Abstract:A layered coordinated control strategy for direct yaw moment control (DYC) and anti-block braking system (ABS) were adopted aiming at improving the performance of electronic stability program (ESP). An upper coordinated controller was designed to adjust the bottom controllers DYC and ABS according to vehicle dynamic information. Simulation results show that the vehicle with coordinated control of DYC and ABS achieve better performances of dynamic stability when steering.

Abstract:An electric drive truck control system composed with a speed-current dual loop was designed to ensure the output power of electromotor and engine were matched and the engine can operate in economical condition. This demand the engine keep maximum permit current and accelerate in the shortest time to keep the vehicle’s best startup capability. Changeless output of vehicle in operation was guaranteed and impact like change when overcoming resistance during driving was overcame. Simulation result with Matlab provide the static and dynamic characteristic of the system.

Abstract:H∞ output feedback control strategy for linear systems with time-domain hard constraints was proposed, and its application to active suspensions was presented. In the framework of linear matrix inequality optimization, sufficient conditions for the existence of such a constrained H∞ output feedback controller, as well as detail steps for the controller designing were given. The proposed approach was applied to design active suspension systems on the basis of a two-degree-of-freedom quarter car model, with vertical body acceleration chosen as controlled outputs and dynamic suspension deflection, relative dynamic tire load, and control force chosen as constrained outputs. Simulation results show that the proposed constrained H∞ controller can achieve a promising improvement on ride comfort, while keeping dynamic suspension deflections, dynamic tire loads and control forces within given bounds, even variations of the vehicle model parameters exist.

Abstract:A double-mass model of air suspension was established. The method based on RBF network for matching optimization of air suspension systems damping and air spring was proposed. When the best match was chose, the vehicle body acceleration and wheels dynamic load were selected for minimum optimization objectives and the suspension dynamic travel was the constraint condition. Simulation results show that the bus ride comfort and road holding ability were improved. The simulation results agree with the testing data of the test bench.

Abstract:Taken the 2-DOF model as the study object, the fuzzy strategies to deal with the semi-active Hydro-pneumatic suspension were presented. In these strategies, the suspension deflection was the controlling objective. Then the simulation for fuzzy control system was developed and field testing was performed. The results show that the performances of semi-active hydro-pneumatic suspension excel that of traditional passive hydro-pneumatic suspension in the respect of ride comfort.

Abstract:For improving automobile ride comfort, safety and decreasing tire dynamic load to road, the four degree of freedom suspension model was established. MOGA (multi-object genetic algorithm) and multi-criteria decision method were applied to multi-objective optimization of suspension parameters, with root-mean-square values of vertical acceleration of body, front and rear tire load at 50, 80 and 100?km/h on A,B and C level road as objective functions. The results show that on average, root-mean-square value of vertical acceleration of body reduces by 40%, root-mean-square value of dynamic load of front and rear wheel reduces by 30%, and the performance gets better. This method, making decision after searching the Pareto solutions, can help the designer get the best answer under different demand. Compared with the traditional multi-objective optimization method, it is more applicable and effective.

Abstract:An evaluation function of muffler was defined to describe the weighted insert loss, exhaust back pressure coefficient and linearity coefficient in a comprehensive quantitative way, so as to analyze sound reduction effect, aerodynamic performance, as well as sound quality characteristics of the muffler in multiple working conditions. The evaluating functions of three different mufflers were computed by simulation with GT-Power and experiment tests. The comparison shows that the evaluation method could describe the comprehensive property of a muffler under multiple conditions, which could be used in muffler's matching design.

Abstract:The paper firstly analyzed the characteristic of vehicle road way test and the structure of the test system, and then brought up the development tendency of high reliability, high integration, synchronizing data acquisition, CAN communication interface, and so on. Thirdly, three key technologies were reviewed concretely in light of the industrialization requirement of vehicle dynamic stability control system, i.e. DSC, which include measurement method of the path and attitude of vehicle, the wheel force measurement technology and the steering input control method. The main stream of measurement technology for vehicle road way test in future may be the GPS only based measurement method of the path and attitude of vehicle, wheel force transducer based wheel force measurement method, the integration measurement of GPS devices and steer robot for the precisely steer control and path following road way tests.

