Abstract:Homogeneous charge compression ignition (HCCI) combustion is still confronted with problems in cycle-to-cycle air/fuel ratio control. Because there are no parameters that characterize air inflow in each cycle, dynamic recurrent neural network (Elman) was adopted for forecasting engine's air inflow in each cycle. Based on accurate air inflow in each cycle, accurate air/fuel ratio control is achieved in steady and transient operating conditions by oxygen sensor's closed loop control and fuel film’s compensation. The experiment results show that prediction model based on neural network and air/fuel ratio control strategy can meet the need of realtime control over HCCI operation. 

Abstract:SI engine experiments were carried out by using hydrogen at equivalent ratio of 0.8, 0.6, and 0.4 and by using gasoline at stoichiometric condition, respectively. Simulation models for gasoline and hydrogen were built based on AVL Boost and calibrated experimentally. The simulation study shows that hydrogen can increase burning rate of hydrogen-air mixture, and shorten combustion duration markedly. As a result, cylinder pressure and thermal efficiency increase accordingly. Hydrogen engine can operate at the equivalence ratio of near 0.4 smoothly and the performance of SI engine is greatly improved. 

Abstract:The mathematical model is established for the conventional pump-pipe-injector fuel system. Through the numerical simulations on diesel and DME injection systems, the effects of temperatures on these two injection systems are disclosed, and their differences are illustrated. At the same temperature, line peak pressure and the rate of pressure increase and decrease for DME are lower than that for diesel fuel. Pressure of DME drops 51.1% and 45.2% than that of diesel at 20℃ and 50℃. DME injection rate and cumulative volume flow through nozzle orifice are much lower than that of diesel. The open timing of nozzle is delayed. DME peak rate drops 38.8% and 36.8% than that of diesel at 20℃ and 50℃. With the increase of temperature, the diesel and DME pressures in nozzle, injection rate and SMD all decrease, and the open timing of nozzle is delayed. 

Abstract:In order to study the ride comfort of semi-active vehicle, a detailed multi-body dynamic model of a passenger car was established by using SIMPACK software, and a seven-degree freedom mathematical model for the semi-active automotive system was also built. A model reference adaptive control based on neural network was designed for semi-active suspension system and worked out by means of Matlab/Simulink. The SIMPACK-Matlab co-simulation method was used to analyze the ride comfort of MR-damper semi-active suspension. The result showed that, comparing with passive suspension, when the car is running at 60km/h on grade C road, the neural network controller could reduce the mean square roots of the vertical acceleration, the roll angular acceleration and the pitch angular acceleration by 32.33%, 28.09% and 35.93%. When the speed of car achieved 120km/h, the mean square roots reduced by 41.56%, 18.52% and 22.97%. It is concluded that the model reference adaptive control based on neural network could reduce the vehicle body vibration and improve the ride comfort.

Abstract:A mathematic model of electro-hydraulic servo driving force control system for a heavy vehicle hydro-pneumatic suspension was established. Through analyzing the influence of the varying stiffness of hydro-pneumatic suspension to amplitude margin and phase margin, a relationship between stiffness of the load and controller parameters was obtained. In order to improve the dynamic performance of the hydro-pneumatic suspension testing system, a two-stage correction segment was introduced which can change its gain and its turning frequency automatically according to the stiffness of the load. Simulation and experimental results both indicate the validity of the proposed control method. 

Abstract:In order to optimize the efficiency of a parallel hybrid hydraulic excavator (PHHE), this paper firstly get started with the analysis of the system's structure, and then the optimal objective function and constraint equations that depict powertrain unit and energy storage unit for PHHE were put forward along with a parameter matching method for the machine. For the purpose of component sizing and matching in PHHE, one case was done in a 5 ton hybrid excavator, and the system with the designed parameters of components could reduce components' peak power, increase system efficiency and decrease fuel consumption rate by using Matlab and Simulink toolbox.

Abstract:An analytical method for vehicle stability control system is proposed based on distributed control structure. By distributing complex control algorithm, the control system is divided into three layers, which are control analysis, control allocation and control actuation. The desired forces and yaw moment are calculated based on sliding mode control method in control analysis. Then these are allocated to proper four wheels by using nonlinear optimal theory, in which the control allocation is realized and optimized. Simulations are implemented in the virtual vehicle dynamics environment CarMaker, and the results indicate that the designed control system enhances the vehicle stability in extreme condition and reduces the driver’s burden. 

