Abstract:A micro drilling process using a turbine driven air spindle was developed to improve drilling quality.Some drilling experiments for drilling 0.5 mm holes magnesium alloy AZ31B sheet were carried out.The influences of rotational speed and feed rate on burr height at the exit of the micro hole,saperture error and roundness error at the entrance were investigated.The aperture error and the roundness error were obtained by the image processing and the least square method.Drilling parameters were optimized synthetically.The results show that performance of the spindle is in a good condition.When the rotational speed is 20 000 r/min and the feed rate is 0.4 mm/s,the comprehensive quality of micro drilling reached the best.

Abstract:Due to the large residual stress existing in micro-structure optical elements after GPM，the glass material D-ZK3 with low transition temperature was selected，and a finite element simulation model of micro V-grooves was developed with the software MSC.Marc.Five-element general Maxwell model was used to describe the viscoelastic properties of D-ZK3 glass at high temperatures，and the fill effect and stress distribution of micro V-grooves were simulated and analyzed under different molding parameters.The simulation results show that the maximum stress increases and filling effects are improved when the V-groove angle increases；the higher molding speed leads to higher maximum stress and molding pressure；whereas the maximum stress decreases with the increasing of molding temperature.

Abstract:The fuel consumption rate of Atkinson cycle engine has always been optimized by GT-Power detail model with Genetic Algorithm (GA) (scheme 1),but this method is hard to converge and its calculation is very slow，so a simplified model coupling GA based on Artificial Neural Network (ANN) (scheme 2) for optimization and comparison was proposed.A detailed simulation model based on GT-Power software for Atkinson cycle engine had been carefully built by scheme 1，and the Knock prediction model was built based on Heywood formula.The fuel consumption was then optimized by scheme 1.Scheme 2 used the Latin Hypercube Sample (LHS) to collect 4 500 experimental points，and simplified the GT-Power model and Knock model into the ANN model，which was optimized by the simplified coupled GA model.The results show that by using scheme 2 for the optimization of Atkinson cycle engine，the actual fuel consumption rate is reduced by 4.6%，and the maximum error rate related to the measured optimization results is 7.3%，while the maximum simulation optimization time was saved 322 times that for scheme 1.As a result，the fast global optimization of the fuel consumption rate for the Atkinson cycle engine is feasible by using scheme 2 rather than scheme 1.

Abstract:This paper focuses on the vehicle compressor.Firstly，the characteristics of flow field and broadband noise of compressors are calculated based on the steady state RANS equations，and the results demonstrate that the main noise source of the compressor locates in the impeller areas.Then，based on the large eddy simulation (LES) and Ffowcs - Williams & Hawkings (FW-H) equation of the acoustic analogy method，the compressor discrete noise is predicted，taking the compressor impeller as the main noise source.The results show that the main noise source of compressor locates in compressor impeller areas.In addition，by means of simulation，the sound pressure varies approximately in the same trend with the experiment value，taking compressor impeller as the main noise source.The simulation value is slightly greater than the experimental value with the error less than 10%.Therefore，it is concluded that the simulation calculation method is feasible，which provides the reference value for further study on the vehicle compressors.

Abstract:In view of the limitation of the current various Q-Morph algorithms that can generate isolated triangles in the process of generating quadrilateral mesh，a new advancing front method with constraint was proposed.The method is a kind of Q-Morph algorithm based on advancing front.First，the two side edges and one top edge are generated according to the current front.Then the triangles in the quadrangle are eliminated from the triangular domain.Finally a quadrilateral mesh is generated.Moreover，some constraining conditions are imposed on the advancing procedure to avoid generating isolated triangles，which can improve algorithm efficiency and mesh quality.Numerical experiments are presented to demonstrate that the new method could generate high-quality quadrilateral meshes for complex surface automatically.

