Abstract:0.8s。 Conventionally, the start-up control strategy of dual mode CVT has focused on obtaining maximum output power of the combination of engine and torque converter; however, this strategy did not pay attention to the efficiency of the metal V-belt unit, which also influenced the start-up characteristics of the system. A start-up control strategy considering both TC and metal V-belt efficiency was proposed. An optimal algorithm was developed to calculate the target CVT ratio in order to obtain maximum driving power with consideration of both TC and metal V-belt efficiency. Simulation and experimental results indicated that, when lock-up speed was 30 km/h and start-up throttle opening was 20%, working time of the TC during the start-up process was reduced by about 0.8 s after the optimization.

Abstract:A method for dynamic performance optimization of continuously variable transmission speed ratio control valve based on improved particle swarm optimization algorithm is presented. First at all, a dynamic model was set up by means of mechanism analysis to predict the valve dynamic performance. Then, an objective function for optimization was established considering dynamic performance indices of speed ratio control valve such as response time, overshoot and saving energy based on its operating requirements. Finally, the optimization problem was solved by using an improved particle swarm optimization algorithm with necessary constraints. The properties of the optimized valve were compared with the prototype workpiece, and the results indicated that the dynamic performance indices of the optimized valve were much better than those of the prototype workpiece.

Abstract:Based on fuzzy control and PID control, a new type of fuzzy self-tuning PID controller was designed. The controller worked for synchronization control of hydrostatic transmission with dual pump and dual motor, which was used to drive a high speed light duty tracked vehicle. The results of simulation and tests showed that during straight running, the controller could restrain the motor speed error effectively when suffering different load disturbances, meanwhile it could get good synchronization results and the synchronization control was quite robust. The new control system is better than common PID control and is suitable for high speed tracked vehicle hydrostatic transmission.

Abstract:To overcome the limitation of traditional absorber systems with invariable damping and stiffness characteristics which can only achieve good absorbing performance under designed conditions, a new absorber based on two magneto-rheological (MR) dampers was proposed to realize the variable damping and stiffness characteristics. As the first step, the theory of variable damping and stiffness characteristics of the proposed absorber was analyzed, and the adjustable range of variable damping and stiffness was also analyzed. Then an adaptive controller based on the energy principle and skyhook control was developed. Finally, a numerical simulation was performed to validate the proposed absorber and the controller. The simulations show that the absorbing system based on the MR absorber could greatly reduce the peak impact load of sprung mass with smaller stroke of absorbing system. Moreover, it has better performance than passive absorbing system, which shows that the absorber based on MR variable stiffness and damping is feasible in practice.

Abstract:The temperature field of damping buffers for viscoelastic suspensions mounted on crawler vehicles was analyzed under typical working conditions. The temperature correlation of the material was ignored to decouple the structure-thermal coupling field. The analytical results of structure were used as the basic conditions for thermal analysis. Because of nonlinear and large deformation under load, the temperature field was calculated by finite element method (FEM). The positions of local hot spots and temperatures under typical loads were obtained by computation. The curves of temperature against factors and its fitting equation on engineering applications were also determined. The results provide reasonable parameters for damping buffers structure optimizing.

Abstract:Based on flow control valve and pressure following element, an improved interconnected hydro-pneumatic suspension was presented. The suspension system achieved rigid-flexible status switching smoothly through effective combination of flow control valve and pressure following element, lifting synchronization of heavy construction vehicle was finally realized. Hydraulic system simulation model of interconnected hydro-pneumatic suspension was established in AMESim and simulation analyses for synchronization performance were carried out at variable load conditions. The test bench was set up and the experimental research was performed. Experimental results showed that synchronization error was less than 2.5 mm in the lifting process and suspension cylinder did not appear jitter when rigid-flexible status switching. The agreement between the simulation results and the experimental data proved the feasibility of the improved interconnected hydro-pneumatic suspension and the accuracy of the simulation model.

Abstract:The surface elevation of a tilled field shows both oriented and random morphologies. Based on stochastic process theory, the temporal variability of the tilled surface roughness over time fulfills the ergodic property. Characterizing the temporal/spatial variability of the tilled surface by using different indices is beneficial in assessing the tilled quality, studying soil water movement, and for optimal management of agricultural field. Therefore, interpretation of various roughness indices has become a focus in precision agriculture worldwide. In this general review, a broad discussion of soil surface roughness that contains multi-scale models, multi-factor analysis on temporal/spatial variability, and direct or potential utilities in agricultural activity was provided.

