• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.1C
• /
• pp.113-119
• /
• 2009

The training sequence with the appropriate length for equalization and initial synchronization is necessary before sending the pure data in the burst transmission type DS-UWB system. The length of the training sequence is one of the factors which make throughput decreased. The noble structure with the variable length of the training sequence whose length can be adaptively tailored according to the channel conditions (CM1,CM2,CM3,CM4) in the DS-USB systems is proposed. This structure can increase the throughput without sacrificing the performance than the method with fixed length of training sequence considering the worst case channel conditions. Simulation results under IEEE 802.15.3a channel model show that the proposed scheme can achieve higher throughput than a conventional one with the slight loss of BER performance. And this structure can reduce the computation complexity and power consumption with selecting the short length of the training sequence.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.227-231
• /
• 2004

In this paper, a robust Sliding Mode Variable Structure (SMVS) controller is designed for Active Queue Management (AQM). This type of controller is insensitive to noise and variance of the parameters, thus it is suitable to time varying network systems. Simulation results conform the robust performance of SMVS controller against the disturbance. At the same time, a complete comparison between SMVS and PI controllers is made. The conclusion is that both transient and steady state performance of SMVS controller is better than that of PI one.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10b
• /
• pp.1833-1838
• /
• 1991

This paper presents a stabilization technique for unstable systems. An inverted pendulum, which is a typical unstable mechanical system, is considered and stabilized by a nonlinear control. The stabilization problem in this system is related to that in postural control of human being. In this paper, the variable structure control (VSC) is applied to the stabilization problem. Robustness by the VSC and that by a conventional linear feedback controller are compared.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 1999.12a
• /
• pp.747-757
• /
• 1999

본 논문에서는 가변구조제어기의 슬라이딩모드이득과 경계층두께(boundary layer thickness)를 신경망을 이용하여 계산하는 신경망 가변구조제어기를 제시한다. 제시된 방법은 신경망의 역전파오차 학습기능을 이용하여 슬라이딩모드이득과 경계층 범위를 계산할 수 있도록 신경망 제어기를 학습시킴으로써, 슬라이딩모드 제어법칙을 단순화 하고, 시스템 불확실성에 대하여 강인하며, 추적오차를 더욱 개선시킬 수 있다. 설계의 예와 시뮬레이션 결과를 통하여 제시된 방법에 대한 유용성을 보인다.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.684-688
• /
• 1996

In this paper, to overcome drawbacks of variable structure control system a self-tuning fuzzy sliding mode control algorithm using gradient descent method is proposed. The proposed method has the characteristics which are viewed in conventional VSC, e.g. insensitivity to a class of disturbance, parameter variations and uncertainties in the sliding mode. To demonstrate its performance, the proposed control algorithm is applied to a one-degree of freedom robot arm. The results show that both alleviation of chattering and performance are achieved.

• 제어로봇시스템학회:학술대회논문집
• /
• 1989.10a
• /
• pp.924-930
• /
• 1989

This paper presents the design of simple robust controller for a class of uncertain multivariable systems. We introduce switching dynamics instead of switching logics unlike variable structure control scheme. Also, we can construct the continuous control law from this switching dynamics and consequently remove the chattering motion. The dynamic equations of the range-space of a switching surface matrix C and uniform ultimate boundedness in the presence of parameter uncertainties are described mathematically.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.308-312
• /
• 1990

In this paper, we propose a simple method to control the servo system with sliding mode in the parameter variation and disturbances. We show the comparison between the conventional sliding line and the new sliding line and the proposed sliding mode control. The performance of the fast response and no overshoot by using the proposed sliding line is obtained.

• Proceedings of the Korea Society for Industrial Systems Conference
• /
• 1998.03a
• /
• pp.313-319
• /
• 1998

본 논문에서는 슬라이딩모드 제어이득을 실시간으로 계산하여 적응시키는 적응 가변구조제어기 설계방법을 제시한다. 제시된 방법은 간단한 계산으로 슬라이딩모드제어의 조건을 만족시키도록 제이이득을 변화시키므로 채터링을 감소시키고 추적오차성능을 개선시킨다. 계산시간이 적어 실시간 제어에 적용이 쉬운 장점이 있다. 제시된 제어방법을 기존의 방법과 비교하여 설계의 예를 보였고 시뮬레이션을 통하여 제시된 방법의 유용성을 보였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2000.05a
• /
• pp.51-54
• /
• 2000

In variable structure control algorithm, sliding mode makes the closed loop system insensitive to modelling uncertainties and external disturbances. However due to imperfections in switching, the system trajectory chatters, which is very undesirable. And the insensitivity property of a sliding mode controller is present only when the system is in the sliding mode. To overcome these shortcomings, in this paper, new sliding mode control algorithm using time-varying sliding surface and fuzzy PI structrue is proposed.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.608-611
• /
• 1997

The soccer robot system consists of multi agents, with highly coordinated operation and movements so as to fulfill specific objectives, even under adverse situation. The coordination of the multi-agents is associated with a lot of supplementary work in advance. The associated issues are the position correction, prevention of communication congestion, local information sensing in addition to the need for imitating the human-like decision making. A control structure for soccer robot is designed and several behaviors and actions for a soccer robot are proposed. Variable zone defense as a basic strategy and several special strategies for fouls are applied to SOTY2 team.