• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2138-2139
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• 2002

In this paper we presents a speed controller for separately excited DC motor using adaptive backstepping technique. The motor was modeled in two local areas the first model is a linear one when speed is under base speed, the other is nonlinear one when field weakening is used to obtain the speed well above base speed. Then linear robust state feedback controller was designed for the linear model while adaptive backstepping controller was designed for the nonlinear model. The adaptive backstepping technique takes system nonlinearity into account in the control system design stage. The proposed controller is proved to be asymptotically stable by the Lyapunov stability theory and some simulations have been carried out to test.

• 수산해양기술연구
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• 제26권3호
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• pp.275-281
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• 1990

This study suggests a new type shaft generator driven by hydraulic power suitable for small size vessels. Since the shaft generator system is very easy to be affected by disturbances such as speed variation of the main engine and the load variation of the generator, a robust servo control must be performed to obtain stable electric power with constant frequency. So, in this study the robust servo control method is adopted to the controller design. Dynamic characteristics on the frequency variations of the electric power output according to the disturbances are investigated by computer simulations. From the considerations of the computer simulation results, it is ascertained that the shaft generator system proposed in this study had good control performances.

• 한국정밀공학회지
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• 제17권3호
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• pp.68-75
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• 2000

The flexibility of a manipulator inevitably yields vibration at the end effector. In this work, position and vibration control for a flexible robot arm was studied using a separate voice coil type actuator to raise the accuracy and speed of end tip. A flexible robot arm with a tip mass is modeled as an Euler-Bernoulli beam. An $H_$\infty$$ controller is adapted to get a robust control against unmodeled higher-order mode vibration, output sensor noise, and etc. Simulations and experiments show that the modeling of the system is acceptable and robust vibration control is also achieved.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3685-3693
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• 2021

This paper presents a disturbance observer-based robust backstepping load-following control (DO-RBLFC) scheme for modular high-temperature gas-cooled reactors (MHTGRs) in the presence of actuator saturation and disturbances. Based on reactor kinetics and temperature reactivity feedback, the mathematical model of the MHTGR is first established. After that, a DO is constructed to estimate the unknown compound disturbances including model uncertainties, external disturbances, and unmeasured states. Besides, the actuator saturation is compensated by employing an auxiliary function in this paper. With the help of the DO, a robust load-following controller is developed via the backstepping technique to improve the load-following performance of the MHTGR subject to disturbances. At last, simulation and comparison results verify that the proposed DO-RBLFC scheme offers higher load-following accuracy, better disturbances rejection capability, and lower control rod speed than a PID controller, a conventional backstepping controller, and a disturbance observer-based adaptive sliding mode controller.

• 수산해양기술연구
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• 제58권3호
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• pp.241-250
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• 2022

This paper describes the design of H-infinity controller for robust control of a DC motor system. The suggested controller can ensure robustness against disturbance and model uncertainty by minimizing H-infinity norm of the transfer function from exogenous input to performance output and applying the small gain theorem. In particular, the controller was designed to reduce the effects of disturbance and model uncertainty simultaneously by formalizing these problems as a mixed sensitivity problem. The validity of the proposed controller was demonstrated by computer simulations and real experiments. Moreover, the effectiveness of the proposed controller was confirmed by comparing its performance with PI controller, which was tested under the same experimental condition as the H-infinity controller.

• 제어로봇시스템학회논문지
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• 제8권5호
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• pp.363-372
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• 2002

In ship operation, the roll motions can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization system design have been performed and good results have been achieved. In many studies, the stabilizing fins are used. Recently rudders, which have been extensively modified, have been used exclusively to stabilize the roll. But, in the roll stabilization control system, the control performance is very sensitive to the ship speed. So, we can see that it is important to consider the ship speed in the rudder roll control system design. The gain-scheduling control technique is very useful in the control problem incorporating time varying parameters which can be measured in real time. Based on this fact, in this paper we examine the;$H_{\infty}$-Gain Scheduling control design technique. Therefore, we assume that a parameter, the ship speed which can be estimated in real time, is varying and apply the gain-scheduling control technique to design the course keeping and anti-rolling control system far a ship. In this control system, the controller dynamics is adjusted in real-time according to time-varying plant parameters. The simulation result shows that the proposed control strategy is shown to be useful for cases when the ship speed is varying and robust to disturbances like wind and wave.

• 한국정밀공학회지
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• 제30권10호
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• pp.1051-1059
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• 2013

In general, lateral ride comfort of railway vehicle is mainly influenced by a secondary suspension placed between the bogie and carbody. Higher operating speeds of train results in increased vibration of carbody, which has a negative impact related to the ride comfort. To solve this problem, researches to replace the conventional passive suspension with (semi)active technology in the secondary suspension of a railway vehicle have been carried out. The semi-active suspension using the magneto-rheological damper is relatively simpler system and has advantage in maintenance compared to the hydraulic type semi-active damper. This study was performed to reduce lateral vibration acceleration of carbody related to ride comfort of railway vehicles with a semi-active suspension system. The numerical analysis was conducted by replacing passive lateral damper with semi-active MR damper, and robust control with the MR damper was applied to the 1/5 scaled railway vehicle model.

• Journal of Power Electronics
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• 제15권5호
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• pp.1244-1255
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• 2015

This paper presents a new multi-machine robust control based on an electric differential system for electric vehicle (EV) applications which is composed of four in-wheel permanent magnet synchronous motors. It is based on a new master-slave direct torque control (DTC) algorithm, which is used for the control of bi-machine traction systems based on a speed model reference adaptive system observer. The use of an electric differential in the design of a new EV constitutes a technological breakthrough. A classical system with a multi-inverter and a multi-machine comprises a three-phase inverter for each machine to be controlled. Another approach consists of only one three-phase inverter for several permanent magnet synchronous machines. The control of multi-machine single-inverter systems is the subject of this study. Several methods have been proposed for the control of multi-machine single-inverter systems. In this study, a new master-slave based DTC strategy is developed to generate an electric differential system. The entire system is simulated by Matlab/Simulink. The simulation results show the effectiveness of the new multi-machine robust control based on an electric differential system for use in EV applications.

• Journal of Electrical Engineering and information Science
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• 제3권1호
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• pp.86-93
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• 1998

In this paper, we propose an effective on-line identification method for rotor resistance, which is useful in making speed control of induction motors without rotational transducers robust with respect to the variation in rotor resistance. Our identification method for rotor resistance is based on the linearly perturbed equations of the closed-loop system for sensorless speed control about th operating point. Our identification method for rotor resistance uses only the information of stator currents and voltages. In can provide fairly good identification accuracy regardless of load conditions. Some experimental results are presented to demonstrate the practical use of our identification method. For our experimental work, we have built a sensorless control system, in which all algorithms are implemented on a DSP. Our experimental results confirm that our on-line identification method allows for high precision speed control of commercially available induction motors without rotational transducers.

• 한국통신학회논문지
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• 제16권9호
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• pp.877-882
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• 1991

전문가 제어는 궤환세어 시스템에 규칙기반 전문가 시스템을 도입한 기법이다. 본 논문에서는 직류 서보전동기 속도 제어를 위한 입력 조절, 감독, 동조에 관한 경험적 규치기 제시되었다. 경험적 규칙이 궤횐제어 시스템의 한 요소로서 사용된 전문가 자동동조 PID 제어기는 수치 알고리즘과 경험적 논리로 구성된다. 견실하고 정밀한 제어기능은 컴퓨터 시뮬레이션에 의하여 확인 하였다