• Journal of Institute of Control, Robotics and Systems
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• v.11 no.3
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• pp.207-213
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• 2005

This paper deals with an autonomous flight guidance and control algorithm design for TR301 tilt-rotor airplane under development by Korea Aerospace Research Institute for simulation purpose. The objective of this study is to design autonomous flight algorithm in which the tilt-rotor airplane should follow the given waypoints precisely. The approach to this objective in this study is that, first of all, model-based inversion is applied to the highly nonlinear tilt-rotor dynamics, where the tilt-rotor airplane is assumed to fly at helicopter flight mode(nacelle angle=0 deg), and then the control algorithm, based on classical control, is designed to satisfy overall system stabilization and precise waypoint following performance. Especially, model uncertainties due to the tiltrotor model itself and inversion process are adaptively compensated in a simple neural network(Sigma-Phi NN) for performance robustness. The designed algorithm is evaluated in the tilt-rotor nonlinear airplane in helicopter flight mode to analyze the following performance for given waypoints. The simulation results show that the waypoint following responses for this algorithm are satisfactory, and control input responses are within control limits without saturation.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.1
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• pp.33-38
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• 2016

The turbocharger is an essential component to realize the engine down-sizing. The moment of inertia of turbocharger rotor is an important parameter with respect to acceleration performance of the vehicle. It can be calculated from the CAD software based the geometry data and the material properties. But the accurate value of the inertia of turbocharger rotor must be measured through the experimental method. In this study, the measurement of moment of inertia of turbocharger rotor for 2.0 L spark-ignition engine was carried out. First, an experimental equipment using a trifilar method was designed and fabricated. Some optical devices, that is, photo sensor, counter, convex lens, etc, were used to increase the accuracy of the measurement. Second, error sensitivity for the equipment was analyzed. The error of period time and the radius can give big affects to the accuracy of the moment of inertia. When the amount of error of these two were each 1.0 %, maximum error of the moment of inertia was under 3.0 %. Third, the calibration for the equipment was performed using a calibration rotor which has similar shape to turbine rotor but simple. Calculated value from CAD software and measured one for the calibration rotor were compared. The total error of the equipment and the measurement is about 1.3 %. This result shows that the equipment can give the good result with resonable accuracy. Finally the moment of inertia of the turbine rotor and compressor wheel were measured. The coefficient of variations, the ratio of standard deviation to mean value, were reasonably small at 0.57 % and 0.73 % respectively. Therefore this equipment is suitable for the measurement of the moment of inertia of the turbine rotor and compressor wheel.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.279-284
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• 1999

This paper presents a parametric study and an optimal design of the ER-SFD supporting a rigid rotor system. An attempt is made to obtain the optimal design of an ER-SFD for a two degree-of-freedom rotor model. Such a simple model is used in order to get a better insight into the physics of the problem, A maximum whirl amplitude, supply pressure and voltage are considered, and a maximum whirl amplitude is minimized over a range of speeds and presented for some values of unbalance mass. The results presented in this paper provide important design information necessary to reduce a whirl amplitude of an ER-SFD.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.12
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• pp.1139-1145
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• 2008

numerical study on the coupled fluid-structure for a rotor blade in hover was conducted. Computational fluid dynamics code with enhanced wake-capturing capability is coupled with a simple structural dynamics code based on Euler-Bernoulli's beam equation. The numerical results show a reasonable blade structural deformation and aerodynamic characteristics.

• Proceedings of the KIPE Conference
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• 2001.12a
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• pp.19-22
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• 2001

A Switched Reluctance Generator attracts much attention in the generator because of high efficiency, simplicity, and ruggedness. However, they require rotor position information to operate. In many systems, the rotor position sensor is expensive, limited and undesirable. This paper describes a new approach to estimating the rotor position of the SRG from the measured terminal voltage and current for rotor position sensorless control. The proposed method is based on the instantaneous flux of the SRG. The proposed technique is very simple. The proposed method is verified by computer simulation and experiments.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.635-637
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• 2001

The faults of the squirrel cage induction motor is grew increasingly complex as the faults resulting in the shorting of a stator winding and the broken rotor bar or cracked rotor end ring, bearing faults, and so on. The users of electrical machines initially relied on simple protections such as over-current, over-voltage, earth-fault, etc. to ensure safe and reliable operation. but this method cause heavy financial losses and the threat of safety therefore it has now become very important to diagnose faults at there very inception. in this paper, we are going to discuss the detection method of broken rotor bar of squirrel cage induction motor by the motor current signal analysis(MCSA) and the opening terminal voltage signal analysis.

• International Journal of Fluid Machinery and Systems
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• v.2 no.3
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• pp.254-259
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• 2009

In this paper it was attempted to treat the hydrodynamic journal bearing as a time-based nonlinear reaction source in each step of rotor rotation in order to observe the bearing effect more realistically and accurately in stead of the conventional method of simple linearized stiffness and damping. Lubrication analysis based on finite element method is employed to calculate the hydrodynamic reaction of bearing and Newmark's method was used to calculate the rotor dynamics in the time domain. Simulation for an industrial electrical motor showed remarkable results with differences compared to those by the conventional method in the dynamic behavior of the rotor.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.681-686
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• 2004

Identification of asymmetry and anisotropy of rotor system is important for diagnosis of rotating machinery. Directional frequency response functions (dFRFs) are known to be powerful tool in effectively detecting the presence of asymmetry or anisotropy. In this paper, an estimation method of dFRFs for rotors is newly developed, when both asymmetry and anisotropy are present. The method transforms the finite degrees-of-freedom time-varying linear differential equation of motion to an infinite degree-of-freedom time-invariant linear one, employing the modulated coordinates. The validity of the method is demonstrated by numerical simulation with a simple rotor model.

• Tribology and Lubricants
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• v.17 no.3
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• pp.216-220
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• 2001

This paper presents a parametric study and an optimal design of the ER-SFD supporting a rigid rotor system. An attempt is made to obtain the optimal design of an ER-SFD for a two degree-of-freedom rotor model. Such a simple model is used in order to get a better insight into the physics of the problem. A maximum whirl amplitude, supply pressure and voltage are considered, and a maximum whirl amplitude is minimized over a range of speeds and presented f3r some values of unbalance mass. The results presented in this paper provide important design information necessary to reduce a whirl amplitude of an ER-SFD.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.411-414
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• 2002

This paper proposed new techniques of rotor position detection for Switched Reluctance Motor(SRM). This technique is very simple and easy to find out rotor position. The main idea uses the impulse responses which have different values between aligned and unaligned. In order to obtain the rotor position, the Impulse applied to the unenergized phases and their responses are analized to control the speed of SRM without shaft sensor, Experimental results verify the feasibility of the proposed method.