Abstract:The vehicle stability characteristic was represented by coupling of state variables, the front or rear tyre side slip angle and its angular velocity. To improve the maneuverability and stability of vehicle, a fuzzy supervisory control based on integrated control algorithm was implemented to coordinate the subsystems of the vehicle chassis control system. According to the control weights assigned by the upper supervisory controller, the subsystems including active steering control, active driveline control and active brake control were proposed to achieve their performance targets independently. An 8-degree-of-freedom nonlinear vehicle model was used in simulation to verify the integrated algorithm through critical test maneuvers. Simulation results confirm that, compared with the conventional stand-alone or combined controllers, the proposed hierarchical control algorithm provides vehicle with better performance of maneuverability and stability, while avoiding conflicts among the subsystems and decreasing consumption of the control.

Abstract:In order to understand the kinematic properties of the tripod sliding universal joint, its kinematic model was established. First, the relation between the input and output angles and the relative displacements of the slide-rods to the input shaft and to the tripod were obtained by using coordinate transformation technology. And then, the expression of the fluctuation of the joint angle was derived from the cross product of the centerlines of the input and output shafts. The numerical results show that the output angle error, the angular velocity error of the output shaft, the joint angle and the relative displacements of the slide-rods to the input shaft and to the tripod are all periodic and similar to a sinusoid. In addition, the output angle error, the angular velocity error of the output shaft and the joint angle have a threefold frequency of the input shaft, whereas the relative displacements of the slide-rods to the input shaft and to the tripod have simple and twofold frequencies of the input shaft respectively. The gained results agree well with the main documents, and validate the present model.

Abstract:Due to the characteristic of non-linear dynamic, time-delays, external disturbance and parameter uncertainty, the automated clutch is difficult to be controlled precisely. A sliding mode controller was introduced to control the automated clutch effectively. The sliding and global stability conditions were formulated and analyzed in terms of Lyapunov full quadratic form. The rapid control prototyping of automated clutch was built based on dSPACE. The experiment results show the controller is effective and robust to the parametric variation and external disturbance.

Abstract:Using three parameters (the change of accelerator aperture, the vehicle speed, the accelerator) shift control in AMT vehicle, the vehicle speed response lagged to the change of accelerator aperture for the large inertia of the automobile, and the phenomenon of shifting frequently occurred when accelerator aperture varied extensively. The fuzzy control method was proposed on the base of three parameters into which the change of accelerator aperture was added. Meanwhile, aimed at the problem of excessive input parameter and rule, the method of double fuzzy rule was proposed which reduced the amount of rule, improved the processor operation ability. The simulation results verify the validity of control strategy.

Abstract:58%。By using powertrain system analysis toolkit (PSAT) which is kind of software with forward simulation approach and divided rectangles (DIRECT) global optimization algorithm, an energy management control strategy for a parallel plug-in hybrid electric vehicle (PHEV) on different charging depleting range (CDR) were studied. The results show that as the CDR increases, the impact of control strategy parameters on PHEV economic performance becomes smaller. By applying small-CDR optimal control parameters to PHEV, its average economic performance is better than that of large-CDR optimal control parameters. The final optimal energy management control strategy can reduce PHEV average equivalence fuel consumption to 2.70L/(100km), which is 58% lower than that of prototype vehicle.

Abstract:Models of the position and tool forces of backhoe hydraulic excavator were built based on the full analysis of kinematics, kinetic performance of working device and mathematic model of tool forces. Various restrictive factors of tool forces, which appeared in the work process, were discussed. A computation program based on VB 6.0 was compiled, which was used to calculate tool forces in any position of the working area. Computer plotting of drawing mine map that was divided by restricting factors was realized. The experimental results demonstrated the feasibility of this method.

Abstract:In order to solve the problem of the high cost and long period of ABS calibration and matching using threshold control method, the theory of brake decay power was applied to ABS calibration. The shortages of conventional method of matching ABS were analyzed. Utilizing the advantages of threshold method and brake decay power theory, the ABS calibration and matching method for vehicle based on brake decay power theory was put forward. According to theory that the slip rate by max of brake decay power approaches slip rate by peak of adhesion coefficient very well, the slip rate by max of brake decay power can be used for ABS control. The curve of relations between slip rate and brake decay power can be obtained simply relatively, so the period of ABS calibration can be shortened. Vehicle test proves that it can enhance matching efficiency observably and economize calibration cost largely.

