automatism collection manner and dry the bale of moisture content in around 40%. Products could be directly baled and stored. The performance test of the equipment and the dry grass and wet harvest were experimented. The tested results were listed as follows: solar drying forage loss was less than or equal to 2%, finished bale moisture content was less than or equal to 17%. The collector efficiency of solar energy air was more than or equal to 50% and handling ability was more than 1t/h. 

Abstract:With innovation cotton 958 cotton stalks as test material, shearing, compression and bending mechanical tests of cotton stalk in harvesting period were carried out in the universal test machine. The results showed that when the sample moisture content was in 30%~50%, the compressive intensity and shear intensity at the bottom and middle of cotton stalk was lesser, the intensity value were 1.66~3.13MPa and 0.74~1.12MPa, respectively. Cotton stalks bending intensity decreased with its moisture content increased. The bending intensity values of samples at the bottom was 4.20~5.08MPa. In the test of shearing, compression and bending, the consumption power of the sample was 2.98~4.32N·m, 2.91~4.34N·m, 1.51~4.18N·m, respectively.

Abstract:Based on the fact that corn circulation layer affects the grading performance in the working process of the hammer mill, piecewise arc-shaped screens were designed for substituting the circular-shaped screen. In order to improve the grading performance of hammer mill, the space between the hammer and screen was changed repeatedly, and the corn circulation layer was destroyed. 15 kinds of piecewise arc-shaped screens were designed for the 4KB hammer mill. The experimental study indicated that the hammer mill with the screen piecewise arc radius of 76mm and the space between arcs of 97mm had the highest production efficiency. Compared with flat circular-shaped screen, the production efficiency and power output in every kW·h increased by 29.8% and 26.6%, respectively. The over grading phenomenon was improved. Particle size of the corn was uniform and the temperature rise of the corn was decreased. 

Abstract:The results from biomass gasification in a pilot-scale (6m tall×0.2m internal diameter) air-blown circulating fluidized bed gasifier was tested and compared with bubbling fluidized bed gasifier. The results showed that the diameters of bed material in bubbling fluidized bed and circulating fluidized bed were different. The bubbling fluidized bed had a dense zone and bed material was homogeneous distribution in circulating fluidized bed. The temperature of the circulating fluidized bed was more uniform than bubbling fluidized bed. The carbon conversion rate, gasification efficiency and low gas heat value of circulating fluidized bed were larger than that of bubbling fluidized bed gasifier.

Abstract:Pig dung and wheat straw (the ratio of pig dung to wheat straw was 1∶1, 2∶1, 3∶1)were used as fermentation materials. The experiments were carried out at 35℃. The biogas production rate, cumulative biogas yield, methane content, material reduction, pH value and NH3-N content were tested. The results showed that the co-digestion of pig dung to wheat straw could increase the biogas yield and material reduction of wheat straw. The biogas production yield of 1∶1 was highest (383.0mL/g), which was 1.6 times of biogas production yield of wheat straw (231.8mL/g). VS reductions of combination materials were 12.0%～26.9% higher than wheat straw. Compared with wheat straw, the NH3-N contents of combination materials increased by 35.6%～64.8%. Reasonable co-digestion ratio of livestock dung and crop straw could increase the biogas production rate and utilization of crop straw.

Abstract:In order to improve the efficiency of two-stage anaerobic fermentation system, the circulation process of sludge, composed of the activated sludge online and the activated sludge of the optimal period from storage tanks, was studied. Three factors, including feed concentration, day feeding quantities and sludge recycle ratio, were selected as independent variables, while COD removal rate and biogas production amount were as evaluating indicators. With the quadratic orthogonal rotating combinatorial method, the effects of different parameters on COD removal rate and biogas production amount were analyzed. The results showed that feed concentration, day feeding quantities and sludge recycle ratio were main influencing factors on two evaluating indication, and the mixed sludge recycle ratio had a significant effect. For the anaerobic fermentation system, the optimum parameters of process were feed concentration of 8.21%, day feeding quantities of 7.15L/d and sludge recycle ratio of 30%, respectively.

