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自律／半自律型双腕水中ロボットの運動制御に関する実験的研究
No full text九州工業大学博士学位論文 学位記番号:工博甲第396号 学位授与年月日:平成27年9月25日1 Introduction||2 Resolved acceleration control (RAC) method for underwater vehiclemanipulator systems||3 Experiment on a 2-link dual-arm UVMS using RAC method||4 Experiment on a 3-link dual-arm UVMS using RAC method||5 Master-slave system for a 3-link dual-arm UVMS||6 Conclusions and future recommendation
Partial Discharge Detection by TEV Sensors and Signal Propagation Analysis in Transformer Model
Get PDFThe 19th International Symposium on High Voltage Engineering, Pilsen, Czech Republic, August, 23 – 28, 2015(ISH 2015)This paper deals with a detailed study on partial discharge (PD) generated in transformers using transient earth voltage (TEV) detection method. Experiment and numerical analysis are carried out using an iron box model which simulates a tank of an actual transformer. In the test model, propagation properties of TEV signal caused by PD occurring inside and outside of the transformer model are examined. Results reveal that the electromagnetic waves generated by PD in the model can leak from the opening window, having special frequency determined by the size of the opening window. It is also found that TEV sensor placed on the surface of the tank detects a TEV signal originating from the leaked electromagnetic wave. On the other hand, TEV signal by electromagnetic waves generated by an external PD source is found to have a wider frequency band than that by leaked electromagnetic wave. In addition, electromagnetic field and surface current analysis are performed using finite difference time domain (FDTD) method and simulated results are compared with experimental ones. As a result, it is shown that leaked electromagnetic wave excites a surface current on the outer tank wall of the transformer model. It is also found that there exists difference in the time required for TEV signal to arrive at the inside and outside sensors. The results indicate that PD emitting electromagnetic waves leaked from the dielectric discontinuities can be detected by the TEV method. Furthermore, these results suggest a combination of the detected waveform and its frequency band could lead to highly reliable diagnosis of the apparatus by TEV detection method
Anti-Loosing Performance of Special Bolts and Nuts Having Enhanced Fatigue Life by Introducing Pitch Difference
Get PDFA slight pitch difference is considered between the bolt and nut in this study. Here, the pitch of nut is a um larger than the pitch of bolt. For four different levels of a , the loosening experiment is performed. Considering both the anti-loosening ability and the clamping ability of the nut, the desirable range of a is discussed. Based on the loosening experimental results, several levels of a are selected in order to clarify the effect of the pitch difference on the fatigue life of bolt. The most desirable pitch difference is discussed in terms of improving both anti-loosening and fatigue life
Tar-free and Benzo[a]pyrene-free Hydrothermal Liquefaction of Bamboo and Antibacterial Property of Recovered Vinegar
Get PDFBamboo, which was treated using superheated steam controlled at a low temperature range, gave tar-free and benzo[a]pyrene-free vinegar. The vinegar’s selective antibacterial activity against Staphylococcus aureus concerned with the atopic dermatitis and Bacillus cereus causing food poisoning in humans was confirmed, while no effect was found against Escherichia coli and Bacillus subtilis as being indigenous bacteria in natural environments
High-precision Real-time Correction Sounding System using MEMS Inertial Measurement Units
No full textThis paper proposes a high-precision real-time correction sounding system using Micro Electro Mechanical Systems (MEMS) inertial measurement units, which can correct the effective depth from the sea surface to the seabed in real-time. The advantages of the proposed system are as follows: (1) The system outperforms a single-beam sounder available on the market in that the range of depth errors caused by the swing of a research vessel is about 2%: (2) Since the proposed system is small compared to the existing attitude and heading reference system, it can be employed for unmanned surface vehicle, remotely operated underwater vehicle, autonomous underwater vehicle, and so on. Experimental results show that an attitude, heading and depth measured by the developed system are within the acceptable range, and the system can give a stabilized attitude, heading and depth information for a long time
