Applied Mechanics and Materials Vols. 143-144

Abstract: A new nonlinear filter method Cubature Kalman Filter (CKF) is improved for passive location with moving angle-measured sensors’ measurements.Firstly,it used Empirical Mode Decomposition (EMD) algorithm to estimate measurement noise covariance; And then the covariance of the procession noise and measurement noise is brought into the circle; Meanwhile,CKF is improved by the way of square root to keep its stability and positivity,and the results of track by Extend SCKF are compared with the results by Unscented Kalman Filter (UKF) in the text;By the tracking results to the velocity of the target, Extend SCKF algorithm can not only track the target with unknown measurement noise but also improve the passive position precision remarkably as the same difficulty as UKF.

Abstract: First of all, the working principle of infrared thermometer and the structural principle sketch map for measuring the temperature of rotary wheel disc through infrared thermometric technology are briefly introduced from the physics aspect. Secondly, the type of infrared thermometer is selected according to the practical request of low or high temperature measure of rotary wheel disc. Finally, the same point temperature of the turbine wheel disc of an engine is measured through infrared thermometer and thermoelectric couple in the heating status, and the measure results are compared, which dictates that the infrared thermometric system could achieve an upper detection precision and satisfy the practical engineering request.

Abstract: Speed signal is an important monitoring signal in Steam Turbine Condition Monitoring And Fault Diagnosis(TDM) system. A review on the existing speed measurement methods of rotary machine was proposed to find out the defects of each method. A new approach was introduced to fulfill steam turbine speed accurate measuring. The periods of phase signal pulse generated by the key groove and speed signal pulse generated by the velocimetry gear, were measured respectively by the two independent 16-bit timer/counters, and the "counter overflow" problem was resolved by calling a byte memory unit. According to the record number of the counter, the value of steam turbine speed was calculated accurately. The method of steam turbine speed measurement proposed in this paper can not only simplify the structure of a TDM system, but also reduce its cost.

Abstract: Digital image technology is the most effective and important way to communicate and acquire information. Image can be used as a mean or carrier of detecting and transmitting information. The accession of image processing technology solves many defects such as time-consuming, complex operation, low precision which existed in manual statistics and analysis on particles. The basic physical properties of particles include pore, shape, size and other parameters. Computer can be used for a variety of image processing, both to speed up the analysis processing and highlight the information people need at the present.

Abstract: To know the influence of deterministic system error to navigation system well, so the precision index of gyroscopes and accelerometers, which are the main components of rate azimuth platform inertial navigation system, and initial calibration precision, can be put forward. Based on the error equations, the characteristic equation of rate azimuth platform inertial system is established, and the solutions of the error equation under static state are obtained with analytical method, and the system error characteristics caused by the accelerometer drifts are analyzed.

Abstract: The DTR100 multimode VHF transceiver produced by Italian OTE company is a state-of the-art communication unit. The air traffic control authorities in many areas currently used DTR100 to protect the VHF communication. The results of measured parameters must be a true reflection of the actual working condition of equipment. According to this thought, this paper first analyses the shortcoming of the standard CMS50 radio comprehensive measurement instrument, then introduces two virtues of OTE test box, and the implementation procedure on audio signal 600Ω impedance matching. Moreover, this paper is to improve to technical staff the routine operations and the maintenance, to play the best performance of the equipment, in order to ensure the rapid development of the civil aviation industry in China.

Abstract: The DTR100 multimode VHF transceiver produced by Italian OTE company is a state-of the-art communication unit. The air traffic control authorities in many areas currently used DTR100 to protect the VHF communication. The results of measured parameters must be a true reflection of the actual working condition of equipment. According to this thought, this paper first analyses the shortcoming of the standard CMS50 radio comprehensive measurement instrument, then introduces two virtues of OTE test box, and the implementation procedure on audio signal 600Ω impedance matching. Moreover, this paper is to improve to technical staff the routine operations and the maintenance, to play the best performance of the equipment, in order to ensure the rapid development of the civil aviation industry in China.

Abstract: Harmonic wavelet function, with the strict box-shaped characteristic of spectrum, has strong ability of identifying signal in frequency domain, and can extract weak components form vibration signals in frequency domain. Using harmonic wavelet analysis method, the selected frequency region and other frequency components of vibration signal of mine ventilator were decomposed into independent frequency bands without any over-lapping or leaking. Simulation and diagnosis example show that this method has good fault diagnosis effect, and the ventilator fault is diagnosed successfully.

Abstract: Power transformers are vital equipments in the grid and their reliability can affect the security of the grid directly. So it is always necessary to monitor the power transformers online. The study designed a multi-parameter online monitoring system for power transformer malfunction utilizing DSP and computer technology. The paper mainly introduced the design and component selection of online monitoring circuit for partial discharge, dielectric loss, gas component in oil and iron core's grounding current. The result showed that this system can diagnose most the malfunctions in power transformers with satisfactory property.

Abstract: Aiming at the extraction of failure character signal for early acoustic emission (AE) signals, a method to combine lifting wavelet packet with spectrum zoom technology is developed. Using lifting wavelet packet de-noising method, not only filters the noise signal, but also retains the feature information. After the signals de-noising, combining the envelope demodulation analysis with the spectrum zoom technology, which can effective extract the weak fault characteristic frequency The result of simulated signals and experimental signals shows that the proposed method has better noise reduction with a higher signal noise ratio (SNR) and lower mean square error (MSE), and it can successfully extract the fault characteristic frequency of rotating machinery early AE signals.