• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1266-1272
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• 2011

For way-point tracking of an autonomous underwater vehicle, a state feedback controller was designed by using pole placement scheme in discrete time domain. In the controller, 4 state variables were used for regulating the depth of the vehicle in z direction, and 3 state variables, for steering the vehicle in xy plane. Assuming constant speed of AUV, we simplified the design of the way-point tracking system. The proposed controller was simulated by MATLAB/Simulink using 6 degree-of-freedom nonlinear model and its performance of way point tracking was shown to be fulfilled within 1 m, nevertheless the proposed controller is quite simple and easy to implement compared to sliding mode controller.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.287-301
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• 2022

This study aims to propose a crane-tip control method to intuitively control the end-effector vertically or horizontally for improving the crane work efficiency and to confirm the control performance. To verify the control performance based on experimental variables, a laboratory-scale crane was manufactured using an electric cylinder. Through a forward and reverse kinematics analysis, the crane was configured to output the position coordinates of the current crane-tip and the joint angle at each target point. Furthermore, a method of generating waypoints was used, and a dead band using lateral boundary offset (LBO) was set. Appropriate parameters were selected using bang-bang control, which confirmed that the number of waypoints and LBO radius were associated with positioning error, and the cylinder speed was related to the lead time. With increased number of waypoints and decreased LBO radius, the positioning error and the lead time also decreased as the cylinder speed decreased. Using the proportional control, when the cylinder velocity was changed at every control cycle, the lead time was greatly reduced; however, the actual control pattern was controlled by repeating over and undershoot in a large range. Therefore, proportional control was performed by additionally applying velocity gain that can relatively change the speed of each cylinder. Since the control performed with in a range of 10 mm, it was verified th at th e crane-tip control can be ach ieved with only th e proportional control to which the velocity gain was applied in a control cycle of 20 ms.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.4
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• pp.291-299
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• 2007

To operate a permanent magnet synchronous motor (PMSM) at a maximum torque per ampere (MTPA) operation point, the exact values of machine parameters such as inductances and back-EMF constant, which are sensitive to motor phase currents and temperature respectively, should be blown. An adaptive estimation method for on-line estimation of the machine parameters is not suitable for practical applications since it has difficulties in estimating exact values and requires complex mathematical calculations. The purpose of this paper is to present a simple MTPA operation point tracking control strategy for vector controlled PMSM drives with slow dynamic loads. The proposed method searches MTPA operation points by modulating current phase angle and observing the variation in command power. The current angle modulation strategy is designed to sense the effect of load variations in the command power. Therefore, the proposed method can track the MTPA operation points of the PMSM regardless of load variations. Computer simulation and experimental study is also presented to show the effectiveness of the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.8
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• pp.661-666
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• 2013

A state feedback controller with integration of output error is proposed for way-point tracking of an AUV (Autonomous Underwater Vehicle). For the steering control on the XY plane, the proposed controller uses three state variables (sway velocity, yaw rate, heading angle) and the integral of the steering error, and for the depth control on the XZ plane, it uses four state variables (pitch rate, depth, pitch angle) and the integral of the depth error. From the simulation using Matlab/Simulink, we verify that the performance of the proposed controller is satisfactory within an error range of 1m from the target way-point for arbitrarily chosen sets of consecutive way-points.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.380-385
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• 2001

In this paper, in order to get rid of danger trapped Local minimum point, disadvantage of General Back-propagation and simultaneously obtain fast teaming-speed. We propose PID Back-Propagation with Momentum Term(PID-BPMT) and Design PID Controller by Neural Network with Momentum term. Consider to apply for that Controller in position control system by driven D.C servo motor. its useful performance is verified by computer simulation

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.688-697
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• 2017

It is very difficult to solve mathematically the optimal control problem for non - linear mobile robots to move to target points with minimum energy related to velocity, acceleration and angular velocity in minimum time. This paper proposes a method to obtain optimal control gains with which mobile robots move with minimum energy related to velocity, acceleration and angular velocity in minimum time using genetic algorithms. Mobile robots are non - linear systems so that their optimal control gains depend on initial positions. Hence initial positions are divided into some partition points and optimal control gains are obtained at each partition point with genetical algorithms. These optimal control gains are used to train neural networks that generate proper control gains at arbitrary initial position. Finally computer simulation studies have been conducted to verify the effectiveness of the method proposed in this paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2737-2743
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• 2015

The wind power plant must be able to produce reactive power at the POI bus of a wind farm connected to power system to keep or control the voltage of POI bus. But, the reactive power capability of wind turbines may not be sufficient to control the voltage of POI bus due to the reactive power losses in connection lines between wind farm and POI bus. The solution of this problem is to install an external STATCOM. The proposed cooperative control method of STATCOM and conventional reactive power compensators such as Switched-shunt and tap changing transformer can control the voltage of POI bus more efficiently. The simulation results are shown that the voltage drop of POI Bus of Test System with the arbitrary load change rate to initial loads is improved more than 60% and the voltage of load bus is maintained more than 95% of rated voltage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.311-312
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• 2011

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.221-222
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• 2014

본 논문에서는 3레벨 NPC 인버터의 전원전압변조 방식을 이용하여 넓은 변조 지수에서 제어 가능한 간단한 중성점 제어 방법을 제안하였다. 제안한 제어 방법은 전원 전압 변조방법을 이용한 중성점 균형 계수와 정확한 옵셋 전압의 제한치를 이용하여 계산된다. 중성점 균형 계수는 전류의 극성과 상하 커패시터의 전압에 의해서 정의되어 진다. 제안된 제어 방법은 중성점 제어를 위해 공간전압 PWM과 불연속 PWM까지 동작범위를 확장하여 동작되어 진다. 제안된 방법은 넓은 변조지수에서 전원전압변조를 이용하여 공간전압 PWM방법을 쉽게 구현할 수 있다. 제안된 중성점 제어 방법의 타당성은 시뮬레이션을 통하여 검증하였다.

• ICROS
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• v.4 no.4
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• pp.41-44
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• 1998

이 글에서는 플라즈마 식각공정의 진행에 있어서 중요한 EPD제어기법과 파라미터 최적화에 대해 서술하였다. 또한 플라즈마 응용 식각장비의 발전경향과 다중체널 제어기의 개발에 대해서도 알아보았다. 현재의 연구는 기존의 장비를 이용하여 회로를 보다 미세화하고자 하는 연구와 새로운 장비의 개발을 통한 고집적화로 구분할 수 있다. 또한 제품의 가격 경쟁력을 위해서 웨이퍼의 대구경화가 일반적인 추세이다. 웨이퍼의 대구경화는 불균일도의 극복을 위해 새로운 제어와 보다 향상된 EPD기법을 필요로 한다. 따라서 기존의 제어기법을 향상시키려는 노력과 새로운 검출기법에 대한 연구도 지속적으로 진행되고 있다.