Abstract:Considering the changeover time in the process of assembly production，a mathematical model with an objective function to minimize the cycle time of robotic assembly line was developed.On the basis of the model，an adaptive strategy was combined into the frame of simulated annealing genetic algorithm，and an Adaptive Simulated Annealing Genetic Algorithm (ASAGA) was then proposed.Finally，an example of the welding assembly for the inner assembly of the left front door in the Body Shop was provided to illustrate greater advantages in the quality of the solution and the algorithm convergence，compared with the SGA (Standard Genetic Algorithm) and SAGA (Simulated Annealing Genetic Algorithm) in solving this problem.

Abstract:As the different automotive seat-pan angle affects driver sitting comfort，musculoskeletal biomechanical characters of different figure drivers were analyzed by simulation and experimental tests.Firstly，based on human musculoskeletal biomechanical computational software，the musculoskeletal models of the 5th，50th and 95th percentile Chinese male drivers were built.Secondly，using the dynamic adjustment of seat-pan angle and the method of correlation analysis，the force and muscle activation of driver lower limb different muscles were described.Finally，a set of EMG tests on real driver leg muscles were carried out in a real vehicle.The result shows that when the automotive seat-pan angle increases，muscles activation of driver gluteus maximus，iliopsoas，semitendinosus，rectus femoris muscle，sartorius，gastrocnemius muscle and tibialis anterior are larger.The ideal variation of seat-pan angle is between 10°and 16°.

Abstract:Adaptive and sparsest time-frequency analysis（ASTFA）is a new method for time-frequency analysis.ASTFA is lack of adaptivity as comparatively accurate initial values have to be set beforehand.Aiming to solve the problem existed in ASTFA，adaptive and sparsest time-frequency analysis method based on initial value optimization was proposed.The energy value of the residue is applied as the optimization objective function，and different initial values are used for signal decomposition.Initial values are considered to be the best only if the energy value of the corresponding residue is the smallest.Therefore，the adaptivity of ASTFA method is improved by the proposed method as the best initial values can be found adaptively. Simulation signal is applied to compare the proposed method and the initial ASTFA method.The results show that more accurate decomposition results can be adaptively obtained by using the proposed method.Analysis of simulation signal and rolling bearing fault signal shows that compared with empirical mode decomposition（EMD）method，the proposed method is superior at least in restraining end effect and mode mixing，anti-noise performance and gaining more accurate components.Meanwhile，the proposed method is effective in rolling bearing fault diagnosis.

Abstract:The diaphragm cylinder diameter of intelligent self-operated pressure reducing valve（intelligent pressure reducing valve for short）have important influence on sealing performance of control unit，which affects the valve performance parameters such as pressure variation range，service life，power and etc.This paper presented a method to optimize the diaphragm cylinder diameter of intelligent pressure reducing valve，including building the pressure correlation theoretical model according to static equilibrium equation，getting the raw data by fluid experiment and high accuracy sampling，building the actual mathematical model by linear regressive，and optimizing the diaphragm cylinder diameter by minimal extreme optimization model with constraint condition.The results show that under the optimization dimension，the sum of pressure difference reduces by 30.6%，the limitation value of the maximal pressure difference reduces by 7.7%，and the limitation value of the minimal pressure difference reduces by 39.6%，which are beneficial for reducing the control system leakage.The pressure correlation model and optimization model offer a good reference for the design of intelligent pressure reducing valve.

Abstract:Based on compressed double segment flexure hinge，the four segment X-shaped flexure hinge was designed，and its structure characteristic was studied.As the major deformation segment of X-shaped flexure hinge is bending-torsional coupling segment，the analysis on the equivalent stiffness of bending torsion coupling was performed by differential method and the method based on compressed double segment flexure hinge，and the theoretical calculation formula of the equivalent stiffness of X-shaped flexure hinge was derived.Several examples of X-shaped flexure hinge with different sizes were presented，the equivalent stiffness of these examples was calculated by two calculation formulas，and the simulation analysis on these examples was then carried out through ABAQUS software.The results of the three methods have showed the correctness of the theoretical calculation formula and the simulation model.Finally，the range of structural parameters that should be avoided when designing the hinge was obtained by the analysis of the structure characteristic.

