Applied Mechanics and Materials Vols. 29-32

Abstract: System torsional rigidity is an important design index, having important influence on operating performance of the advanced actuator; therefore, this paper emphasizes the study on calculation of system torsional rigidity. This paper firstly introduces working principle and structural features of the novel ball screw transmission. Then uses commercial CAD and FEM softwares, SolidWorks and Cosmos/Works, fulfils deformation analytical computation for such three key parts as driveshaft, fixed guiding sleeve and straight-rotary sleeve. Next, sum up each term of torsional rigidity. Finally, makes a conclusion that the system torsional rigidity of the advanced actuator satisfies the designing demand.

Abstract: With the development of power electronics，the technology of Switching Mode Power Supply(SMPS) is gradually perfected. However，there is no end to the demand for a high power and high performance power supply. Nowadays, Power Factor Correction (PFC) technique is widely researched. This paper mainly analyzes the fundamental configuration of the switching power supply. And we study the basic structure and the operating principles of ZVT-boost soft-switching PFC circuit and the implementing principle of soft switch. For the power requirements, the two-stage PFC circuit is used. The forward stage is a single-phase Boost Power Factor Correction circuit and the backward stage main circuit is a full-bridge converter with the phase-shifting control soft-switching technique. Finally the simulating analysis is performed to the designed system.

Abstract: Fingerprint identification is one of the most important biometric technologies, which has drawn a substantial amount of attention recently. Fingerprint enhancement algorithm is an important component of fingerprint identification. Normalization is the first step of enhancement algorithm. In this paper, the VLSI design of normalization algorithm is proposed. This paper performs these following tasks. Firstly, the flow of enhancement algorithm and the basic principle of normalization algorithm is introduced. Then, a scheme of VLSI design of normalization algorithm is proposed and described in detail. Finally, we implement this design with Verilog language and present the simulation result with Modesim9.0. The simulation result shows that the scheme proposed in this paper has improved the fingerprint image quality to a certain extent.

Abstract: The Stewart manipulator has characteristics of low natural frequency, high cost and large size which make it difficult to obtain optimum performance with high dynamic response. The lowest natural frequency in the total workspace and average of six frequencies at home configuration of Stewart manipulator are introduced as indices to evaluate dynamic stability. Multi-criteria optimal design based on genetic algorithm (GA) was presented synthetically considering the workspace requirement, lowest natural frequency, average frequency and global dimensionally homogeneous Jacobian matrix condition number. An optimal result was obtained through standard GA using penalty function and the Pareto-optimal set was also obtained through parallel selection method.

Abstract: Considering the nonlinear relationship of the joint surface between parts in machine tool assembly, a finite element analysis method based on assembly relationship is proposed. By this method, a finite element model is set up. Based on the analysis of experimental data, the result is close to the actual working conditions, which proves that this analysis method based on the machine tool assemble relationship is feasible and reliable

Abstract: The restraints and conflicts between indexes in the project decision-making often influence rationality of outcomes. Through applying PPE model to project decision, the author makes use of RAGA to optimize the projection direction, turns multi-dimension data into low dimension space, so the value of projection function can be calculated by way of seeking the optimal projection direction, thereby, according to the value, project decision can be processed. The outcome from concrete application indicates that it is very reasonable, has avoided the problem of calculating coefficient of weight subjectively, and it provides we with a new method and thought to project decision.

Abstract: It analyses different kinds of risk factors of real estate investment, and establishes a suit of scientific index system about the risk assessment of real estate investment. And this paper not only establishes the risk assessment model of real estate projects in view of fuzzy-synthetical evaluation, but also uses this model to make a risk assessment of Ganzhou Tianyue real estate project, showing the feasibility of the model by examples.

Abstract: Power factor correction (PFC) is an effective method to reduce harmonic current in power grid. A novel boost high power factor rectifier with UCC28019 is proposed. The UCC28019 8-pin active Power Factor Correction controller uses the boost topology operating in continuous conduction mode (CCM). It does not need multipliers. The use of the IC will make the PFC circuit design easily and the volume of the rectifier small. The fundamental principle of the proposed rectifier is introduced. Its sections such as current loop and over-current protection, voltage loop and over-voltage protection, and so on, are analyzed and designed respectively in detail. Experimental results of the designed 350W prototype prove that the boost high power factor rectifier is rational and reliable, its power factor can reach 0.992, and its application prospect is wide.

Abstract: Boost converter occupies a very important position in the area of switching power supply, it is widely used in various power equipment for a long time, while the transient working process from start to steady-state are not involved in textbooks and reference books available. PSpice is a powerful general purpose analog circuit simulator that is used to verify analog or mixed digital circuit design and to predict the circuit behavior. Its simulation waveforms are nearly as same as the experimental waveforms. The overall working stages of Boost converter, especially the transient process from start to steady-state, are simulated and analyzed by PSpice in this paper. All the stages of store energy element of Boost converter are also introduced. Some simulation waveforms are given to verify the analysis. Thus the understanding of Boost converter for designers is deepened.

Abstract: This paper designs a novel single phase high power factor rectifier with IR1150 as its main control chip, which main circuit uses boost topology. The fundamental principle of the proposed rectifier is introduced. The IR1150 control IC based on one cycle control is intended for boost converters for power factor correction operating at a fixed frequency in continuous conduction mode (CCM). The use of the IC will make the PFC circuit design easily, the volume of the rectifier small and the efficiency enhancing. The modules of the proposed rectifier such as current loop and over-current protection, voltage loop and over-voltage protection, soft start, and so on, are analyzed and designed respectively in detail. Experimental results of the designed 600W prototype prove that the boost high power factor rectifier designed is rational and reliable, its power factor can reach 0.994.