• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.747-749
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• 1998

A new $H_{\infty}$ robust controller is proposed by using Sliding Mode Control (SMC). The combination of $H_{\infty}$ with SMC is achieved by proposing a novel sliding surface which has a virtual state. This sliding surface has the nominal dynamics of an original system controlled by $H_{\infty}$ controller. Its design is based on the augumented system whose dynamics have one higher order than that of the original system. The reaching phase is removed by setting an initial virtual state which makes the initial sliding function equal to zero.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.89-93
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• 2000

Robust control for DC motor is needed according to the highest precision of industrial automation. However, when a motor control system has an effect of load disturbance, it is very difficult to guarantee the robustness of control system. Generally, it is known that sliding mode controller has robustness. But, after it is assumed that we known the disturbance uncertainty, sliding mode controller is designed. Thereafter, if we are not known th disturbance uncertainty then controller design is difficult. As a method solving this problem, in this paper, Expert sliding mode control method for motor control system is presented.The proposed controller can eliminate load disturbance effectively. The effectiveness of the control scheme is verified by simulation results.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.903-905
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• 1999

In this paper, a novel sliding surface is proposed by defining a novel virtual state. This sliding surface has nominal dynamics of an original system and makes it possible that the Discrete-Time Sliding Mode Control(DSMC) technique is used with the various types of controllers. Its design Is based on the augmented system whose dynamics have a higher order than that of the original system. The reaching phase is removed by using an initial virtual state which makes the initial sliding function equal to zero.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2289-2291
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• 2001

In this paper, a novel sliding surface is proposed by defining a novel virtual state. This sliding surface has nominal dynamics of an original system and makes it possible that the Sliding Mode Control(SMC) technique is used with the various types of controllers. Its design is based on the augmented system whose dynamics have a higher order than that of the original system. The reaching phase is removed by using an initial virtual state which makes the initial sliding function equal to zero.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1735_1736
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• 2009

This paper discusses about a robust servo system applying PID control to PMSM. The system has robustness by Sliding Mode Controller. A novel sliding surface is defined by virtual state. This sliding surface has nominal dynamics of an original PID control system. So Sliding Mode Control(SMC) technique can be used with PID controller. Its design is based on the augmented system whose dynamics have a higher order than that of the original system. The reaching phase is removed by using an initial virtual state whitch makes the initial sliding function equal to zero.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1656-1657
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• 2007

In this paper, a sliding mode controller with SVM sliding surface is proposed. In the conventional sliding mode control, the dynamic of sliding surface is not as same as nominal dynamic of original system. Therefore the aim of this paper is to design sliding surface without defining any additional dynamic state by using support vector machines. As a result, the proposed controller can have the same dynamic of nominal system controlled by $H_{\infty}$ controller.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.2
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• pp.152-162
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• 2008

This paper presents a sliding mode controller (SMC) to directly control the active and reactive powers of a doubly ffd induction generator (DFIG) for wind turbines. Sliding-mode control (SMC) and space-vector modulation (SVM) are combined to ensure high-performance operation. SMC scheme is designed to provide robust and fast power controls without frame transformation and current controller used in the conventional FOC drive. Simulation results and experimental results demonstrate that proposed methods preserve the effectiveness and robustness during variations of active and reactive power.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.747-752
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• 2006

In this paper, the adaptive fuzzy sliding mode controller with two systems is designed. The existing sliding mode controller used to $approximation{\^{u}}(t)$ with discrete sgn function and sat function for keeping the state trajectories on the sliding surface[1]. The proposed controller decrease the disturbance for uncertain control gain and This paper is concerned with an Adaptive Fuzzy Sliding Mode Control(AFSMC) that the fuzzy systems ate used to approximate the unknown functions of nonlinear system. In the adaptive fuzzy system, we adopt the adaptive law to approximate the dynamics of the nonlinear plant and to adjust the parameters of AFSMC. The stability of the suggested control system is proved via Lyapunov stability theorem, and convergence and robustness properties ate demonstrated. Futhermore, fuzzy tuning improve tracking abilities by changing some sliding conditions. In the traditional sliding mode control, ${\eta}$ is a positive constant. The increase of ${\eta}$ has led to a significant decrease in the rise time. However, this has resulted in higher overshoot. Therefore the proposed ${\eta}$ tuning AFSMC improve the performances, so that the controller can track the trajectories faster and more exactly than ordinary controller. The simulation results demonstrate that the performance is improved and the system also exhibits stability.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.756-762
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• 2009

As nonlinear friction, stick-slip friction in hydraulic actuators are a problem for accuracy and repeatability. Therefore friction compensation has been approached through various control algorithms. A Adaptive discrete time sliding mode tracking controller has been applied in order to compensate the nonlinear friction characteristics in a hydraulic Actuator. Based on the diophantine equation, a new discrete time sliding function is defined and utilized for the control law which includes a friction and modeling error. Robustness is increased by using both a projection algorithm and a sliding function-based nonlinear feedforward. From the results of simulation and experiment good tracking performance is achieved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1759-1771
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• 2017

In this paper, an improved continuous integral variable structure systems(ICIVSS) with the prescribed control performance is designed for simple regulation controls of uncertain general linear systems. An integral sliding surface with an integral state having a special initial condition is adopted for removing the reaching phase and predetermining the ideal sliding trajectory from a given initial state to the origin in the state space. The ideal sliding dynamics of the integral sliding surface is analytically obtained and the solution of the ideal sliding dynamics can predetermine the ideal sliding trajectory(integral sliding surface) from the given initial state to the origin. Provided that the value of the integral sliding surface is bounded by certain value by means of the continuous input, the norm of the state error to the ideal sliding trajectory is analyzed and obtained in Theorem 1. A corresponding discontinuous control input with the exponential stability is proposed to generate the perfect sliding mode on the every point of the pre-selected sliding surface. For practical applications, the discontinuity of the VSS control input is approximated to be continuous based on the proposed modified fixed boundary layer method. The bounded stability by the continuous input is investigated in Theorem 3. With combining the results of Theorem 1 and Theorem 3, as the prescribed control performance, the pre specification on the error to the ideal sliding trajectory is possible by means of the boundary layer continuous input with the integral sliding surface. The suggested algorithm with the continuous input can provide the effective method to increase the control accuracy within the boundary layer by means of the increase of the $G_1$ gain. Through an illustrative design example and simulation study, the usefulness of the main results is verified.