• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1358-1363
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• 2011

In this study, GEC, VVVF train is mounted in the cab on the Improvement of Brake Controller checks were carried out. Brake Controller in a single-acting snap action switches, double acting snap action switches, and terminals associated with all the parts individually checked, rather than the current trains, and the same conditions, the overall depth review and analysis through the improvements in the meantime, failure to advance found by processing station Minimal and directly related to the safety of disabled passengers, the train station to contribute to safety in this study began.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.513-518
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• 2001

As the machining depth increases, the drilling torque increases and fluctuates and the risk of drill failure also increases. Hence, drilling torque control is very important to prevent the drill from failure. In this study, a PID controller was designed to control the drilling torque in a machining center. The plant including the feed drive system, cutting process, and spindle system was modeled for controller design. The Ziegler-Nichols rule was used to determine the controller gain and control action times. The root locus plot was used to tune the controller gain for a certain cutting condition. Also, suggested was a simple method to obtain the tuned controller gain for an arbitrary cutting condition not using the Ziegler-Nichols rule and root locus plot. The cutting torque control, performance of the designed controller and the effect of gain tuning on the control performance were examined.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.30-41
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• 2001

In Underwater Flight Vehicle depth control system, the followings must be required. First, It needs a robust performance which can get over the nonlinear characteristics due to hull shape. Second, It needs an accurate performance which has the small overshoot phenomenon and steady state error to avoid colliding with ground surface and obstacles. Third, It needs a continuous control input to reduce the acoustic noise. Finally, It needs an effective interpolation method which can reduce the dependency of control parameters on speed. To solve these problems, we propose a Intelligence depth control method using Fuzzy Sliding Mode Controller and Neural Network Interpolator. Simulation results show the proposed control scheme has robust and accurate performance by continuous control input and has no speed dependency problem.

• Journal of Ocean Engineering and Technology
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• v.20 no.6 s.73
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• pp.7-17
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• 2006

Depth and heading control of an AUV are considered to follow the predetermined depth and heading angle. The proposed control algorithm is designed. based on a sliding mode control using estimated hydrodynamic coefficients. The hydrodynamic coefficients are estimated with conventional nonlinear observer techniques, such as sliding mode observer and extended Kalman filter. By using the estimated coefficients, a sliding mode controller is constructed for the combined diving and steering maneuver. The simulation results of the proposed control system are compared with those of control system with true coefficients. This paper demonstrates the proposed control system, discusses the mechanisms that make the system stable and follows the desired depth and heading angle, accurately, in the presence of parameter uncertainty.

• International Journal of Ocean System Engineering
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• v.1 no.1
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• pp.16-27
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• 2011

The depth and heading control of an autonomous underwater vehicle (AUV) are considered to follow the predetermined depth and heading angle. The proposed control algorithm was based on a sliding mode control, using estimated hydrodynamic coefficients. The hydrodynamic coefficients were estimated employing conventional nonlinear observer techniques, such as sliding mode observer and extended Kalman filter. Using the estimated coefficients, a sliding mode controller was constructed for a combined diving and steering maneuver. The simulated results of the proposed control system were compared with those of a control system that employed true coefficients. This paper demonstrated the proposed control system, and discusses the mechanisms that make the system stable and accurately follow the desired depth and heading angle in the presence of parameter uncertainty.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.3-4
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• 2011

In this study, the nonlinear mathematical model of Manta type UUV is derived the hydrodynamic derivatives and the sliding mode controller of Manta type UUV test bed is designed. The sliding mode control scheme is used for robust control on the nonlinear motion. The designed controller is used the depth and heading control. It is based on the 6 DOF mathematical model with effect of the ocean currents. As a result, the performance of the designed controller is confirmed by computer simulation.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.3
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• pp.201-209
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• 2016

Supercavitation is a technology that reduces frictional resistance of an underwater vehicle by surrounding it with bubbles. Supercavity is divided into natural supercavity and ventilated supercavity which is formed by artificially supplying gas. Planing forces are present when a section of the underwater vehicle goes outside of the cavitation region in the supercavity condition. Planing often leads to an unstable flight because it acts vertically on the body suddenly. In this paper, a relationship between the ventilation rate and the cavitation number is determined. Based on the relationship, desired cavitation number which can avoid to planing is determined and then ventilation controller is designed. The performance of the ventilation controller is verified with a depth change controller using the cavitator. Simulation results show that the ventilation controller can minimize the planing force and moment.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.359-363
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• 2011

In this paper, automatic control system for the Manta UUV are constructed for the diving and steering maneuver. PID controller and Fuzzy controller are adopted in this system. Based on the 6DOF dynamic equation, simulation program has been developed using the Matlab. Using this program, depth control system and heading control system with tidal current are evaluated.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.257-264
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• 2015

For the tracking of the way-points of hovering AUV (HAUV), we suggest a simple PID controller. The way-points are designed to approach to a virtual underwater structure and the heading angles at each way-point are set to look at the structure in the face. The proposed controller consists of a vertical controller to maintain the depth and pitch angle, and a horizontal controller to move to the desired position as well as to adjust the heading angle of the HAUV. In the simulation using Matlab/Simulink, the HAUV with the proposed PID controller is shown to track all the way-points within 1 m range while maintaining proper heading angle at each way-point.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.3
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• pp.850-860
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• 1996

This paper considers a sliding mode controller for a depth and course control of a class of submersible Vehicles. Since the vehicle used here shows complex dynamic characteristics sensitive to speed variation and buoyancy, robustness in control of vertical and horizontal plane motions of the vehicle is achieved by using the sliding mode controller of which a structure varies according to a pre-designed principle, so called the variable structure control. To compare this controller with another in robustness, PID controller for the same model of vehicle is designed. From various simulations for two controllers, it is shown that the sliding mode controller is the more robust anainst to modeling errors and disturbances.