Abstract:The parameter matching of the hydraulically interconnected suspension（HIS） system has a critical effect on its dynamic performance. To improve the overall dynamic performance of the system，the global sensitivity analysis and multi-objective optimization are proposed for an anti-pitch and anti-roll HIS system. Firstly，a seven degree-of-freedom vehicle dynamic model is established in the frequency domain. Then，the riding comfort，stability，and anti-pitch and anti-roll performance of the vehicle are evaluated by stochastic road input. In addition，the global parameter sensitivity analysis of the HIS system is presented using the Sobol method to evaluate the influence of each parameter and find out the critical parameters of the HIS system. Furthermore，a multi-objective optimization procedure is proposed to optimize vehicle performance by the NSGA-II algorithm. The result illustrates that the linear loss coefficients of the damping valves on cylinders and accumulators have a significant influence on each performance index，and the interaction effect of some parameters has a great influence on vehicle anti-roll performance. After multi-objective optimization，the optimization result obtained by the weighted coefficient method shows that：the root mean square（RMS） value of sprung mass′s weighted acceleration is decreased by 20.94%；the RMS value of pitch acceleration is decreased by 12.95%；the RMS value of roll acceleration is decreased by 8.05%；the mean value of tire dynamic force RMS value is decreased by 11.17%. Through the global sensitivity analysis and multi-objective optimization，the overall vehicle performance can be improved significantly.

Abstract:To consider the problem of collision avoidance and stability when planning the emergency collision avoidance path of lateral lane under high speed scenarios，a path planning algorithm based on non-uniform B-spline curve is proposed，which meets the requirements of multi-constraint. The proposed collision-free path model constructed by two non-uniform B-spline curves has continuous curvature with trapezoidal change and satisfies the slope and curvature constraint at the starting point and end point; and then，the environmental information is combined to generate a collision-avoidance path cluster whose path shape is controlled by two parameters. On this basis，a passenger comfort objective function is constructed，aiming to select a local path with the best comfort from the path cluster when the collision avoidance requirement is met. Furthermore，the objective function and multi-constrains of the vehicle are used to obtain the optimized longitudinal acceleration so as to complete the collision avoidance motion planning. Finally，the model predictive control (MPC) algorithm specialized in multi-constrained problem is selected to develop a linear time-varying MPC controller，and the feasibility of the proposed path planning method is verified.

Abstract:To solve the problems of large scale and low efficiency in the solution of intelligent vehicle trajectory tracking algorithm based on model predictive control，this paper proposes a time-domain splitting method to accelerate the calculation. First，global consistency variables are introduced to transform the time-domain coupling constraints of the adjacent control cycles into global consistency constraints，thus to achieve time-domain decoupling. Then，under the framework of Alternating Direction Method of Multipliers，the block updating method of optimization problem after time domain splitting is derived，and the stop criterion of block updating numerical solution is designed. Therefore，the large-scale optimization problem is converted into several small-scale sub-problems. Finally，the Simulink-CarSim platform is set up and the algorithm is verified by simulation. The simulation results show that，under the same accuracy of the solution，the efficiency of solution is improved by 24.21% on average with the proposed method，achieving accelerated solution for vehicle trajectory tracking based on model predictive control.

Abstract:In order to ensure the safety and rationality of the new generation wheeled mobile platform and to study the influence of the key brake elements in the braking system on the braking performance of the new generation wheeled mobile platform，a theoretical analysis model of the two-loop foot brake valve and the relay valve is established based on the new-generation hydraulic brake system developed by a model 8×8 full-electric drive off-road vehicle. Based on AMESim software，a simulation model of a new generation of full-hydraulic brake system of wheeled mobile platform is established. The influence of cover quantity，stiffness of upper spring and initial compression of reset spring on braking performance is analyzed，and the accuracy of the simulation model is verified by experiments. The analysis results show that the output braking force increases and the response time increases as the stiffness of the upper spring increases and the initial compression of the reset spring decreases； As the cover of the valve core of the foot brake valve decreases，the compression of the upper spring increases during balance and the output braking force increases； The output braking force is sensitive to the cover of the valve core and the stiffness of the upper spring，and the response time is sensitive to the stiffness of the upper spring. The theoretical model and the simulation model provide reliable basis for the performance adjustment and further optimization of the new generation wheeled mobile platform.