Abstract:The ABS ECU indoor performance testing bench was developed to test the ECU fault diagnosis and control functions. The test bench consisted of the reoccurrence equipment of wheel speed signals, the measuring and controlling system, the data collection system, the basic brake system and the constant-pressure hydraulic power. The test result shows that the bench can satisfy the requirement of testing the ECU control. It was easy to set the faults of sensors, and easy to test the ECU diagnosis function for the test bench.

Abstract:An approach to modeling parameterized FEM tire based on experimental modal parameters was proposed. Natural frequencies, mode shapes and damping ratios of FEM tire model with the optimal parameters had good agreement with modes acquired by the experiment. With Craig-Bampton method and tire-ground contact characteristic obtained from tire static radial compression experiment, normal and constraint modes of FEM tire model were extracted for building dynamic substructure model of tire. The coupling of tire substructure model and vehicle multi-body model was realized through modal synthesis, which can contribute to vehicle dynamic simulation and optimization design.

Abstract:The process of sand-wall collision was performed to analyze the relationship between the collision and clogging of labyrinth channel emitter. First, the effect of Rc on pass rate of sand was analyzed using the CFD method. It was found that Rc has a great impact on the anti-clogging characteristics of labyrinth emitter and should be determined through experiments. In order to provide the experimental basis for the setting of sand Rc in numerical simulation, experiments of PTV were carried out for the determination of Rc under various pressure and different structure of labyrinth channel emitter, so that the anti-blocking performance can be more accurately evaluated.

Abstract:60.0°。 The influences of angles (45.0°, 60.0°, 67.5°, 75.0°) of dental labyrinth channels drip emitter on hydraulic and anti-clogging performance was studied by the following methods: the CFD numerical simulation of the velocity in the flow field, the PIV observation of the trajectories and velocity of particles in flow path and the samples experiment. The results showed that there is a negative relationship between angle and discharge coefficient together with flow state exponent, in addition with the increasing of the angle of emitters, the anti-clogging ability declines. Therefore, combining the hydraulic and anti-clogging performance, a reasonable angle of 60.0° is put forward.

Abstract:Disc infiltrometer with two diameters (diameter of 5cm and 15cm) and two distinctly textured soil (Yangling caly soil and Shenmu sandy loam soil) were used to carry out disc 3D laboratory infiltration experiment under five pressure heads (0，－3，－6，－9，－12 cm). The effects of different disc diameters and pressures on cumulative infiltration were studied. Four methods of estimating sorptivity were applied to calculate permeability of these two soils and their applicability were analyzed according to Vandervaere equation. The results are as followed: the cumulative infiltration capacity of 5cm disc diameter is bigger than that of 15cm disc diameter in the same while. The cumulative infiltration capacity of Shenmu soil is higher than that of Yangling soil under the same pressure. Among these four methods, Haverkamp equation provides the closest estimate to the references for the two textured soil.

Abstract:Based on the assumption that every section of pipeline is composed of two diameters, a mathematical model for optimizing the pumping tree pipe network was presented with the objective function of annual cost, using pump head, pipe length and standard diameter as decision variable. The infeasible degree function of solution in the species group was defined, and the constraint condition was handled by adopting annealing algorithm based on the infeasible degree of solution. The infeasible degree of solution was locally optimized through simulated annealing, to make it gradually approach feasible solution. Combined with the genetic algorithm global optimization and good local search capabilities of simulated annealing, a simulated annealing-genetic algorithm for the optimized design of the pumping tree pipe network was established. Simulation results showed that the model and algorithms have good performance for optimizing the pumping tree pipe network.

Abstract:Rotational flow self-priming pump’s volute is different from conventional pump, with special flow structure. 3-D unsteady turbulent flow of rotational flow self-priming pump under design condition was simulated by using large eddy simulation method and sliding mesh technique. In the impeller and volute, pressure distribution, velocity distribution and vortex’s structure and evolution characteristics of wake region and other flow message were captured. The results showed that static pressure is asymmetric in impeller. And the reason for vortex forming in separation chamber was analyzed. The gas fraction distribution shows that gas phase mainly centers on the blade suction interface zone in the impeller. Performance prediction was carried out and performance curves were gotten. The performance experiment results was conducted and compared with prediction results. Large eddy simulation was accurate in predicting performance and interior flow characteristics.