Abstract:A plate sinkage test was conducted on remolded soft soil with small-sized plates to determine the effects of plate size, soil moisture content, soil bulk density and the diameter of sampling cores on the soil bearing capacity. Curve fitting on the resultant data revealed a 2nd order polynomial model of remolded soil bearing capacity. Further analysis on the fitted equation revealed a trend of logarithmic variation of each coefficient of the model with moisture content, a linear trend with soil bulk density, a logarithmic trend with the coupling of density and moisture content. The change of core diameter led to a shift of sign of the second order coefficient. A trial test on the field soil also showed a 2nd order trend of the bearing curve.

Abstract:Aimed at the specialties of infiltration head higher and varying under the condition of water storage pits irrigation, numerical model of 3-D infiltration and the soil moisture movement of complicated boundary conditions in water storage pits was established. ADI method and Gauess-Seidel iterative method were used in numerical simulation followed by verification tests. The results showed that the calculated values were in accordance with the experimental results. This indicated the numerical model was correct and the method of solution was feasible.

Abstract:Research was carried out to determine the compensation effects of water stress and rewatering on the structure of rice canopy by pot and test-pit experiments. The results showed that water stress inhibited the number of leaves and leaf area, and effectively induced the rice canopy structure that was beneficial to the compensation effect of post-drought watering. By post-drought watering, the panicle nodes were elongated, senescence speed of leaves was restrained, and rice adaptabilities to next drought were increased. The compensation effects of rewatering are best after heavy drought at late stage of seedlings and light drought at early stage of jointing. Continuous drought by two rice growth stages and heavy drought at jointing stage should be avoided.

Abstract:The Bayes method sampling plan of water saving irrigation products was established by using the prior data and experiment. The Bayes sampling plan results of plastic pipes, microirrigation emitters and rotating sprinkler were collected and showed the sample decrease ratio E mainly had a relationship with prior product qualified ratio variance S2R and average Ra. In normal lot it was less than 1200, if S2R=0.002 and Ra=0.95, sample decrease ratio of plastic pipes and micro-irrigation emitters was higher than 62%, also sample decrease ratio of rotating sprinkler was higher than 85%. Compared with normal sampling plan, the Bayes sampling plan could reduce the sampling number more than 20% in the condition of same inspection effect; therefore the Bayes sampling plan reached the purpose of reducing the sampling number, lowering the inspection cost and increasing the inspection benefit.

Abstract:In conventional computational theory of cavitating flows, it is assumed that the pressure within the cavity or on the cavity surface remains constant and is equal to the vapor pressure of the clean water at 20℃ and at zero altitude. The cavitation is confused with the vaporization, and the effect of water quality on cavitation pressure characteristic is not taken into account. The effect of water quality on cavitation pressure characteristic was analyzed and the computational theory and method of cavitating flows that considered the influence of water quality was proposed. The theory is suitable for both the potential theory and two phase method for cavitating flow simulation. Finally the validation results for cavitating flows in a hydraulic turbine indicated the significant influences of water quality on the cavitating flow performance.

Abstract:On the basis of micro-scales flow field detected by Micro-PIV experiment, Fluent numerical analytic computing software was utilized to design the optimum micro-scales flow simulating plan. In accordance with features of micro-scales, the micro-scales effect manipulating approaches setting wall roughness element and the porous medium simulating wall roughness element was adopted during the design. In the experiment, using realizable k-ε model and standard k-ω model provided by Fluent software, the relative numerical simulations on the rectangle cross section micro-scales water flowing with side length of 600μm in the case of Re=100 and Re=300 was done. With the comparison of velocity field computed from various numerical analyses and the fitting degree of Micro-PIV experimental outcome, the optimum plan that designing case via the porous medium simulating wall roughness element under the solution of realizable k-εwas acquired.

Abstract:15～18年和7～10年。 A dynamic planning model for single-unit pump variable speed optimal operation was developed in which peak-valley electricity prices and variable water levels in down-stream were considered. In this model, the minimum electricity consumption cost in one-day operation was the objective function. The speed of pump was a decision variable and specified pumping water volume was the constraint. A comparison between optimized variable speed and fixed speed operations of a single-unit in Jiangdu No. 4 Pumping Station was made. The results show that within the head amplitude and with full-load operation, regardless of considering peak-valley electricity prices, the benefits of variable speed operation was not enough to compensate for energy losses of the VFD and considering the peak-valley electricity prices and part-load operation, the benefit was excellent while without considering peak-valley electricity prices and single-unit operates at 80% and 60% loads, the saving 15 to 18 years and 7 to 10 years can compensate respectively for the VFD investments.

