• 제어로봇시스템학회논문지
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• 제2권1호
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• pp.60-66
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• 1996

Model Based Predictive Control(MBPC) has been widely used in predictive control since 80's. GPC[1] which is the superset of many MBPC strategies a popular method, but GPC has some weakness, such as insufficient stability analysis, non-applicability to internally unstable systems. However, CRHPC[2] proposed in 1991 overcomes the above limitations. So we chose RHPC based on CRHPC for electric furnace control. An electric furnace which has nonlinear properties and large time delay is difficult to control by linear controller because it needs nearly perfect modelling and optimal gain in case of PID. As a result, those controls are very time-consuming. In this paper, we applied RHPC with equality constraint to electric furnace. The reults of experiments also include the case of RHPC with monotonic weighting improving the transient response and including unmodelled dynamics. So, This paper proved the practical aspect of RHPC for real processes.

• 한국정밀공학회지
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• 제18권5호
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• pp.120-129
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• 2001

As many sensors and actuators are used in many automated systems, various industrial networks are adopted for real-time distributed control. In order to take advantages of the networking, however, the network implementation should be carefully designed to satisfy real-time requirements considering network delays. This paper presents the implementation of a remote feedback control system via Profibus-DP net work for real-time distributed control More specifically, the effect of the network delay on the control performance evaluated on Profibus-DP testbed. Also, the traditional PID gain tuning methods are used to demonstrate the feasibility of the remote feedback control.

• Journal of Advanced Marine Engineering and Technology
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• 제24권4호
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• pp.470-477
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• 2000

The states of control loops in existing actual systems are changed according to time varying conditions of controllest process and other system components. Adjusting control parameters properly at site which is performed generally by Ziegler & Nichols mthod is important for safe and efficient operation, but the method may require much time to adjust and not easy to inexperienced engineers. This study is aimed to propose more handy method to adjust control parameters by plotting operating conditions on the space of adjusting parameters. One loop of model control system without perturbation condition has been adopted and its stability limit was plotted on the coordinates of Gain and Integral time which was acquired after analyzing Nyquist diagrams and time domain responses. The result showed that the sets of adjusting parameters according to critical stability and proper stability could be acquired reasonably through both responses and the curves on parameter space revealed available patterns for the purpose of easy maintenance of control characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3089-3091
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• 1999

To control IWR-III Biped Waking Robot, those complex modules are necessary that concurrent control multi-axes servo motors, PID & Feedforward gain tuning, initial value calibration, display current status of system, user interface for emergency safety and three-dimensional rendering graphic visualization. It is developed for various-type gait $data^{[1]}$ and for control modes (i.e open/closed loop and pulse/velocity/torque control) that Integrated Control Enviroment with GUI( Graphic User Interface) consist of time-buffered control part using MMC (Multi-Motion Controller) and 3D simulation part using DirectX graphic library.

• Journal of Advanced Marine Engineering and Technology
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• 제3권1호
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• pp.19-31
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• 1979

Recently the adaptive control system, which keeps the control system always optimal by adjusting the control parameters automatically according to the variations of the plant parameters, have become very important in the field of control engineering. The adaptive control systems are usally composed of the plant identification, the decision of the optimal control parameters, and the adjustment of the control parameters. This paper deals with a method of the adaptive control system when PI or PID controller is used in the feed back control system. Its controlled object (the plant) is assumed to be described by the transfer function of $\frac{ke^{-LS}}{1+TS}$ where k, T and L are steady state gain, time constant and pure dead time respectively, and their values are variable in accordance with the change of environmental circumstance. It has been known that a pseudo-random binary signal is quite effective for the measurement of an impulse response of a plant. In adaptive control systems, however, the impulse response itself is not appropriate to determine the control parameters. In this paper, the authors propose a method to estimate directly the parameters of the plant k, T and L by means of the correlation technique using 3 level M-sequence signal as a test signal. The authors also propose a method to determine the optimal parameters of the PI or PID controller in the sense of minimizing the square integral of the control error in the feed back control system, and the values of the optimal parameters are computed numerically for various values of T and L, and the results are examined and compared with those of the conventional methods. Finally the above-mentioned two methods are combined and an algorithm to struct an adaptive control system is suggested. The experiments for the indicial responses by means of both the model of the temperature control system using SCR actuater and the analog simulations have shown good results as expected, and the effectiveness of the proposed method is verified. The M-sequence generator and the time delay circuit, which are manufactured for the experiments, are operated in quite a good condition.

