Abstract:This paper proposed a precise construction method for automobile drawing die surface, which can improve spot rate in the debugging process of drawing die and shorten the period of die spotting. Based on stamping simulation, the gap between punch and the die grids is adjusted to be consistent with the thickness distribution of the stamped part by applying methods of gird mapping, shape function interpolation calculation and node translation. Furthermore, the accurate die grids were constructed to fit the thickness distribution of the stamped part. To make the deformation of surface fit the accurate die girds automatically, the control points of the die surface and the corresponding trimming curves were moved according to the translation values of the nodes. Consequently, the accurate surface of die can fit the thickness change of the stamped part. The case study has demonstrated that the proposed method is effective and the spot rate of drawing die can be improved in the design stage.

Abstract:Experiments of laser lap welding of two 1.2 mm thick galvanized steel planks with different Cu powder concentrations were performed by using a 4 kW fiber laser. The transverse weld topography, the mechanical properties, fracture morphology, component distribution and the main phase of the welded joint regional were studied under the optimal welding process parameters acquired through process optimization. It is shown that, when Cu powder concentration is 2.82%, the average tensile strength and elongation of the welding joints is 382.5 MPa and 32.5% respectively. When Cu powder concentration is not more than 3.46%, the tensile specimens are broken in the base material due to ductile fracture. On the contrary, the tensile specimens are broken in weld area due to the mixture of predominant ductile fracture and subordinate brittle fracture. Element distribution and phase in the galvanized steel interface are changed with the addtion of Cu powder added. In the weld area, the width of mixing zone of C, Al, Mn, Fe, Zn, Cu elements is larger. When Cu powder concentration is 2.82%, Cu element changes stably and Cu element in the weld area plays an important role in solid fusion reinforcement with the formation of Cu-Zn solid solution, and therefore, the strength of the weld area is improved. When Cu powder concentration is 8.06%, Cu element may spread from weld area to heat affected zone and is therefore prone to form brittle intermetallic compound Cu5Zn8, making specimens easily fractured in the weld area.

Abstract:In order to solve the interference problem of the accelerating pedal and the front floor, and to improve the ride comfort and safety, a 3DCS assembly variation analysis model was built. Running Monte-Carlo visual assembly, the probability distribution of the analysis target and the sensitivity analysis result of contributors were obtained, and then, a robust optimization for datum layout of the accelerating pedal and the mounting panel was presented. The significant Geo-Factor, quality loss level and failure rate of assembly quality of the accelerating pedal between the original design and the robust optimization design was analyzed and compared, and the probability distribution image of assembly quality was drawn to verify the availability of robust optimization. Robust optimization based on the assembly variation analysis result can improve the efficiency of robust optimization design, and the product quality can meet design requirements.

Abstract:Aiming at the defects of parameter estimation in VPMCD, BP neural network nonlinear regression method was used instead of the least squares method to solve the ill-conditioned problem that exists in the least square method. Therefore, a fault diagnosis method for rolling bearing based on improved Variable Predictive Mode on the basis of Class Discriminate (VPMCD) was proposed. Firstly, Ensemble Empirical Mode Decomposition (EEMD) approach was used to decompose the rolling bearing vibration signal into a number of single components; and then, the singular values were abstracted from the component matrix and formed feature vector which will act as an input in the improved VPMCD; finally, the work states and faults pattern of the rolling bearing can be identified. The analysis results from the experimental rolling bearing vibration signals have demonstrated that the proposed method can be effectively applied to the rolling bearing fault diagnosis.

Abstract:In order to optimize the ride comfort of mining dump trucks of 393 tons in bad driving traffic, the nonlinear stiffness and damping characteristics of hydro-pneumatic suspension were optimized. A 7-DOF full model, more realistic than traditional vehicle models, was derived. And considering the uncertainty of mass and position of centroid in the process of transportation, some factors of stiffness and damping of suspension having greater influence on target were selected as the design variables. The target function contains the body's vertical acceleration, roll angular acceleration, pitch angular acceleration, dynamic displacement of suspension and dynamic load of the wheel. An approximate model between design variables and objective function was established by High Dimensional Model Representation based on Thin Plate Spline Interpolation (TPS-HDMR).This model adopts multi-objective optimization with genetic algorithm based on the concept of Pareto, and then gets the Pareto optimal solution set. The simulation results have shown that multi-objective optimization can improve the performance of 11 targets and ride comfort.

