Abstract: The process estimated temperature model of molten steel is based by analyzing the various factors which influence the rise and fall temperature of molten steel and the arts and crafts process of the production. The model has been used to estimate the temperature of molten steel in LF refining. And results of statistic analysis on estimated temperature show when the deviation of process estimated temperature by this model in LF refining is on more than ±5°C to the measured temperature, the hitting probability arrives at 85%.
Abstract: With the electric power industrial development, electric power device was abroad using as the core of switch converter. For a clear near-field characterization quantitative electromagnetic interference of converter circuits, this paper applied finite element method to analyze a Boost circuit. Transform topology structure of circuit and build corresponding entity finite element modeling. Quantitative analysis for different topology structure electromagnetic distributing and near-field characteristics, and it become clear that the distribution and the role of electromagnetic field of the circuit through the results. The objective of the analysis is to provide the principle and put a new way for the Layout and component design of the power electronic circuits, at the same time above research works make a foundation for further studying EMI problem of the power electronic devices and are of academically and application worthiness.
Abstract: The paper proposes a quasi resonant direct power control algorithm for three-phase grid-connected inverters without grid voltage sensors in distributed generation systems. According to the active and reactive power references, grid virtual flux and the inverter output current references are calculated. In order to accurately and fast track the output current references, the quasi proportional resonant (QPR) controller is used. The theoretical principle of this method is discussed. The steady-state and dynamic experimental results of quasi resonant direct power control that can illustrate the operation and performance of the presented control strategy are displayed. It is shown that the control system exhibits several advantages, such as constant switching frequency, sinusoidal grid currents and good dynamic response. Experimental results are provided to demonstrate the effectiveness of the proposed control strategy.
Abstract: Aiming at rapid response to requirements of mechanical transmission products customization, a system for rapid locking assembly variant design was proposed in terms of features of locking assembly. The bases of the system are Product Configuration Model (PCM) and Case-Based Reasoning (CBR). According to the system, PCM of locking assembly was built by extending traditional Generic Bill of Materials (GBOM). In addition, integration of PCM and CBR was completed by combining method of transforming PCM to a case with similarity assessment algorithm. Moreover, a rapid variant design software system based on PCM and CBR for locking assembly was developed. Finally, the software system was applied to design new locking assembly. Results demonstrate that it is effective for PCM-CBR to support rapid response to customization.
Abstract: Incremental point clouds registration is studied in this paper. A rapid method for point clouds registration based on reference points is proposed, which consists of the coarse registration and fine registration. Firstly, a set of reference points is applied as an assistant utility to measure the object. The transformation parameters are estimated by using the reference points only for coarse registration, and then dense point clouds data will be transformed to the same coordinate system. Secondly, taking the coarse registration results as the initial value, the improved Interactive Closest Point (ICP) algorithm is used in fine registration the original corresponding points are established rapidly by using the k-d tree searching algorithm. Finally, Preview Model Parameters Evaluation Random Sample Consensus (PERANSAC) algorithm is utilized to remove outliers. The experimental result shows that this method in finding original corresponding points can greatly improve the computation efficiency and also improve the registration accuracy.
Abstract: Regularity is one of important properties of curves in computer aided design. In this paper, we convert the problem of determining regularity of Bézier curves to that of detecting existence of zero points of polynomials. Based on the properties of algebraic equations and isolation theorem of roots, a simple and practical method is presented. Regularity of Bézier curves and number of singular points can be determined by easier computation.
Abstract: In this paper, we address the problem of automatic inspection complex surface using an ultrasonic technique and the reliability of inspection. First, an automatic ultrasonic inspection manipulator is introduced. Through ultrasonic inspection and defect analysis, the parameters of flaws can be calculated automatically. Then, a POD analysis method is provided to assess the reliability of inspection. Finally, Experiments are conducted and the POD curves with the sizes of flaws and the scanning gaps are obtained.
Abstract: A growing number of distributed generators have been connected to urban distribution networks in recent years, which brings great challenges to the traditional reliability evaluation of the distribution grids. Island is a new kind of operation mode of the city grid. In consideration of the importance factor of system load, establish the model of island taking the maximum equivalent workload capacity as objective function and heuristic search technology is proposed to solve the problem. According to the island mode of operation, assess the reliability of the network with islands based on equivalent resistance and minimal path, which have certain instructive significance to the improvement of reliability of the modern urban distribution nets.
Abstract: In the preliminary stage of mechanical and electrical products reliability prediction, due to the lack of reliability data, the reliability prediction is expected to be difficult. But also in the design process, lots of fuzzy and uncertain information is existence. In view of this, the reliability prediction model based on triangular fuzzy number is proposed. This model is consistent with the mode of thinking, can also merge the fuzzy information very well and make the fuzzy decision . On this basis, according to the influence factors of mechanical and electrical products reliability, analytic hierarchy process (AHP) is applied to determine weights, the model of the fuzzy comprehensive evaluation is built and a new operator is introduced for the triangular fuzzy number. Therefore a more objective prediction can be expected to make for the reliability of mechanical and electrical products.
Abstract: In this paper, a remote Distribution Transformer (DT) monitoring system is presented and developed to solve the problems of existing remote monitoring system wiring too much, too complicated, fault diagnosing and maintaining difficulty. The system hardware design based on 16 bit PIC18F458 chip and GSM module TC35i is proposed. The system software design with MySQL and Visual C++6.0 are discussed in detail. A real-time monitoring of parameters such as three-phase voltage, current, power factor and transformer temperature is finally realized. Experiment results show that the system possesses accurate data gathering, strong anti-interference and good operation performance.