Abstract:The change of respiration rate of Agaricus bisporus , packed in film, with storage time was studied at the storage temperature of 5℃、10℃、15℃、20℃ and 25℃. The results indicated that the mushroom respiration rate showed a significant decrease with increasing storage period until dynamic equilibrium. A respiration model of Agaricus bisporus, based on Langmuir adsorption theory, was proposed at different temperatures. The results suggested that the mushroom respiration rate increased with increasing of O2 concentrations, and decreased with increasing of CO2 concentrations. The maximum rate increased with temperature, and the relationship between maximum rate and temperature was well described by the Arrhenius equation.

Abstract:The effects of 4kJ/m2 UV—C irradiation on main qualities and antioxidants of tomato during storage were investigated. The experimental results indicated that 4kJ/m2 UV—C irradiation maintained a high level of firmness and delayed the color development, significantly promoted the accumulation of phenolics, flavonoids and lycopene, increased the antioxidant enzyme activities of CAT, SOD, APX and GR, consequently showed higher antioxidant ability during storage. The results suggested that UV—C irradiation had the potential to apply on extending the shelf life and enhancing antioxidants of tomato fruit. 

Abstract:The extraction technology and antioxidant activities of the bioactive components from Terminalia chebula Retz. were studied. The results showed that the optimal parameters of the extraction technology were that the concentration of ethanol was 50%, the ratio of extraction solution to sample was 20, the extraction temperature was 60℃, the extraction times was 4 and the extraction time was 7min. The crude extracts from this plant were proved to have strong antioxidant activities through the results of the reducing power, the FRAP assay and the DPPH radicals scavenging percentages. The bioactive antioxidants of Terminalia chebula Retz. were mainly laid in the ethyl acetate fraction based on the bioassay-guided method. The OD values at 700 nm (reducing power)，FRAP values (OD593nm) and DPPH radicals-scavenging percentages of this fraction with the concentrations of 25 and 50μg/mL were 0.197±0.002 and 0.380±0.006, 0.272±0.023 and 0.631±0.002, (86.838±0.600) % and (90.318±0.917)%, respectively. The correlation showed that the strong antioxidant activity mainly resulted from the high contents of total phenols and total flavonoids.

Abstract:In order to increase the yield of sea buckthorn leaves flavonoid aglycones converted from flavonoid glycosides by the enzyme-Pectinex Ultra SP-L, on the basis of single-factor test, response surface analysis method was used. Hydrolysis time, hydrolysis temperature and pH value were chosen to be independent variables. The value of flavonoid aglycones quality was regarded as the response value. The results showed that the hydrolysis time was a significant effect factor and hydrolysis temperature and pH value had no significant impact. The optimum conditions for enzymatic conversion were hydrolysis temperature of 50.8℃, pH value of 5.16, hydrolysis time of 2.5h. Under those conditions, the total aglycones quality obtained from 15mg sea buckthorn leaf extract was 0.1801mg and the conversion rate to flavonoids aglycones was 62%.

Abstract:The reflectance spectra of 189 samples within 450~2500nm were collected. Firstly, the spectra were denoised using the orthogonal wavelet functions sym8 (level was 3). And then the spectra variables were compressed to 14 variables by successive projections algorithm (SPA). The MLR model with 14 variables as inputs could result in that prediction correlation coefficient was 0.8855 and prediction root mean square error was 0.5111. Then the group of wavelengths derived from SPA was screened by their contributions to the total sugar content. After screening on contribution, the number of wavelength variables dropped to 11. Finally, the MLR, PLS and BPNN calibration models were built with 11 wavelength variables as inputs and compared. The results demonstrated that wavelength variables were decreased to 0.54 % of the original variables by SPA and screening on contribution, and this could help to make the model more concise and robust. 

