• Journal of Ocean Engineering and Technology
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• v.12 no.2 s.28
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• pp.130-138
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• 1998

본 논문은 AUV의 수직면 운동제어를 수행하기 위하여 의사 슬라이딩 모드 제어기를 이용한 모델링 기법과 제어기 설계법에 관한 것으로서, 샘플링 간격이 길어지는 경우에도 시스템의 강인성이 확보되며 심도 제어가 안정적으로 수행되는 실용성을 실험과 수치 해석을 통하여 검증하였다. 제어기는 참고문헌에서 제안한 방법을 이용하였으며, 한국기계연구원 선박해양공학연구센터(KRISO)에서 개발한 VORAM호를 제어 대상 AUV로 선정하였다. PMM 시험으로 얻어진 운동 계수를 이용하여 수치 해석을 수행하였으며, KRISO의 장수조에서 실험을 수행하였다. 수치 해석과 실험 결과로부터 샘플링이 길어짐에 따라 의사 슬라이딩 모드 제어기는 연속계에 대한 슬라이딩 모드 제어기에서 발생하는 과도한 채터링 및 불안정성을 보이지 않았으며, 시스템의 안정성이 확보되고 불확실성에 대하여 강인한 제어 성능을 보였다. 또한, 본 논문에서는 수치 해석과 실험 결과를 근거로 의사 슬라이딩 모드 제어기의 설계를 위한 제어 변수의 선정 기준을 제시하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.116-121
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• 2018

In this paper, we propose the SIIM fuzzy Quasi-sliding mode controller for the system of a double inverted pendulum on a cart. Since it is difficult to handle this 6th-order system, we decoupled the entire system into three $2^{nd}$ order subsystem, and we designed the SIIM fuzzy Quasi-sliding mode controller for each subsystem, which was easy and did not require the derivation of the equivalent control. The stability of the entire system is guaranteed using Lyapunov function. The validity and robustness of the proposed controller are demonstrated through the computer simulation, and the results are compared with the results of former studies.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.169-179
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• 1997

This paper presents a discrete-time sliding mode control of an autonomous underwater vehicle with parameter uncertainties and long sample interval based on discrete variable structure system. Although conventional sliding mode montrol techniques are robust to system uncertainties, in the case of the system with long sample interval, the sliding control system reveals chattering phenomenon and even makes the system unstable. This paper considers the AUV which acquires position informations from a surface ship through an acoustic telemetry system with a certain discrete interval. The control system is designed on the basis of a Lyapunov function and a sufficient condition of the switching gain to make the system stable is give. Each component of the switching gain can be determined separately one another. The controller is robust to the uncertainties, and reaching condition of the control system is satisfied for any initial condition. This control law is a generalized form of the discrete sliding mode control and reduce the chattering problem considerably. Motion control of the AUV in the vertical plane shows the effectiveness of the proposed technique.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.315-321
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• 2014

This paper presents an integrated chassis control system with fail safety using optimum yaw moment distribution for a vehicle with steer-by-wire and brake-by-wire devices. The proposed system has two-level structure: upper- and lower-level controllers. In the upper-level controller, the control yaw moment is computed with sliding mode control theory. In the lower-level controller, the control yaw moment is distributed into the tire forces of active front steering(AFS) and electronic stability control(ESC) with the weighted pseudo-inverse based control allocation(WPCA) method. By setting the variable weights in WPCA, it is possible to take the sensor/actuator failure into account. In this framework, it is necessary to optimize the variables weights in order to enhance the yaw moment distribution. For this purpose, simulation-based tuning is proposed. To show the effectiveness of the proposed method, simulations are conducted on a vehicle simulation package, CarSim.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.527-534
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• 2015

This paper presents an integrated chassis control with electronic stability control (ESC) and active front steering (AFS) under lateral force constraint on AFS. The control yaw moment is calculated using a sliding mode control. The tire forces generated by ESC and AFS are determined using weighted pseudo-inverse based control allocation (WPCA) in order to generate the control yaw moment. On a low friction road, AFS is not effective when the lateral tire forces of front wheels are easily saturated. To solve problem, the lateral force of AFS is limited to its maximum and the braking of ESC is applied with WPCA. To evaluate the effectiveness of the proposed method, a simulation was performed on the vehicle simulation package, $CarSim^{(R)}$. From the simulation, it was verified that the proposed method could enhance the maneuverability and lateral stability if the lateral force of AFS exceeds its maximum.