• 제어로봇시스템학회논문지
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• 제15권1호
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• pp.67-71
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• 2009

This paper presents a rank-constrained linear matrix inequality (LMI) approach to the design of a multi-objective controller such as $H_2/H_{\infty}$ control. Multi-objective control is formulated as an LMI optimization problem with a nonconvex rank condition, which is imposed on the controller gain matirx not Lyapunov matrices. With this rank-constrained formulation, we can expect to reduce conservatism because we can use separate Lyapunov matrices for different control objectives. An iterative penalty method is applied to solve this rank-constrained LMI optimization problem. Numerical experiments are performed to illustrate the proposed method.

• 한국항공우주학회지
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• 제34권7호
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• pp.45-54
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• 2006

일반적인 항공 촬영용 무인비행선은 GIS 데이터를 획득하기 위하여 기체 조종사와 영상 장치 조종사가 필요하며, 좋은 영상을 위해서는 이들의 호흡과 정확한 위치로의 이동이 중요하다. 본 논문에서는 이런 인력의 소요를 줄이고 정확한 위치/고도의 사전 계획된 비행경로를 자동비행하는 11m급 무인비행선의 고전제어 기반의 자동비행 제어법칙을 소개한다. 또한 이를 검증하기위해 실시한 비행시험의 각 단계별 절차와 유의사항, 외란에 의한 추종 오차를 줄이는 LOS 가이던스 알고리즘을 제시하고 비행시험 결과를 통한 게인 튜닝절차를 소개한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1836-1840
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• 2005

This work proposes a controller tuning method of a Hyundai 8608 robot in order to improve its performance. For this, we analyzed the control structure of the robot, and the functions of all the adjustable parameters in the robot controller with a reference 'NACHI Technical Report'. Through the analysis, we found out that 3 important parameters(VRRL, VRF, VRGIN) act like a conventional PID gains and other parameters are closely related to these 3 parameters. Conclusively, parameter tuning of these 3 parameters is enough in most cases of applications with other parameters fixed. The conventional PID tuning is performed to each joint of the test robot with Robot Performance Evaluation System(shown in our companion paper) so that the acceptable gain ranges for each joint are determined and then the robot performance tests are repeatedly done with the combination of the acceptable gains. Finally, the best combination is selected for its best performance. For the effectiveness of the proposed method, it was implemented on a Hyundai 8608 robot and its results are compared with the results of NACHI's Semi-Auto Tuning Method and the results which are done by a tuning expert with his eyes.

• International Journal of Internet, Broadcasting and Communication
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• 제9권1호
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• pp.1-8
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• 2017

Nowadays many articles describe the controlling models for four rotor flying vehicle. Basic approaches to the problem of these articles are mathematical expressions describing dynamics of the models of the vehicle and PID control for manipulating the object in 3 dimensional space. Design of control systems is usually started by careful consideration of its mathematical model description. We present a detailed mathematical model for a quad rotor. This paper first considers simulation of quadcopter control based on full state feedback technique with linearization in MATLAB environment and shows the results of the simulations. Finally will be shown experimental results of the state feedback control implemented in real model.

• Journal of Advanced Marine Engineering and Technology
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• 제39권6호
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• pp.633-641
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• 2015

선박, 발전소, 석유화학 등의 분야에서 운전되고 있는 많은 프로세스들은 강한 비선형성을 보일 뿐만 아니라 동시에 시변 특성도 가지고 있다. 이런 프로세스에 기존의 고정-파라미터 PID 제어기를 적용하면 성능이 나빠지고 경우에 따라서는 불안정해질 수도 있다. 따라서 본 연구에서는 복잡한 프로세스를 제어하기 위한 비선형 PID 제어기를 제안한다. 제안되는 제어기의 이득은 오차와 오차의 변화율의 비선형 함수로 기술되며, 사용자 파라미터들은 ITAE를 최소로 하는 관점에서 유전알고리즘으로 동조된다. 제안된 방법은 열분해반응 또는 촉매를 이용한 고분자합성에 널리 사용되는 연속 교반탱크반응기를 대상으로 시뮬레이션을 실시하며, 그 유효성을 보이기 위해 다른 두 비선형/적응 제어법과 비교한다.