Advanced Materials Research Vols. 301-303

Abstract: This paper introduces the characteristics of the traction power system of electric railway, and explores the harms to the power system caused by electric railway and the necessity of harmonic suppression of traction power supply system. In order to achieve real-time detection and compensation for harmonic waves of electric railway traction power system, this paper provides an improved harmonic detection method with initial compensating angle of delay time. Detection method is simple, and has better real-time, it can be used to detect selective harmonic for electrified railway.

Abstract: Airborne cloud liquid water content (CLWC) sensors have been used in weather observation and weather modification for years. However, traditional CLWC sensors are relatively bulky and heavy. Additionally, it is inconvenient to use wind tunnel to calibrate traditional sensors. In order to meet the need of wind tunnel calibration tests, reduce the wind signal interference and reduce the cooling effect of high water content cloud, two new types of hot-wire water meter content sensors are designed in this paper. Using steady-state heat transfer theory, a finite element method is used to simulate temperature distribution of the new water content sensors, including the scenario in which cloud water droplets evaporates as colliding the sensors. In order to minimize sensor error, convection is also considered in the finite element model. Through the numerical analysis of the two new types of hot-wire water content sensors, it is concluded that the sensors designed in this work are able to reduce the wind interference error and extend the CLWC measurement range of the instrument.

Abstract: Guidance law The optimal direct-impact guidance law for space-based anti-missile of ballistic missile in boost phase is considered. First the relative motion equation between missile and target is built, then the optimal guidance law based on terminal miss distance is designed. using minimum energy as the optimum index. The simulation results show the effectiveness of our guidance law.

Abstract: This paper discusses the principle of SPWM, as well as its mathematical models, highlight introduce the generation principle of SPWM wave based on TI digital signal processor TMS320LF2407A. The formula and mathematical model are simplified by using the symmetric regular sampling method. Update the value of the program by comparing the look-up table, this method improves the operational efficiency, and reduces the error generation. The paper detailed analysis the configuration of each register in event manager module, and gives a critical interrupt subroutine. Through online simulation debugging, get the correct SPWM and the corresponding dead-time waveform.

Abstract: Interference image processing is the key technology of optical interference measurement. This paper introduced the problems on automatic interference fringe processing in absolutely measurement based on laser interference, digital image processing technology. The image acquisition of the SiO₂ film and the pre-processing of interferogram was performed.Decimal part of the interference fringes is obtained. Using high-resolution image acquisition system and computer reads and processes the interference image, replaces the traditional work of skilled workers of high intensity for a long time and improves the film thickness measurement accuracy.

Abstract: Power line carrier, which was one of communication styles, had lots of merits, such as without dedicated data lines or modified the layout of communication, higher safety and application to the communication in a small distance. This paper presents the analysis and demonstration of the key technology in detail so as to indicate the operation feasibility of the system from the technological level and the application perspective. This paper established and tested the system, the test results indicate that the system could operate stably, and it has higher safety and higher application value merits.

Abstract: In recent years, more attention is given to solar blind ultraviolet (SBUV) detection in corona discharge detection and defect diagnosis of partial discharge has been widely used. However, there are still such key techniques should be further studied such as electro-optic characteristics and the quantitative relationship between corona current and UV emission intensity in the process of corona discharge. With different AC voltage and different humidity, corona current and UV pulses are measured. It is shown that corona current and pulse number rise with the voltage mounting up, and decline very weakly with humidity increasingly. In addition, further discusses about the quantitative relationship between electro-optic parameters is implemented by using transfer function. The experiment results, under the conditions of different AC voltage and different humidity, indicate that transfer function maintained between 2.00 to 4.25 changes little, varied no more than 52.9%. UV pulse number, therefore, can be used to characterize corona current intensity. The conclusions above are significant for characterizing the level of corona discharge directly by UV emission intensity, and they are helpful for improving the accuracy of defect diagnosis.

Abstract: Simple lidar detecting wake profiles based on laser backscattering by wake bubbles at 180° is firstly introduced. Then the various noises of this simple lidar, including the background light, power frequency of 50Hz and its harmonics, radio frequency noise and inherent noise within the electronic system, are analyzed in detailed, and the relationship of the minimum detectable signal power and the echo signal power is discussed. Finally, under the condition of satisfying the noise level, the data processing method of wake profiles is given. For this method, the power spectral density estimation method is used to process the bubble laser scattering signal and cubic spline interpolation is used to obtain contour map of wake profile. The results show that the data processing method of wake profiles meets the noise level and the obtained contour map is reasonable.

Abstract: In this study, a calibration method to determine the coordinate transformation between the robot tool and the external axle worktable based on ant colony optimization algorithm is discussed. The approach can be divided into three different steps. Firstly, the transformation relationship between the robot wrist and the contact position sensor tool is calibrated. Secondly, the transformation relationship between the robot tool and the external axle worktable is determined by the robot and the contact position sensor joint measurement system. Finally, ant colony optimization (ACO) algorithm is employed to optimize the key parameters to improve the system accuracy. Based on the presented method, the robot system with external axle is calibrated with successful results. The presented approach is validated to be effective via a real experiment.

Abstract: To counter the influencing emission of the diesel engine by the EGR rate, the emission model of the diesel engine was set up by combining Radial Basis Function neural network with Adaptive Neural Fuzzy Inference System. The model first draws on the nonlinear approaching capacity of the RBF network to forecast the diesel engine emission which takes no account of the factor of the EGR rate, and then, based on influencing the diesel engine emission by the EGR rate, the ANFIS system was used to modify the results of the diesel engine emission obtained by using the RBF network so as to acquire the EGR rate curve. The result showed that the emission model of the diesel engine was reasonable; the forecasting strategy had the good resolving power and could be much fitted for the on-line aging forecast of the EGR rate.