• International Journal of Advanced Culture Technology
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• v.3 no.2
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• pp.67-76
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• 2015

This paper aims to study and design of Organic Rankine Cycle (ORC) Machine using Isopentane as working fluid expanding through Tesla turbine. The study on ORC machine expanding through Tesla turbine has result on the efficiency of Tesla turbine. In addition, Thermodynamics theory on isentropic efficiency proved to be a successful method for overcoming the difficulties associated with the determination of very low torque at very high angular speed. By using an inexpensive experiment device and a simple method, the angular acceleration method, for measuring output torque and power in a Tesla turbine is able to predict a tendency of output work. The experiments using two Tesla turbine sizes, the first size is 1.6 bigger than the second one. In comparison with the first size, the tesla turbine can produce power output more than 62% of the second size. Further study on the machine can be developed throughout the county due to its low cost and efficiency.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.29B no.3
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• pp.25-34
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• 1992

This paper proposes a Self-Tuning control algorithm for tracking the reference trajectory by measuring the end-point of robot manipulator whose links are light and flexible, and the performance of it is tested through the computer simulation. As an object of system, a flexible robot manipulator with two-links is considered and an assumed mode shape method including gravity force is adopted to analyze the vibration modes for each links and dynamics equation is derived. The controller is designed as a combined form which consists of dynamic feedforward compensator and self-tuning feedback controller. The one supplies nominal torque and the other supplies variational torque to manipulator. Apart from the, K-incremental predictor is also proposed in order to eliminate the offset error. and it shows that the result of simulation adapted well to load change and rapid velocity.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.3
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• pp.243-251
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• 2014

In inference fit assembly process of the industrial robot, it basically needs the force data. One of the typical methods to get the force data is attaching torque sensors on the robot arm joint or end effector. This is effective way to reduce time delay and to improve preciseness of force control, but this method has several problems. To solve that problem, this paper suggests method which measures assembly force without torque sensor by using the sliding perturbation observer(SPO) and assembly process based on SPO to assemble successfully in inference assembly

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.750-752
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• 2003

This paper presents a method of tolerance analysis for a electric machine. Tolerance analysis technique is required to find the tolerance band of design variables and estimate the characteristic distribution of the electric machine, because that manufacturing tolerances as well as measuring errors have a great influence on the electric machine. Therefore, this paper introduces Stochastic Response Surface Methodology to achieve the tolerance analysis. As an example, the tolerance analysis is applied to the analysis of torque characteristics for a BLDC motor from the electric point of view.

• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.771-782
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• 2017

This paper describes the development of a wearable robot to assist ankle power for the elderly. Previously developed wearable robots have generally used motors and gears to assist muscle power during walking. However, the combination of motor and reduction gear is heavy and has limitations on the simultaneous control of stiffness and torque due to the friction of the gear reducer unlike human muscles. Therefore, in this study, Mckibben pneumatic muscle, which is lighter, safer, and more powerful than an electric motor with gear, was used to assist ankle joint. Antagonistic actuation using a pair of pneumatic muscles assisted the power of the soleus muscles and tibialis anterior muscles used for the pitching motion of the ankle joint, and the model parameters of the antagonistic actuator were experimentally derived using a muscle test platform. To recognize the wearer's walking intention, foot load and ankle torque were calculated by measuring the pressure and the center of pressure of the foot using force and linear displacement sensors, and the stiffness and the torque of the pneumatic muscle joint were then controlled by the calculated ankle torque and foot load. Finally, the performance of the developed ankle power assistive robot was experimentally verified by measuring EMG signals during walking experiments on a treadmill.

• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.263-267
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• 1992

We have developed new techniques to measure the magnetization and coercivity of a uniaxial magnetic material using a torque magnetometer. The magnetization could be measured from the slope of the linear region in a plot of the torque ${\tau}/H$ versus the applied field H, when the direction of the applied field was normal to the uniaxial orientation. While, the coercivity could be obtained by taking the value of applied field where the torque was zero, when the direction of the applied field was $(180+{\delta})$ degrees from the uniaxial orientation. The techniques were applied to determine the magnetizations and coercivities of several Co /Pd multilayer thin films and the results were confirmed to be similar within a 2 % difference to those obtained by a vibrating sample magnetometer.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.7
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• pp.713-721
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• 2005

A marine diesel engine should realize optimal operation efficiency while reducing NOx, PM (Particulate Matters) and other emissions. Fuel injection systems that use electronic control can become an effective means of achieving that objective. However. it still needs some accurate and instant information in order to bring its ability into full potential while sailing on the sea. The important information of them are a shaft torque and continuous combustion pressures of all cylinders. The shaft torque and the propeller thrust described in this paper are measured at an intermediate shaft by using a unique principle that one of two electromagnet coils oscillates a vibrating strip which the length changes with force and the other coil picks up the change of the frequency of the vibrating strip. For further reference, the shaft power meter multiplied the torque by the shaft revolution has already had about 750 sets of sales performance. The research presented in this paper started about ten years ago and is concerned with the development of a combustion pressure sensor that uses the same principle. Recently, the pressure sensor which bears continuous operation has been developed after a hard struggle, that is, the system that consists of a shaft horsepower meter, a propeller thrust meter and a combustion pressure sensor has been completed and has been shown to be reliable. This paper describes the configuration of this system, the material of the combustion pressure sensor, the principle of that, and the improving point of the sensor, and, we finally consider the use of this system.

• Journal of Biosystems Engineering
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• v.20 no.3
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• pp.245-249
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• 1995

In this study power requirements to saw shoots with circular saw were determined by measuring and analyzing the required maximum torque to provide the information for the mechanization of Korean pine cone harvest. Two levels of feed rate of shoots, 10.4mm/s and 20.8mm/s, three levels of sawing speed 5.8㎧, 11.6㎧, and 17.4㎧, and 14 levels of shoot diameter from 7.7 to 18.1mm were used as variables. 1) The maximum torques were significantly affected by all three variables. The average maximum torque, 18.2 N-cm for feed rate of 20.Bmm/s was greater as much as 80% of 10.1 N-cm for feed rate of 10.4mm/s. 2) As the sawing speed was increased from 5.8㎧ to 11.6㎧ and 17.4㎧, the maximum torques were decreased to 14.8N-cm, 8.5N-cm, and 7.IN-cm, respectively when the feed rate was 10.4mm/s. The maximum torque ranged from 4.5 to 19.3N-cm as shoot diameter increased from 7.7 to 18.1mm. The minimum power requirements to saw shoots of 18.1mm with circular saw was 30W for the feed rate of 10.4mm/s. 3) The maximum torques were 28.6N-cm, 14.6N-cm, and 11.4N-cm when sawing speeds were 5.8㎧, 11.6㎧, and 17.4㎧, respectively when the feed rate was 20.8mm/s and these torques were increased as much as 93%, 36%, and 61% of those for the feed rate of 10.4mm/s. The maximum torque increased from 9.7N-cm to 30.7N-cm as shoot diameter increased from 7.7 to 18.1mm. The minimum power requirements to saw shoots of 18.1mm was 54W which was 1.8 times of 30W for the feed rate of 10.4mm/s.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.2
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• pp.142-149
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• 2010

Interior Permanent Magnet Synchronous Motor(IPMSM) have gained an increasing popularity in recent years for a variety of industrial applications, because of their high power density, high efficiency and possibility of flux weakening operation. Because the efficiency of IPMSM is one of the important performance characteristic, the Maximum Torque Per Ampere(MTPA) operating method has been indispensible. In theory, MTPA operating point can be calculated using the exact values of the machine parameters. However, the values of the IPMSM parameters are known to vary widely according to the operating condition. Therefore, to operate the IPMSM in the MTPA operating point, the machine parameters should be estimated in real-time. In this paper, the new MTPA operating method based on the signal injection is presented. By injecting the high frequency current signal, the MTPA operating criteria can be calculated by measuring the input power to IPMSM. The proposed method can find the MTPA operating point with simple signal processing regardless of the parameter variation.