• 대한전기학회논문지
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• 제41권7호
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• pp.773-783
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• 1992

There have been several control schemes for the single input systems with unmeasurable state variables using variable structure control(VSC) theory. However, each of them is a study on the systems which can be represented in the phase canonical form or non-phase canonical form dynamic equation separately. As these control algorithms have difficulties in practical application by its theoretical limitations, in this paper we propose a new VSC theory which overcomes those limitations, in this paper we propose a new VSC theory which overcomes those limitations of proposed schemes. This new control scheme can be realized for the general linear systems which have unmeasurable state variables. And the switching function of this VSS algorithm consists of measurable state variable function(reduced-order switching function) and its derivatives. Also in the construction of control imput only measurable state variables are used.

• 대한전기학회논문지
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• 제41권8호
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• pp.902-913
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• 1992

There have been several control schemes for the single input systems with unmeasurable state variables using variable structure control(VSC) theory. In the previous VSC, the systems must be represented in phase canonical form and the complete measurements for each state variable must be assumed. In order to eliminate these restrictions several VSC methods were proposed. And especially for the systems in phase canonical form with unmeasurable state variables, the reduced order switching function algorithm was proposed. But this method has many drawbacks and can not be used in the case of general form (not phase canonical form) dynamic system. Therefore this paper propose new construction method of switching fuction for the systems in phase canonical form, which reduce the restriction of reduced order switching function algorithm. And this algorithm can be realized for any state representation and adopted in the systems where not all states are available for switching function synthesis or control.

• 유공압시스템학회논문집
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• 제7권3호
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• pp.20-27
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• 2010

A vehicle suspension system performs two functions, the ride quality and the stability, which conflict with each other. An active suspension system has an external energy source, from which energy is always supplied to the system for continuous control of vehicle motion. Therefore, an active suspension system can have even more improved performance. Some control laws have been proposed for active suspension system, but in this paper, an optimal variable structure control(VSC) is proposed. The VSC method is well suited for a class of nonlinear system and can address the robustness issues to constant modelling errors and disturbances. This paper develops an optimal VSC controller and compares its performance to those of a passive suspension system and an active suspension system with an optimal controller. The transient and frequency responses are analyzed respectively.

• 한국지능시스템학회논문지
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• 제5권1호
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• pp.25-32
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• 1995

In this paper, the FLVSC (Fuzzy Logic Variable Structure controller), of which control rules are extracted from the concepts of the VSC(Variable Structure control) is proposed and diesgned for drum motor(BLDC motor) in home VCR. The FLC (Fuzzy Logic Controller) based on linguistic rules has the advantages of not needing of some exact mathermatical model for plant to be controlled. The proposed method has the characteristics which are viewed in conventional VSC, e.g. insensitivity to a class of distrubances, parameter variations and uncertainites in a sliding mode. In addition, the method has the properties of the FLC-noise rejection capability etc. The computer simulation and experiment using DSP(TMS320C30) have been carried out for the servo control of VCR drum motor to show the usefulness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.149-151
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• 2007

For several decades, VSC has gained much attention as one of the useful design tools for handling the practical system with uncertainties or disturbances. Generally, the disturbances in the matching condition can be perfectly rejected via VSC; however, these in the mismatching condition are known to be hardly rejected. There have been some trials on it, in which the resulting controls in fact belong to the class of robust control guaranteeing disturbance ${\gamma}$-attenuation. Therefore, in this paper, we propose a new Variable Structure Control (VSC) for a system with mismatched disturbances. The proposed controller is composed of linear and nonlinear parts; the former plays a role in stabilizing the system and the latter takes care of attenuating the disturbances. The main contribution is to introduce the concept of switching-zone, rather than switching-surface, that is designed through piece-wise Lyapunov functions. The resulting non-convex conditions are formulated with an iterative linear programming algorithm, which provides an excellent performance of almost rejecting the disturbances.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.813-816
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• 1999

In this paper is Proposed a VSC(variable structure controller) for a high-speed and high-precision position control of a XY Table, which is based on the PI type reaching mode. Also the comparative study between the proposed method and the conventional PID controller is presented as well. Designed and tuned under repeated experiments, the proposed method showed a better reasonable performance than PID controller in the aspect of tracking error.

• 대한전기학회논문지
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• 제45권1호
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• pp.60-66
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• 1996

Brushless DC(BLDC) motor have been increasingly used in machine tools and robotics applications due to the reliability and the efficiency. In control of BLDC motor, it is important to construct the controller which is robust to parameter variations and external disturbances. Variable structure controller(VSC) has been known as a powerful tool in robust control of time varying systems. In practical systems, however, VSC has a high frequency chattering which deteriorates system performances. In this paper, a binary controller(BC) which takes the form of VSC and MRAC combined is presented to solve this problem. BC consists of the primary loop controller and the external loop controller to change the gain of primary loop controller smoothly. So it can generate the continuous control input and is insensitive to parameter variations in the given domain. To confirm the validity, various investigations of control characteristics for various design parameters in a position control system of BLDC motor are carried out. (author). 11 refs., 18 figs., 1 tab.

• 전자공학회논문지SC
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• 제37권3호
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• pp.19-32
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• 2000

본 논문이 제안하는 제어기는 새로운 가변 경계층을 이용하여 가변 구조 시스템의 정확한 추적 제어가 이루어지게 한다. 지금까지 가변 경계층을 적용한 가변 구조 제어기는 고정된 슬라이딩면의 사용으로 초기 위치가 제한되었으며 이로 인해 임의의 초기 위치에서부터 시스템 상태 궤적의 채터링을 감소시킬 수 없다. 그러나 제안된 제어기는 선형 시변 슬라이딩면을 이용함으로서 모든 상태로부터 외부 외란과 불확실한 매개변수에 대한 강인한 특성을 지니게 되며 새로운 가변 경계층의 적용으로 채터링과 추적 성능에서 기존 방법에 비해 우수한 특성을 보이고 있다. 따라서 본 논문은 2 관절 매니퓰레이터에 제안된 알고리즘을 적용하여 제시한 방법의 타당성을 입증하였다.

• 제어로봇시스템학회논문지
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• 제8권8호
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• pp.639-648
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• 2002

The stewart platform manipulator is a manipulator that has the closed-loop structure with an upper plate end-effector and a base frame. The stewart platform manipulator has the merit of high working accuracy and high stiffness compared with a serial manipulator. However, this is a complex structure, so controllability of the system is not so good. In this paper, we introduce a new robust motion control algorithm using partial state feedback for a class of nonlinear systems in the presence of modelling uncertainties and external disturbances. The major contribution of this work introduces the development and design of robust observer for the state and the perturbation, which is integrated into a variable structure controller(VSC) structure. The combination of controller/observer improves the control performance, because of the robust routine called sliding mode control with sliding perturbation observer(SMCSPO). Simulation and experiment are performed to apply to the manipulator. And their results show a high accuracy and a good performance.

• 한국조명전기설비학회지:조명전기설비
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• 제9권4호
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• pp.55-61
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• 1995

Variable structure control (VSC) can be used for the control of power plants required stability and robustness such as elevator control. It has no overshoot and is insensitive to parameter variations and disturbances in the sliding mode where the system structure is changed with the sliding surface in the center. But in the real system, VSC has a high frequency chattering which has a bad influence upon the control system proformances. In this paper, to alleviate the high frequency chattering, a binary controller (BC) with inertial type external loop is implemented by DSP and applied to position control of brushless DC motor. Binary controller has external loop to generate the continuous control input with the flexible variation of primary loop gain. Thus it has the property of chattering alleviation in addition to advantages of the conventional variable structure control.