• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.205-208
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• 1986

The synthesis of control structure involves the selection of controlled variable (or measured variable), and the structure interconnecting measured and manipulated variables (control loops). This paper deals with the synthesis job by using the structural analysis and block relative gain. This synthesis tool is very useful because they require minimal information, and the results show that this is a systematic and efficient metholodgy.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.6
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• pp.625-632
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• 1992

This paper presents a new dc-motor position control approached by Variable Structure System. In order to eliminate a steady-state position error, we propose a switching function composed of position error, velocity, and current ripple. The switching function has an advantage compared to other ones. To determine the control signal voltage, we use a fuzzy logic method. The simulation results show expected performances.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1982-1984
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• 1997

In this paper, adaptive variable structure control is proposed for Electromagnetic Suspension(EMS). Although variable structure control shows excellent robustness to unstructured modelling uncertainty, such as flux leakage and saturation, it has several drawbacks that severely limit practical applicability such as high control activity and control chattering. To minimize these effects, the mass of the electromagnet and efficiency of levitation force are estimated on-line to reduce the range of system uncertainty. The effectiveness of the proposed control scheme is verified by experimental results using a 1.5kg electromagnet and DSP (TMS320C31).

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.69-71
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• 1997

The direct drive motor is directly coupled by load. So, it is directly affected by load and disturbances. To control the direct drive motor, a robust controller is need. The main feature of variable structure system is that system trajectories are robust and insensitive to parameter variations and disturbances in the sliding mode. In this paper, adaptive variable structure controller, is used for the BLDD SM(Brushless Direct Drive Servo Motor) control. The chattering problem is reduced by using the saturation function.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.8
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• pp.124-133
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• 1996

This paper presents the implementation of variable structure control system for a linear or nonlinear system using neural networks. The overall control system consists of neural network controller and a reaching mode controller. While the former approximates the equivalent control input on the sliding surface, the latter is used to bring the entire system trajectories toward the sliding surface. No supervised learning procedures are needed and the weights of the neural network are tuned on-line automatically. The neural netowrk-based variable structure control system is applied to a nonlinare unstable inverted pendulum system through computer simulations, and implemented using a microcomputer (80486-50MHz) and applied to the DC servomotor position control system. Simulation and experimental results show the expected approximation sliding property is occurred. The proposed controller is compared with a PID controller and shows better performance than the PID controller in abrupt plant parameter change.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.569-575
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• 1997

모델 불확실성이 있고 n축 자유도(degree of freedom)를 갖고 있는 로봇 동작부(manipulator)에 대해서 위치 정보만을 이용하여 가변 구조 제어기(variable structure controller)를 설계하였다. 모델의 불확실성이 존재하는 경우에도 제어기에 사용되는 속도를 잘예측하기 위해 고이득 관찰기를 사용 하였으며 고이득 관찰기를 사용할때 발생할 수 있는 상태변수의 피킹현상(peak phenomenon)를 적게 하게 하기위하여 제어기의 값을 제한 (globally bounded)하여 제어기를 설계하였다. 부하(payload)의 범위만 알고 있는 2축 자유도를 갖는 로봇 동작부에 대해서 제안된 제어 방법에 따라 제어기를 설계하여 그 성능를 확인 하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.249-252
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• 1997

In this paper the sway-control problem of a container crane is investigated in the perspective of controlling an underactuated mechanical system. For fast loading/unloading of containers from the ship, quick suppression of the remaining swing motion of the container at the end of each trolley stroke is crucial. Known nonlinearities are fully incorporated by feedback linearization. Robustness is enhanced by variable structure control. Compared with the linear LQ control, much better performance can be obtained.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1414-1417
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• 2003

In this paper, sliding mode controller for discrete-time nonlinear systems with uncertainties and disturbances are proposed. The concept of time-delay control (TDC) which consists of estimating the uncertain dynamics of the system through past observations of the system response is used. The proposed controller guarantees that the closed-loop system states are globally uniformly ultimately bounded (GUUB). It is also shown that the closed-loop system states are globally uniformly asymptotically stable (GUAS) if uncertainties are constant.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.267-270
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• 1995

In this paper, a variable structure control scheme with a terminal sliding mode is proposed for robot manipulators. The proposed control scheme guarantees that the output tracking error converges to zero in finite time, and the overall system shows robust property against parametric uncertainties and external disturbances all the time.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.253-256
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• 1996

In this paper, A new time-varying sliding surface design using eigenvalue locus is proposed to achieve fast and robust in a class of high-order uncertain dynamic system. A moving sliding surface(MSS) was proposed earlier for the second-order variable structure control systems(VSCS). This methodology led to fast and robust control responses of the second-order VSCS. However, the moving algorithm of the MSS was too complicated to be employed the high-order VSCS. To resolve this problem, we propose a new moving algorithm that switching surface moves such that the eigenvalues of equivalent system in the sliding mode have a predetermined locus. Using the proposed surface fast and robust behaviors are accomplished. The problem of chattering can be eliminated by using a boundary layer of switching surface. The efficiency of proposed algorithm is illustrated by an application to four-order workbench.