• 전기학회논문지
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• 제59권7호
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• pp.1289-1294
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• 2010

In this paper, a new discrete integral static output feedback variable structure controller based on the a new integral dynamic-type sliding surface and output feedback discrete version of the disturbance observer is suggested for the control of uncertain linear systems. The reaching phase is completely removed by introducing a new proposed integral dynamic-type sliding surface. The output feedback discrete version of disturbance observer is presented for effective compensation of uncertainties and disturbance. A corresponding control with disturbance compensation is selected to guarantee the quasi sliding mode on the predetermined integral dynamic-type sliding surface for guaranteeing the designed output in the integral dynamic-type sliding surface from any initial condition for all the parameter variations and disturbances. Using discrete Lyapunov function, the closed loop stability and the existence condition of the quasi sliding mode is proved. Finally, an illustrative example is presented to show the effectiveness of the algorithm.

• 전기학회논문지
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• 제59권3호
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• pp.623-629
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• 2010

In this paper, a new robust variable structure controller based on a nonlinear integral type sliding surface is presented for the control of uncertain systems with mismatched uncertainties and disturbance. A nonlinear integral type sliding surface is suggested for removing the reaching phase. After its ideal sliding dynamics is obtained, the two design methods are presented. A corresponding control input is proposed to satisfy the closed loop stability in the sense of Lyapunov and the existence condition of the sliding mode on the nonlinear integral type sliding surface, which will be investigated in Theorem 1. Through a design example and simulation study, the usefulness of the proposed controller is verified.

• 전기학회논문지
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• 제66권12호
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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.

• 전기학회논문지
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• 제59권6호
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• pp.1167-1172
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• 2010

In this paper, a new discrete integral variable structure controller based on the a new sliding surface and discrete version of the disturbance observer is suggested for the control of uncertain linear systems. The reaching phase is completely removed by introducing a new proposed integral sliding surface. The discrete version of disturbance observer is derived for effective compensation of uncertainties and disturbance. A corresponding control with disturbance compensation is selected to guarantee the quasi sliding mode on the predetermined integral sliding surface for guaranteeing the designed output in the integral sliding surface from any initial condition for all the parameter variations and disturbances. Using Lyapunov function, the closed loop stability and the existence condition of the quasi sliding mode is proved. Finally, an illustrative example is presented to show the effectiveness of the algorithm.

• 전기학회논문지
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• 제59권5호
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• pp.950-960
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• 2010

In this paper, a multi-input multi-output(MIMO) integral variable structure system with an integral-augmented sliding surface is designed for the improved robust control of uncertain multivariable system under the matched persistent disturbance. To effectively remove the reaching phase problems, the integral augmented sliding surface is proposed. Then for its design, the eigenstructure assignment technique is introduced to. To guarantee the designed performance against the persistent disturbance, the stabilizing control for multi-input system is also designed to generate the sliding mode on the integral sliding surface. The stability of the global system together with the existence condition of the sliding mode are investigated and proved for the case of multi input system in the presence of uncertainty and disturbance. The reaching phase is completely removed in proposed MIMO VSS by satisfying the two requirements. An example and computer simulations will be present for showing the usefulness of algorithm.

• 전기전자학회논문지
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• 제11권1호통권20호
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• pp.1-14
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• 2007

In this paper, a design of an integral augmented nonlinear optimal variable structure system(INOVSS) is presented for the prescribed output control of uncertain MIMO systems under persistent disturbances. This algorithm basically concerns removing the problems of the reaching phase and combining with the nonlinear optimal control theory. By means of an integral nonlinear sliding surface, the reaching phase is completely removed. The ideal sliding dynamics of the integral nonlinear sliding surface is obtained in the form of the nonlinear state equation and is designed by using the nonlinear optimal control theory, which means the design of the integral nonlinear sliding surface and equivalent control input. The homogeneous $2{\upsilon}(\kappa)$ form is defined in order to easily select the $2{\upsilon}$ or even $(\kappa)-form$ higher order nonlinear terms in the suggested sliding surface. The corresponding nonlinear control input is designed in order to generate the sliding mode on the predetermined transformed new surface by means of diagonalization method. As a result, the whole sliding output from a given initial state to origin is completely guaranteed against persistent disturbances. The prediction/predetermination of output is enable. Moreover, the better performance by the nonlinear sliding surface than that of the linear sliding surface can be obtained. Through an illustrative example, the usefulness of the algorithm is shown.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1534-1544
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• 2002