Abstract:The road simulation shaking table has a high requirement on real-time performance and rapidity. At first the integral scheme was designed. On the hand of hardware, the control system used TMS320C2812 to acquire the analogous and digital variables, and used TMS320C6713 to operate algorithm and communicate with embedded processor S3C2410 with dual-RAM in order to improve real-time and rapidity of the system. This paper presented the implementation of a rapid prototyping control system, which involves the design of DSP algorithms using Matlab/Simulink blocksets to setup the Simulink module of the road simulation shaking table. This module can automatically generate code in the CCS integrated development environment, and download executable code to the Texas Instruments’TMS320C2812 and TMS320C6713.

Abstract:Aiming at the problem of greater measurement error of pressure sensor in continuously variable transmission (CVT), a method of establishing error compensation model using support vector machine (SVM) was presented. Firstly, the basic structure of error compensation model was determined based on the analysis of the factors inducing measurement error. Secondly, training set was constructed by experiment, and the error compensation model was trained with the training data. Finally, the model parameters were optimized by the genetic algorithm during th e training process. The experiment results indicate that the proposed error compensation model improves the linearity of the pressure sensor, and reduces the maximum absolute error from 0.5MPa to 0.15MPa, which greatly improves the performance and measurement accuracy of pressure sensor. 

Abstract:Aiming at the problem of multi-objective, nonlinearity, interaction and fuzziness of transplanting mechanism of rice transplanter in optimization process, calculation model of kinematical parameter that could satisfy the performance requirements for transplanting seedlings was established. Firstly, by blurring the performance requirement, the membership was obtained and interference judgment method was put forward. Then the optimization model was built up, which took the maximum of every membership as the object function, and adopted motion non-interference as the restrictive condition. Based on the optimal result, the solution was expanded as an interval and the interval reaching was converted as multi-objective optimization. Then automatic search of the non-inferior solution was realized by coding the optimization program with Visual Basic 6.0. The results showed that by using the method it could quickly search the interval that could meet the kinematical performance requirement and it was easier and more efficient to manipulate than human-computer conversation. 

Abstract:In order to analyze the factors that affect the performance of a furrow opener, the two-dimensional DEM (discrete element method) analyzing models of two types of furrow openers and soil particles were built up. Through changing the CAD models of furrow openers, for each type of furrow openers, the operating processes and resistances in three kinds of soils with different moisture content at three different velocities and depths were analyzed by using the DEM. The performance of the openers was tested at each operating states in lab. The simulation results is in good correlation with the experimental results and the relative errors are within 10%～20%. It can be proved that it’s feasible and favourable to analyze the performances of furrow openers by using the DEM and it provides a new method to study and design furrow openers. 

Abstract:50～120倍。According to the analyses of the texture differences between straw and soil, a new BP neural network measuring system for residue cover rate is designed. By taking the filed photos as the research objectives, this system was developed through VC++ programming tools. Straws were detected by combining the texture features and BP neural network. Selection standard of learning samples for input nodes was constructed based on the entropy in the system. Artificial simulation and field testing indicated that the new measuring system could detect over 90% of the straws in the field and control the counting error of residue cover rate under 5%. Compared with the traditional manual measuring, the measuring efficiency in the new system could be improved by 50～120 times. 

Abstract:A novel grain-flow yield sensor was designed. The grain-sensor impact FEM model was established with LS—DYNA software, and the impact process was simulated to discover how the sensor material influences the grain impacting sensor process. The physics grain impacting sensor test system was developed by applying LabView and a kind of high performance piezoelectric ceramic newly developed. This system was used to testify simulation result. The research shows Si3N4 is the best material of making sensor among Si3N4, PP and 1Cr18Ni9; the physics grain impacting sensor test system meets the requirement of the grain impacting sensor test without pre-amplifier by using this kind of high performance piezoelectric ceramic newly developed. The test cost is reduced greatly, the test precision is increased, and the test circuit is simplified greatly. 

