• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1720-1727
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• 2003

The object of this work is to develop the measurement method of the transmission error of the helical gears. For this purpose, experimental set up is designed by 3D CAD software. It consists of the motor, inverter, powdered brake equipment, torque sensor and helical gearbox. In this study, tangential linear accelerometers were used as the methods for the transmission error measurement. the acceleration signals are transmitted to the signal conditioners through the slip rings and the transmission errors are obtained by a specially designed circuit board. The transmission errors are analyzed in the frequency domain. As a result, The periodicity of the transmission error is confirmed in the mesh frequency and its harmonics. The magnitude of harmonic components is very dependent on the natural frequencies of the gear system. It usually increases with the rotational speed. However, it does not always increase with torque.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.652-655
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• 2008

Despite of the laminar-turbulent transition region co-exist with fully turbulence region around the leading edge of an airfoil, still lots of researchers apply to fully turbulence models to predict aerodynamic characteristics. It is well known that fully turbulent model such as standard k-${\varepsilon}$ model couldn't predict the complex stall and the separation behavior on an airfoil accurately, it usually leads to over prediction of the aerodynamic characteristics such as lift and drag forces. So, we apply correlation based transition model to predict aerodynamic performance of the NREL (National Renewable Energy Laboratory) Phase IV wind turbine. And also, compare the computed results from transition model with experimental measurement and fully turbulence results. Results are presented for a range of wind speed, for a NREL Phase IV wind turbine rotor. Low speed shaft torque, power, root bending moment, aerodynamic coefficients of 2D airfoil and several flow field figures results included in this study. As a result, the low speed shaft torque predicted by transitional turbulence model is very good agree with the experimental measurement in whole operating conditions but fully turbulent model(k-${\varepsilon}$) over predict the shaft torque after 7m/s. Root bending moment is also good agreement between the prediction and experiments for most of the operating conditions, especially with the transition model.

• Journal of Drive and Control
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• v.20 no.1
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• pp.41-47
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• 2023

The aim of this study was to develop a method for installing strain gauges on moving, lubricating oil-filled, and sealed parts, such as drive shafts of equipment, including construction machinery. A measuring device was constructed using an embedded CPU and an IoT sensor to measure the strain of the strain gauge, which allowed for the measurement of axial torque and axial force, and subsequent analysis. To verify the performance of the developed device, the axial torque and axial force of the forklift were measured during operation using a strain gauge attached to the inside of the drive shaft. This study confirmed the possibility of measuring and analyzing the strain of a moving part, such as the inside of a drive shaft, which is sealed and filled with hydraulic oil.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.8-13
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• 2016

Purpose: The aim of this study was to compare the accuracy of two different styles of mechanical implant torque wrenches before and after sterilization and repeated use. Materials and methods: Thirty new spring-style and friction-style mechanical implant torque wrenches from five different manufacturers were selected as subjects of study and assessed in terms of accuracy. Three manufacturers produced, spring-style (Dio, Neobiotech, Osstem) torque wrenches, and other three manufactures produced friction-style (Dentium, Osstem, Shinhung) torque wrenches. The procedure of target torque measurement was performed 10 times for each device and a digital torque gauge (MGT-12, Mark-10 Corp, USA) was used to record the measurements. All torque wrenches were used repeatedly for 20 times and then sterilized. This whole procedure was repeated 100 times and all torque wrenches were retested. The collected data was analyzed using a SPSS Statistics Analysis program to evaluate the accuracy of the torque wrenches and Mann-Whitney-U test was used for a comparative analysis. Results: After sterilization and repeated use procedure, results did not show any significant difference between error values in the spring-style torque wrench group. However, the results demonstrated an increase in error values within the friction-style torque wrench group (P<.05). Conclusion: There was no difference between the accuracy of new spring-style torque wrenches before and after 100 cycles of sterilization and repeated use (P>.05). There was significant difference between the accuracy of new friction-style torque wrenches before and after 100 cycles of sterilization and repeated use (P<.05). Within the limitation of this study, spring-style torque wrenches were more accurate than friction-style torque wrenches in delivering target torque values.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.19-25
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• 2017

The aim of this study was to evaluate Magnetic Resonance Imaging safety by measuring the translational attraction, torque and susceptibility artifact for Bone-Anchored Hearing Aid (BAHA) implant at 1.5 T and 3.0 T MRI by standard criteria. In vitro assessment tools were made of acrylic-resin by American Society for Testing and Materials (ASTM) F2052-06 and F2119-07 standard. Translational attraction of BAHA implant was measured by the maximum deflection angle at 96 cm position, where the magnetically induced deflection was the greatest. The torque was assessed by the qualitative criteria of evaluating the alignment and rotation pattern, when the BAHA implant was positioned on a line with $45^{\circ}$ intervals inside the circular container in the center of the bore. The susceptibility artifact images were obtained using the hanged test tool, which was filled with $CuSO_4$ solution. And then the artifact size was measured using Susceptibility A rtifact Measurement (SA M) software. In results, the translational attraction was 0 mm at both 1.5 T and 3.0 T and the torque was 0(no torque) at 1.5 T, and +1(mild torque) at 3.0 T. The size of susceptibility artifacts was between 13.20 mm and 38.91 mm. Therefore, The BAHA implant was safe for the patient in clinical MR environment.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.998-1001
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• 1988

A robust control method for robots in presented. In this method, a phase-lag controller is used for reducing the effect of the unknown payload without the measurement of joint accelerations and torque/force. Simulation results for the lower 3 joints of PUMA 560 show considerable reduction of position errors due to the unknown payload, compared to the computed-torque method.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.131-134
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• 2001

The accurate identification of the motor parameters is crucially important to achieve high dynamic performance of induction motors. In this paper, the motor parameters such as rotor resistance, stator(rotor) leakage inductance, mutual inductance are measured for torque monitoring and indirect vector control. To demonstrate the practical significance of the results, some experimental results are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.281-282
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• 2011

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.249-255
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• 2017

Efficient operation of induction motor at light loads has been getting wide attention recently because the operating of induction motor at light loads occupies big portion of its operating regions in many applications such as environment friendly vehicle. As one of approaches to improve efficiency, Adaptive Maximum Torque Per Amp (Adaptive MTPA) control for induction motor drives has been proposed to achieve a desired torque with the minimum possible stator current. However, the Adaptive MTPA control was validated only at heavy load where, in general, control scheme tends to perform better than at light loads since the error in measurement of sensors is lower and signal to noise is better. Thus, although the performance of a control scheme is good at rated operating point, its performance at light load is somewhat in doubt in practice. This has led to considerable interest in efficiency of Adaptive MTPA control at light loads. This work experimentally demonstrates performance of Adaptive MTPA control at light loads regardless of rotor resistance variation, thus showing its good performance over all operating conditions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.12
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• pp.815-821
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• 2015

Maritime safety has been more critical recently due to the occurrence of shipboard accidents involving prime movers. As such, the propulsion shafting design and construction plays a vital role in the safe operation of the vessel other than focusing on being cost-efficient. Smaller vessels propulsion shafting system normally install high speed four-stroke diesel engine with reduction gear for propulsion efficiency. Due to higher cylinder combustion pressures, flexible couplings are employed to reduce the increased vibratory torque. In this paper, an actual vibration measurement and theoretical analysis was carried out on a propulsion shafting with V18.3L engine installed on small car-ferry and revealed higher torsional vibration. Hence, a rubber-block type flexible coupling was installed to attenuate the transmitted vibratory torque. Considering the flexible coupling application factor, reduction gear stability due to torque variation was analyzed in accordance with IACS(International Association of Classification Societies) M56 and the results are presented herein.