Abstract:An experimental analysis of HCCI by port injection of DME was carried out on an engine retrofitted from a diesel engine. The in-cylinder pressure with and without knock were processed by discrete wavelet transform. Wavelet energy of different levels were calculated and analyzed to obtain DME knock characteristics. The analysis shows that the energy distributions with and without knock display different characteristic. Without knock, the energy value of the detail D3 at level 3 is the largest, and the value of the detail D1 at level 1 is the largest with knock. With the increase of engine speed, or adding LPG into DME injected in the port have little effects on energy distributions. The knock intensity, however, plays a key role in determining their distribution. The more intensified the knock is, the larger the energy values of D1 goes. The energy value of D1, D2 and D3 can be used to detect knock.

Abstract:The basic methods of H-infinity control theory and model of standard H-infinity design problem were described. The H-infinity robust control theory was applied to the design process of CNG engine idle speed control. The dynamic model of CNG engine was established. The diagram of engine uncertainty was stated. A controller of CNG engine idle speed was successfully developed based on H-infinity control theory and Matlab robust toolbox. The simulations and experiments about the CNG engine were done and the results show that the H-infinity controller possesses good robust features and can improve the stability of CNG engine idling operation.

Abstract:This paper presented the different mass motion and the mechanism, analyzed the effect of the mass motion on the combust process of the engine. Combustion chambers with different structure and size that fit the combustion of the lean burn CNG engine were given and the effect of the chambers with different structure on the performance of CNG engine was studied through numerical study and experiment. The result shows that the combustion of lean burn engine with high turbulence chamber is fast, provides more power and economic performance, but high NOx emissions.

Abstract:Based on the analysis of liquid fertilizer deep application characteristics, against the problem of the artificial ditching and hard burying during the process of fertilizer deep application, a kind of device which can apply liquid fertilizer deeply was designed. Quadratic rotation orthogonal experiment was conducted to test the fertilization performance of this device, Design-Expert 6.0.1 software was used to analyze, then, the influence of interaction of pump pressure, nozzle diameter, the forward speed of soil-bin trolley and the closing valve opening to fertilization loss rate were obtained. Ultimately, the optimum performance parameters of liquid fertilizer device are ascertained: the pressure of liquid pump is 0.2MPa, the nozzle diameter of spraying-fertilizer needle is 3mm, the forward speed of soil-bin trolley is 0.975m/s, the opening of the closing valve is 60% and fertilization loss rate is 2.8%. With the optimum performance parameters of liquid fertilizer device, the verification experiment result shows that the obtained fertilizer amount from the optimum combination of parameters can meet the design requirement, and the fertilizer loss rate is the least.

Abstract:。On the basis of analyzing disadvantages of conventional prediction model, a novel prediction model based on modified PSO least square support vector machine was proposed. Based on the new model, the design steps and learning algorithm were given. The practical experimental results show that the construction speed of this modified PSO LS-SVM model is 10 times less than that of the LS-SVM model, while the prediction error is 50%. Moreover, compared with BP model, the prediction accuracy is about 10 times higher than that of the former. The effects of electrostatic spraying parameters on atomization performance of electrostatic spraying nozzle can be predicted with the limited test data. Thus the variation law of atomization performance of electrostatic spraying nozzle following electrostatic spraying parameters can be obtained.

Abstract:5%。A dual-plate differential impact-based yield sensor was designed to eliminate the influences of the vibration signal. Two similar parallel plates were mounted in front of the outlet of the combine harvester. The front plate was used to detect the impact of grain out of elevator the harvester as well the vibration. The rear plate was used to detect the vibration only. A differential circuit was used to eliminate the vibration signal of the harvester. The experimental waves showed that the vibration signals of the two plates were similar while the harvester runs with no grain input. The influence of the vibration could be eliminated by the differential circuit. The zero drift of this sensor is less than 0.01g/s. The error of the yield sensor is less then 3% at flow rates 0.5～2kg/s in lab. It is not greater than 5% in field condition.

Abstract:The grain dropped to longitudinal cleaning sieve from threshing unit mound in the right corner of the screen deck will block cleaning. The theory of non-uniform air-flow cleaning was put forward and the conical centrifugal fan, resource of non-uniform air-flow was designed. Theoretical analysis and experimental verification show that, as the diameter difference between the small-end and big-end of conical centrifugal fan, the wind pressure difference of non-uniform air-flow forms, which results in high transversal wind velocity in the front of vibrating screen (the highest velocity is 2.6m/s). The wind pressure difference puffs falling grain to the other side, which changes initial distribution apparently and improves cleaning quality of transversal axis-flow feed combine.