Abstract:3-D simulation was performed for the gas-liquid two-phase turbulent flow in self-priming pump by using Fluent software with Mixture model, SIMPLEC algorithm and Realizable turbulence model. The gas-liquid two-phase flow in self-priming pump was investigated in the pressure in the pump, the velocity in the pump, the distribution of gas and liquid phase in the pump. To some extent, the results reveal the self-suction process of the two-phase flow in self-priming pump, and provide references for self-priming pump design.

Abstract:Based on Matlab, BP neural network model for efficiency and head of centrifugal pumps with compound impeller predicting was established. Seventy-three groups of experimental data were selected as samples for BP neural network training with Levenberg-Marquardt law. Then twelve experimental data extra was random selecting to test the trained BP neural network. The main parameters for experimentation are flow rate Q, the number of blade z, outlet angle of blade β2, inlet diameter of splitter blade Di, outlet width of impeller b2, efficiency η and head H. Select Q, z, β2, Di , b2 as input layer, η and H as output layer. The results show the predicted value favourably accorded with experiment. So it is possible to use BP neural network for predicting performance of centrifugal pumps with compound impeller. BP neural network can be applied to compound impeller designing, which can shorten experimental time and reduce cost.

Abstract:In order to implement the parametric optimization design of centrifugal pump blade, the partial differential equation was used to design the impeller meridian plane and the 3-D blade surface. Firstly, quartic Bezier curve was employed to design the meridian plane, and then the partial differential equation was introduced to produce the original streamline and meridian quasi-orthogonal lines. Secondly, the partial differential equation was used to generate the centrifugal pump blade surface. According to the blade streamline equation, the angular coordinates of dispersed points on pump blade boundary was calculated from the distributions of blade angle on boundary. Consequently the boundary-value of the partial differential equation was determined. The blades geometries was controlled by adjust the distribution of the blade angle along hub and shroud. The relation between the 3-D model of pump blade and the pump design parameters was built, to achieve the parametric design of pump blade. The gradient optimizing method was introduced to realize the optimization of pump blade. The calculation result of the flow field was used to renew the shape of pump blade. The calculation case shows that the presented inverse method of centrifugal pump blade is rational.

Abstract:The performance deficiency of non-overload centrifugal pumps was analyzed. A design idea of non-overload centrifugal pumps was suggested that combined the enlarged flow design with the clogged flow passage design. And, three improved attempts on IS50-32-160 non-overload centrifugal pump were carried out supported by commerce software Fluent to forecast the performance of centrifugal pumps. The forecast results indicate that by adopting this design thought, the head and efficiency of non-overload centrifugal pumps is increased. Furthermore, a reference is provided for optimal design of low specific speed centrifugal pump.

Abstract:The diffuser grid was mounted at the impeller inlet to improve the anti-cavitation properties of high-speed magnetic drive pump. The fluid field of two high-speed magnetic pump, with the diffuser grid and not, was numerical simulated by Fluent program. The distribution of pressure was taken out, and the trace of the particle was plotted. The main characteristics of the interior fluid field of the two pumps were obtained by comparing with two groups of data. The results show that the pump with the diffuser grid of changeable position in axial direction can improve the anti-cavitation performance. The application examples from practical tests favorably validated the results of simulation, which provide theoretical basis for improving the design.

Abstract:The flow field at the outlet of impeller in the designed axial-flow pump was measured by using the five-hole probe. Three velocity components and circulation curves were obtained. The measured results show that the flow field at the outlet of impeller is a spiral movement. Under the optimum condition, the rotary kinetic energy occupies 34％ of the total outlet kinetic energy and decreases with the increase of the flux. Accompanied by the small radial velocity, the axial velocity increases with the flow intensifying. The velocity circulation decrease from the hub to the flange, wherefore the more circular velocity at the flange and the less at the hub are needed. The 3-D velocity distribution of flow field can be measured accurately by the probe. This method has the merits of simple operation and well applicability.