Abstract:A lubrication theoretical calculation model of thermal characteristic is proposed to study the temperature characteristics of a novel three-pad radial gas foil hydrodynamic bearing. The numerical simulation method is used to calculate the film temperature distribution of the gas foil bearing by coupling the non-isothermal Reynolds equation and the energy equation，and the effects of the rotor thermal expansion and the rotor centrifugal expansion on the bearing clearance are taken into account. The effects of the bearing load，speed and cooling gas flow on bearing temperature are analyzed. The results show that the peak temperature of the film is located at the downstream of peak pressure；the air film temperature increases with the rise of bearing load and rotor speed，and the results indicate that the rotational speed has a larger effect on the bearing temperature than the bearing load; the cooling effect of the airflow is obvious，and the bearing temperature decreases rapidly with the rise of the cooling airflow and then gradually calms down.

Abstract:To improve the ability of aircraft assembly schedule to deal with unqualified assembly quality，the mapping between assembly quality and quality-related factors and the expression of uncertainty in different decision-making cycles are studied，and the integer programming model is established with the objective function of the scenario-based project expected value. Moreover，based on the trained prediction model of aircraft assembly quality，a multi-layer cyclic iterative search algorithm is designed. The first layer optimizes the execution order of activity based on the activity list coding; The second layer optimizes the personnel allocation through the assembler allocation list; The third layer solves the objective function according to the result of personnel allocation. The numerical results show that the multi-layer cyclic iterative search algorithm can keep the deviation of activity start time below 2 when the predicted workpiece quality is inconsistent with the actual value，which indicates that it is adaptable to the changes of uncertainty factors and can meet the requirements of constructing dynamic schedules for aircraft assembly.

Abstract:Aiming at the problem of flow field non-uniformity of the post-mixed abrasive nozzle at present，the FLUENT simulation software is used to calculate the internal flow field of a new type of post-mixed abrasive water jet nozzle. The influence of conical baffle on the uniformity of flow field is analyzed by comparing the internal flow fields with and without conical baffle. By analyzing the spray effect of tapered baffle nozzles with different parameters，the influence rule of different parameter structure of the new-type post-mixed abrasive water jet nozzles on the uniformity of internal flow field is obtained，so as to improve the mixing uniformity of water and abrasive in the post-mixed abrasive water jet nozzles. The results show that air pressure reduces and fluid collection is eliminated in mixing chamber when increasing the diameter of the shrinking outlet on precondition of assuring high outlet velocity. On this basis，the abrasive volume fraction of outlet is nearly 15% with the minimum fluctuation，the abrasive mixing uniformity is greatly improved when a cone baffle structure of quadric B-spline curve is added inside the nozzle and abrasive inlet leans toward axis of the nozzle at the angle of 45°. The effects of multi-parameters on the uniformity of the abrasive were analyzed by orthogonal test to obtain the optimal structural parameters.

Abstract:In path planning，in order to obtain an optimal path suitable for actual situation and overcome the inherent shortcomings of genetic algorithm，such as easy converging to local optimal and high complexity，a Q-standard Improved Genetic Algorithm （Q-IGA） based path planning algorithm with dynamically fitted Bezier curve is proposed in this paper. The proposed algorithm replaces the static fitting method of directly using Bezier curve in order to simultaneously search the path and control points of Bezier curve. What's more，an additional judgment criterion based on Q value is added into selection operator，which can eliminate the solutions with high similarity and enhance the diversity of the population. At the same time，the proposed method optimizes the fitness function by taking robot volume and turning angle into consideration，so that the selected path is not only short but also a reasonable path which keeps a safe distance from the obstacles. Simulation results show that the paths produced by Q-IGA algorithm are more reasonable than those produced by improved artificial potential field algorithm and hybrid genetic algorithm. As it can reduce the search time and the energy consumption of the robot，the proposed method is more suitable for practical industrial applications.

