Applied Mechanics and Materials Vol. 740

Abstract: We propose an aerial robot-based system for monitoring environmental nuclear radiation in real time by taking advantage of the robot responsiveness and efficiency. In the proposed system, we employed small-sized nuclear radiation monitors, 3G/2.4G wireless communication and information distribution techniques to quickly and accurately image the site as well as to measure dose and distribution parameters of nuclear radiation. These data can be sent to the on-site center and the data center via 3G network, allowing data analysis, processing, storing and distribution. Our tests showed that our system was capable of satisfying environmental monitoring requirements on real-time data collection and transmission. Our system provides a novel monitoring platform for transmitting, storing and processing data of environmental nuclear radiation.

Abstract: For sets of measurements does not follow a Gaussian distribution, the conventional principal component analysis (PCA) method has the disadvantage of low diagnostic yield. An integrated fault diagnosing method based on the independent component analysis (ICA) and support vector machine (SVM) was proposed. The observed data is preprocessed and feature extracted by ICA and a monitoring model was developed. When the fault is detected, SVM is adopted to classifying and diagnosing the type of faults. It is applied for fault diagnosing in the Three-Tank water level control system. The simulation results show that the fault diagnosis rates of this method is 99.8%, which can effectively detect and diagnose the fault.

Abstract: In the process of acceleration dynamic measurement, the measurement results have quite large dynamic errors, due to the resonance of acceleration sensors. Using the system identification theory and combining with the dynamic calibration experimental data of acceleration calibration system based on Hopkinson bar, the dynamic model of the sensor is deduced, the dynamic compensation filter is designed. Simulation results show that the compensation filter can broaden the work band effectively. It improves the system dynamic response speed by nine times and advances the measuring accuracy of the test system.

Abstract: It is important to obtain the 3d coordinate in the field of measuring. How accurate, fast, convenient to obtain the 3d coordinate affects the accuracy and reliability of measurement directly. Through studying the basic theories of machine vision this paper focus on the study of a stereo vision measurement model based on the intersecting axis. In view of the parameters in the model of binocular stereo vision, this paper uses the Zhang Zhengyou calibration method to calibrate the system of Stereo vision. In order to test the accuracy of the system, this paper measures the distance of two standard circular. Finally, the machining experiment validates the proposed method.

Abstract: Headlight detection was an important item of vehicle safety testing which main detection contents included light intensity and beam irradiation direction. It was to ensure the safe operation of vehicle at night or in adverse visual conditions. The basic concepts and testing standards of headlight were introduced, and the reasons of high failure rate for headlight detection were discussed. The main error correction methods of vehicle parking position in headlight detection were compared, and their advantages and disadvantages were analyzed. An error correction system of headlight testing measurement data was designed based on machine vision, and the process of system realization was given. It could provide a method to get more accurate measurement results of automobile headlight detecting.

Abstract: In order to load a missile with T-drawbar into the rack fixed in a fighter plane automatically and quickly, the relative position between the rack and the T-drawbar must be measured. The principle of the relative position measuring method is introduced, the parameters calculating equations are derived, and the precisions are analyzed. The measuring system is composed of lens, planar array CCDs, lasers, and cooperative objects. By analyses, the system can measure the relative position information including X, Y and Z between the drawbar and the rack. The precisions of length are 7.8mm in X, and 1.2mm in Y and Z.

Abstract: With the increase of requirement for the quality of raw materials in industry, surface defect inspection of steel bar has been an essential part of industrial production. The characteristics of vision-based detection technology for steel bar surface defect and the newest research development were introduced. The working principle of vision inspection technology and key issues were analyzed. Finally, the current domestic research emphases and development trends were proposed.

Abstract: Measurement error often exists during hot pressing of the wood-based panels due to the complex mechanism of the process, technological conditions, environment noises and performance of the sensors. Multi-sensor technology is used for mat temperature and pressure data processing to improve the precision and reliability of data. By determining the information weight coefficient with the corresponding measurement variance of each sensor the weighted least square algorithm is applied to achieve high accuracy of overall estimation. The precision of overall estimation value is preferable than the partial estimation of each sensor. A target recognition frame of control strategy is set, and D-S evidence combination principles and reasoning theory are introduced to select the object of greatest credibility for decision making. The results of experiment demonstrate the effectiveness and reliability of the algorithm.

Abstract: Use scissors and cutting pliers to produce some striation marks. The data collection apparatus is used to collect the surface data of such marks produced by scissors and cutting pliers, and then get the profile curve that is vertical to the surface of striation marks. In application of fractal theory, the fractal dimension of such profile curve is then calculated, and further studies are made on its fractal characteristics. As an exploration on tool types and individual identification, this is aimed to provide a new theory and approach to examination identification of striation tool marks.

Abstract: An identification method for exciting force source inside underwater elastic structure by matched field processing (MFP) is presented. An underwater elastic cylindrical shell in free field is selected as the investigated subject, and the copy field of sound radiation transfer function is constructed by numerical method. The particle swarm optimization (PSO) algorithm is adopted for the search strategy. Both the simulation results and the experiment results show that: this identification method for exciting force source is effective for locating the exciting force source and analyzing the source intensity. The identification result can be applied to predict the radiated noise of the structure accurately.