• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.531-536
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• 2007

In this paper we present an interpolation-LQ control technique which tunes continuously the controller gain by interpolating the gains of sub-LQ controllers. The proposed controller design technique is applied to the container crane system for simulations. Several cases of simulations are carried out in order to prove the control effectiveness and robustness. The simulation results of the proposed controller are compared with those of LQ controllers. The results showed better control performance than those of LQ controllers.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.2
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• pp.25-36
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• 2000

본 논문에서는 구조물이 과도한 기진력을 받을 때에 구조물의 진동 제어를 위하여 제안 되어진 여러 가지 포화 제어 알고리듬들의 유용성을 실제적인 관점에서 살펴보았다 제안된 포화 제어 알고리듬 중세서 수정된 뱅뱅 제어 알고리듬이 매우 유용한 것임을 확인할 수 있었으나 이는 제어력 파형 결정 파라미터의 어떤 범위내에서만 효과적이며 그 범위를 넘어서는 경우에 있어서는 제어기를 불안정하게 할 수 있음을 확인할 수 있었다 따라서 수정된 뱅뱅 제어 알고리듬의 적용시에 과도한 외부 기진력에 대하여 제어기의 안정적인 작동에 의한 구조물의 진동제어효과를 얻기 위해서 제어력 파형 파라미터를 과도 기진력의 크기에 따라 변화시키는 적응형의 방법을 제안하였고 이의 유용성을 수치실험 및 유압식 질량 감쇠기를 장착한 축소 구조물 검증 실험을 통하여 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.817-823
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• 2017

In the past, research has been conducted on the development of an adaptive cruise control algorithm considering fuel efficiency, and an adaptive cruise control system considering fuel efficiency have been developed. However, research on optimizing vehicle and adaptive cruise control parameters in order to maximize performances is insufficient. In this study, the design optimization of vehicle and control parameters considering fuel efficiency, trackability, ride comfort and safe distance is performed. This paper proposes performance measures of vehicle behavior and develops an adaptive cruise control system. In addition, based on the screening of vehicle parameters that significantly influence performances, kriging surrogate models are constructed through a sequential design of experiment, and kriging surrogate model-based design optimization is performed to maximize fuel efficiency and satisfy target performances.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.390-395
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• 2003

PMSM 드라이브의 벡터제어를 위한 속도제어기는 일반적으로 PI 알고리즘을 사용한다.［1］PI 알고리즘에서는 플랜트의 동적 특성을 동정하기 위하여 연속적인 측정이 가능한 플랜트 파라미터의 자동동조 또는 적응 알고리즘을 추가하여 사용하기도 한다. 그러나 PI 제어기는 플랜트의 변동이 발생하여 연속적으로 적응추종을 해야할 경우, 계산이 매우 복잡하고 응답특성이 저하된다.(중략)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.8
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• pp.535-542
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• 2016

In this study, a model reference adaptive controller is developed to regulate the outlet air flow rate of centrifugal compressor for automotive supercharger. The centrifugal compressor is developed using the analytical based method to predict the transient behavior of operating and the designed model is validated with experimental data to confirm the system accuracy. The model reference adaptive control structure consists of a compressor model and a MRAC(model reference adaptive control) mechanism. The feedback control do not robust with variation of system parameter but the applied adaptive control is robust even if the system parameter is changed. As a result, the MRAC was regulated to reference air flow rate. Also MRAC was found to be more robust control compared with the feedback control even if the system parameter is changed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2421-2427
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• 2012

This paper is discussed the design on non-linear adaptive attitude controller for quadrotor UAV. Quadrotor UAV featured to have four rotor, required the special controller to compensate for the model parameter uncertainties as the unstable nonlinear system. In this research, we designed the adaptive controller to compensate for the payload changes even though it is changed with industrial applications. Especially, based on the mathematical model of UAV, non-linear adaptive controller is suggested and the stability is verified using the Lyapunov function and finally proved its performance and effectiveness of update laws with various payload by simulation.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.5
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• pp.39-50
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• 2017

Moving object tracking techniques can be considered as one of the most essential technique in the video understanding of which the importance is much more emphasized recently. However, irregularity of light condition in the video, variations in shape and size of object, camera motion, and occlusion make it difficult to tracking moving object in the video. Swarm based methods are developed to improve the performance of Kalman filter and particle filter which are known as the most representative conventional methods, but these methods also need to consider dynamic property of moving object. This paper proposes adaptive parameter control method which can dynamically change weight value among parameters in particle swarm optimization. The proposed method classifies each particle to 3 groups, and assigns different weight values to improve object tracking performance. Experimental results show that our scheme shows considerable improvement of performance in tracking objects which have nonlinear movements such as occlusion or unexpected movement.

• Journal of Navigation and Port Research
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• v.31 no.1 s.117
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• pp.55-64
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• 2007

In general mechanical servo systems, friction deteriorates the performance of controllers by its nonlinear characteristics. Especially, friction phenomenon causes steady-state tracking errors and limit cycles in position and velocity control systems, even though gains of controllers are tuned well in linear system model. Even if sensor is used higher accuracy level, it is difficult to improve tracking performance of the position to the same level with a general control method such as PID type. Therefore, many friction models were proposed and compensation methods have been researched actively. In this paper, we consider that the variation of mover's mass is various by loading and unloading. The normal force variation occurs by it and other parameters. Therefore, the proposed control system is composed of main position controller and a friction compensator. A parameter estimator for a nonlinear friction model is designed by adaptive control law and adaptive backstepping control method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.22 no.3
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• pp.11-15
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• 1985

A Novel design of MRAC for achieving independent tracking and regulation objectives by applying Pad e-Type approximation in the controller parameter estimation is presented. The design of the controller is done with the unknown plant parameters from the first. The result of the design is a simple control scheme with the reduction of estimation para-meters. The performance of rho proprosed contiol structure in tracking and regulation is compared with the other method by computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2C
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• pp.200-208
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• 2009

A macroblock layer rate control for H.264/AVC has the problem that allocated target bits for current frame occasionally are exhausted too fast due to inadequate quantization parameter assignment. In this case, the maximum permissible quantization parameter is used to encode for remaining macroblocks and it leads to degradation of the visual quality. In addition, the header bits length estimation algorithm used for quantization parameter assignment takes the average header bits length for the encoded macroblocks of the previous frame and the current frame. Therefore, it generates a big mismatch between the actually generated header bits length and the estimated header bits length. In this paper, we propose adaptive quantization parameter decision method to prevent early exhausting target bits during encoding the current frame by considering the number of macroblocks that have negative targets bits in previous frame and the improved header bits length estimation scheme for accurate quantization parameter decision.