• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.54 no.2
• /
• pp.181-187
• /
• 2018

In order for the probe to perform ocean exploration and survey research, it is necessary to adjust the position of the ship as desired by dynamic positioning system. The dynamic positioning system of T/S NARA is applied to K-POS dynamic positioning system of Kongsberg, which makes maintaining the ship's position, changing position and heading control possible. T/S NARA is not capable of dynamic positioning if one or more propulsive forces are lost with DP Level One. However, it is predicted that dynamic positioning can be achieved even at the time of missing one thrust in a good sea condition. Therefore, we want to analyze the effect of each propulsion on the performance of dynamic position system. When one of the bow thruster and azimuth thrusters lost their propulsion, maintaining the ship's position, changing position and heading control performance were compared and analyzed. If the situation occurred disable from using the bow thruster, they can not maintain ship's position. Azimuth thruster was influential for the ship's position control and bow thruster was influential in heading control. The excellent dynamic positioning performance can be achieved, considering the propulsion power that will have a impact on each situation in the future.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.19 no.4
• /
• pp.342-348
• /
• 2014

In this paper, a BLDC(Brushless DC) motor control system for driving fins to control the flight attitude of the guided artillery munition is developed. This system adopts a sensorless control scheme without any position sensor such as a Hall sensor fragile at high altitudes. The sensorless control of the BLDC motor is achieved by using commutation signals obtained from the measured pole voltages. The position control of the fin is also performed by using of the estimated speed from the commutation signals. The experimental results on the actual fin drive system demonstrated that the developed sensorless control algorithm can give an excellent position control performance.

• Journal of Institute of Control, Robotics and Systems
• /
• v.13 no.12
• /
• pp.1213-1221
• /
• 2007

In most case of previous research about vehicle control system, external error occurred by unexpected environmental situation was hardly considered. However, in this paper, to have more accurate position control of differential derive vehicle, we separate the error as an internal error and external error. To calculate the vehicle position in real time, we introduced the Dead-Reckoning algorithms and the simulation result show that the proposed internal and external error control system has fast and accurate position tracking with remarkable diminishment of orientation error. The results reported here can easily be extended to the control of similar type vehicle.

• 제어로봇시스템학회:학술대회논문집
• /
• 1988.10a
• /
• pp.299-304
• /
• 1988

This paper describes the application of the variable structure control(VSC) concept for the position control of electro-hydraulic servomtor system. The basic philosopy of VSC is that the structure of the feedback control is altered as the state crosses discontinuity surfaces in the state surface with the result that certain desirable properties are achieved. The switching of the control function yields total(or selective) invariance to system parameter variations and disturbances, and closed loop eigen value placement in time-varing and uncertain systems.

• 제어로봇시스템학회:학술대회논문집
• /
• 1993.10b
• /
• pp.513-518
• /
• 1993

In this paper, we consider the handling f a flexible object using dual-arm manipulators. We choose both the side arms as rigid, and the objects to be manipulated as flexible. Our purpose is to realize position control for the flexible object while suppressing its vibration. In particular, the problem taken up here is the stability of the control system while manipulating the object. We propose that the traditional approach to investigate the robot system be expanded to include the object's characteristics (thus transferring the stability of the robot system into the full assembly system). We define a handling characteristic while manipulating the object. Finally, the relationship between the handling characteristic and the positional constraint condition in the hold position of the arms is studied while considering the stability of the control system.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.3
• /
• pp.228-236
• /
• 1989

The theroy of variable structure control system (VSS) is applied to the position control for DC servo-motors. In order to use the microcomputer as a control device, the principles of VSS for the continuous-time system are extended to the discrete-time system. A new switching law is proposed to achieve the reduction of chattering. It adds a new switching structure to the conventional switching sturctures. This switching region is set near and including the conventional switching curve. The new algorithm is obtained for single-input second order system, and applied to the position control of a DC servo-motor. Experimental results show that the transient behavior is improved due to the reduction of chattering and good robustness properties are demonstrated.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.530-535
• /
• 2002

Pneumatic control system has been applied to build many industrial automation systems. But most of them are sequence control type because of their low costs, safety, reliability, etc. Pneumatic servo system is rarely applied to real industrial fields because accurate position control is very difficult due to its nonlinearity and compressibility of air. In pneumatic servo control system, a pneumatic servo valve can be applied, But it is very expensive and has no advantage of low cost compared with a common pneumatic system. This paper is concerned with the accurate position control of a rodless pneumatic cylinder using on/off solenoid valve. A novel Intelligent Modified Pulse Width Modulation(MPWM) is newly proposed. The control performance of this pneumatic cylinder depends on the external loads. To overcome this problem, switching of control parameter using artificial neural network is newly proposed, which estimates external loads on rodless pneumatic cylinder using this training neural network. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied in the switching control the system. The effectiveness of the proposed control algorithms are demonstrated through experiments nth various loads.

• Journal of Power System Engineering
• /
• v.17 no.5
• /
• pp.94-99
• /
• 2013

This paper presents some experimental results about Position Mooring (PM) system applied to the barge ship. In PM operation, the station keeping in surge, sway of vessel is provided by the mooring system. In this paper, a system, consisting of a barge vessel and mooring lines, is mathematically modeled. The position and orientation of vessel is controlled by changing the tensions in the mooring lines. The PID control strategy is applied to evaluate the efficiency of proposed system. Experimental result which corresponds to the applied control strategy is presented and discussed.

• Journal of Hydrospace Technology
• /
• v.1 no.1
• /
• pp.75-88
• /
• 1995

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship's direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dimension in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.521-527
• /
• 2002

This paper presents a dynamic modeling and a robust PID controller design process for the wire bonder head assembly. For the modeling elements, the system is divided into electrical system, magnetic system, and mechanical system. Each system is modeled by using the bond graph method. The PID controller is used for high speed/high accuracy position control of the wire bonder assembly. The Taguchi method is used to evaluate the more robust PID gain combinations than conventional one. This study makes use of an L18 array with three parameters varied on three levels. Computer simulations and experimental results show that the designed PID controller provides more improved signal to noise ratio and reduced sensitivity than the conventional PID controller.