Abstract:To solve the problem of capturing artificial raised locusts in net house, a cyclone locusts capturing machine is designed. By using CFD software Fluent the airflow field in the suction nozzle and separate device is simulated. The test results of the sample machine indicated that when the inclination angle of suction nozzle was 75°, the airflow speed of the suction nozzle was 14m/s, the distance between the suction nozzle and ground was 40mm and the forward speed of the capturing machine was 0.4m/s, high rate capturing and low rate of break up were got. When practically working in locusts artificial raising net house, the airflow speed of the suction nozzle and the forward speed of the capturing machine were adjusted according to the distribution density of locusts on the ground, to improve the capturing efficiency and reduce the energy consumption.

Abstract:The method of digital image processing is used to study the damage of cavitation on the surface of the aerofoil subarea. The cavitation corrosion's images of the aerofoil are gained with SEM. First, fuzzy enhancement is used. Second, threshold analysis is applied to pick-up the shallow pit. Third, morphology method is used to process the edge and work out the cavitation values. The idiographic numerical and quantitative values such as cavitation area, quantity are obtained.

Abstract:Based on the comparison of different research methods on the hydraulic losses of suction boxes and discharge passages, the computational fluid dynamics method is adopted to simulate the internal flow of four different pumping systems and to investigate the influence of rotational speed of pumps on hydraulic losses of suction boxes and discharge passages. The computed results indicate that the internal flow of suction box is affected by the pre-swirl caused by impeller rotation, the value of hydraulic loss is smaller than that when the suction box is operated solely without pump. The hydraulic loss of suction box keeps unchanged at the same flow rate when the rotational speed of pump is changed. The hydraulic characteristics of discharge passage are influenced by the flow conditions and residual circulation of pump diffusers. The internal flow field is not conformed to the affinity law and the hydraulic loss of discharge passage is unequal at the same flow rate when the rotational speed of pump is changed. The validity and reliability of numerical computation are verified by model test results of pumping systems. 

Abstract:According to the sensitivity of pressure fluctuation amplitude related with the change of cavitation, the cavitation was first simulated on the centrifugal pump experimentation bed. It was found that the shaft frequency of the pump outlet pressure signal increase; many low frequencies appeared at the time of cavitation happening by using the outlet pressure signal. The natural state time serials model was established by the surface vibration and the outlet pressure signal of pump. Thus the state of centrifugal pump is distinguished and the feature extraction of cavitation is recognized by the variance of the model residual. 

Abstract:The main influencing parameters for water-hammer prevention characteristic of air valves are analyzed through experiment. The result indicates that the air valve with reasonable size and installation position can prevent high water hammer pressure caused by water column separation. However, the prevention effect is impressible to the size and installation position of air valve: too large size will cause large pressure during the venting process, while too little size can not obtain prevention effect for insufficient air quantity and slow intake speed. So the air valve should have rapid intake speed and slow venting speed. For the experimental system in this study, the air valve should be installed in the position where the water column separation occurs firstly. Based on the analysis result, the optimization model for the air valve parameters and closure procedure of pump outlet valve is set up and solved by using genetic arithmetic. In the end, the above optimization method is used for the water-hammer prevention of a practical water-supply project and the suggestion of suitable prevention measure is proposed. 

Abstract:Temperature/oxygen concentration-based aeration control system was designed and realized to control the process of aerobic composting. The outline, method, function and process of realization of the system were described in detail. By 2 week aerobic composting with this system, it showed that the system could run stably during composting and the composting temperature, humidity, and oxygen concentration can be monitored by the system. The time of temperature remained at 55～65℃ was more than 9 days. The pathogenic microorganism can be killed and the stability of product is good. 

Abstract:A design method of wind energy conversion system based on the concept of power factor is proposed. The optimal power energy and electricity quality are considered as optimization objects. The blades are extended to improve power out-put at low wind speed and shrunk with regulating mechanism at high wind speed to adjust power out-put. Taking the rated wind speed, the maximal length of an extended blade, the minimal length of a shrunk blade and the central radius of a blade as optimization variables, an optimization model of the wind turbine is proposed to obtain optimal design parameters using genetic algorithm. Finally, the availability of optimal design of wind energy conversion system is validated by a case of wind turbine. 

Abstract:Numerical simulation on unsteady rotated flow of a straight-blade vertical axis wind turbine (VAWT) is done based on moving meshes by means of the software Fluent. The wake velocity and the variation of velocity at the special cross-section are obtained. The results of unsteady flow are compared with ones solved by the multiple stream-tube model, and good coincidence is obtained. The conclusion can be made that the numerical simulation on unsteady rotated flow of a straight-blade VAWT based on moving meshes can represent its flow field. 