Abstract:An assist regenerative braking system based on neural network was proposed to combine driving safety and braking energy recovery. An experiments-based fuzzy neural network of the vehicle braking was established to ensure driving safety. The look-up table of the regenerative and friction braking force was achieved through calculation. The fuzzy neural network and the look-up table were inserted in the braking system with a proportion valve to accomplish the assist regenerative braking system. The simulation results in Simulink have shown that the braking system can assist braking effectively, avoid rear-end collision and can adequately recycle braking energy.

Abstract:According to the special requirements of the electric vehicle, a method on the basis of topology optimization and genetic algorithm was presented. In a sample of an electric vehicle, the optimization process includes structural topology optimization and section optimization through topology optimization model, finite element conceptual model, size optimization and manufacture of prototype, which indicates that the forward design can be achieved. In the process of optimization, the objectives are bending stiffness and torsional stiffness, and meanwhile, the minimum weight was set as a constraint. By choosing high sensitive beams, the multi-objective optimization was presented with genetic algorithm. Compared with the results of the real car, this method can meet the requirements of light weight design and manufacture, which provides theoretical significance in increasing the efficiency and accuracy of optimization.

Abstract:This paper analyzed the mechanical characteristics and dynamic stability of the finite element muscle model with activation behavior in order to better apply it in the simulation of head-neck dynamic response. A coupling constitutive material combining quasi-linear viscoelastic element and Hill type element，representing the passive behavior and active behavior respectively, was applied to the rabbit tibialis anterior FE model. The model was validated with eccentric contractions tests under different strain rates published by Myers. The mechanical characteristics of the muscle were also analyzed under isometric contractions and axial compressions. The results have shown that the strain-stress characteristics are consistent with the reference tests and the maximum stress differences are less than 0.07MPa under the same strain condition. This constitutive model has a good stability and biofidelity that can fulfill the requirement of neck muscle system modeling for biomechanical study.

Abstract:This paper studied the global dynamic properties of a quasi-Hamiltonian vibro-impact system. By referring to Melnikov function for homoclinic orbit in the quasi-Hamiltonian system, the subharmonic Melnikov function for periodic orbit was constructed. A quasi-Hamiltonian vibro-impact system was given to illustrate the application of the procedures, and the validity of the function was verified with numerical results. At the same time, the global bifurcations and coexistence of multiple solutions for this vibro-impact system were analyzed in the improved cell mapping method. The number of coexistent attractor changes with the change of external excitation force, and domains of attraction with complicated fractal boundaries are intertwined.

Abstract:With the combination of production, profits and benefits, this paper proposed a model for the economic analysis of the vehicle engine remanufacturing by adopting Venism of system dynamics to evaluate and dynamically simulate the benefits of the engine remanufacturing.Based on the model, an engine-remanufacturing enterprise was selected as an example to conduct a simulating analysis of its production, profits per item and overall benefits. It has been concluded that enterprises' profits mainly come from contracting vehicle engines, and the profits from overhauled and scrapped vehicles are relatively low. Therefore, the relevant laws and regulations and policies for subsidies should be improved to increase the rate of recovery so that the scale effect of the enterprise could be advanced.

Abstract:The equivalent circuit of a new transformer with additional filtering and power compensating winding was calculated. Firstly, the polygon basic equivalent circuit was analyzed of the transformer with four windings. Secondly, according to the unique designs of the new rectifier transformer, the simplified ray-shaped equivalent circuit was derived. At last, the equivalent circuit model of the new rectifier transformer was built by PSB of Matlab/Simulink, and the correctness of the equivalent circuit was verified by simulation. The ray-shaped equivalent circuit proposed is very simple and clear, which provides an effective method for analysis on its various operating characteristics.

Abstract:EPRI-E' equivalent law was adopted to model the simulation system which includes ultra-high voltage system and high voltage distribution network. The influence on the security and stability of receiving-end grid with the operation of UHV was analyzed under three situations, including UHV fault, internal line fault and the main power plant fault of the distribution network. And then, this paper defined the shortest path to determine the affected area. The research has shown that, if double lines of UHV system jump after line fault, the flow of the outlets of 220 kV site with 5 of the shortest path becomes larger, and some lines will even overload and cascading failure may be caused. The risk of system collapse increases if the internal line or the main plant fault and UHV fault occur simultaneously. Finally, according to the operation characteristics of UHV, this paper proposed the corresponding stability control measures to ensure the normal operation of the power grid.

