• International Journal of Precision Engineering and Manufacturing
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• v.2 no.1
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• pp.11-17
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• 2001

In drilling of composite laminates, it is important to minimize of reduce occurrences of delaminations. In particular, a peel -up delamination at entrance and push-up delamination at exit are common. Deleaminations may by avoided by regulating the drill thrust force can be controlled by adjusting the feedrate of the drill. Dynamics involved in drilling of composite laminates is time varying and nonlinear. In this paper, a fuzzy logic model and control strategy are proposed. Simulation results show that the fuzzy model can describe the nonlinear time-varying process well. The fuzzy controller realizes a fast rise time and a little overshoot of drilling force.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.138-143
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• 2017

A performance analysis for a pulsed plasma thruster(PPT) has been conducted to predict the thrust and current change. Two models were implemented - a one-dimensional lumped circuit analysis model and the Teflon ablation model provided by Michael Keidar. The circuit model incorporating resistance and inductance models was adapted to predict the magnitude of the discharge current. Numerical simulations like current discharge rates with different voltages were reasonably well compared with experimental data. The effects of Teflon ablation on thruster characteristics were investigated.

• Ocean Systems Engineering
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• v.1 no.4
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• pp.297-315
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• 2011

New applications of streamlined Autonomous Underwater Vehicles require an AUV capable of completing missions with both high-speed straight-line runs and slow maneuvers or station keeping tasks. At low, or zero, forward speeds, the AUV's control surfaces become ineffective. To improve an AUV's low speed maneuverability, while maintaining a low drag profile, through-body tunnel thrusters have become a popular addition to modern AUV systems. The effect of forward vehicle motion and sideslip on these types of thrusters is not well understood. In order to characterize these effects and to adapt existing tunnel thruster models to include them, an experimental system was constructed. This system includes a transverse tunnel thruster mounted in a streamlined AUV. A 6-axis load cell mounted internally was used to measure the thrust directly. The AUV was mounted in Memorial University of Newfoundland's tow tank, and several tests were run to characterize the effect of vehicle motion on the transient and steady state thruster performance. Finally, a thruster model was modified to include these effects.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.151-154
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• 2004

To use the SLIM for servo system, the exact account of thrust about the initial speed is needed, but analyzing by equivalent circuit analyzing methode such as rotary induction motor, the error occurs because of the end effect. So, we applied the equivalent circuit considering the end effect of SLIM in this paper. The current control system is advanced the space vector pulse width modulation by using high arithmetic performance microprocessor such as DSP. In this paper, we use the dynamic characteristic analyzing methode that can calculate efficiently the end effect by using equivalent circuit methode in the operating SLIM system modeling and examine the output characteristics of SVPWM with PI controller.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.417-418
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• 2009

Aiming at time-dependent performance prediction of Liquid Rocket Engine(LRE) system, Program for Dynamic Characteristic Prediction of LRE is overviewed, and a modeling and dynamic analysis of rocket engine system with reference to developed transient simulator for LRE is outlined.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.389-392
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• 2000

This paper presents a performance Analysis of electrically exhaust gas recirculation valve using commercial electromagnetic simulation software, Flux2D. Under the assumption of 2D axi-symmetric magnetic field, the characteristics of EEGR valve by revising the design parameter, has ken investigated by estimating the variation of thrust force with respect to the pintle position. The mode shapes and the frequency response functions were computed by using three dimensional finite element modeling of the whole EEGR valve and their accuracies were verified with experimental FFT analysis technique.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.993-996
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• 2000

A brushless linear motor is suitable for a high-accuracy servo mechanism. It is also suitable for operation with higher speed and precision. Since it does not involve some sort of mechanical coupling, linear driving force can be applied directly. Basic models including magetomotive force and electromotive forces are introduced and simplified. Both conventional PID and fuzzy controllers are implemented and performance results using those controllers are compared. Along with better simulated performance observed using fuzzy controller, further fabrication is to be included with various empirical results. Several system operational characteristics have been observed. Typical nonlinearities as friction, cogging and torque or thrust ripple that might deteriorate system performance would be tackled using presumably effective method such as neural network based learning controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.973-976
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• 2000

A brushless linear motor is suitalbe fur a high-accuracy servo mechanism. It is also suitable for operation with higher speed and precision. Since it does not involve some sort of mechanical coupling, linear driving force can be applied directly. Basic models including magetomotive farce and electromotive forces are introduced and simplified. Both conventional PID and fuzzy controllers are implemented and performance results using those controllers are compared. Along with better simulated performance observed using fuzzy controller, further fabrication is to be included with various empirical results. Typical nonlinearities as friction, cogging and torque or thrust ripple that might deteriorate system performance would be tackled using presumably effective method such as neural network based learning controller.

• Journal of the Korean Society of Combustion
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• v.15 no.2
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• pp.12-18
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• 2010

A numerical analysis was performed to predict the thermo-fluid dynamic characteristics of hydrazine monopropellant reaction in the thruster combustor and nozzle. A 1-D porous model was introduced to simulate catalytic reaction by iridium in the combustor while 2-D axisymmetric analysis was applied to predict the nozzle flow. The chemical species and temperature variations were predicted by changing the injection pressure and mass flow rate and their results were validated by comparison with limited experimental data. The thrust variation with injection pressure could be estimated using the current 1-D combustor modeling.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.299-303
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• 2000

A brushless linear motor is suitable for operation with higher speed and precision. Since it does not involve mechanical coupling, linear driving force can be applied directly. Conventional PID and fuzzy controllers are implemented and performance results using those controllers are compared. Along with better simulated performance observed using fuzzy controller, further fabrication is to be included with various empirical results. Several system operational characteristics have been observed. Typical nonlinearities as friction, cogging and torque or thrust ripple that might deteriorate system performance would be tackled using presumably effective method such as neural network based learning controller.