Abstract:22.78%和64.14%。Based on the single factor analysis, the effect of liquidsolid ratio, ultrasonic power, extraction temperature, and extraction time on enhancing oil yield from Paeonia suffruticosa Andr. seed was evaluated by response surface analysis. A 4-factor, 3-level Box-Behnken experimental design was applied and the interactions of each factor on the oil yield were also investigated. The optimal conditions were at 54℃ extraction temperature, 11mL/g liquid-solid ratio, 300W ultrasonic power, and 60min extraction time using petroleum ether with a boiling range of 60～90℃ as the extraction agent. Under such conditions, the oil yield is 24.12% after three runs. The extracted oil was analyzed by GC—MS to determine the oil constituents. Unsaturated fatty acids such as linoleic acid and linolenic acid are abundant in Paeonia suffruticosa Andr. seeds. 

Abstract:The purpose of this study is to investigate the feasibility using near-infrared spectroscopy (NIRS) technology for determination of the 1000-grain weight of paddy. Seventy varieties of paddy samples were scanned in the NIR spectral region 4000～10000cm-1. Ten pretreatment methods were used to process the NIR spectrums. NIR calibration models were developed by using the partial least squares (PLS) technique. The best calibration model was determined based on the highest determination coefficient (R2) of cross-validation and the lowest root mean of standard error for cross validation (RMSECV). It was shown that the best model, with the determination coefficient 0.773 and RMSECV 1.67g, could be obtained based on the processed spectral data by the pretreatment min—max normalization in spectral range 11998.9～7497.9＋6101.7～5449.8＋4601.3～4246.5cm-1.The validation results indicated that the best calibration model had correlation coefficient (r) between the NIR predicted and the actual values of 0.945 and standard prediction error (SEP) of 0.76g, showing that the NIR technology is a potential tool to estimate the 1000-grain weight of paddy.

Abstract:91.25%。A new method of utilizing microwave to modify alcohol leached rapeseed protein concentrate was studied. The influence factors on the NSI were analyzed， such as RPC concentration，microwave power，modification time and pH value. The orthogonal test results showed that the optimum modification parameters were as follows: RPC concentration 5%，microwave power 300W，modification time 1min and pH value 10. Under the above-mentioned modification parameters，the modified alcohol leached rapeseed protein concentrate with NSI of 73.38% and foaming stability of 91.25% were obtained.

Abstract:The effect of maturity, cooling method and bagging on the color changes of Yali pear after harvest using CIELAB color variables were studied. The results showed that late picking improved the maturity together with L, a and b (no-bagging fruits) value of Yali pear, decreased the chlorophyll content, and increased the carotenoid content of Yali pear. Slow cooling brought increases of L and a value and degradation of chlorophyll, but had not distinct influence on no-bagging fruit. Bagging treatment improved L and a value, decreased b value of Yali pear, decreased the chlorophyll content, made the peel color shallow, and slowed down the color change of the fruit peel. 

Abstract:110g/L、流速4mL/min。With the aim to remove deltamethrin residue in apple juice, the techniques of separating deltamethrin in apple juice with macroporous adsorption resin were studied. Through static adsorption experiment, the macroporous adsorption resins were screened. Based on dynamic adsorption study, the separation condition was optimized. The result showed that the LS—803 resin had the strongest absorption capacity for deltamethrin residue in apple juice. The static absorption balance time of the LS—803 resin was 100min. The optimized condition was obtained as temperature 20℃, the concentration of apple juice 110g/L, and flow rate 4mL/min. 

Abstract:The in Vitro anti-oxidative activity of pine needle flavonoids（PNF）and enzymatic hydrolysis were investigated. It is found that the DPPH radical scavenging activity of PNF is similar to that of ascorbic acid. The hydroxyl radical and super-oxide radical scavenging activity of PNF are 4 times and 2 times as that of ascorbic acid, respectively. As for reducing power, EC50 ratio of PNF to ascorbic acid is only 1/2.8. β-glucosidase is used to hydrolyze PNF. The optimal hydrolyzing conditions are 40℃ of reaction temperature，1/1000 of enzyme addition，0.6g/L of substrate concentration, and 5h of reaction time. The anti-oxidative activity of enzymatic hydrolyzed PNF is increased obviously. 