Abstract:In order to offer a meter with the characteristics of easy taking,quickly measuring, high precision, being suitable for online detection, and overcoming influence of temperature on measurement for honey water content detection, based on the experiment and electrical conductivity detection principle, a honey water content meter was designed. Firstly, yellow-locust honey was used to establish the mathematical model among water content (17%~34%), temperature (5~40℃) and electrical conductivity. Then the hardware was designed with single chip micro-computer (SCM) of 8 bits as controller, DJS—1 electrode and DS18B20 as sensors of electrical conductivity and temperature, respectively. The software was programmed with C language of SCM. The detection results showed that the measurement time of one sample was within 3s and the precision was ±0.5%.

Abstract:For the white noise always embeds in signals of gas sensor array, there must be bad influence on the accuracy and reliability of test results while micro or trace organophosphorus pesticide residues in vegetables detection. To solve the problem, acephate and phoxim were selected as test object. A denoising method of gas sensor array signals based on wavelet packet decomposition and reconstruction was practiced. With the help of principal component analysis (PCA) and Fisher discriminant analysis (FDA), the identification results of different concentrations corresponding to the two kinds of pesticide residues were explored and compared, respectively. The results showed that the different concentrations samples corresponding to acephate and phoxim were all well discriminated after the gas sensor array signals treated by the wavelet packet denoising. Therefore, the wavelet packet denoising method could improve identification effect of pesticide residues in vegetables using gas sensor array.

Abstract:The image denoising variational method possesses higher numerical precision but lower computational efficiency, especially in processing the remote sensing images which is usually larger. To this problem, an adaptive 2-D wavelet interpolation operator was constructed based on quasi-Shannon wavelet function, and then adaptive wavelet precision integration method (PIM) on solving 2-D partial differential equation was proposed by combining with PIM. This proposed method combined the multi-scale property of the wavelet transformation with the higher precision of PIM, which could improve the computational efficiency effectively so that the lager remote sensing image could be processed.

Abstract:The object-oriented classification approach was employed in loess hilly-gully region. Taking typical watershed Yan’gou as example, ALOS satellite images were used. The object-oriented multi-segmentation was carried out with multi-spectral, panchromatic imagery, auxiliary data of digital evaluation model (DEM) and the normalized difference vegetation index (NDVI). The land-use categories closely related to ecosystem restoration, farming and living, such as forest, grass, farmland, orchard, settlement and water, were classified with thresholds. The classification results had promising accuracies, and the overall classification accuracy was 77.73%.

Abstract:Acoustic emission (AE) signals of tomato plants were collected with AE signal detecting system. The collected data were processed and analyzed by using the upper machine software. By statistical analysis on changing of AE signal count with tomato late blight disease stress level, it was concluded that the plants with AE signal would not occur in physiological cycle like healthy plants. In the prophase of blight disease, the AE signal frequency dramatically increased, but decreased slowly in the crop disease progress. The multi-peak phenomenon emerged. Then, noise source location could be identified with time difference between two sensors and changing frequency distribution between different signals.

Abstract:In order to realize the geometric modeling of plant flowers of crown united, taking tobacco flower as an example, a flower modeling method based on ball B-spline curve and parametric surface was proposed. Morphological characters were analyzed. Firstly, 3-D shape of each parts with mathematics were described and the control parameters were get. And then, visualization of them with relative color and topology information were realized. The results showed that proposed method could effectively simulate tobacco flower with good controllability. The models showed more reality, which provided a new technique for explicit modeling of other similar flowers.

Abstract:An optimal feature subset selection method based on improved ant colony algorithm was presented. The initial probability of the feature was related to the ability of classification of the separate feature, which was advantageous to reduce the redundancy and the hunting zone of the optimized algorithm at the same time. Section variation of the feature set avoided local convergence. Experimental results indicated that the proposed algorithm further reduced the search time, got a smaller subset of the optimal feature set of cotton fibers and better classification performance. The classification accuracy rate increased from 84% to 93%.