The TDCSA(Time Delay Control with Switching Action) method, which consists of Time Delay Control(TDC) and a switching action of sliding mode control(SMC), has been proposed as a promising technique in the robust control area, where the plant has unknown dynamics with parameter variations and substantial disturbances are preset. When TDCSA is applied to the plant with saturation nonlinearity, however, the so-called windup phenomena are observed to arise, causing excessive overshoot and instability. The integral element of TDCSA and the saturation element of a plant cause the windup phenomena. There are two integral effects in TDCSA. One is the integral effect occurred by time delay estimation of TDC. Other is the integral term of an integral sliding surface. In order to solve this problem, we have proposed an anti-windup scheme method for TDCSA. The stability of the overall system has been proved for a class of nonlinear system. Experiment results show that the proposed method overcomes the windup problem of the TDCSA.

• 전기전자학회논문지
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• 제9권2호
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• pp.87-100
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• 2005

본 연구는 불확실성이 존재하는 다이나믹 시스템을 고 강인성 및 성능 사전 결정 제어를 하기 위하여 적분 최적 가변구조 시스템을 설계한다. 제안된 제어기에서는 적분 슬라이딩 면을 이용 리칭 문제를 완전히 제거하여 시스템이 초기 값에서부터 바로 슬라이딩하여 외란과 불확실성에 무관하게 사전에 결정된 슬라이딩 면을 슬라이딩 모드 상태로 추종하므로 고 강인성 제어가 이루어진다. 적분 슬라이딩 면이 정의하는 이상 슬라이딩 동특성을 상태방정식 형으로 얻고, 고급 최적 제어 이론을 통하여 최적 의미로 설계한다. 이는 바로 슬라이딩 면과 등가 제어입력의 설계가 된다. 사전에 선정된 슬라이딩 면 위에 슬라이딩 모드를 발생할 제어입력을 설계하였다. 그 결과 외란과 불확정성에도 불구하고 주어진 초기 값에서부터 원점까지 전체 슬라이딩 출력이 완전하게 보장받는다. 더구나 기존의 최적 VSS에서는 설계 성능의 강인성을 보장받기 어려운데 반하여, 제안된 IOVSS에서는 실제 출력의 예측과 사전 결정이 가능하다. 예제를 들어 제안된 알고리듬의 성능을 검진한다.

• 전기학회논문지
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• 제63권4호
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• pp.519-525
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• 2014

In this paper, an alternative variable structure controller is designed for the point-to-point regulation control of uncertain general linear plants so that the output of plants can be controlled from an arbitrarily given initial point to an arbitrarily given reference point in the state space. By using the error between the steady state value of the output and an arbitrarily given reference point and those integral, a transformed integral sliding surface is defined, in advance, as the surface from an initial state to an arbitrarily given reference point without the reaching phase problems. A corresponding control input is suggested to satisfy the existence condition of the sliding mode on the preselected transformed integral sliding surface against matched uncertainties and disturbances. Therefore, the output controlled by the proposed controller is completely robust and identical to that of the preselected transformed integral sliding surface. Through an example, the effectiveness of the suggested controller is verified.

• 전기전자학회논문지
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• 제10권2호통권19호
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• pp.97-102
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• 2006

In this paper, a new simple integral variable structure controller is designed with incorporating the actuator dynamics. The formulation of the VSS (variable structure system) controller design includes integral augmented sliding surface and the dynamics of the actuator expressed as the state equation. An illustrative example is given to show the effectiveness of the developed controller.