Abstract:According to the special operation conditions of low-head pumping stations with variable speed devices (VSD) in China’s South-to-North Water Diversion Project, the changing rules of pumping system performances under variable speed operation were investigated. It was pointed out that the conventional pump affinity laws were not suitable any more when the net head was greater than zero while VSD were used, and a new affinity law was proposed. By means of linearized pump performances at rated rotational speed, simplified methodologies predicting pumping system performances with VSD were put forward. After introducing the conception of specific energy, the energy consumptions of variable operation and other regulation methods were analyzed to pump a specific quantity of water within stipulated period. Based on the consideration of VSD efficiency, electric motor efficiency and the relationship of specific energy with the change of pump efficiency at different rotational speed, a method was brought forward to determine the reasonable and economic scope of variable speed under different net heads.

Abstract:Aiming at the problem of reverse flow which occurred under low flow rate in a low specific speed double suction centrifugal pump, the inner flow of pump and suction chambers were simulated, velocity analysis of fixed-points which was proposed to simulate probe-sampling system in experiment was used in reverse-flow research. After the statistics and analysis of velocity changes of fixed-point in the inlet of impeller in different flow rates, it was found that the curve got from simulation accord with the theory analysis and experimental curve in other literature. Based on the analysis of curve, reverse occur flow rate, reverse stable flow rate and reverse flow range were defined and explained. A new method which was used to predict the effective thickness of reverse flow field according to theory analysis was proposed.

Abstract:Detailed flow characteristics in the impeller side chamber of a centrifugal pump were studied using CFD method. The computational domain was made up of impeller passages, volute casing, impeller side chamber and seal clearance. Under the hypothesis of steady flow, the RNG k-εturbulence model and RANS equations in multiple reference frames were used to simulate the flow fields. The good agreement of computational and experimental data shows that the CFD method is appropriate for the present study. Computational results reveal that the flow fields are unaxisymmetric in the impeller side chamber, and much more complex than that in an enclosed rotor-tator system. Nevertheless, along axial direction, the velocity profiles are similar with each other both in the impeller side chamber and in the enclosed rotor-stator system.

Abstract:Because of the sharp fluctuation of the load condition, the working points of the engine are mostly distributed in the high fuel consumption area. This causes low fuel economy of the power source and is the main reason of high power losses in conventional hydraulic excavators. In order to solve this problem, a new control strategy based on hybrid technology was presented. Its target was to achieve power matching and optimize the working condition of the power sources simultaneously. Experimental results show that the control strategy can realize the target. It reduce the speed fluctuation and optimize the working points of the engine. Meanwhile, it achieves higher fuel economy than conventional methods.

Abstract:According to the analysis of the unique working condition in hydraulic excavators, a structure of arm potential energy recovery in parallel hybrid hydraulic excavators was put forward. The force condition of cylinder was analyzed, and the mathematical models of hydraulic components (e.g. cylinder, throttle and hydraulic motor) and electric components (e.g. electric motor and NIMH batteries) were built up. Also, the control strategy of the hybrid excavator, which is equipped with arm potential energy recovery, and the control method of energy recovery were proposed. Theory analysis and simulation results present that, based on the fuel efficiency of the parallel hybrid hydraulic excavator, system's fuel efficiency will be further improved by means of arm potential energy recovery. The energy recovery system has the characteristics of simple structure, higher energy recovery efficiency and controllable recovery speed.

Abstract:K2CO3 loaded hydrotalcite catalyst was prepared by impregnation method and the condition of preparing catalyst with K2CO3 loaded 20%, blend temperature 80℃,roasting temperature 600℃ and roasting time 6h was confirmed. Biodiesel was prepared from rapeseed oil by transesterification with the solid base catalyst of K2CO3 loaded hydrotalcite. Factors that affected the reaction’s conversion like reaction temperature, molar ratio of methanol to oil, mass ratio of catalyst to oil and reaction time were investigated. The content of methyl ester was analyzed by GC. The conversion of 96.9% was achieved using a 12 methanol to oil molar ratio at 60℃ for 60min and 4% catalyst. The catalytic activity is closely related with its formation of new crystalline phase by the method of XRD and TG analysis.

