Applied Mechanics and Materials Vols. 336-338

Abstract: Corona discharge signal from the high-voltage transmission line exhibits unique characteristics compared to other radiation signals, which include wide distribution of frequency, small signal amplitude and strong randomness. The properties of frequency distribution of corona discharge signal and noise were tested in the range of 0 MHz-1.5 GHz to obtain the most beneficial detecting band. Based on the characteristics and properties, a high-gain helical antenna with the center frequency of 250 MHz was designed, and the performance of the antenna was tested. The corona discharge signal from 550 kV extra-high-voltage power line at the distance of about 320 meters was successfully detected by the helical antenna. The results showed that this design achieves the expected requirements and have a good practical performance. The design of antenna may provide supports for the further research on remote detection system of corona discharge signal.

Abstract: Based on the analysis of infrared detection technology and Lambert-Beer law a new kind of quad-channel non-dispersive infrared (NDIR) gas concentration analyzer is designed by applying the modulated IR light source and a quad thermopile sensor into automobile exhaust gases concentration detection. The emphasis is paid on the analysis of modulated light source, gas chamber, sensor and the acquisition and processing circuit of the signal. The result of simulation and analysis of the designed circuit proved the feasibility of the design.

Abstract: Concerning the intelligent technical control of sectional warping machine in textile process, Hall speed encoder is used to detect the speed of the drum and weavers beam so as to adjust the rotating speed with the help of PLC and VVVF to maintain constant tension of warp, the displacement sensor can be used to monitor the sidesway and thickness of warp stripe winded on the drum of sectional warping machine.

Abstract: Measurement of underground displacement is of great significance. Now, there are various measuring methods to detect underground displacement. But each of them has its own scope of application and limitation. According to actual demand, this paper puts forward an integrated sensor which utilize three-dimensional measurement method to supervise the underground displacement. This sensor can not only measure the size and direction of the displacement, but also can achieve real-time measurement data. Method and realization of displacement measurement are introduced, as well as the experimental data. Comparing with other several measurement methods, three-dimensional measurement method is much better than the normal ones, including high data transmission speed, high sensitivity, strong practicability etc.

Abstract: The trajectory correction capability of the Simple guided munitions is directly affected by measurement accuracy of attitude angle. A gesture detection method based on geomagnetic gyro combination is proposed in this paper in order to detect the projectile flight attitude, The yaw angle of the projectile is solved by using runge-kutta algorithm with angle information of MEMS gyro. Then roll angle and pitch angle of the projectile is solved by magnetic field component of the three-axis magnetic sensor. Finally, the whole attitude detection system is installed in three-axis non-magnetic turntable to have a performance test. Experimental results show that the attitude solution results error is small. Nearby blind area, the roll angle error reduced to 5° and the pitch angle error reduced to 4°. In other locations, the roll angle error reduced to 2° and the pitch angle error reduce to 1°. The measurement accuracy increased nearly tenfold, can satisfy the trajectory correction demand of simple guidance ammunition.

Abstract: The arrangement positions and the quantities are different for different types of cranes. In order to make suitable decision, much investigate and survey was done at preliminary stage, and we know that the flange connected gate legs and turntables, the connections between load-bearing beam and rotary column under the engine room and the connections between jib and turntable are easy to lose efficient, and their mainly failure modes are cracks. By the method of finite element, 32 sensors (including 21 welding strain FBG sensors and 11 temperature FBG sensors) were used after doing much investigate and survey and finite element modeling analysis, which are arranged in different places of a gantry crane of MQ2533, for real-time structure health monitoring. This method makes the sensor data obtained more realistically reflects the crane structural condition, which provides reliable data support for crane safety monitoring and safety evaluation. Then a software platform is developed to monitor the real-time stress. If the real-time stress exceeds the allowable stress, it issues an alarm signal to the operator.

Abstract: The performance of the fiber distributed vibration monitoring technology based on the phase sensitive optical time domain reflectometer (φ-OTDR) is reseached. the principle of fiber distributed vibration monitoring of the φ-OTDR and multi-point positioning are illustrated. And this paper indicates the feasibility of realizing multi-point positioning by the φ-OTDR system, and carry on a further research on the φ-OTDR system ́s frequency response range, measuring distance, spatial resolution and other aspects. The inverse proportion relations between the frequency range and distance of the φ-OTDR system, and the relations among spatial resolution, laser pulse width, refractive index and sampling rate are illustrated.

Abstract: Because the stricter emission regulations of diesel engine particulate matter are continuously presented, the new type sensors for diesel on-board diagnostics (OBD) are needed to detect PM emissions accurately. Sufficient heat resistance and endurance, ability to endure the harsh environment of the exhaust are necessary for these sensors. The working principles of several kinds of sensors are introduced in this paper. The flow field is simulated for resistive soot sensor, the forcible soot collection method is introduced for the capacitance PM sensor and the electrode of electrochemical sensor added ionomer is analyzed. At the same time, the application of the sensor is introduced for the future.

Abstract: In maneuvering multiple targets tracking problem, Probability Hypothesis Density(PHD) filter can be used to estimate the multi-target state and the number at each time step, but single model method may not provide accurate estimates. In this paper, an interactive multiple model PHD filter is proposed, and then multiple sensor interactive multiple model PHD filter is proposed to improve the tracking of multiple maneuvering targets. PHD particle filter implementation is used to perform the proposed method consisting of multiple maneuvering targets.

Abstract: This paper applies wireless sensor network to the shipping laterite nickel ore moisture content monitoring, and design a set of real-time monitoring of lateritic nickel ore moisture content monitoring system in the process of actual transportation, and formulate a specific implementation plan. According to the structure of laterite nickel ore bulk carriers and the characteristics of the wireless sensor network, this paper also solve the design and layout problems of wireless sensor nodes, the problems of energy saving and data transmission from the inside cabin to the outside, etc. In addition, the system has strong portability, and can be used for monitoring in other related fields.