Abstract:In order to improve the response speed and accuracy of automotive electronic throttle valve opening control，a Non-singular Fast Terminal Sliding Mode (NFTSM) control strategy was designed.Firstly，the non-linear mathematical model was obtained by analyzing the nonlinear and disturbance of the electronic throttle valve control system.Secondly，a NFTSM surface and a terminal attractor were constructed by using the error between electronic throttle opening and the desired opening and the derivative of the error，at the same time，an extended state observer was applied to estimate the first order derivative of the opening degree.Meanwhile，a NFTSM controller with no singular control and fast convergence was designed，which verified the stability of the controller by using Lyapunov's stableness theory.A number of simulations were conducted to test and verify the performances of the NFTSM control method and conventional sliding mode control method in MATLAB/simulink by using sine signal，step signal，triangle wave signal and approximate stair-step signal as the input signals respectively.The simulation results show that the NFTSM control method has shorter settling time and smaller tracking error compared with the conventional sliding mode control method.NFTSM controller can keep the electronic throttle opening consistent with reference signals in 0.1 s and has steady-state error less than 0.2°，while the conventional sliding mode controller needs more than 1 s and has large tracking error.In addition，the simulation results of the system under the impulsive disturbance signal show that the NFTSM controller has excellent robustness.

Abstract:In the hybrid AC-DC-AC electric drive system of engineering equipment，the PMSM usually regenerates excessive braking energy to the D.C bus during the regenerated braking process.The excessive energy is likely to cause the D.C bus voltage pumping and reduces the operating performance of engine.To solve this problem，this paper analyzes the reason of D.C bus voltage pumping in the braking process from the view of the non-coincidence of the DC/DC and the inverter.On this basis，a control strategy of a feed-forward compensation added to the FOC outer loop is proposed.This strategy uses the PD controller to deal with the error between the D.C bus voltage and its reference value，and then adds the outputs of PD controller to the reference of iq，so that the iq and the duty cycle of inverter can be both reduced.The regenerated power of PMSM is also limited.The simulation results show that the proposed control strategy can effectively improve the problem of D.C bus voltage pumping during the PMSM regenerated braking process，which is good for the electrical safety protecting in the D.C bus.

Abstract:Based on the electromagnetic shielding properties of high permeability ferromagnetic material and high conductivity materials，a three-dimensional finite element method analysis was performed to evaluate the magnetic characteristics of the cylindrical shield immersed in a steady uniform magnetic field generating by the copper coil on the iron core.The effects of the thickness of the magnetic shielding material，the number of layers of the cylindrical shell，and the excitation frequency on the magnetic shielding effectiveness were studied.The problem of optimal magnetic shielding method for different magnetic shielding materials such as the high permeability material and high electrical conductivity material is to be solved.The new technologies are explored to improve the efficiency of the magnetic shielding，which has important theoretical and applied significance in the electromagnetic compatibility problem.

Abstract:In view of the problem in which most target bodies are continuously changing and the distribution is complex in the actual geological structures,2-D magnetotelluric forward modeling is simulated combined with the advantage of meshfree method where parameter loading is convenient,calculation accuracy is high and adaptive analysis is convenient.The shape function of the continuous medium model is constructed by the radial basis function,the equivalent linear equations are derived and the corresponding program is compiled.The optimal values of the shape parameters are given by numerical experiments.The correctness of meshfree method is verified by a horizontal continuous variation layered model.The root mean square error of the calculation results is not more than 0.36%,and its accuracy is superior to the finite element method.The electromagnetic response of the horizontal layer with the continuous variation of electrical conductivity and the uniform block model is discussed,and a graben terrain model and a reservoir water flooding model whose conductivity is continuously variable are calculated,respectively.The conclusions are given: the electromagnetic responses between the continuous variation model and uniform block model are significantly different,the use of the continuous variation model is helpful to improve the accuracy of inversion in the actual interpretation,and the observation method of the TM mode has better resolution for the inclination distribution of anomalous body.The meshfree method does not need the complicated mesh generation,and it is more suitable to calculate the response of continuous variation and complex distribution models.Therefore,meshfree method is expected to be a new and robust method for the numerical simulation of complex medium and complex structures.