Abstract:A series of tests were conducted in a laboratory to improve cavitation monitoring techniques. The best run condition together with the cavitation at the same rotary speed-dropping flow rate and same rotary speed-flow rate were simulated on this test-bed. Moreover, the inlet water sound and enclosure vibration signal of the pump were acquired. The results of the cavitation experimental study showed that pumps NPSH3 was increased by flow rate at 100, 110, 120m3/h; the inlet water sound and enclosure vibration signal of pump were followed uniformity by sound pressure rule; according to the distribution of experimental data points and NPSH3 distinguishable curve，as well as sound pressure curve, the range of lift declined 3% which was regarded as inceptive cavitation that used in project was near the pressure energy maximal position; pump cavitation real time monitoring was carried through sound pressure curve peak value and 3σprinciple.

Abstract:As relative motion is existing between the impeller and volute, periodical pressure fluctuations is produced by the flow interaction of the impeller and volute. Numerical simulations showed that obvious high speed regions were formed along the direction of the absolute velocity in the casing at the down-stream of the trailing edges. The pressure fluctuations in casing present periodical features, have five peaks and five valleys according to the number of vanes. Frequency spectrum showed that the dominate frequency of the pressure fluctuation was the blade passing frequency. Pressure acquisition in experimental test was executed by a high-frequency pressure sensor installed in the pump outlet flange. FFT technology was used to analyze the measured signals, and it also showed that the dominate frequency was the blade passing frequency. A new technology to measure the pump rotating speed was developed according to the feature of the rotorstator interaction. The original contents were those pressure signals at the pump outlet. The dominate frequency of the contents was calculated by the technology of FFT, and then the rotating speed was calculated.

Abstract:In order to study solid-liquid 3-D two-phase turbulent flow in a pump, the SIMPLEC algorithm was used with the casing to calculate the coupling question of a centrifugal impeller based on N-S equations and the standard two equations k-ε turbulent model. From the computed information, the distribution of solid particles of different particle sizes and different volume fractions, at off-design conditions and different specific gravities were obtained, and the characteristic of pump was also calculated. The results indicated that specific gravity and particle diameter, which are the nature of particles, had more influence on the distribution of solid particles. Particles with large specific gravity value and diameter were easy to trend to working face by the effect of inertia force. The volume fraction also had an effect in particle distribution; because of relative flow angle changing in off-design conditions, particles had different distribution and movement laws. Increasing specific gravity, particle size and solidphase volume would cause the reduction of head.

Abstract:The pressure fluctuation of interflow fields in a centrifugal pump is a major factor affecting unit operating stability. The unsteady flow feature was investigated by RNG k-εturbulence model with sliding mesh technology. The pressure fluctuation and the corresponding frequency spectra at different monitoring points for different operating conditions were obtained. The results showed that the main factor, which created the pressure fluctuation in the pump, was the interaction between the impeller and the tongue, and the pressure pulsation spread widely inside the whole passage. The results also indicated that the blade passage frequency dominated for all operating conditions. The amplitude of the pressure fluctuations on the pressure side of the blade passage is larger than that on the suction side, and the pressure fluctuation was similar at the same measured surface for the outlet.

Abstract:Experimental research on suction performance was carried out on high-speed centrifugal pump with inducer by using closed test. The effect on the characteristic and suction performance of the centrifugal pump was analyzed with no inducer, one and two-phase inducers. It was found that one or two-phase inducers had little influence on the characteristic performance of a centrifugal pump. Compared with no inducer, the head and efficiency decreased slightly by using one inducer, and they slightly increased by using a two-phase inducer. But suction performance of centrifugal pump was improved by using a two-phase inducer.

Abstract:Aimed at the limitation of the ordinary methods of reverse engineering at present in unable showing the inner construction of pump parts, a new way on reverse engineering for impeller of pumps was presented. It utilized the multi-slice CT to scan its inner construction, and used a series of algorithms on digital image processing to treat the obtained images which contained information of design and inner construction of impeller on VC++ 6.0, 3-D model of surface was reconstructed and transformation from surface model to solid model was also fulfilled by pre-processing, 2-D image processing, 2-D geometric processing and 3-D reconstruction.

