• Journal of Navigation and Port Research
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• v.31 no.5 s.121
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• pp.325-332
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• 2007

This study develops a control algorithm on berthing/unberthing system using a joystick for ships with thrusters and a rudder. A nonlinear mathematical model for low speed maneuvering of typical container ships is used to develop a MIMO(multi-input multi-output) nonlinear control algorithm for velocity feedback joystick control. Also a virtual HILS(hardware in the loop simulation) software program for berthing/unberthing is developed to test the performance of the nonlinear and a PID control algorithm. The program is developed using LabWindow/CVI, and a user can see current position and desired trajectory of ship in a monitor, then he can control forward and yaw velocities of a ship using a joystick. The simulation results show that the nonlinear mfd the PID controller have superior performance over a simple open loop joystick control algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.5
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• pp.431-438
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• 2012

Non-linear turbojet engine controller with high operational performance has been designed for the high maneuverability UAV. The turbojet engine dynamic performance code has been developed to reflect the non-linear characteristics on controller design, by which the necessity of non-linear controller design was justified by investigating the limitation of linear model derived from the dynamic performance. The PI-like fuzzy controller was designed and enhanced by combining with conventional derivative control. This designed fuzzy controller proves its effectiveness by showing superior control performances over the conventional PID controller along with guaranteeing the safe operation within compressor surge, flame out and turbine temperature limits etc.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.183-190
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• 2016

In this study, we conduct linear and nonlinear modeling of the DC motor driving system of a wheeled mobile robot, which is a nonlinear system involving dead zone, friction, and saturation. The DC motor driving system consists of a DC motor, a wheel, and gears. A linear DC motor driving system is modeled using a steady-state response and parameter measurements. A nonlinear DC motor driving model is identified with the use of the Hammerstein-Wiener method. By using these models, PID controllers for the DC motor system are then established. Each PID controller is applied as a low-level controller in order to achieve posture stabilization control for the real mobile robot. We also compare the performance of the proposed PID controllers in posture stabilization experiments by using several different final robot postures.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.400-405
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• 2023

Currently, inverted pendulums are being studied in many fields, including posture control of missiles, rockets, etc, and bipedal robots. In this study, the vertical posture control of the pendulum was studied by constructing a rotary inverted pendulum using a 256-pulse rotary encoder and a DC motor. In the case of nonlinear systems, complex algorithms and controllers are required, but a control method using the classic and relatively simple PID(Proportional Integral Derivation) algorithm was applied to the rotating inverted pendulum system, and a simple but desired method was studied. The rotating inverted pendulum system used in this study is a nonlinear and unstable system, and a PID controller using Microchip's dsPIC30F4013 embedded processor was designed and implemented in linear modeling. Usually, PID controllers are designed by combining one or two or more types, and have the advantage of having a simple structure compared to excellent control performance and that control gain adjustment is relatively easy compared to other controllers. In this study, the physical structure of the system was analyzed using mathematical methods and control for vertical balance of a rotating inverted pendulum was realized through modeling. In addition, the feasibility of controlling with a PID controller using a rotating inverted pendulum was verified through simulation and experiment.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1392-1395
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• 1996

Nonlinear PID controllers have increasingly used in current industrial practice because it is robust and is easy to operate. Little guideline and tuning method, however, has been recommended for the nonlinear PID controllers while a lot of result is available for the linear PID controllers. Application guideline and tuning formulae are presented for error square type nonlinear controllers, which are most popular currently, are presented.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.45-52
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• 1998

The contact roll is often used to regulate the winding tension as well as the entrained air in a wound roll by adjusting the contact force to the winding roll. But the contact force generated by other rolls, like assistant nip rolls, in a winding(or roll changing) process may act as disturbance to the control of the winding tension. In this paper, the mechanism of a roll change process is analysed. Ana, the behavior of the contact and the nip rolls are mathematically modeled. A nonlinear PID(NPID) controller is designed to control the winding tension and to reject the effect of disturbance generated by the nip roll on the winding tension variation. Computer simulation study showed that the performance of the suggested NPID controller is improved compared with that of the PID controller in controlling the winding tension and in rejecting the effect of the disturbance.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.2
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• pp.149-155
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• 1997