Abstract:4.12%。Using seven types of biomass as raw materials, such as Chinese fir sawdust, corn stalks, rice husks and so on, experiments of biomass vacuum pyrolysis to prepare bio-oil were carried out in the home-made vacuum pyrolysis device. Seven kinds of bio-oil yields are more than 55%, and the bio-oil yield from Chinese fir sawdust is more than 67%. Component analysis results show that bio-oil is a kind of organic compounds with higher oxygen content. The major chemical components of seven kinds of bio-oil are similar, but large differences are in their relative contents. The phenol and phenol derivatives content in the bio-oil from Chinese fir sawdust is up to 72.81%. The bio-oil from Chinese fir sawdust contains eugenol whose relative content is 4.12%.

Abstract:Effect of four different emulsifiers on the physicochemical properties and stability of β-carotene nanoparticles in oil-in-water dispersions produced by a solvent displacement technique were examined. The β in carotene particle size was measured, and the stability and retention of β-carotene during storage were determined by HPLC. The particle size of β-carotene nonodispersions stabilized by sodium caseinate (SC) was generally larger than that in the presence of Tween 20, sucrose fatty acid ester (SE) or decaglycerol monolaurate (ML750). The addition of SE or ML750 could increase the ability of sodium caseinate to stabilize β-carotene particle formation. It is suggested that sodium caseinate can be useful to partly replace SE as emulsifiers in the preparation of β-carotene nanodispersions with less than 50 nm mean diameter. During storage at 4℃, although the β-carotene content in the nanodispersions showed a significant decrease with increasing storage period, especially in the case of Tween 20 as emulsifiers, the size distribution was almost unchanged in all prepared β-carotene nanodispersions.

Abstract:The parameters of one-component kinetic model (OKM) and two-component kinetic model (TKM) for extracting flavonoids from scutellaria radix were calculated when the kinetic curves at 4 different temperatures were obtained under 50% ethanol as solvent, liquor-to-solid ratio of 20g/mL and scutellaria radix particles with the size of 20～40 mesh as the experimental material. It indicates that both of the regression results of the two models fit the experimental data well with the correlation coefficient of regression (R2) more than 0.9800 and the relative standard deviation of regression (RSD) less than 1.00%. And although the regression result of TKM was better than that of OKM, the changing of some TKM parameters with temperature were unreasonable.

Abstract:The pyrethroids and carbamate pesticides in apple juice were treated by 60Co-γ irradiation. The effect of irradiation dose on degradation rate of pesticides and changes of main chemical and physical indexes of apple juice were researched on system. The result shows that 6Co-γ irradiation can degrade both pyrethroids and carbamate pesticides effectively: when the irradiation dose was 9kGy, the degradation rate of pyrethroids is Permethrin 65.72%, Cyfluthrin 94.14%, Flucythrinate 72.41% and Deltamethrin 67.84%; when the irradiation dose is 7?kGy, the degradation rate of carbamate pesticides is Lannate 61.64%, Primicarb 76.55% and Carbofuran 63.17%. 60Co-γ irradiation could affect main chemical and physical indexes of apple juice to some extent, the soluble solid concentration and the total sugar content decrease slightly, the total acid content increases slightly, the transmittance and the color value significantly increase.

Abstract:In order to determine the effectiveness of nano-CaCO3 appendix on chitosan, fresh cut yam were treated by chitosan coating with nano-CaCO3 appendix before stored at 10℃. The results indicate the titratable acidity (TA), Vitamin C content and L value of treated fruit by chitosan coating with nano-CaCO3 appendix was 10.5%, 8.4% and 6.9% higher than that of chitosan coating fruit, while the weigh loss and total phenolic content were 9.2% and 8.3% less than that of chitosan coating fruit. It also inhibited the activities of polyphenol oxidase (PPO) and peroxidase (POD) maintained lower level of BI and prolonged shelf-life. Therefore, chitosan modified with nano-CaCO3 have potential use in fresh cut yam storage.

Abstract:5min。Based on virtual instrument and bionic olfaction technology, the sampling method, sampling time and sample weight of silver carp stored at 4℃ were investigated by our home-made electronic nose with four gas sensor array during storage; PCA (principal component analysis) method was employed to optimize experiment parameters. The result indicated that the improved free air diffused method was the optimal sampling method, which can simplify the sample equipment compared to the traditional headspace method. The optimal measurement conditions for evaluating freshness of freshwater fish are 60gfor sample weight, free air diffused method for sampling method and 5min for sampling time.