Abstract:28308.7mL。 Fermentation of raw materials can be mixed to make up for deficiencies of the single fermentation and in different degrees to enhance the effect of fermentation of raw materials. This research was carried out in controllable constant-temperature fermentation equipment. Cow dung, chicken manure and rice straw were selected with the proportions of TS ratio(0∶2∶1、0.4∶1.6∶1、0.8∶1.2∶1、1.2∶0.8∶1、1.6∶0.4∶1、2∶0∶1) as raw materials, and biogas fermentation at temperatures of 15℃,20℃,25℃and 30℃ was studied. The main conclusions were drawn as follows: the biogas production rate and cumulative biogas yield of each proportion rose with the increase of temperature; the fermentation period was longest at 15℃, but there were no difference among the other temperatures; the cumulative biogas yield was first increased and then decreased with the change of proportion, that was fermentation of a mixture of three types of raw materials——cow dung, chicken manure and rice straw, was significantly better than the effect of the mixture of cow dung and rice straw, as well as the mixture of chicken manure and rice straw, but no significant impact on the fermentation period. The model predicted, with the optimal combination of technology, the temperature of 30℃ and the TS ratio of cow dung, chicken manure and rice straw was respectively 1.22∶0.78∶1, the cumulative biogas yield was expected to reach maximum 28308.7 mL.

Abstract:98.6877%。 The LS-SVM model of the rice straw gasification tar removal process by the catalytic cracking was improved. Linear kernel function was chosen as the kernel function of the model. Moreover, the validation of the improved model was conducted. On this basis, an optimized calculation of the rice straw gasification tar removal process by the catalytic cracking was done. The results indicated that the improved model had better simulation effects and generalization ability, and when the catalytic cracking temperature reached 949.1356℃, the gas residence time was 0.9819s, the maximum of the tar catalytic cracking rate can be 98.6877%.

Abstract:33.2。 A pulsed vacuum drum dryer was designed. This machine consisted of a drying drum, heat system, rotary joint, control system, vacuum system and drive system. The pressure in the drying drum can be changed between vacuum and atmospheric pressure by opening or closing an electromagnetic valve. The drying drum can increase the load of materials, and at the same time can make heating more uniform by rolling. So, the efficiency of the machine can be increased. The experimental results of centennial seedless drying demonstrated that the machine could produce raisins with moisture content of 16.4% (w.b.) and acid-sugar ratio of 33.2 in 12h. when the pressure was 7kPa, vacuum drying was 20 min and atmospheric drying was 4 min for one cycle, drying temperature was 60℃.

Abstract:The technology of processing sweet potato flour using a drum dryer was studied. Effect of the material temperature, material thickness, roller rotating speed, and roller temperature on the technology in which flour color and the cumulate density were taken as response values was analyzed with response surface methodology. For design of process requirement, optimum conditions were as follows: material temperature was 42℃, material thickness was 13.6%, roller rotating speed was 3.0r/min, and roller temperature was 143℃. Under such conditions, the cumulate density was 0.51g/mL, which coincided with actual values within the 95% confidence interval. Predictive models are feasible in practice.

Abstract:In order to further understand the heat transfer characteristics of pulse combustion drying process, a Helmholtz type pulsing burner was used to carry out heattransfer experiments. Through a convective heat-transfer experiment between pulsing air and brass ball by the method of lumped heat capacity, the convective heat-transfer coefficient in different frequencies pulse air was determined, and the impact of pulse frequency on the convective heat-transfer coefficient between material and airflow was investigated, the criterion correlation between Nu and pulse frequency was also established. By using the established correlation, the drying process of the refractory clay particles in the pulse combustion was forecasted. Compared with the experimental value, the results showed that the predicted values and the experimental results matched well.