Abstract:Currently, the ferrite plates are widely utilized in couplers of wireless power transfer systems in electric vehicles. In this paper, the nonlinearity of the self-inductance and mutual inductance for the couplers with ferrite plates is intensively studied by numerical calculation method，and four key parameters including the thickness of the ferrite plates，the spacing between the coils and the ferrite plates, the size of ferrite plates and transfer distance are considered. It is found that the nonlinearity of self-inductance and mutual inductance is greatly affected by the thickness of the ferrite plates，followed by the spacing between the coils and the ferrite plates and the size of the ferrite plates，and little affected by the transfer distance. In addition, the saturation current corresponding to the nonlinearity of the self-inductance and mutual inductance is positively correlated with the thickness of the ferrite plates and the spacing between the coils and the ferrite plates，and negatively correlated with the size of the ferrite plates. The saturation current corresponding to the nonlinearity of the mutual inductance increases slightly with the increase of transfer distance. Then, the combination of the four parameters corresponding to the minimum saturation current is provided, and the minimum saturation current is 160 A. That is, when the coil current is less than 160 A，the self- inductance and mutual inductance of the coupler are linear, and the coupler can be treated as a linear device. Finally，the correctness of the simulation is verified by experiment. The linear characteristics of the coupler are used to analyze the magnetic field around the coupler when the current is not large.

Abstract:A front-end circuit without Sample-and-Hold Amplifier（SHA） is presented for reducing power consumption and increasing input range of pipelined ADC. Removing Sample-and-Hold Amplifier and improving switching timing reduce the circuit power consumption，while improving the traditional switched-capacitor comparator inputs to make ADC achieve a 0-3.3V full supply voltage quantization range. The front-end circuit without Sample-and Hold Amplifier is verified in a low power 12 bit 50 MS/s pipelined ADC. The circuit is implemented in a 0.18 μm 1P6M process，and occupies a chip area of 1.95 mm2. The test results with a 5.03 MHz input wave under a sampling rate of 50 MS/s show that the ADC achieves a 64.67 dB signal-to-noise and distortion ratio（SNDR） as well as a 72.9 dB spurious-free dynamic range（SFDR），while it consumes the power consumption of 65 mW.

Abstract:In order to improve the accuracy in analyzing magneto-electro-elastic (MEE) structures, a stabilized node-based smoothed radial point interpolation method (SNS-RPIM) was proposed. Based on the traditional node-based smoothed radial point interpolation method, the stable item related to the gradient variance of the field variables was introduced to eliminate the uncertain parameter. The SNS-RPIM equations for multi-field coupling problems were derived, and the static responses of MEE structures were also solved. The results of SNS-RPIM were compared with those of finite element method. Numerical examples showed that SNS-RPIM can provide the result closer to the real solution and effectively solve the problem of 'overly-stiff' of finite element method. SNS-RPIM is better than FEM in terms of accuracy and convergence, which provides an effective analysis method for further application of MEE materials.

Abstract:Outlier detection is one of the hotspots in the field of data mining. The main purpose is to identify the abnormal but valuable data points in the data set. With the expansion of data scale，the efficiency of processing massive data is reduced，and then a distributed algorithm is introduced. At present，most of the existing distributed algorithms are used to solve the homogeneous distributed processing environment. However，in practical applications，due to the differences in processor configuration involved in distributed computing，the existing distributed outlier detection algorithms cannot be well applied to heterogeneous distributed environments. In view of the above problems，this paper proposes an outlier detection algorithm for heterogeneous distributed environments. Firstly，a grid-based dynamic data partitioning （GDDP） method is proposed，which makes full use of the computing resources of each processor and divides the data according to the spatial location information of the data points，which can effectively reduce the network communication. Secondly，based on the GDDP algorithm，a parallel GDDP-based Outlier Detection Algorithm （GODA） is proposed. The algorithm consists of two stages：in each processor，filtering according to the order of the data points in the index and obtaining the outlier candidate set by two scans；determining the candidate outliers requiring network communication and using low network overhead leads to global outliers. Finally，the effectiveness of the proposed GDDP and GODA algorithms is verified by a large number of experiments.