Abstract:This article studied the operation optimization of a microgrid power system consisting of EVs（electric vehicles), a photovoltaic power, wind power, gas turbines, batteries and energy storage unit. When the loads, photovoltaic and wind power output for effective monitoring and forecasting conditions are met, we proposed to reduce the constraints in fuzzy control method, to remove the battery and EV constraints, and then the microgrid with nonlinear constrained optimization problem was transformed to a linear optimization problem. Compared with the traditional optimization methods and the unconstraints in fuzzy method, the optimization efficiency of the system has been greatly improved.

Abstract:Boundary handling and global best guider selection operators play an important role in the multiobjective particle swarm optimization (MOPSO) algorithm. Considering the characteristics of different operators, an improved adaptive MOPSO was proposed. When the algorithm falls into a local optimum, enable the crossover and mutation operators; when the convergence of algorithm hasn’t improved in a given duration, switch the boundary handling operator between the truncation and the exponential distribution truncation methods; when the diversity of algorithm hasn’t improved in a given duration, switch the global best guider selection operator between the probability inverse proportion to the crowding distance and the probability inverse proportion to the number of dominating solutions methods. The results of the benchmark functions and the optimal allocation problem of flexible AC transmission system (FACTS) devices confirm the effectiveness of proposed algorithm.

Abstract:This paper presented a design and implementation study of a three-order all-digital MASH Σ-Δ modulator, which can be used in Fractional-N Frequency Synthesizer applications. To achieve the desired operation frequency while providing low-power dissipation and small area, the pipelining technique was utilized in the design. The circuit was described by using the Verilog hardware description language, and the operating frequency of the modulator is 240.56 MHz based on QuartusⅡ. Eventually, the SMIC 0.18 μm CMOS process was adopted, and the circuit layout was completed. The chip's area is 34148.5 μm2, and the total power of the chip is 1.28 mW. Compared with traditional design, it can result in a 31.23% area reduction and 46.14% power reduction.

Abstract:Based on the observation requirement of global change study, the point-by-point method was used to calculate the coverage indicators on the basis of orbit simulation and spherical ground triangulation. Then, a comparison was made among three platforms in space: Geostationary satellite, the Moon and the Earth-Sun L1 point. The result has shown that, though the temporal-spatial coverage from the Moon is only a little larger than that from Geostationary orbit, the moon offers a much better angular coverage, which is of great significance to the multi-angle remote sensing and the observation system to detect the Earth's energy balance.

Abstract:The stateful firewall is a new type of firewall, and the traditional firewall decision diagrams (FDD) construction algorithm does not apply to stateful firewall rule set. This paper presented a stateful firewall decision diagrams (SFDD) construction algorithm, which transforms the stateful firewall ACLs into equivalent stateful firewall decision diagrams, and is applied to the stateful firewall rule set comparison. Theoretical analysis and simulation results have shown that the method can effectively detect all the differences between the rule sets. And when the number of rules for both the stateful and stateless section is 3000, the time cost is less than 2 s.

Abstract:An application specific instruction set for multimedia and communication was introduced. A unified DSP plus general-purpose CPU processor based on this instruction set was designed and implemented. The CPU instruction set was compatible with the MIPS 4KC instruction set and the DSP instruction set was designed independently by analyzing the characteristic of the application. This paper presented the instructions and their operation logic in detail. The proposed instructions are suitable for 'pixel', 'vector' and 'complex' operations according to the high parallelism of the application. The test results have shown that the instruction set presented has obvious advantage in some multimedia and communication arithmetic, such as image interpolation, reconstruction and filter and FFT. The chip test result has shown that this architecture is feasible.

Abstract:The process of data preprocessing in data visualization leads to data uncertainty inevitably. Taking voxels in the boundary as our objects, this paper raised the possibility distribution measure based on multi-scale space to calculate the distribution of multiple kinds of data. Meanwhile, information entropy was introduced to quantify their uncertainties, which were then displayed as color gradient clothed on surface of volume data. Experiments have shown that our measures are able to effectively quantify and display the uncertainties of the boundaries.

Abstract:At present, there are few methods for the design and optimization of scale-free network routing algorithms. This paper studied the relationships between classic local routing algorithms, network topology, and nodes processing speed. At first, a few relationships were revealed and proved theoretically and experimentally. And then, by using such relationships, the influence of parameters on the performance of routing algorithms was analyzed. Based on such analysis, some rules on the design and optimization of dynamic routing algorithm for BA network were proposed. Simulation experiments have shown that, compared with classic local routing algorithms, the dynamic local routing algorithm based on these principles can effectively improve the performance of BA scale-free networks.