Abstract:Pulp browning seriously limits the dietary property and commercial value of plum fruit. In order to elucidate the browning mechanism of plum and to inhibit pulp browning, the effect of 1-MCP treatment and different storage temperature on chilling injury browning, mechanical injury browning, PPO activity, total phenols concentration and ethylene production of Friar plum was studied. The results indicated that, chilling injury browning of Friar plum developed after 75 or 60 days of storage at (0±0.5)℃ or (3±0.5)℃, but never developed when fruits were stored at (7±0.5)℃, at which temperature, the storage period was short. Moreover, mechanical injury browning developed in pulp near peel after two days of storage at low temperature. Browning symptoms were efficiently reduced by 5μL/L 1-MCP treatment for 12h when fruits were stored at (0±0.5)℃. However, when the storage temperature was (3±0.5)℃ or (7±0.5)℃, fruits treated with 1-MCP showed more serious browning symptoms than untreated fruits. In any case, both two kinds of browning are related to PPO activity and total phenols concentration.

Abstract:In order to explore the potential of dielectric properties in determining fruit internal quality, peaches with different maturities were selected and coaxial open-ended probe technology was used to measure permittivity of peach pulp and juice over the frequency range from 10 to 4500 MHz at 25℃. The moisture content of peach pulp, soluble solids content, pH value and electrical conductivity of juice were also measured. The results showed that the dielectric constants of pulp and juice decreased with increased frequency, while the loss factors changed with “V” type. The ionic conduction and dipolar polarization were the major loss mechanisms at lower frequencies and higher frequencies, respectively. The relationship between permittivity and soluble solids content, pH value, and moisture content was non-linear.

Abstract:Full-frequency drop in temperature and conversion drop in temperature were compared. The latter had some merits of smooth drop and small amplitude of temperature (in despite of shortage of longer time). Several modes of providing wind ventilation were studied. Flow equalization with a pore plate was better than the traditional methods such as one fan, two fans and a jacket. Heat impact on the circumstance in the cold storage was analyzed considering of the door open and some precautionary measures were introduced.

Abstract:Non-destructive detection methods of sugar content and valid acidity of Gongchuan Wenzhou citrus fruits were investigated based on computer vision. Factors which influenced the accuracy of detection were studied. Citrus fruit images from computer vision system were cut, the background was removed and conversion from RGB to HSI space was made. These images were segmented according to hue value ranges which are 0°～20°, 20°～40°, 40°～60°, 60°～80°, 80°～100° and 100°～120° hue. Fractal dimensions of each segment were calculated as inputs of BP neural network which modeled sugar content and valid acidity of citrus fruits. Results of 167 test samples showed the correctness for accuracy ±1.5°Brix of sugar content is 66.6175%, for valid acidity, the correctness for accuracy ±0.5 is 73.9275%. From these results it concluded that sugar content and valid acidity of Gongchuan Wenzhou citrus fruits has significant correlation with fractal dimension of hue value of fruit pericarp. Computer vision can be utilized to non-destructively detect these two parameters.

Abstract:Quality of milk after its packaging is damaged or unsealed is a great problem. Storage quality of milk was studied based on the electronic nose. Firstly, the samples of milk were measured by a gas sensor array, and different dynamic response values corresponding to the response times of 50, 100, 150, 200, 300, 400, 500 and 600th seconds were selected as the test samples. With the help of principal component analysis (PCA) and Fisher discriminant analysis (FDA), the change of milk quality was explored along with the increasing days of storage. At the same time, the preferable analysis range of dynamic response of the array was given, namely the 300~ 600thsecond. Secondly, the mean values of dynamic response values of the range were also selected as representative results of the test samples, and the PCA and FDA were carried out respectively. The results showed that the two representative methods of the samples could discriminate the change of milk quality by PCA and FDA. So it is an effective method to analyze the change of milk quality in condition of non-encapsulation with an electronic nose.

Abstract:The denaturalization mechanism of ultra-high pressure treated wheat gluten (room temperature, 400MPa,10min) was studied by scanning electron microscope and DSC, and the effects of ultra-high pressure treated wheat gluten and ordinary wheat gluten on the quality of noodle were investigated by sensory evaluation, texture analyzer and farinograph. The results indicated that ultra-high pressure treatment increased the crosslinked extent of wheat gluten and the temperature of denaturalized peak was changed from 117.02℃ to 119.76℃.Ultra-high pressure treated wheat gluten and ordinary wheat gluten could improve the wet gluten content of flour, and greatly influenced the noodle’s sensory evaluation score, breaking force and hardness under the addition amount from zero to 3.5%. The quality of noodles processed with ultra-high pressure treated wheat gluten was better than ordinary wheat gluten at the same addition amount（p<0.05）, and the optimal addition amount of ultra-high pressure treated wheat gluten was 3%. Compared with ordinary wheat gluten, the farinograph property of flour added with 3% ultra-high pressure treated wheat gluten was also better.