Abstract:The simulation of cavitating flows in hydraulic runner for the hydraulic optimal design was presented by using the two-phase flow method through the solution of the time-average Navier-Stokes equations based on the mass transport equation. The results show that the efficiency apparently increases from 93.4% to 94.7% when the wrap angle of the blade enlarges and the trailing edges of the blade extend. The pressure on the blades is well distributed and the critical cavitation coefficient at optimum operating condition is lower than unmodified, 0.03, and the cavity domain are also decreased. Finally, the cavitation performance of runner is improved. The computational results, which agree with experimental data, provide a correct direction for further optimal design for the runner.

Abstract:For the sake of CFD simulation on the turbine flow field and practical manufacturing, the 3-D modeling of bent-elbow draft tube was analyzed, which showed that the common methods have a fussy process, not easy to modify and smooth. Therefore, this paper proposed a new method that overcomes the defect of the common method, has simple process, generates smooth surface, modifies flexible, and has a large adaptability. So the design intent can be more accurately realize through this method. Validated by instance and CFD analysis, the design method of draft tube agrees with the requirement of design assumption, and the flow of the draft tube are smooth and good.

Abstract:In electrostatic charged spray, the electrostatic and polarization forces produced by high electrostatic field coupled with fluid forces act on the droplets which has a marked effect on the motion characteristics of the droplets. To analyse the charged twin-fluid spray structure, the effects of electrification on spray structure and aggrandizement of heat and mass transfer were discussed. Furthermore, PIV technology was employed to measure the gas-liquid twin-fluid electrostatic spray, and the collected flow image was send to the computer via data line by the image grabber card. The spray images data were analyzed by using Insight 3.3 software and then flow velocity and streamlines were gained. The experiment results indicated that the twin-fluid electrostatic spray has the special spray flow structure. The distinctly different structures with main jet flow section, up convolution section, down convolution section and influence section in the spray flow field were formed. The complicated eddy current effect comes into being in the twin-fluid electrostatic spray from single convolution phenomena, which could make the droplets contact with gas medium easy, and enhance the droplets absorbency.

Abstract:Emulsified fuel from biomass pyrolysis derived bio-oil and diesel was prepared and fueled to a laboratory diesel engine tester. The experimental bio-oil was obtained from the pyrolysis of corn stalk powders in a fluidized bed reactor. The emulsified fuel was produced by mixing the bio-oil with commercial No.0 diesel oil as well as surfactants using a homogenizer. The performances of bio-oil/diesel oil emulsified fuels with two different bio-oil/diesel oil ratios were tested on a ZS1110 diesel engine. Consequently, the load characteristic and exhaust emission characteristic curves of diesel engine were determined, and the specific fuel consumption and effective thermal efficiency of the engine fueled with the emulsified fuel were analyzed in comparison with that of the pure No. 0 diesel oil. The experimental results show that, when the engine is fueled with the emulsified fuel at bio-oil concentration of 15%, the specific fuel consumption is lower and the effective thermal efficiency is higher than that of the pure No.0 diesel oil. The highest fuel saving rate reached 10%. Moreover, the NO and CO emissions are lower than that of the pure No.0 diesel oil.

Abstract:The effects of temperature on anaerobic digestion for biogas production were investigated. The tests were carried out in self-made anaerobic fermentation devices, with cabbage leaves as raw materials. Results showed that the value of VFA, NH+4-N and pH values at mesophilic fermentation ((35±1)℃) was in normal range superior to thermophilic ((55±1)℃) and room temperature. The total yield of biogas at mesophilic fermentation was 42.5% higher than thermophilic fermentation. The CH4 content at mesophilic fermentation was 7.6% and 19.1% higher than thermophilic and room temperature fermentation, respectively. Therefore, mesophilic fermentation condition is considered suitable for biogas production from cabbage leaves.

Abstract:A transient shrinkage model was proposed for bio-porous material on the base of the relationship between the shrinking volume and average moisture content of particle. The changes of boundary radius, shrinkage displacement and the tissue shrinkage of every element layer of the pea at 40℃ were calculated. As suggested in the result, the external of the pea firstly appeared contraction due to water loss, rather than synchronous contraction from the outside to the inside with the wet sub-external migration and humidity decrease during the drying process for the pea. There is no shrinkage of parts of no loss water. Furthermore, the external shrinked more greatly than the internal due to more water loss in the external of the pea.

