• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.534-537
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• 2008

하이브리드자동차의 연료소비율 시험 시 초기 SOC 조건에 따른 SOC와 연비 변화 특성을 파악하기 위해 2종의 차종을 선택하여 UDDS 모드주행 실험을 실시하였다. 실험결과 Strong type 자동차는 주행시작 약 550초 경과 후 SOC 52 $\sim$ 54%로 수렴하였다. 또한 일반 시가지 주행조건에서는 SOC를 50$\sim$55 % 범위에서 제어함을 알 수 있으며, 초기 SOC 조건에 따라 연비는 약 79%의 편차가 나타났다. 이는 저속구간에서 순수 전기자동차 구동이 구현됨으로써 SOC 70%에서 큰 연비 상승 효과가 나타나는 것으로 판단 된다. Mild type 자동차는 연비가 초기 SOC 조건에 따라 약 5%의 편차가 나타남을 알 수 있었으며, SOC 변화특성은 배터리 충전상태에 따라 충전량 제어는 이루어지나 가속 시 어시스트만 이루어지는 시스템적 특성상 효율적인 SOC 제어가 이루어지지 않아 연비에는 큰 영향을 주지 않는 것으로 생각된다.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.78-85
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• 2013

This paper presents the sliding mode control methods for anti-lock brake system (ABS) with the friction force observer. Using a simplified quarter car model, the sliding mode controller for ABS is designed to track the desired wheel slip ratio. Here, new method to find the desired wheel slip ratio which produces the maximum friction force between road and tire is suggested. The desired wheel slip ratio is varying according road and tire conditions to produce maximum friction force. In order to find optimum desired wheel slip ratio, the sliding mode observer for friction force is used. The proposed sliding mode controller with observer is evaluated in simulation, and the control design is shown to have high performance on roads with constant and varying adhesion coefficients.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.6
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• pp.575-582
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• 2015

The Durability cycle is very important for the success of vehicle testing to evaluate Retarder. The purpose of this study is to develop the durability mode on performance evaluation of retarder. Commercial vehicles are equipped with an auxiliary braking device in order to increase safety. A typical device for retarder depends heavily on imports. Domestic development has now become an urgent task. But, No state has an evaluation method for performance evaluation of the auxiliary braking device. We presented the durability test mode for the performance evaluation of the retarder was verified experimentally.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.223-224
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• 2015

도시철도에서 사용하는 전력공급 장치는 대부분 다이오드를 이용하여 전차선(DC)에 공급하고 있으며, 다이오드 특성상 단방향 전력공급이 가능하기 때문에 전동차의 회생제동으로 발생하는 회생 전력을 재사용 할 수 없는 단점을 가지고 있다. 따라서 본 논문에서는 전동차에서 발생하는 회생전력을 교류 모선으로 환원시켜주기 위하여 사이리스터를 이용한 양방향 더블컨버터를 제안한다. 더블컨버터의 제어 목적은 전차선의 부하에 따라 전압을 일정하게 유지시키면서 부하 조건에 따라 안정적인 모드 전환을 하는 것이다. 이를 위하여 더블컨버터의 병렬로 운전을 통하여 순차적인 모드 전환을 위한 알고리즘을 더블컨버터 시뮬레이션을 적용하여 검증하였다.

• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.281-295
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• 1994

In this paper, the Variable Structure System(VSS) theory with new continuous switching dynamic equation is used to design an automatic controller for the active nutation damping in momentum bias stabilized spacecraft. In the application of VSS theory to a linearized multivariable system with the nutation damping systems, there exist some disadvantages such as how to determine the switching gains and how to reduce the chattering phenomina and reaching phase in input and state trajectories. To solve these drawbacks, this paper presents the continuous switching dynamic equation instead of the discontinuous switching logics to obtain the sliding mode. The new design approach is much simpler than the VSS theory. And there do not exist chattering phenomina in this method because the obtained control inputs are continuous. Simultaneously the reaching phase is reduced by a suitable choice of design factor.

• 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 Automotive Engineers
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• v.18 no.2
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• pp.14-23
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• 2010

This paper analyzes braking performance of ABS with Sliding Mode Controller, which is designed in this research and compared with that of a commercial ABS-ECU only. HILS system for this paper has an existing hydraulic brake line with an ECU of commercial passenger vehicle and it is designed to be cooperated with Sliding Mode Controller and hydraulic line. This paper shows the simulation results to meet the target slip ratio on the various road conditions and displays the performance with Sliding Mode Controller has an improvement than a commercial ABS.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.14-16
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• 2001

The Eigen-Sensitivity theory at full system is used to supplement drawback of the existing PSS gain tuning methods in this paper. Hessenberg method is used to linear analysis. This proposed method is successfully tested on KEPCO 2003 off-peak power system to improve local mode. The designed PSS at 2003 off-peak system is installed in 2003 peak system to improve robustness.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1032-1034
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• 1999

The design of an $H{\infty}$ controller for a TCSC to enhance the damping of an inter-area oscillation in a Power system is presented. The paper describes a comprehensive and systematic way of applying the $H{\infty}$ control design algorithm in power systems. Eigen sensitivity analysis to selction a TCSC location is described. Time simulation and eigenvalue analysis show that the proposed TCSC $H{\infty}$ controller can suppress the inter-area oscillations efficiently with robustness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.45-50
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• 1995

본 연구에서는 기존에 널리 사용되고 있는 스카이훅 제어 알고리즘(skyhook control algorithm)[3]을 바탕으로 확장 개발된 모드 스카이훅 제어(mode skyhook control) 개념 및 주파수 감응식 제어(frequency dependent control)개념[4][5]을 실용화하기 위하여 응답속도가 20msec이하의 비교적 빠른 응답 속도를 갖는 전자기식 작동기 (electro-magnetic actuator)에 의해 가변되는 4단 반능동형 가변 댐퍼 시스템을 개발한 후, 다음과 같은 성능의 향상을 시험결과를 통하여 보이고자 한다. -저속에서의 승차감 향상과 고속에서의 주행 안정성 향상 -커브 주행 또는 급격한 핸들 작동시의 롤안정성 (rolling stability) 향상 -제동 및 급발진시의 차체 피칭 운동 방지 (anti-dive, anti-squat)