Abstract:With the aim to improve the purity of total flavonoids of Cyclocarya paliurus leaves, the suitable resin for separating and purifying total flavonoids of Cyclocarya paliurus leaves and the optimum parameters of purification were studied. The optimal techniques of separation and purification of flavonoid were obtained by static adsorption and elution tests, and the separation techniques were evaluated by measuring the concentration of total flavonoids of Cyclocarya paliurus leaves with ultraviolet spectrophotometer. The results showed that the AB—8 macroporous resin gave the best effect of separation with the sampling rate 2BV/h and concentration 1.0mg/mL, respectively, and the concentration of elution was 70% alcohol, with eluting velocity 2BV/h. In conclusion, AB—8 resin could be applied to purify total flavonoids of Cyclocarya paliurus leaves.

Abstract:Food packaging is important for food safety, shelf-life extension, cost-efficiency, environmental issues, and consumer convenience. In order to improve the performance of food packaging, active packaging is being developed. Antimicrobial packaging, a form of active packaging, is an extremely challenging technology that could control the microbial population and target specific microorganisms to provide higher safety and longer shelf-life food. The characteristics of different types of antimicrobial packaging systems, and their research and application are reviewed. The antimicrobials including inorganic, organic and natural antimicrobials in the antimicrobial packaging systems are reviewed. In the end, the future trends of antimicrobial packaging are described.

Abstract:The appearance quality of flue-cured tobacco leafs of 14 main planted varieties in Yunnan Dali were analyzed by using the two-step cluster method. Based on the result, the appearance quality of flue-cured tobacco leafs were less affected by vary zoology spots and different varieties. The 100 samples of flue-cured tobacco leafs were divided into 3 clusters. This method defines the important characteristics in a cluster and the classification among types. The conclusion is objective, reasonable and reliable, coincided with the field performance of appearance quality of flue-cured tobacco leafs.

Abstract:。To control the take-off, landing and flying of ultra-low altitude UAV remotely, navigation and control methods were studied with virtual reality technology. With the aid of Multigen Creator, we built 3-D model of UAV, generated terrain by DEM data, and studied drive technology. According to the parameters from GPS receiver and other sensors fixed on the UAV, the 3-D model and scenes were derived. Meanwhile, feed back signal was given to adjust the plane’s gesture to insure the plane to fly along the route. GIS technology was used to display the UAV trace in digital map. Virtual experiment shows the feasibility of navigation and control of ultra-low altitude UAV.

Abstract:The multi-body dynamic model of the straw-checkerboard barriers paving robot is built through the combination of the Pro/E and ADAMS software. After the model is added with the required boundary conditions, the vibration state of the strawcheckerboard barriers paving robot is simulated when the pressing wheel and insert blade work normally. Through the simulation, the displacement, velocity and acceleration curves of the mass centers to the robot’s tractor, longitudinal paving mechanism, horizontal paving mechanism, pressing wheel and insert blade are obtained. Through the analysis of the fluctuation curves, the improvement solution is proposed, which provides data for further optimization of the robot. At last, the experiment curves in the actual state are obtained by the experiment. By the contrast of the experiment and simulation curves, it is confirmed that the simulation results of the straw-checkerboard barriers paving robot are reasonable and reliable.

Abstract:0.1s。The residue blockage to the soil engaging parts is one of the key problems affecting the performances of no-till planter and other machine working in conservation tillage farming. Visual guidance system was studied to guide the machine working in between the stubble rows thus to solve the blockage problem in standing stubble conditions. The maize stubble rows were detected by image processing and the saturation of the field image was selected to segment the dry stubble and soil surface background. By comparing different methods of determining threshold, the iterative method was proved to be the most effective to segment the image automatically. The improved Hough transform was used to detect the inter-row line and the stubble row line to guide the machine. The experiments with large number of field images showed that the algorithm proposed can obtain the target navigation path rapidly within 0.1s and accurately for most conditions of standing stubble covered field. 