Abstract:Using the winter wheat in North China as research object, AquaCrop model was applied in different technology of irrigation, included drip irrigation, sprinkler irrigation and furrow irrigation. The main parameters like soil and crop characteristics and so on, were adjusted. In addition, the effective simulation method for crop yield and biomass was researched. The study showed that some simulated values like yield and biomass of soil were significative. The relative error (RE) was low. Simulated data was a little higher than the observed one. All of the modeling efficiency (EF) was more than 0.95. The modeling was better for yield than that for biomass. The modeling was also the most efficient for drip irrigation in the three kind of irrigation technology.

Abstract:In order to reduce herbicide dosage and automatic precise weeding in cotton fields，a variable target weed spraying system uses fuzzy control algorithm with processor core of S3C2410 was designed. This system achieved automatic weeds identification, system speed and flow information collection, flow and pressure adjustment and other functions. A dual-input single-output fuzzy controller was designed and simulated. Simulation results showed that the controller could control the amount of spraying with the speed and density in real-time changed. An indoor test bed which could simulate cotton environment was built and the spraying system was tested. The results showed that over 90% weeds were sprayed with speed of 0.2m/s.

Abstract:CH4 emissions from liquid pig manure stored in under-floor pits were investigated using an empty full-scale pig house in Denmark in winter season. The experiment designs were three manure depths of 0.15, 0.40 and 0.65m, four ventilation rates of 211, 650, 1852 and 3088m3/h, and with or without pit curtains. The three parameters that explained most of the variability of the CH4 emissions were manure temperature, manure depth and ventilation rate. There were no significant differences in CH4 emission rates among four ventilation rates with diffuse ceiling inlet and negative pressure exhaust. However, the lower manure temperature could reduce CH4 emission or compensate the effects of higher ventilation rate. CH4 emission rate reduced with decreasing manure depth in pit. No significant differences in CH4 emission rates were found by using manure pit curtains. The emission rates were more sensitive to manure temperature than to manure depth and ventilation rate due to higher sensitivity percentages. At the lower ventilation rate and manure depth ranges, the emission rates were more sensitive to ventilation rate change compared to the higher ones. However, the contrary sensitivity responses for different manure temperature ranges were obtained.

Abstract:The curvature stagnation point curve would degenerate in two straight lines, when the given Ball point was located on the fixed bar and an instantaneous center coincided with a fixed pivot. A random bar laid on the vertical straight line would produce an approximate straight line mechanism. The synthesis formulae and figures of crank linkages solution region on the coordinate plane, based on crank linkages analysis, were presented. Some useful conclusions were obtained by analyzing special points in the solution regions. According to different design demands, the corresponding evaluating functions were adopted in order to calculate the feasible solution region and the optimal mechanism solution automatically. The proposed method was visual and automatic. Both the blindness of choosing optimal mechanism and the lowness of design efficiency were overcome observably.

Abstract:6—UPU electric platform was analyzed considering of the different points of the structural type. An integrated dynamic model of 6—UPU electric platform was built and written to general form based on kinematics analysis, considering of centroids of electric actuator deviating the axes of themselves and snail-mechanism going around the axes of themselves. Taking the heavy load electric platform with low speed as example, both integrated and simplified dynamics model were emulated and analyzed. The reasonability of the simplified condition of dynamics model was verified. The error tolerance was within 1% to 2.2%. A numerical example showed that this model had universality for the move platform of the similar mechanisms.

Abstract:Based on the different geometric design and calculation of involute internal gear pair, the calculation methods and applicability of involute internal gear pair with few teeth difference were presented when using different processing methods, including hobbing, gear shaper and wire cut EDM, and different top gaps. The influenced factors such as modification coefficient, engaging angle, contact ratio and the interference of tooth profiles were investigated via different calculation methods of addendum circle diameter. To meet the constraints of contact ratio and tooth profile interference, modification coefficient and the minimum angle of engagement were obtained by using Newton’s iterative method through different calculation methods of addendum circle diameter. The calculation results indicated that under the restrictive conditions of contact ratio and tooth profile interference, regardless of hobbing or gear shaping process, angle of engagement and modification coefficient of the top gap of mixed mode of involute internal gear pair with few teeth difference were smaller when obtaining the minimum engaging angle.