Abstract:A software package for the calculation of microstrip antenna with finite base plate is developed. The microtrip antenna is partitioned into triangle and tetrahedron using moment method. The impedance matrix is divided into four types：conductor-to-conductor，conductor-to-medium，medium-to-conductor and medium-to-medium. By calculating the four types of impedance matrix，the current coefficient is obtained and the performance of the antenna is analyzed. Finally，the software package is implemented based on matrix laboratory（MATLAB） programming environment. Compared with the simulation results of FEKO software，the software package has the advantages of simple operation，high visibility and high calculation accuracy. It can be used for the analysis and calculation of microstrip antenna with finite base plate.

Abstract:Aiming at the problems such as high complexity and poor robustness for current video watermarking algorithms，a video watermarking algorithm based on residual texture feature is proposed by adopting an energy difference modulation. Firstly，the residual DCT coefficients obtained from the video coding process are used to model the regional texture intensity，and then the energy of the DCT coefficients on the middle and high frequency are adjusted adaptively according to the texture intensity to realize the watermark embedding. Under the condition that no additional complicated computational process is introduced，the algorithm embeds different intensity watermark information adaptively for different regions to ensure the video quality and improve the watermark robustness. The scheme takes the H.264/AVC video codec as a verification example. The experimental results show that，under the premise of guaranteeing video quality and encoding rate，the watermarking algorithm proposed in this paper has good robustness to resist attacks such as re-encoding，filter and noise. Meanwhile，the watermark extraction process meets the demand of blind detection for practical applications.

Abstract:To improve the current situation of excessive dust concentration in the places of mobile grinding, this thesis, based on the research background of CRCC Changke grinding workshop, establishes an unsteady single-dust diffusion model with the guidance of Gaussian diffusion model. The liner regression method is used to investigate the rules on the diffusion of multi-point dust interactions. It makes a comparative analysis of the data on the dust concentration in single point or multi points, which varies with the height. And combined with the equation for Groundwater Flow and the method of Gradient Decent, it finds out the coefficient of particle diffusion and multipoint dust interactions. The result shows that a gathering point can form between any two grinding points and it may also change with the altitude. The dust concentration of the multi-point grinding is 2 to 3 times of the single point grinding, and the maximum value is up to 45.73 mg/m3，which is higher than the standard of the state health. The average error of the dust diffusion model is verified as 14.67%, and it can be used for subsequent research on the protection technology from the dust and workshop spatial structure.

Abstract:In order to fully understand the pollution situation of the production site left by a coating enterprise and evaluate the risks to the surrounding environment and human health after the development of the site according to the latest planning，the pollution survey and risk assessment of the production site are launched. The field investigation results show that heavy metal pollution mainly exists in the production site，and the concerned pollutants are As，Cr，Pb，Cu，Zn. No organic pollution is found，and the groundwater satisfies the quality standard of groundwater. The results of risk assessment indicate that the carcinogenic risk and hazard quotient of As and Cr in soil through all pathways are higher than the acceptable risk level of 10-6 and 1，respectively，and the total hazard quotient of Cu and Zn through all pathways are less than 1. The carcinogenic hazard and non-carcinogenic hazard of As and Cr have potential health risks to human health，while non-carcinogenic hazard of Cu and Zn would not cause harm to human health. Finally，the target values of soil cleanup for site pollutants are determined as As 50 mg/kg，Cr 400 mg/kg，Cu 300 mg/kg，Zn 500 mg/kg，Pb 280 mg/kg，respectively. It is suggested that remediation measures should be taken for polluted soil to ensure that the soil quality meets the requirements of planned land use.