Abstract:A field information acquisition instrument to measure the soil pH value and electrical conductivity (EC) was designed. Based on the measurement theory and the software and hardware design of the instrument, the calibration test to the acquisition instrument measuring pH value and electrical conductivity by means of two-point and the standard KCl solution was carried out. Then 15 soil samples were taken from a piece of bean field with the sampling interval of 14m×14m. The validation test to the calibration equation was carried out. The results showed that the relative error between the calibration result and the accurate value for soil pH value is less than 1%, and the relative error between the calibration result and the accurate value for soil EC is less than 14%, the linear regression model significance probability of the soil pH value calibration results and exact value is 0.0478,R2=0.8978,the linear regression model significance probability of the soil EC calibration results and exact value is 0.0004,R2=0.9716,it is proved that the calibration equations of the pH value and EC are reliable.

Abstract:Aiming at grading flue-cured tobacco leaves, an intelligent method based on rough set theory was proposed. Traditional rough set theory was generalized for the characteristics of flue-cured tobacco leaves’grading, and relevant algorithms of discretization and attribute reduction based on rough set theory were also given. In order to obtain knowledge with reasonable granularity, a two-level reasoning model that consists of grouping and grading was constructed. By parallel grouping according to leaves’positions and colors based on chemical compounds, inference rules and importance degree of each chemical compound can be obtained. Then, through multi-attribute evaluation found on the importance degree and the group inferred from the rules, final grade of the given flue-cured tobacco leaf was determined. Experiment results prove that this method is effective and credible, and has advantages over the previously proposed methods.

Abstract:In view of the factors affecting profit maximization, such as the relation between photosynthetic rate and CO2 concentration in greenhouse, the plant market price and the cost of CO2 enrichment, a decision-making method for CO2 control quantity was presented to achieve the profit maximization. Taking lettuce planting as an example, a non-linear model was set up for forecasting plant growth rate by neural network, and a market price model was established for forecasting plant market price by polynomial fitting function. In terms of the above two models and the cost of CO2 enrichment, the optimal set-point of CO2 concentration was found out. According to the experimental data of lettuce growth and the seasonal changes of market prices from 2004～2006 offered by Ling Jiatang wholesale market, prediction models were established and finally information fusion was achieved, which provided a theory for the decision-making of CO2 control quantity in greenhouse control system.

Abstract:The temperature profiles in spatial and temporal field inside the glasshouse are coupled to outside climates. Especially, the discrete ordinate (DO) radiation model was applied to solve the temperature profiles inside the glasshouse. The 3-D numerical simulation was done based on the CFD technique for the natural ventilated Venlo glasshouse, and the measurement was conducted to validate the CFD model. The results showed that the simulation values agreed well with test values about the average temperature in the empty glasshouse for the different time, the max relative error and the average error was 11.3% and 7.6%, respectively. The spacial temperature grades were obvious inside the glasshouse. A homogeneous temperature field was obtained at crop level, the average temperature was about 28.5～28.8℃. The DO radiation model was proved effective in modeling the effect of solar radiation on the thermal climates inside the glasshouse.

Abstract:A vibration isolation device is proposed to absorb multidimensional vibration. The device is composed of double Stewart mechanisms, up-platform, and down-platform. It provides an easy way of multidimensional vibration isolation. The kinetic equation is derived from motion analysis and force analysis. Its roots show that the innate frequency of the device is lower than 5Hz and the vibration of the device attenuates rapidly. ADAMS simulation and experiment prove that the device absorbs multidimensional vibration very well. So it can be used in vibration isolation when its stiffness coefficient, damping coefficient and the sizes are designed according to the formulae derived.

Abstract:To eliminate the errors of cylinders’dynamic output positions of master side and the influence of random disturbance of slave side, disturbance state observer optimal control and robust dynamic compensate PD feedback control algorithm was presented for master-slave side, which is aiming at the nonlinearity and uncertainty of master-slave position control in the electro-hydrauli servo-telerobot. A linear-quadratic with disturbance observer and a dynamic robust compensator position controller were developed. Simulation and experimental results were given to demonstrate the availability of the proposed algorithm. The experimental results show that the designed controllers both improve position tracking precision for master-slave side and possess of good adaptive ability and robustness in existence of out side disturbance, enhances the operation of electro-hydraulic servo telerobot with force feedback.

