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A method of torque control in induction motor drives that requires not shaft encoder is presented. Both the torque control and the speed control are based on vector control. The proposed scheme of vector control is based on the self-control of rotor flux velocity, which is controlled with the torque-producing current and the rotor flux derived from the(More)
Development of accurate surface assessment technology is of vital interest to modern wood industries. In this experiment we investigated new and fast noncontacting sensors to determine their usefulness for wood surface evaluation and to verify their accuracy. Two types of laser displacement sensors [equipped with a position sensitive detector (PSD) and a(More)
Knowledge of the occurrence of sound and dead knots on the surface of sugi is important for the classification and application of the material. This study examined a color vision system for detecting sound and dead knots on sugi. The system can be conceptually divided into three components: a CCD-camera scanning system, an image-segmenting module, and a(More)
Thermal effects at the surface of a sample wood specimen while it is rubbed by reduction with a metal disk rotating at high speed are investigated. The results provide fundamental data for the development of new surface processing methods. The results of high-speed friction tests showed that the wood surface developed high-temperature regions due to the(More)
This paper reports on the performance of coated carbide tools in turning wood-chip cement board. The coating materials studied were titanium carbonitride (TiCN), titanium nitride (TiN), chromium nitride (CrN), and titanium nitride/aluminum nitride (TiN/AlN), which were synthesized on the P30 carbide substrate. The aim is to investigate the effect of coating(More)
The split and the hole are two common defects on sugi (Cryptomeria japonica D.Don). They have a common feature in that they are associated with surface irregularities. We have developed a laser scanning system to detect the splits and the holes based on their thickness, which correlates spatially with the profile information. The displacements measured by(More)
In this study we investigated the abrasive wear property of Douglas fir (Pseudostuga menziesii Franco) on abrasive paper using test specimens with various dimensions and annual ring widths. The effect of the annual rings on the abrasive wear property of Douglas fir was clarified from the relation with the compression strength of the wood specimens. The(More)
This paper presents an on-line method for detecting damaged teeth in the bandsaw using acoustic emission (AE) signal energy. The method is based on an analysis of differences in AE energies generated by normal and damaged teeth during sawing. Because of the difference in the amount of sawing, the AE energy was low for sawing by the damaged tooth and high(More)
Under fixed cutting conditions, the surface finish roughness is correlated to the grain angle. However, the means of determining the grain angle automatically and accurately is still a challenge for on-line control of the router. It is therefore necessary to develop a new technology to determine the grain angle accurately and automatically. In this(More)
This paper presents the performance of coated carbide tools when grooving various density hardboards and wood-chip cement boards. Work materials of low density (about 0.8g/cm3) and high density (about 1.2g/cm3) were tested. The coating materials studied were chromium carbide, titanium carbonitride, and titanium carbide, which were synthesized on P30 carbide(More)