Abstract:Combined with the feature of near-surface electromagnetic emission signals in the frequency domain，an average current and a voltage feedback control were introduced.A digital dual-loop feedback control system was built based on DSP (Digital Signal Processor).A feedback model was also built in z domain to make the system stable.The steady voltage in low frequency and steady current in high frequency were realized.The amplitude of the load-current range of transmitting antennas was reduced，while the requirements of antenna design were decreased.The problems that the broadband detection transmitter is not enough to cause the antenna current damping in the high frequency and the broadband detection transmitting is not stable to the large current in low frequency were avoided.Further，a protection of circuit was provided.Through comparing the simulation after the introduction of dual-loop feedback and open-loop，the parallel dual-loop feedback output current variation was 8.5% of that for open-loop with low to high frequency.The measured results achieve the purpose of design and provide references for the improvement of near-surface electromagnetic launch system.

Abstract:In order to optimize the excitation control problem of hydro-generator,a mathematical model was presented.With the fuzzy theory and the advanced intelligent optimization control method,a hydro-generator excitation controller was proposed based on the integration of particle swarm algorithm (PSO) and fuzzy PID.The initial parameters of controller were selected by PSO,and the system was dynamically controlled by FAPID.Finally,compared with the traditional PID control and fuzzy control PID control,the simulation results show that the fuzzy adaptive PID excitation control based on the particle swarm optimization algorithm has faster response speed (less than 1 second rise time) and smaller overshoot (less than 5% overshoot).The control system as an advanced control method can be faster,more accurate and stable.

Abstract:A low-noise preamplifier applied to the intraocular pressure signal-detection system with 180 nm CMOS process was proposed.The amplifier adopts a diode-connected MOS transistor to achieve a large resistance of GΩ level.In the feedback loop,the pseudo-resistor and the feedback capacitor are connected in parallel to generate a high-pass cutoff point in the low frequency,which can suppress the DC-offset voltage and the noise in low frequency to achieve better noise performance.The post-simulation results show that the low noise preamplifier has a DC-gain of 40 dB,the effective bandwidth is from 0.25 Hz to 46 kHz,and an equivalent input noise is 197.3 nVrms at 100 Hz.The power consumption of the core circuit is 32.4 μW at a supply of 1.8 V,and the chip area is 0.75 mm×0.62 mm.

Abstract:The fuzzy system is used to model contact resistance.Firstly,the test is processed by the total factor method,and lots of data are obtained.The part that can reflect the characteristics of whole sample space is selected as the training data to train fuzzy system.The other part called testing data is used to evaluate the fuzzy system and verify the dependability of fuzzy system.Afterwards,according to the characteristics of basic genetic algorithm and recursive least square algorithm,the two algorithms are combined to form hybrid algorithm,where the recursive least square algorithm is processed after basic genetic algorithm.By training data,fuzzy system is trained by recursive least square algorithm,basic genetic algorithm and hybrid algorithm,and it is found that the convergence of hybrid algorithm is better than that of the other algorithms.Through using regression analysis,the model of contact resistance is found.All models are tested through testing data,the dependability is verified and the prediction result is compared.The fuzzy system obtained by hybrid algorithm has the best prediction effect.The result of the prediction and comparison shows that if the training data is enough,the fuzzy system trained by hybrid algorithm is reliable to predict contact resistance.

Abstract:With the development of system on chip (SOC),the precision and power consumption requirements of bandgap reference are becoming more stringent.Until now,high order temperature compensations still have some restrictions in the process compatibility,design complexity and power consumption.In this paper,the temperature characteristic of a new current mode bandgap reference operating in saturated region is derived,and effective curvature compensation is implemented by current ratio subtraction in the output branch circuits with double bandgap structures.Thus,a new CMOS bandgap reference of double bandgap structures is implemented.Layout area of the bandgap reference is 0.066 mm2 in GSMC 0.18 μm process.The results of Monte Carlo post-simulations show that the average temperature coefficient is 14.27 ppm/℃ in the temperature range from -40～125 ℃,and the average reference voltage is 1.201 V at 27 ℃.The average static current is 9.865 μA and the power supply rejection is -37.21 dB at 3.3 V operating voltage.The bandgap reference designed in this paper has the characteristics of high precision,low power consumption and simple structure,which indicates that it is a better choice for SOC.