Abstract:On the basis of rub-impact dynamics equation of rotor system with rub-impact fault, according with the reliability design theory and sensitivity analysis method, the reliability sensitivity analysis method of the rotor system with rub-impact was extensively discussed by applying the random perturbation theory, Kronecker algebra, the fourth moment technology and matrix calculus theory. A numerical method for reliability sensitivity design of rotor system with rubimpact was presented. The variation regularities for reliability sensitivity of random parameters statistics characteristic were obtained and the effects of random parameters statistics characteristic on reliability of the rotor system were studied. The presented method provided the theoretic basis for the reliability design of the rotor system with rub-impact. A numerical example demonstrates that the result of presented method is accord with the qualitative analysis, the proposed method is efficient and accurate.

Abstract:Based on the mathematical model for the tooth form analysis of spiral bevel gears, the tooth form errors between the theoretical tooth flank and the inaccurate one, in the normal direction of the theoretical tooth flank, were calculated by applying optimization algorithm and a new computing method. By introducing the machine setting errors and cutter parameters errors, the effect of various errors on the tooth form of spiral bevel gears was analyzed. The deviating direction from the theoretical tooth flank and the values of tooth form errors were expressed by graphics. The results provide a reference for precision design of machine tools, correction of tooth form errors and practical processing. The algorithm and analysis results are validated via experiment.

Abstract:In order to study quantitatively the trapped-oil phenomenon, with distance between meshing point and nodal point as a variable, a formula for calculating trapped-oil area and a fit formula for calculating relief-load area were derived from the geometrical relationship of gear transmission and positional relationship of relief groove. The calculated results were compared with the measured results from an accurate 3-D model. The results indicated that trapped-oil area and relief-load area could be expressed by a parabola with different index; simplified transition curve is feasible for calculating the two areas; fitting constant derived could be directly used aimed at different tooth number and module for calculating relief-load area. Finally, the two area-formulas were proved feasible to be used for forecasting the trapped oil pressure. 

Abstract:A test apparatus of metal’s dry friction characteristic was built to measure the dry friction hysteresis characteristic curve of metallic material specimens under given normal force. A corresponding MSC/MARC finite element model is developed to simulate the friction stick-slip hysteresis characteristic of contact dry friction for any prescribed quasistatic load cycle. Comparisons of test data and simulation data demonstrate the accuracy of the FEM model. The simulation result is consistent with the test and theory data which can help analyzing the material’s dry friction characteristic of real project and provide the reliable computation for the NVH simulation of engine.

Abstract:In order to improve the real-time performance of inverse kinematics for 6R robots, a real-time and efficient algorithm based on vector dot product was proposed. The complex matrix equations were transformed to 10 pure algebraic equations containing 6 unknown joint variables, and symbolic preprocessing was applied in simplifying equations without any error accumulations caused by floating-point calculations. The production of extraneous roots in the solving process of the 5th and 6th joint variables was avoided by optimizing the linear combinations of related equations, which greatly improved the efficiency of the algorithm. Experiments on a 6R robot show that, the proposed algorithm has a stronger real-time performance than those of others to get the same precision solutions, the average time for gaining 8 accurate closed-form solutions is only 0.014ms, and it can be applied efficiently in the practical on-line robot control. 

Abstract:Several specific and feasible changing topology ways of variable topology parallel mechanism are given. The 4—TPT parallel mechanism is selected for further analysis on one of the changing topology ways and a large number of symmetrical or unsymmetrical variable topology structure parallel mechanisms are obtained, which verifies the validity of the process mentioned above. And also, the characteristics of this kind of variable topology structure parallel mechanisms are explored. The results show that workspace and dexterity of type variable topology structure parallel mechanism obtained are enhanced remarkably. 

Abstract:In order to improve the accuracy and reliability of defect detection for packaging cans production lines, an inner surface inspection system with a single camera was studied. By using morphological region extraction algorithms the inspection region of interest image can be obtained from the whole inner image. For defect feature detection an approach based on multivariate image analysis (MIA) was proposed. To cancel the effect of seam regions in the inner images, a method of images fusion was implemented to form the ring-like good sample image without seam region. By stacking both the ring-like good sample images and the test image, the multivariate test images were constructed with their overlapping part. By using MIA technique with principal component analysis (PCA), the principal component scores of the multivariate test images were obtained. As the feature space for defect detection the Q statistic image was derived from the residuals which were left after the extraction of the first PC and noise. The surface defects can be effectively detected using an appropriate threshold. The experimental results show that the proposed inspection system has less sensitivity to the inhomogeneous of illumination, and has more robustness and reliability with pseudo reject rate reducing to 2%.