Abstract:In order to find a method of vinegar detection based on ultraviolet fingerprint technology, different vinegars were used as materials, evaporation and ultraviolet spectra were studied to investigate how the factors of wavelength, dilution ratio of the liquid, evaporation temperature and mass concentration of reference affect ultraviolet vinegar curves. Finally the experiment conditions of the method were determined: wavelength at 245～330nm, quantity dilution ratio of the liquid at 1∶6,evaporation temperature at 45℃, mass concentration of reference at 45g/L. Similarity was used as the indicator to evaluate the ultraviolet curves’ feature of reproducibility, stability and difference. Three replicates of each measurement the result show that the similarity among vinegar samples fingerprints was more than 0.90, the similarity of the fingerprint of each vinegar samples in different depositing time was more than 0.90, the similarity of different fingerprint of different vinegar samples was less than 0.90. The method with excellent repeativeness, stability and differentiae.

Abstract:10%。A non-destructive detection method based on near infrared reflectance (NIR) spectroscopy and chemometrics was put forward for discriminating varieties and detecting soluble solids content (SSC) of fresh jujube. A FieldSpec 3 spectroradiometer was used for collecting 30 sample spectra data of the three kinds of jujube separately. Then principal component analysis was used to process the spectral data after pretreatment. Six principal components (PCs) were selected based on accumulative reliabilities, and these selected PCs would be taken as the inputs of the three-layer back-propagation artificial neural network (BP—ANN). A total of 90 jujube samples were divided into calibration set and validation set randomly, the calibration set had 75 samples with 25 samples of each variety and the validation set had 15 samples with 5 samples of each variety. The BP—ANN was trained using samples in calibration set. The optimal three-layer BP—ANN model with 6 nodes in input layer, 10 nodes in hidden layer, and 2 nodes in output layer would be obtained. Then this model was used to predict the sample in the validation set. The result show that a 100% recognition ration was achieved with the threshold predictive error ±0.17, the bias between predictive value and standard value was lower than 10%.

Abstract:db5小波。By using db1～db10 (10 in total) wavelet transform with the decomposing level of 4, the near-infrared spectra (NIRS) signals obtained from 120 umbilical orange samples were denoised, the PLS models of vitamin C (VC) content were established by each wavelet base. Through comparing the prediction accuracy of PLS models, it shows that all db wavelet transform can eliminate the noise in VC NIRS effectively, the prediction accuracy of PLS models are higher than models not being treated. When the wavelet was db5, the best prediction effect was obtained, with the correlation coefficient R between the prediction and true values being 0.9427 and the expected variance RMSECV being as low as 2.02mg/(100g). In conclusion, the db5 is the best wavelet for NIRS denoising of VC content in umbilical orange.

Abstract:Through the experiment of selective infrared radiation and vacuum drying and drying quality for litchi, it is found that the spectrum matching of litchi's flesh for radiation source has significant effect on drying rate, and the matching between vacuum and radiation heat flux has effect on drying rate and drying quality. The results show the optimum drying conditions are radiation source SZ, radiation distance 120mm, heating and tempering time 15min/15min and vacuum degree 0.02MPa respectively.

Abstract:0.26m。The method for fuzzy control steering and the construction of fuzzy controller were described in detail at first. On a refitted storage battery car, an automatic navigation control system was developed with DGPS, digital compass and angle sensor. The construction and work principle of the navigation control system were introduced. Line path tracking and curve path tracking methods were brought forward. At last simulation was taken using kinematics of two-wheel vehicle, at the same time line path tracking and curve path tracking experiments were conducted. Results of simulation and experiments indicate that navigation control system can make the vehicle run following the predefined path. The lateral error is less than 0.19m when the car ran following the predefined line route, and the lateral error is less than 0.26m when the car ran following the predefined curve path.

Abstract:On the basis of analyzing the temporal and spatial distribution of cotton leaf inclination angle, the ellipsoidal function was used to simulate the dynamic distribution of cotton leaf inclination angle. Cotton growth period was divided into four phases, and cotton canopy was divided into five layers according to Gauss distance. The model simulated the leaf inclination angle density distribution of different highness during different growth period that it can reflect leaf inclination angle distribution accurately. The model was validated by experimental data of different sowing dates. The coefficient of determination (R2) based on the 1∶1 line and the root mean square error between the simulated and measured values are 0.945 and 6.3% respectively. It proved that simulation results of the model come very close to the actual values.

