• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.512-514
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• 1997

In this paper, a quasi-sliding mode (QSM) control with load observer is discussed for field-oriented induction motor speed drive. The proposed QSM control, which is defined in the discrete time domain and act with the load torque observer eliminating impacted load torque, restricts the bound of chattering within specified band. With this strategy, we can obtain fast dynamics without overshoot and robustness to parameter variation and disturbance. The proposed scheme is verified by digital simulation.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.799-801
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• 2001

본 논문에서는 대역폭이 보장되지 않는 네트워크 상에서 비디오 서비스를 제공하기 위한 매체변환 방법 중 비디오 프레임 크기를 변환시켜 비트율을 효율적으로 제어하는 방법을 제안한다. H.263으로 부호화된 스트림을 DCT 공간에서 크기를 변환시킴으로써 완전 복호화 후 다시 부호화하는 과정에서 생기는 계산량을 대폭 감소시켜 보다 효율적인 방법으로 비트율을 제어할 수 있다. 움직임 정보뿐만 아니라 이전 프레임과의 차이값을 다시 사용하기 위해 크기변환 후 H.263 표준의 향상된 예측 모드 (Advanced Prediction Mode)를 사용하여 화질열화도 최소화한다. 실험결과 화질면에서는 블록화 현상(Block Artifact)이 크게 감소하였고, 프레임이 진행됨에 따라 PSNR은 낮아졌지만, 매체변환은 기존의 방법에 비해 라론 속도로 이루어 질 수 있었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.35-38
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• 2010

본 논문에서는 flexible guideway 교량과 능동적으로 제어되는 자기부상 열차간의 동적 상호작용에 대한 수치해석 모델을 개발하였다. 중 저속 자기부상열차의 동적 응답에 대한 열차와 guideway 사이의 특성에 대한 연구를 실시하였다. 동적 지배방정식은 10자유도계의 자기부상열차 모델, guideway구조물의 모드 특성과 UTM02 부상제어모델을 결합함으로써 유도하였다. 수치해석으로부터 열차의 부상공극은 차량의 속도, 트랙조도의 영향을 크게 받는 것을 발견하였다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.528-529
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• 2012

연료전지는 매우 늦은 응답속도를 가지므로 부하 증가시 Li-Ion 배터리나 슈퍼 커패시터 같은 별도의 에너지 저장장치로부터 필요한 전류를 공급받도록 구성되는데 이들 사이에서 전력전달을 위해 DC-DC 컨버터가 필수적으로 요구된다. 본 논문에서는 상태평균화 기법과 PWM 스위치 모델을 사용하여 DC-DC 컨버터를 해석하고 시뮬레이션 하였다. 또한 배터리 등가회로를 구성해서 배터리 등가 임피던스를 고려한 이중루프 제어기를 설계하고 정전류/정전압 충전모드 시뮬레이션을 통해 효과를 확인하였다.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.331-333
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• 1995

A high performance motor drive system must have a good speed command tracking, a insensitivity to a parameter variation and sampling time. In this paper, a robust speed controller for an induction motor is proposed. The speed controller is fuzzy-sliding adaptive controller and its system continuously is varied. That is, only P gain act in dynamic state, I gain in steady-state. Because this system is a sort of adaptive control system, global stability analysis is used to Lyapunov function. Consequently, in this paper application of fuzzy sliding adaptive controller to induction motor controlled by vecter control is presented and the control system is digitally implemented within DSP.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.1145-1146
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• 2023

모빌리티 기술이 발전함에 따라 기존 차량에서 선보이지 못했던 다양한 주행기술이 가능해졌고, 이에 따라 많은 장점을 지닌 모빌리티 기술들이 등장하고 있다. 4 륜 독립 구동, 제동, 조향 시스템은 바퀴 별 독립 제어가 가능하여 여러 주행 모드를 구현할 수 있다. 본 연구에서는 4 륜 독립 구동, 제동과 독립 조향이 가능한 모빌리티 플랫폼에 대해 평행 주행, 제자리 회전, 축 회전 주행 등을 구현하는 방안과, 더 나아가 각도 속도를 일정하게 유지함으로써 오차를 최소화하는 제어 방법에 대해 살펴보고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.9
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• pp.801-806
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• 2015

In this paper, we propose cascade-form velocity controller for a permanent magnet synchronous motor (PMSM). The proposed controller consists of a sliding-mode controller (SMC) for the inner current control loop and a model-predictive controller (MPC) for the outer velocity control loop. With SMC, we can ensure that the current tracking error always converges to zero in finite time. The SMC is designed to track the desired currents. Additionally, with MPC, we can obtain the optimal velocity control input which minimizes the cost function. Constraint conditions for input and input variation are included in the MPC design. The simulation results are included to validate the performance of the proposed controller.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.249-255
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• 2010

The paper proposes a new type of robust speed control strategy for permanent magnet synchronous motor by using PD-sliding mode hybrid control. The PD control has a good performance in the transient region while the sliding mode controller provides the robustness against system uncertainties. Taking advantages of the two control strategies, the proposed control method utilizes the PD control in the approaching region to the sliding surface and the sliding mode control near at the sliding surfaces. The chattering problem of the sliding mode controller is eliminated by applying the saturation function for the switching function of the sliding mode control. The stability of the sliding mode control is verified by using Lyapunov function with the proper selection of variable gains. It is shown that with this simple switching algorithm, stability of the overall hybrid control system is ensured. Through the simulations, the PD-sliding mode algorithm is shown to have a good performance in the transient response as well as being robust against disturbances. The robustness of the PD-sliding mode algorithm is further demonstrated against various external disturbances in the real experiments of SPMSM motor control.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.163-170
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• 2016

In the condition of electronic controlled acceleration system, APS Sensor is the only and the most important parts to reflect the will of driver. Especially, the non-reference type APS is the critical part of this system. It can't provide the cross-reference values and it will make the vehicle goes into the 'NMC(Non-moveable condition)' or 'Limp-home mode' on the malfunction situation easier. If the situation is happened, it's very dangerous condition for the drivers, soldiers and war material systems of battlefield. The electronic control is not a necessary system for the tactical vehicles. The tactical vehicles must be prepared the manual control system independently from the electronic control system to escape, save and rescue the soldier's life and war materials. Therefore it was studied the water-penetrated broken APS output. If the output value was changed without driver's will, even the cross-reference type APS, it will effect the uncontrollable engine RPM changing or the performance down on limp-home mode. It means the manual control system of tactical vehicle is needed for any kinds of APS.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1152-1160
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• 2007

In this paper we deal with a design of integral sliding mode controller to reject the disturbance force acting on the suspension system in the magnetically levitated system which is propelled by the linear induction motor. The control scheme comprises an integral controller which is designed for achieving zero steady-state error under step disturbances, and a sliding mode controller which is designed for enhancing robustness under plant uncertainties. A proper continuous design signal is introduced to overcome the chattering problem. The disturbance force produced by the linear motor is formularized by using a curve fitting of the experimental raw data. Computer simulations show the effectiveness of the designed integral sliding mode controller to reject the disturbance force.