Abstract:Due to the variable heat source problem for an adsorption cooling system in the practice, a silica gel-water adsorption chiller was experimentally studied, which was driven by recovered heat from gas engine. The chiller consisted of two desorption/ adsorption chambers and one heat-pipe working chamber of evaporator. The experimental results show that the cooling power with the 65℃ variable hot water temperature attains 63% of one under 90℃, and the COP (coefficient of performance) of the chiller has a small change which may be ignored. The transient refrigeration performance of the chiller has the good repeatability and stability. It was proved that the chiller driven by variable heat source is very reliable and good for low-grade heat source. This technology approach is feasible to be used for low temperature grain storage with combination of adsorption cooling and solar thermal or waste heat utilization.

Abstract:15%和10%。 An L9(3)4 orthogonal test was carried out to evaluate the storage quality of Agaricus bisporus under active modified atmosphere packaging with different temperature, packaging material, O2 and CO2 volumetric concentrations. Weight loss, fructification firmness, degree of browning, the respiration rate, membrane permeability, soluble solid content, polyphenoloxidase (PPO) and peroxidase (POD) activity of Agaricus bisporus were determined on the 3th day, 5th day, 7th day, 9th day, 11th day after storage, respectively. Study results suggested that, storage temperature was the most important factor affecting the storage quality of Agaricus bisporus, and a low storage temperature was essential to the preservation of Agaricus bisporus; the optimum treatment of active modified atmosphere packaging for Agaricus bisporuswas that storage temperature 2℃,packaging material PVC2, 15% O2 volumetric concentration, 10% CO2 volumetric concentration.

Abstract:In order to reduce the content of patulin in apple juice and improve the security, the ultrasonic degradation technology of patulin was studied. Based on the single-factor test, the optimum condition of ultrasonic was developed throughorthogonal design. The results showed that the best process parameters of patulin ultrasonic degradation in apple juice is power 420 W, time 90 min, frequency 28kHz,temperature 30℃, with the patulin degradation rate of 69.43%. There is minor impact on the key quality parameters of apple juice.

Abstract:80%。 A method of utilizing ultrasonic to modify alcohol leached rapeseed protein concentrate was studied. Then the functionalities and physico-chemical properties of the modified products were compared. The influence factors on the NSI were analyzed，such as pH value，modification time，ultrasonic power and RPC concentration. The orthogonal test results showed that the optimum modification parameters were as follows: RPC concentration 3%，modification time 5 min，ultrasonic power 300 W and pH value 11. Under the above-mentioned modification parameters，the modified alcohol leached rapeseed protein concentrate with NSI 86.94% and foaming stability 80% can be obtained.

Abstract:Two kinds of persimmon vinegar after accomplishing fermentation with natural and conventional fermentation ways was aged for 180 days at 3～6℃. Aroma components in the two kinds of persimmon vinegar were extracted by solid phase micro-extraction (SPME), then separated and analyzed by GC[CD*2]MS. About 63 kinds of volatile compounds were identified from persimmon vinegars with two different fermentation ways, respectively. Acids, esters, alcohols, hydrocarbon, aldoketones, phenols and a few other compounds exist in the volatile compounds. The content of esters, alcohols and hydrocarbon in volatile components from persimmon vinegar fermented with conventional way is 33.78%, 32.38% and 1.08%, respectively, and is bigger than with natural fermentation way. The content of acids, aldoketones and phenols fermented with natural fermentation way is 61.25%, 9.66% and 6.13%, and is bigger than fermented with conventional way. The sensory quality of persimmon vinegar fermented with conventional way is better than fermented with natural fermentation way.

Abstract:221.9μm。 The improvement of the crystalline technique of fructose was reported. The effect of sucrose ester S-570 and surfactant Span 60 on crystals was studied, and the results show that the CV of crystals can be reduced by 51.5% when adding 100mg/kg Span 60. The optimal glucoamylase is utilized to hydrolyze oligosaccharides in fructose syrup, under the optimal conditions: enzymes/oligosaccharides 600mg/kg and hydrolysis time 20h, pH value 4.0, reaction temperature 55℃, fructose syrup concentration 60%. The optimized cooling-crystallization conditions are as follows, seeds amount 2%, initial supersaturation degree 1.02～1.08, cooling rate before adding ethanol 0.4℃/h, ethanol concentration 0.2, cooling rate after adding ethanol: 0.28℃/h (52～46℃), 0.55℃/h (46～43℃), 0.80℃/h (43～35℃), 0.90℃/h (35～25℃). With the optimized parameters, the final product yield is 56.92%, and the mean size is 221.9μm.