Abstract:RMSE）为2.51。It was studied that using spectral analysis to quantitatively analyze the rape total nitrogen content. Stepwise regression was used to select the characteristic wavelength of total nitrogen content against rape leaf spectra for nitrogen content prediction. The method of principal component analysis (PCA) was used to avoid the effect of multiple co-linearity among the spectral data. In order to enhance model forecast precision, the method of support vector machine regression（SVR）was used to establish the model between the rape total nitrogen content and the spectral characteristic wavelength data. From the rape spectral data under different nitrogen level, it was found that the linear relationships between rape total nitrogen content and spectral reflectance value of 406, 460, 556, 634, 662, 675nm are very notable. The correlation coefficient between the predict value and the real value is 0.89, the RMSE is 2.51.

Abstract:88.0%。An automatic detecting and grading method of potatoes with computer vision was studied. Potatoes were graded according to their size by computing the potatoes’ longest axis and potatoes were grading according to the shape by computing the eccentricities. Sprouting potatoes were detected by computing the difference values of green channel gray value and misshapen potatoes were detected by computing sampling normalized radius differences’ absolute values. A potato grading software was designed to grade potatoes by size, shape and detect at the same time. The experiments show that the result with grading method described above is steady, and its precision was up to 88.0%.

Abstract:94％。Taking the seeds of “Zhongmian 35” as research objectives, a method of surface damages detection was developed based on morphology of cottonseed by the digital image technology. The boundary was picked up with chain code operator and smoothed by the Fourier operator. Find the tip of the cottonseed after analyzing the curvatures of contour points. Detect the local damaged cottonseeds according to the symmetry of the boundary. Area and elongation were used to identify seriously damaged cottonseeds with statistical method. The experiments show that the detecting accuracy is 94% with 200 damaged cottonseeds and 200 cottonseeds without damages.

Abstract:A novel method for automatic color grading of beef lean tissue was developed using computer vision and BP neural network (BP-NN) techniques. 160 beef rib-eye cross-section images were collected and color score of each sample were manually determined by a five-number panel. The segmentation of lean tissue region from rib-eye cross-section image was carried out and color features of each image were extracted using computer image processing technologies. A BP neural network model, with inputs of color features and outputs of color scores, respectively, was designed to automatically estimate the grade of beef lean tissue color. The optimum structure parameters of the BP model were determined by training. Finally, the proposed BP model was employed to predict the color score of each sample in validation set. Results show that average 95% of samples can be assigned a correct color score in 0.25s, indicating that the proposed method permits accurate, rapid and reliable prediction of color grade of beef lean tissue.

Abstract:An integrated module division method based on the combination of axiomatic design and fuzzy dendrogram was proposed. The product was divided step by step using the framework of zigzagging map between the functional domain and physical domain of axiomatic design. In the case that the design matrix are diagonal matrices, the substructures of the division meet the functional and structural independence and can be considered as a separate module, then the division of module can be ended. When the design matrix are triangle matrices or fall rank matrices, the correlation of function and structure between the substructures were analyzed and then fuzzy dendrogram was used to cluster the substructures into modules. An example was used to illustrate the validity and rationality of the proposed approach.

Abstract:Self-synchronous vibrating system which was driven by two rotating exciters and moved in a 2-D space can be simplified as a self-synchronization system with dual-rotors. A typical omnipotent vibrating synchronization experiment machine was used as a prototype, variation rule of each parameter and synchronous characteristics about self-synchronization vibrating system at several representative state were quantificationally discussed and validated owning self-synchronization ability. Base on measured data of omnipotent vibrating synchronization experiment machine, the synchronous characteristics of the system were compared with measured data. Its rationality was testified. Besides, base on the measured data and emulational result, the system was found to own the self-synchronization ability for the uneven vibration force in self-synchronization vibrating system at the measure and emulation mode, even though the power supply of motion with big vibration force was shut off.

Abstract:Fully compliant mechanism of incomplete distributed compliance is a kind of new compliant mechanism whose compliance is between lumped and distributed. According to the characteristic of this compliant mechanism, a new analyzing model based on pseudo-rigid-body model named imitate-compliant-body model was presented. The imitate-compliant-body model of rectangular flexure hinge and link was established. The coefficient of load ratio μF and correct coefficient μλof the model were also defined. Finally the results of five samples using the imitate-compliant-body model were presented. Through the experimental test of the five samples and the compare of the results with computer and test, the validity of this model was proved.