Abstract:As the traditional all digital phase-locked loop has the shortcomings such as a long period of lock phase and a large quantization error of TDC,this paper proposes a fast digital phase-locked loop based on high resolution TDC.The new design characterizes that the phase adjustment circuit makes the quantized phase difference restore to time series,which can comprehensively consider the reconstruction signal under the control of the state machine.In this case,the phase can be aligned for the maximum of two reference clock periods,and the phase lock time is controlled within 0.72 μs when the phase difference is detected.Meanwhile,when the reconstructed signal and the reference one are at the same frequency,the rising edge detection circuit can accurately detect whether the rising edges of signals are arriving simultaneously or not,and can generate the suitable enable signal to turn off the TDC circuit reducing the power consumption.Moreover,the design optimizes the coarse quantization method of TDC with multi-clocks and multi-phase and increases the measuring range.Additionally,the quantization error is controlled within 0.25 ns.Finally,the whole design is modeled in the RTL level and simulated,which shows that the new all digital phase-locked loop has the high speed of locking phase,high precision,high stability,low power consumption,and convenience to adjust the output frequency.

Abstract:Generally speaking，distortion will change the statistical characteristics of low frequency and high frequency components of images.With this consideration，a novel no-reference image quality assessment algorithm was proposed to the predict the perceived quality of multiply-distorted images.First，the images were transformed into local Walsh Hadamard Transform maps by local Walsh Hadamard Transform.Then，the features (i.e.,rotation invariant local binary pattern features of zero sequency term and non-zero sequency term) were extracted on local Walsh Hadamard Transform maps to reflect low frequency and high frequency components of images.Finally，the extracted features were trained using support vector regression to form the model，which implemented mapping from the feature space to the quality scores.Comprehensive evaluations were conducted on two multiply-distorted databases (MLIVE database and MDID2013 database)，and experimental results show that the proposed method consists well with human subjective perception.Besides，the performance of algorithm is statistically superior to the existence of better full-reference image quality assessment and non-reference image quality assessment algorithms.

Abstract:Internet of Vehicles (IoV) based on crowdsensing technology,which gets traffic data by smartphone or panel PC from ordinary person,has solved the problem that getting sufficient data at low cost.However,it also makes a new problem that the data quality of the system is deteriorated.To solve this problem,by analyzing the structure of crowdsensing data and the characteristics of abnormal data in crowdsensing IoV,a data detection algorithm is put forward to eliminate the abnormal data in IoV system and consequently improve data quality.In the algorithm,kernel density estimation theory is used to estimate the probability density of traffic data,and a belief function is then constructed to derive the confidence value of every detected data.According to the statistical theory,the data whose confidence value is less than 0 is regarded as abnormal data.Finally,the feasibility and performance of the presented algorithm are simulated.The results show that the proposed algorithm can meet practical demands and achieve better performance than that of traditional statistical detection methods.

Abstract:The failures of node are the common phenomena in the massive distributed storage system.To prevent the data loss,the system must solve the problem of self-repairing for failed nodes.Using regenerating codes,the data of failed nodes can be recovered without downloading the whole source file,so repairing bandwidth can be effectively saved.This paper presents an exact-repair minimum bandwidth regeneration code (ER-MBR) by using Cauchy matrix as coding matrix.ER-MBR can exactly repair the failed nodes.The whole process of coding,decoding and node repairing is demonstrated in the finite fields by an instance.Theoretical analysis and simulation experiments prove that by using Cauchy matrix as coding matrix,the operation efficiency of this algorithm is better than that of using Vandermonde matrix or random matrix.