Abstract:18%。 Heat recovery system of the self-excited oscillation heat pipe heat exchanger was designed and experimented. The effects of humid gas and operating parameters on heat recovery efficiency were studied. The results show that self-excited oscillation heat pipe heat exchanger can meet heat recovery requirements for the high humid exhaust gas. Under the given operating conditions, the system's heat recovery efficiency is higher than 18%.

Abstract:0.53。 The hardware system of an intelligent detection for growing crop was developed based on multi-sensor information. The stable light source was obtained from the detection chamber, and the temperature, humidity and lighting levels could be set in the system that could be used to simulate some growing environment of crops. The information including the spectrum information, multi-spectral image, canopy temperature and canopy lighting level for crops and ambient temperature, humidity information was collected by multi-sensor information acquisition system by which the crop growth information could be monitored effectively. Then, the system was used to detect the spectral and the multi-spectral image characters for the rape nitrogen level and the water content. Meanwhile, the influence of the light intensity was investigated for the detection system. The results showed that the influence of the environment factor on the results can be eliminated. The exact and quantitative analysis about the rape nitrogen content and the water content can be carried out by means of the multi-sensor information technology. The linear relationships between nitrogen content and spectral reflectance value is 0.92, with the RMSE of 0.53.

Abstract:In order to raise position and posture precision of farming robot, double three-point fix disposition principle and method of farming autonomous mobile robot were proposed which were used to implement position and posture precision of the robot when it was moving independently, and the laser survey sensor and ultra audible sound receiving sensor were employed to build up the measure and test system and realized examination. The experiments show that operation speed and controlling precision are increased by using the methods, its absolute error is aggrandized, whereas its relative error is reduced obviously, and it is sensitive for barrier on the ground, and its stability can enhance by raising its weight.

Abstract:42.3%和3.3％。 To improve the grafting rate of 2JSZ-600 vegetable grafting machine and the survival ratio of vegetable seedling grafted，a high-speed vegetable grafting machine with double manipulators was developed based on the essential structure of the old machine with a set of manipulators for transporting stock and scion added and the geometrical parameter of cutting mechanism optimized. The key structural parameters were determined by mechanism analysis and experiment. The cutting effects of stock and scion were best when angular velocity of cutter was 210r/min. The experimental results indicate that the average grafting rate of the machine is 854 seedlings per hour and the survival ratio is 93.3％, compared with the old machine, under the condition of the same grafting success rate and adaptability to seedlings. The grafting rate and the survival ratio are increased respectively 42.3% and 3.3％.

Abstract:A module partition method for product design was proposed. Firstly, fuzzy dendrogram clustering algorithm was used to illustrate the generating process of modules based on the correlativity analysis of function and structure between the sub-structures of product and then several module partition programs were obtained. Secondly, based on information entropy theory, mathematical evaluation model of module partition program for product design which considering the complexity of cross-series design, longitudinal series design and replacement design as the optimization goal was established, by which module partition programs obtained from fuzzy dendrogram clustering algorithm can be evaluated in order to get the most reasonable module division program. Lastly, straight-lead flower-line products machining equipment was used to illustrate the validity and rationality of the proposed method.

Abstract:A conceptual design of a novel six-axis hybrid machine tool with five-face machining capability was proposed. Based on the relative motions between the typical cutter and workpiece, the transformation matrix between the cutter and the workpiece was obtained. The transformation matrix was realized by the hybrid kinematics model of the machine tool. In this conceptual design, the few degree-of-freedom 3-PRS parallel mechanism was adopted at the spindle component to realize the linear Z-axis motions and rotary A and B-axis swinging motions, and the X-Y parallel driven mechanism and the C-axis NC rotation workbench were employed at the worktable side. The spindle component driven by 3-PRS parallel mechanism has the capability to swing ±45° by lean layout and designing component reasonably. The kinematics, rigidity and the workspace of the 3-PRS parallel mechanism were analyzed. Also the force bearing of the X-Y parallel platform and the 4 guides of the X- and Y-axis sliding tables was investigated.