본 논문에서는 비선형 시변 시스템을 제어할 경우 제어시스템의 안정성을 보장하고 성능을 향상시키기 위한 새로운 적응제어 구조를 전개하였다. 주어진 플랜트가 선형 시불변이라는 가정하에 표준 기준 모델 적응제어기가 적용될 경우 발생되는 출력오차는 플랜트의 비선형 시변특성으로 인하여 점근적으로 0에 수렴되지 않는다. 이때 미지의 출력오차를 점근적으로 0에 수렴시키는 방법으로 퍼지보상기를 사용하였으며 결과적으로 플랜트의 비선형 시변 특성을 보상하는 효과를 얻을 수 있었다. 퍼지 보상기로는 출력오차등의 조건에 따라 이득이 변하는 퍼지 PID 보상기를 도입하여 안정하게 설계되도록 노력하였다. 또한 출력오차를 점근적으로 0에 수렴시키는 것은 표준 기준 모델 적응제어기 내부의 모든 파라미터와 신호가 유한하게 됨을 의미하기 때문에, 제어시스템 전체의 안정도를 보장할 뿐만 아니라 결과적으로 과도응답 성능을 향상시킬 수 있게 되었다. 몇가지 예제를 대상으로 시뮬레이션을 수행하고 그 결과를 분석함으로써 비선형 시변 시스템을 제어할 경우 본 논문에서 전개된 새로운 적응제어 구조의 타당성을 확인하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.80-83
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• 2002

정밀한 서보기술에 바탕을 두고 있는 산업용 로봇 팔은 기계적인 강성도와 서보기구들로 인하여 정확한 제어가 가능하다 그러나 로봇팔은 동작중비 관성모멘트의 변화와 기하학적인 구조로 인하여 비선형적인 시스템이다. 특히 관성모멘트의 변화는 로봇팔의 회전속도와 로봇팔이 이동시키는 대상물의 무게 등에 따라 관성모멘트는 변할 수 있다. 이로 인하여 관성모멘트의 변화에 따라 로봇팔의 정확한 위치제어가 힘들어진다. 따라서 본 논문에서는 관성모멘트의 변화에도 불구하고 강인한 응답특성을 나타내는 제어기의 설계가 요구된다. 일반적으로 PID .제어기는 설계의 용이성으로 산업현장에서 널리 사용된다. 그러나 PIB 제어기의 각 계수값을 설정하는데 많은 어려움이 발생한다. 따라서 본 논문에서는 PID 제어기의 각 계수 값을 퍼지알고리즘을 이용하여 자동으로 설계할 수 있는 자기동조 PID 제어기를 설계한다.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.2
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• pp.124-129
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• 2007

Recently, the application of the linear machine for industrial field is remarkably increased, especially for the gantry machine, machine tool system and CNC. However a linear meter remains the vibrational characteristic itself therefore, In these application fields, high position control performance is essentially required in both the steady and the transient states. In this paper, the design method for a position control is proposed by using the two-degree-of freedom PID controller. This method has great features for the linear machine drives such as no over-shoot phenomena and single gain tuning strategy. By comparison with conventional PID controller, the improvement of performance of a linear motor control system using two degrees of freedom controller are discussed. Through the simulation results, the usefulness of the proposed algorithm is proved. With the simulation results, it was made clear that the introduction of two degrees of freedom controller designed by the proposed method not only improves the over shoot and starting characteristic of response but also removes the undesirable characteristic variation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6289-6295
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• 2014

Rework systems are the equipment used to install or remove semiconductor chips with BGA or SMD forms in printed circuit boards. The rework systems have hot air outlets. At the outlets, precise temperature control is needed to avoid heat shock. The aim of this paper was to suggest a new controller for temperature control at the hot air outlets. The suggested controller was a fuzzy PID controller. The fuzzy PID controllers were composed of TSK fuzzy rules and had outstanding ability for nonlinear systems control. This paper reports the design algorithm of fuzzy PID controllers, and the design process of the fuzzy PID controller for the temperature control of the outlets. Temperature control experiments were performed to verify the ability of the suggested controller. As a result, the RMS of the proposed method is 9.44 and the general method is 15.88. The experiments showed that the temperatures at the outlet using the suggested fuzzy PID controller followed the desired ones better than the commonly used PID controller.