Abstract:Damping estimation is difficult as a result of modal interference existing in closely spaced modes, a combinational method of inner product calculation and iterative algorithm was presented. Firstly, resonant frequency of the topmost spectral peak was counted by the application of FFT-FT. Secondly, inner product was conducted between response signal and the constructed exponential function. According to the theorem of Cauchy-Schwarz inequality, the attenuation coefficient was achieved by calculating the maximum of the inner product module, meanwhile, the amplitude and phase of the corresponding modal signal were obtained. One modal signal could be estimated from the above calculations. Thirdly, the estimated signal was subtracted from the overall response signal, and then estimated the next modal signal. In this way, an iteration process was formed by repeating the above diagnosing procedures, which could solve the modal interference. Both simulation calculation and experiment were conducted to validate the method.

Abstract:During the process of quality assessment, aiming at the dynamics of measurement error and the two kinds of decision mistakes, namely accepting a defect and rejecting a qualified component, an online assessment strategy of component quality was proposed. Dynamic measurement process analysis and Bayesian minimal cost decision rule were combined to evaluate the quality of components. A Kalman filtering model for dynamic estimation of systematic measurement error was established and the adaptive windowing approximation method was adopted to online adjust the variance of dynamic random measurement error. In the decision process, Bayesian minimal decision cost method was used to evaluate component quality and the decision confidence was provided as well. Finally, by taking the rotor dynamic balancing process as an example, the proposed method was validated. The results indicated that this method could trace the change of measurement error, decrease the risk of the two wrong decisions, and improve the reliability of quality decisions.

Abstract:To solve assembly optimal tolerance allocation for composite dimensional and geometric tolerances on the basis of Jacobian-torsor tolerance model, a nonlinear optimal tolerance allocation model was established aiming to minimize the total manufacturing cost. First, the accumulated assembly error was calculated based on spatial dimension chains propagation in tolerance model. The assembly functional requirement was regarded as constraints of optimization model. Optimal dimensional and geometric tolerances could be obtained by genetic algorithm. A gear pump assembly was used as a typical example for testing the proposed method. The obtained results were guaranteed to minimize processing costs while satisfying the product assembly quality at the same time.

Abstract:Based on the piezoelectric driver, a macro-micro dual drive precision positioning system was designed. The macro stage of the system was drove by servo motor. The micro stage was consisted of piezoelectric driver and flexible hinge, and drove by the former. The micro stage was mounted on the macro stage and showed a series connection. The macro stage and micro stage were used to realize large workspace and compensate the error of position, respectively. With the open serve control of motion control card, the control system of macro motion and micro motion was harmonized. The positioning feedback was realized by two high precision optical grating. The precision detection was completed by laser interferometer. In the whole closed loop control system, the micro stage compensated the position error when the macro stage finished moving. Experiment results showed that within the travel range of 100mm,the position error in every millimeter was less than ±100nm.

Abstract:Diameters of morphology zones of crater processed by femtosecond laser were measured in the range of laser fluence from 0.108J/cm2 to 28.68J/cm2. Thermal melting on the surface of a hole and the heat conduction rule were studied. The melting zones were calculated according to the traditional thermal conduction formula. The calculated results matched with the experiment results very well. It suggested that the thermal diffusion in super power femtosecond laser micromachining was inevitable. Besides, reasonable parameters were acquired for the better quality of the micro-holes.

Abstract:This paper presented a fast forward algorithm for 3—RPS (revolute-prismatic-spherical) parallel mechanism. Based on the structure feature of 3—RPS parallel mechanism, firstly, a group of position and orientation coordinates were calculated as the initial value, then the coordinates of each hinge fulcrum on the platform by means of reverse algorithm were obtained and adjusted. No derivative operation or Jacobi matrix inverse operation was needed in proposed algorithm. It effectively reduced the computational load, and the formula was simple. In the same computing environment, the calculation experiment results showed that the amount of programming of the proposed algorithm was only 40% of the existing algorithms, the calculation speed of the proposed algorithm was about 1.5 times of the existing algorithms to achieve the same accuracy. It can be applied to online control. 