Abstract:2UPS-2RPS is a 4-DOF parallel mechanism with two different structure limbs. It has the advantages of simple mechanical structure, low manufacturing cost, and simple control algorithm. The number of its DOF is less than six, the limbs not only transmitting driving force but also constraint force at the same time. So both the required driving and constraint force analysis are necessary in the dynamic control and optimization design of the mechanism. Inverse dynamics equations of the mechanism were modeled by using the Newton-Euler formulation, through solving the equations, the required driving and constraint forces can be obtained when the motion of moving platform and working load were given. A computational example was also provided.

Abstract:The mathematic model of joint friction in mechanical system was put forward, in which the action forces in joint were converted into ideal constraint force and friction moment. The friction was dealt as exterior non-inertia force, and the dynamics equation including nonlinear friction of planar 5-bar parallel mechanism using the method of reduced model was presented. A sliding mode controller was designed for compensating the influence of nonlinear friction and time variable parameters. The stability analysis using Lyapunov’s direct method shows that the controller is asymptotically stable. The results of experiment demonstrate the effectiveness of the proposed model and controller.

Abstract:Based on chaos theory and via experiments, the evaluation for the nonlinear characteristics of the time series of the rolling element bearing friction torque was studied in order to lay a foundation of accurately calculating the dynamic performance of the rolling element bearing friction torque. The standard deviation of the relation dimension was used to depict the uncertainty of the friction torque and the mean of the relation dimension was used to describe the evolutive history of the nonlinear characteristics of the friction torque. The investigation indicates that the rolling element bearing belongs to the certain nonlinear dynamics system, but its friction torque presents the obvious uncertainty. As the rotational speed is raised both the standard deviation and the mean of the relation dimension of the rolling element bearing friction torque take on the nonlinearly increasing trend.

Abstract:Hydrodynamic retarder under different vane degree condition was simulated. By using the time averaged N-S equation and the standard k-εturbulence and the SIMPLEC algorithm simultaneously, the internal characteristics of flow field were simulated. The calculated velocity, pressure and turbulent kinetic energy distribution of the turbulent flow in hydrodynamic retarder were given. The method of loss analysis was proposed which changed value of Rothalpy was used to compare the retarder ability. The result shows that the model under 55° vane degree has the biggest impact because the loss of friction and impact made hydrodynamic loss most.

Abstract:A finite element simulation model of the high-speed electro-pneumatic ejector valve actuator was built to analyze its steady state and transient performances. Optimal design was implemented by turning the fringe part and boring the center part of the armature base on steady state finite element analysis. Comparing with the original actuator, the optimized actuator has an almost 71% reducing in the armature weight whilst without significant steady state solenoid force loss in the actuator and without significant increase in structure dimensions that it gets a considerable improvement in armature acceleration, so the response times decrease by typically 8% under different work conditions. Finally, prototype electro-pneumatic ejector valves were fabricated according to the optimized actuator model, and a test facility was also built up to obtain the valve’s dynamics. The agreement between the simulation results and the experimental data proves the effectiveness of the simulation model.

Abstract:The dynamics of a pilot-operated two-stage solenoid valve used in power system were studied numerically. A dynamic model coupling vibration of solenoid valve with fluid flow in the valve was derived. While solving the system equations, vibration of the valve spindle, various pressure-flow characteristics across the valve ports and orifices and pressure variation in chambers were taken into consideration. The model was validated by experimental results. The simulation results present stability of the spindle for different operating conditions and effect of working pressure and working flow rate on dynamics of the solenoid valve.

Abstract:The mathematic model on the leaking flow field of the piston sector considering the high press and high velocity in the piston pump was established, and the numerical simulation and analysis were done. At first, the 3-D dynamic analysis on the piston sector was done and the force change principle of the piston sector was analyzed in the Matlab program. Then, the theoretical mathematic model about the flow field in the piston sector with the acentric and inclined armillary seam was built based on two parameters: the inclined angle φ and the acentric distance e. These two parameters φand e were numerically solved with the theory of dynamic pressure supporting and the result of the dynamic analysis on the piston sector. The numerical analysis on the leaking flow field in the piston sector with the acentric and inclined armillary seam was done in the Matlab program with the method of 1-D searching in some conditions. At last, the simulation was done with Fluent and the experimentation was conducted. The computing and analysis results indicate that the armillary seam in the piston sector is acentric and inclined considering the high press and high velocity, the change extent of the leaking flow rate in the piston sector is broader than which in the piston sector with the assumed homocentric armillary seam, but the average leaking flow rate is less in practice.