Abstract:95%。 For the existence of foreign fibre during cotton processing, machine vision technology and image processing were used in order to not only extract foreign fibre goals, but also collect characteristic data of foreign fibre. Decision tree theory and feature vectors extracted were used to recognize foreign fibre after eigenvectors of aimed foreign images were effectively extracted through an improved version of rough set theory. Experimental results showed that feature vectors extracted from the image of foreign fibre for the identification of cotton foreign fibre was effective and the recognition rate reached more than 95%.

Abstract:An improvement of LEACH algorithm was proposed, named LEACH-SMC. The LEACH-SMC protocol algorithm was carried out round by round, and every round was divided into two sections of setup phase and steady station. A critical distance was specified for every cluster head to judge when to use the single-hop or the multi-hop mode between the cluster heads and the base station. The coverage area was greatly improved by the multi-hop manner, and this manner also provided practical value in the nodes distribution in the farm field. It was effective for transmitting the message by single-hop mode, and it could greatly reduce the information delay and packet loss rate too. The coexistence of single-hop and multi-hop can combine the advantages. Simulation results demonstrated that LEACH-SMC protocol could increase network effective coverage area and prolong the network lifetime.

Abstract:A grape grading system based on computer vision was developed. The system consisted of 5 parts: the driving unit, conveying unit, holding unit, image grabbing-processing unit and grading control unit. Through a special chain, bunches of grapes were hung and conveyed continuously along a path. Two CCD cameras were installed to capture two images from two sides of each bunch simultaneously under external trigger motion. The color feature was extracted on RGB space, the size and shape features were calculated from the projection area and pixel accumulation curve. Then external inspection and grading of grapes were conducted. Twenty bunches of grapes were graded on the system for three times. Experiments showed that the accuracy was 90% for color grading and 88.3% for size-shape grading. The grapes were not damaged during grading.

Abstract:A simple modeling method for translucent flower was presented. The geometric model for flower can be built through change basic shape. According to the distribution feature of floral envelope, the distance between petals to calculate translucent shadow distribution was used. 3-D space question was changed to 2-D space question thought many times mapping and many buffer zone. With this method the modeling can be quickly realized and the experiment results showed the simulation effect is better.

Abstract:A simple control method for virtual plant morphology was presented. The topology structure of plant was obtained from L-system. In L-system, the value of plant parameters was controlled by regular curve, cubic spline curve and B-spline curve. The plant morphology was varied by the modified parameters curve shape, the hypotaxis was determined by using correlation model with both plant parameters and curves. The results showed that the length parameters, angle, and color could be represented by B-spline curve, cubic spline curve and regular curve respectively, and the plant morphology was similar with curve shapes. The method is helpful in future plant modeling.

Abstract:The process of transforming the combinatorial complexity in the system to the periodic one which contained in the complexity theory based on axiomatic design put forward by Suh was analyzed. Meanwhile, through the integration of c/p transformation and TRIZ theory, a design model for the combinatorial complexity elimination process was proposed. Firstly, the combinatorial complexity exists in the system was judged, and the functional structure to determine the functions that led to the time-dependent combinatorial complexity of the system was drawn. Then, the functions were analyzed with TRIZ tools, and a reasonable combinatorial complexity of the functional period was put forward. Finally, the virtual functional period description was transformed to an improved design plan. It was verified by the engineering practice of “capacitive online thickness measurement system”.

Abstract:A multi-objective particle swarm optimization algorithm based on dynamic crowding distance (DCD-MOPSO) was proposed. Applying the improved quick sorting to reduce the time for computation, both the dynamic inertia weight and acceleration coefficients were used in the algorithm to explore the search space more efficiently. A new diversity strategy called dynamic crowding distance was used to ensure sufficient diversity amongst the solutions of the non-dominated fronts. Some benchmark functions and the optimization of four-bar plane truss were tested to compare with the performance of DCD-MOPSO and NSGA-Ⅱ. The results show that DCD-MOPSO has better convergence with even distributing of Pareto set.

