Applied Mechanics and Materials Vol. 722

Abstract: To meet the requirement of precision, machining efficiency and surface quality of film cooling holes, an electrical discharge machining (EDM) equipment was developed with the function of high-accuracy rotation of tool electrode and performances of both high machining efficiency and thin recast layer. The equipment mainly consists of inchworm spindle, pulse power generator with high peak current and control system based on PMAC. Key problems were solved including precision and consistency of holes diameter, compatibility between high peak current and small pulse width and openness of the control system. Performance tests of the equipment show that runout error of the electrode is less than 25 μm, maximum peak current is 50 A while the minimum pulse width being 1μs, positioning accuracy of the control system is less than 2 μm. Machining experiments of vertical and inclined holes verified the feasibility of the designed equipment.

Abstract: The intrinsic problems of hidden/exposed terminal may bring about threat of conflict in inter-vehicular communication, and thus decrease network throughput. In this paper, we take the unidirectional feature of road into consideration, design single-channel transmission scheme for decreasing communication conflicts with position information and directional antenna, including the identification and notification of relative positions among adjacent nodes, the identification of node transmission state, and the method of directional transmission scheduling. By simulation experiments of inter-vehicular communication in NS-2, we verify that this scheme can discern the hidden/exposed terminal nodes and decrease conflicts effectively, and thus improve network performance.

Abstract: Bridge health monitoring has become an important means of transportation for bridge management, and the bridge strain is an important health detection index of bridge. In order to simplify the wiring complexity of test site, this paper aims to research a wireless bridge strain acquisition system based on Wheatstone bridge. The instrument can realize accurate acquisition of bridge strain data, then collects and transmits data remotely to the monitoring data processing system of PC through WIFI. This paper will make a detailed introduction of the system through two aspects of hardware and software.

Abstract: This paper puts forward a classification method of imitating the human eyes to recognize image as a whole which combined chaotic neural network and the Empirical Mode Decomposition (EMD). The method takes the individual of weeds plant as the research object and utilizes the chaotic neural network, the EMD, Teager energy operator and cluster analysis technology comprehensively. Firstly take the two-dimensional gray image matrix as the chaotic neural network weight matrix directly. Use the chaotic neural network with n neurons expression to iterate and get the one-dimensional output curve. Secondly, make the EMD decomposition for the curve and get the corresponding intrinsic mode function (IMF) curves. Then make the Teager energy transformation for each IMF component and get the average Teager energy. Finally use the fuzzy clustering algorithm to cluster analyze and get the clustering results. It can realize the classification of different categories of weeds through analysis and contrast the results with the original images. The experiment proves the effectiveness of the proposed algorithm for classifying weeds, and it is a universal new method of weeds classification.

Abstract: This paper introduces a methodology for creating geometrically of real terrain based on DEM data, which provided by the international scientific data sharing center.The method is to convert the DEM data in Global Mapper, AutoCAD and other softwares, process batch of data using office software, based on APDL language programming in ANSYS software , so as to realize the real remote sensing data to establish 3-D geological model in finite element software. An example illustrates the capabilities of the proposed methodology in this paper.

Abstract: The paper designed a safety monitoring network system which is composed of the wireless sensor network based on the emerging wireless communication technology.Tests indicate that the system runs well with small consumption and good mobility, and the data can be uploaded to host computer for real-time display and record so that it can provide effective help to quickly carry out rescue work.

Abstract: First in this paper, we will introduce a map matching algorithm based on fuzzy logic, and how we use it to fuse the navigation data. Then we will introduce a kind of iterative algorithm what we use to optimize the parameters of the map matching algorithm we mentioned before. So we can improve the precision of our map matching algorithm.

Abstract: The accuracy and stability of circular conical surface is easily influenced by the different distribution of noise and points in point cloud, when 3D point cloud data fits conical surface. For this reason, this paper proposes a novel method of establishing and optimizing the objective function with conical vertex. First, calculate the axis direction and half-apex angle of the cone; second, calculate conical vertex according to the result got in the first step; third, establish objective function with axis direction and half-apex angle and vertex, and optimize it with Levenberg-Marquardt. The method’s feasibility and robustness are verified by simulating and real experiments. The proposed algorithm has been successfully applied to a self-development 3D measuring system (TN 3DOMS) of Mianyang Saint Buffalo Technologies Limited Company.

Abstract: The measurement technology of 3D scanning in automation level is low, its measurement process is not stable, and the measurement error is large. After the principle of binocular structured light measurement was analyzed, match the marked point to multi-view registration based on the relative distance of any two marked point in space is unchanged. A multi-view registration is proposed using triangle constraint and global optimization. The method includes: remove the false matching points in possible matching points by joining triple constraint; after the first registration, use the center of marking points to global optimization through least squares principle method. The realization of the algorithm by use of tools such as VC++ and Open CV demonstrates that this method has the advantage of better restraining the accumulative error, keeping the process stable, and fast and realizing automatic registration.

Abstract: A decorrelation-based data association algorithm for heterogeneous sensors system is proposed, which first fusions multiple measurements to estimate a target position using the pseudo linear estimation method, then a decorrelation-based data association model is built and the unscented transform is proposed to compute the mutual covariance between measurements and the pseudo ones. Meanwhile, taking the real-time problem into consideration, when calculating the cross covariance, the minimum skew simplex sample is used to reduce the complexity of the algorithm.