Abstract:For reduction of scattered point cloud data, one algorithm based on non-uniform subdivision was put forward. The space partition of point cloud was generated using octree structure. k neighborhood was constructed through partition result. All the points in the k neighborhood were approximated by quadratic parametric surface of which the mean curvature determined whether to carry out non-uniform subdivision for the octree space or not. In the process of subdivision, the degree of subdivision depended on the maximum interval angle of each data point. Boundary points were identified and protected by constructing curvature difference function. The algorithm was applied for reduction of point cloud with curvature diversification. The reliability and accuracy of the algorithm were validated by experimentation.

Abstract:In order to eliminate the additional moments of force, the magnetic force, gravity force and friction force were studied in a novel two-degree-of-freedom (2-DOF) nanopositioning magnetic levitation stage. The structure of the nanopositioning stage was designed in terms of the theory of force balance, then, the direction and coordinate point of the drive force of the nanomotor were gained. The experiment of linearity and repeatability of the stage were carried out, and the experiments results indicated that the yaw error was less than 5 arcsec, the pitch error was less than 15 arcsec and the repeatability of these two errors were nearly 1 arcsec per one millimeter. The stage movement was stable.

Abstract:In order to design and manufacture the bionic skateboard with the super slippery function for catching insects, simulation on bionic slippery microstructure surfaces based on OpenGL was presented and performed. The wax microstructure of Nepenthes' pitcher superfaces was examined in scanning electronic microscopy S-3400N, and the images were collected for digital image processing and analyzing. Under the Visual C++6.0 compile environment, the graphics development framework of the OpenGL was established to realize the visualized simulation system of wax crystal layer, for different status parameters. The simulation results show that simulation crystal plates' length, thickness and height were (1.00±0.20)μm, (0.10±0.02)μm and (1.00±0.70)μm respectively. Compared with experiment data, the computer simulation has well accuracy and operation performance.

Abstract:By means of scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and optical contact angle measuring instruments, the microstructure, ingredient and hydrophobicity of dragonfly wing surface was investigated. Results show that dragonfly wing surface is covered with large number of papilla, leading to the composite contact between liquid droplet and dragonfly wing surface, which enhances the hydrophobicity of dragonfly wing surface. The waxy layer increases the hydrophobic capacity of dragonfly wing surface. Moreover, the hydrophobic equation of dragonfly wing surface was established through the Cassie model, and the multivariate coupling mechanism of dragonfly wing surface was analyzed. It is the conclusion that the hydrophobicity ascribes to co-coupling of the microstructure and ingredient of dragonfly wing surface.

Abstract:In order to understand the effect of condition and design parameters on trapped oil pressure in external spur-gear pump, based on the geometrical relationship of gear transmission of external spur-gear pump and relative position with relief groove, a new dynamic trapped oil model including equation of trapped oil pressure and dynamic coupled equation of gear pair was derived from the calculations of trapped volume and it’s first derivative and exchange flux from inside to outside of trapped volume and dynamic backlash value. Thereby simulation results of trapped oil pressure were produced and compared with tested results published in a literature. All results indicated the simulation results from dynamic trapped-oil model were greater in value than static trapped-oil model with trapped-oil pressure p2 exceeding p1, besides, all involved parameters discrepantly influenced trapped-oil pressure, accordingly optimization of operate parameter was necessitated. Finally, the validated trapped-oil model was thought to be right and reliable for forecast on trapped-oil pressure as well as vibration analysis along with vibration evaluation and optimization of entire design of gear pump.

Abstract:The drive screw was simplified as a rotating Timoshenko beam bearing the pre-tension force and moving forces, and the frequency equation of the screw with the elastic end supports was derived under considering the effect of gyroscope, the pre-tension force，the moving forces on the screw vibration, and the bearing stiffness. The dynamic model of the drive screw was established using Lagrange equation, and was analyzed adopting the mode superposition and Runge-Kutta method to calculate the transient response. Eventually, the effect of the system parameters on the whirl speed and lateral vibration was studied to supply a base for designing the drive system.