Abstract:A fully compliant five-link mechanism of two-DOF was analyzed with both pseudo-rigid-body and imitate-compliant-body models. The pseudo-rigid-body and the imitate-compliant-body model of the fully compliant five-link mechanism were also established and the equation of relationship for load and displacement was presented. A symmetry fully compliant five-link micro-mechanism was designed. By using the geometric relationships of the rigid five-link mechanism and the iterative program, the results of deformation analysis in imitate-compliant-body model method for this micro-mechanism were given. At the same time, the simulation analysis in the FEM method for the micro-mechanism was also given. Compared the results with computer and FEA, the validity of the imitate-compliant-body model was proved to be effective.

Abstract:Based on NC machining, the tooth surface errors correction of spiral bevel gears was investigated. A new method for the machining settings transformation from cradle-type hypoid generator to Free-Form one was proposed, and the tooth errors mathematical model based on NC machining was established. The minimum of square sum of tooth surface errors was the objective function to optimize the cradle-type hypoid generator machine settings and transform those parameters into NC form so as to realize the NC machining correction of spiral bevel gears. Finally a numerical example was presented. The results showed that it could achieve precise correction after altering relative weight coefficient and optimizing for several times.

Abstract:Non-free-cutting is an effect which affects the mechanism of micro cutting greatly. The influence of cutting intervene between elementary cutting tool on chip flow direction was analyzed, and chip flow intervene of the rounded-edge tool was mathematically modeled aims at the increase of cutting intervene caused by chip flow in the rounded-edge of micro cutting tool. Furthermore, chip flow direction, equivalent cutting edge and chip flow angle were deduced with Stabler rule and minimal energy dispersion principle respectively. Those above parameters were numerical predicted under different feed rate and cutting depth, and the prediction results can be used for the evaluation and improvement of micro-cutting status, as well as the optimization of cutting regimes.

Abstract:In order to explore methods that can process effectively nonlinear signals, the nonlinear wavelet, morphological wavelet (MW) was introduced into the field of vibration signal processing. Because of the decline of decomposition signal layer by layer, one kind of morphological un-decimated wavelet construction method based on the cascade of morphological opening and morphological closing was proposed. According to the general structure of morphological un-decimated wavelet (MUDW), the filtered signal, filtering by the cascade of morphological opening and morphological closing, constructed the approximate signal, and detail signal was equal to the original signal subtract the approximate signal. Obviously through the process of decomposing, the approximate signal or detailed signal of current layer and low level layer had the same data length to avoid information leaking and provide enough information for signal processing. The method was used in the feature extraction of vibration signal in automobile main reducer. Results showed that the mentioned MUDW had better filtering effect than the existing MUDW and linear wavelet (sym8 wavelet), and it also had better demodulation effect than Hilbert envelope analysis. The mentioned MUDW can extract the feature from nonlinear vibration signal effectively and have good application value.

Abstract:Based on the two-phase flow cavitation model, a numerical model of the thermohydrodynamic lubrication of spiral-oil wedge hybrid journal bearing was built up. By using finite differential method, the generalized Reynolds equation, simplified energy equation of oil film and heat conduction equation of the bush were solved. The pressure distribution of oil film and the influences of supply temperature and supply pressure on bush inner surface temperature were carried out. The results indicated that rupture area of oil film initially increased, then decreased. The rupture location in circumferential direction moved a distance which related to spiral angle. Supply temperature had a great effect on the bush inner surface temperature distribution, but contrarily, supply pressure had a little effect.

Abstract:Effective fluid bulk modulus is an important parameter in hydraulic systems. The major factors of effective fluid bulk modulus were analyzed, and a mathematical model with entrapped air content and working pressure at constant temperature was developed. A device for removing air content based on the method of vacuum-pumping in a closed reservoir was developed to increase bulk modulus. And bulk modulus was measured by the device when vacuum-pumping had been completed. Experiments were carried out in a large hydraulic system, and the results showed that vacuum-pumping is an effective method to reduce air content, and the device increased fluid bulk modulus from 821.3MPa to 1201MPa. Bulk modulus can be improved by using this method in the closed hydraulic system.

Abstract:A design algorithm of a triangular mesh model was proposed, that included four steps: first, the reference surface of the triangular mesh model was obtained with least square method; second, the projection point of vertex on mesh was calculated and the mapping relationship of mesh vertex and projection point was built; third, the coordinates of mesh vertexes were changed according to the displacement of projection points when adjusting the control points of reference surface; and fourth, the fairing of mesh model was built with triangular Bézier surface design method, which proved that the deformation region of triangular mesh model was effectively controlled. The smoothness of mesh model and the efficiency of innovative deformation designing have been improved effectively.