De En

Analysis of the Shortest Path of GPS Vehicle Navigation System Based on Genetic Algorithm

The shortest path is one of the key problems in the GPS vehicle navigation system. Genetic algorithm is one of the useful methods in solving the shortest path problem. First, the genetic algorithm is analyzed and improved. Its population is optimized before being initialized aiming at reducing the needless paths and nodes. A combination of roulette and elite protecting method is used to protect the population’s best individual in each generation. The improved genetic algorithm can advance the convergence rate and the quality of solution in searching the shortest path. The functional demands of GPS vehicle navigation system can be met by using this method.

Design of Double Y Branch Waveguide in Acceleration Seismic Geophone

Dual M-Z interferometer is the sensitive element of three-component acceleration seismic geophone, while Y branch waveguide is the basic optical components composed of dual M-Z interferometer, so the design of Y branch waveguide directly affects the performance of three-component acceleration seismic geophone. Firstly, branch waveguide and S-shaped bent waveguide are introduced, and symmetrical double Y branch S-shaped bent waveguide is designed based on this. Secondly, the bending loss of the branch waveguide is analyzed and calculated. The transmission of 1/2Y branch waveguide and 1/4Y branch waveguide , and the bending loss changes with the length of 1/2Y branch waveguide and 1/4Y branch waveguide is simulated by MATLAB. The result shows that the maximum bending loss of 1/2 Y branch waveguide is the 0.156dB, and the bending loss is close to 0 after L >320μm; the maximum bending loss of 1/4 Y branch waveguide is 0.058dB, and the bending loss is close to 0 after L >200μm. The design of double Y branch meets the requirement of low loss. Thirdly, the optical power conversion of branch waveguide in 3dB coupler is simulated and analyzed. Finally, proton exchange and Ti diffusion technique are compared; the advantages of proton exchange technology are summarized; the principle of proton exchange is introduced; and a good proton exchange annealing condition is summarized.

Finite Element Analysis for Harmonic Oscillator of Acceleration Seismic Geophone

In the oilfield development stage, more recoverable reserves can be found by using the more sophisticated seismic methods with stimulation. Three-component seismic exploration technology comes into being, and it is becoming a major oil exploration seismic technology currently. As the sensitive element of seismic geophone, the performance of the harmonic oscillator is vitally important to the entire seismic exploration. The working principle of the harmonic oscillator is introduced, the solid model of harmonic oscillator mass is created by using the finite element method, and its three-dimensional static analysis and modal analysis are carried out. Load is applied and solved. The first fourth-order model is taken for analysis. The frequency of twentieth order vibration mode of physical model is 78 kHz; the total displacement of twentieth order is 0.122×10 -6 μm; and the total displacement of the solid model is 0.236×10 -19 μm.

Adaptive Filter with Multiple-Scale Decomposition Rotor Broken Bars in Induction Fault Diagnosis

There is a very small additional current component of frequency in the stator current signal when motor has broken rotor bars.So adaptive notch filter is applied to process the signals of the stator current in induction motors.The variable step size LMS algorithm and the multiple-scale wavelet transform are merged into the adaptive filtering system.A method is proposed, that is a LMS adaptive filtering algorithm with modified variable step size based on multiple-scale wavelet transform(MSWT-MVSS-LMS).It can eliminate interference from power frequency component to frequency component of broken rotor bar and achieve precise identification to frequency component of broken rotor bar from FFT.The result is a great help to extract the feature component of rotor fault and improve the sensitivity of fault diagnosis.The simulation show that the method is valid and effective.

Research of the Seismic Wave Data Processing Based on the Wavelet Transform

Seismic exploration is a effective methods to ascertain underground structure and looking for oil. As the data collected in the wild are often subjected to the interference of noise, is not conducive to the analysis and interpretation of seismic data, therefore removing noise is the premise of data interpretation. To use the Fourier transform and wavelet analysis denoising a synthetic seismogram in this paper, by comparing denoising results, wavelet soft threshold denoising waveform is smooth, and it can better reconstruction original waveform.

Research of MOEMS Pressure Sensor

In recent years, with the development of optical communication by leaps and bounds, promote the Micro-opto-electro-mechanical system (MOEMS) development. As a new technology, the MOEMS have been widely used in optical communication, optical switching, data storage, optical sensing and etc.. Compared with the traditional pressure sensors, the optical pressure sensor based on MOEMS has some unique advantages. In this paper, the structures, operation principles and fabrication processes of various MOEMS pressure sensors are described mainly. Finally, the structure and Key technology of a MOEMS pressure sensor array is presented in brief.

Design of Collecting and Processing System of GPS Information Based on ARM and Linux

GPS information collecting and processing is an important part of the navigation and positioning system. Through the establishment of cross-compiler environment, using the ARM processor S3C2440A and Linux operating systems as the hardware and software platform and the GS87 is used as GPS receiver module, the NMEA-0183 communications protocol and serial asynchronous communication between the ARM platform and GS87 module are analyzed. Through the serial port programming, GPS information collecting and processing system is realized. By querying the GPRMC statement and the corresponding conversion, the useful information is separated. The final practice has proved that the system data is of high precision, real-time property and good practical value.

Real-Time Detection System of State of Train Wheels Based on LabVIEW

Virtual instrument (VI) is the computer technology and traditional instrumentation technology product of the combination, and is an important direction of development of the instrument. LabVIEW is a graphical programing language based on virtual instrument software development tools. This paper uses the LabVIEW 2010 point-by-point analysis of the database, sets up the state of the train wheels real-time detection system. It can carry on the examination in the train normal operation situation to the wheel’s condition. As can be seen from the simulation, the test results are precise and rapid, with high practical value.

Analysis and Design of Sensors Based on MEMS Process

Due to the features of light weight, small size, high intelligence, MEMS is widely used in the field of nature and engineering science, such as communication, aerospace, biomedical and materials science and so on. In this paper, MEMS manufacturing process is introduced, the structure and working principle of MEMS’ acceleration seismic sensors are analyzed and designed.

Research on Decoupling of Multivariable System in MOEMS Three-Component Acceleration Seismic Geophone

We found the dynamic behavior of detected signals by MOEMS three-component acceleration seismic geophone has nonlinear, time-variation, multi-variable and strong-coupled. We proposed a method used a multivariable fuzzy-neural net work decoupling controller, designed and simulated the corresponding decoupling scheme. The results show that this method is stable and reliable, giving some help to the development of three-component acceleration seismic geophone.