• 한국도로학회논문집
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• 제14권1호
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• pp.9-16
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• 2012

운전자 생명선인 차선은 주간 시인성, 야간 시인성, 야간 젖은 상태 시인성, 야간 강우시 시인성으로 구분된다. 본 연구는 특히, 비와 관련되어 기상이 불안전한 조건에서 운전자의 주행 안전 확보를 목적으로 하였다. 차선의 시인성은 사전 인지시간(Preview time) 과 감지거리(Detection distances)와 밀접한 관계가 있으며, 야간 교통사고 감소를 위하여 차선 재료 성능을 향상시켜 차선의 주야간과 우천시 주야간 시인성의 척도인 Dry 재귀반사도(Dry retroreflectivity) 및 Wet 재귀반사도(Wet Retroreflectivity)를 높이기 위한 방안을 마련하는 데 있다. 이를 위하여 일반적으로 사용되고 있는 차선 도료용 유리알 굴절률 nD=1.50의 분석과 시인성의 척도인 재귀반사도를 향상시키기 위하여 가장 중요한 변수인 기능성 차선 도료용 유리알 굴절률 nD=2.2.을 도입하였다. 국내외 최소 한계 재귀반사도(Minimum threshold retroreflectivity) 및 최소 인지 재귀반사도(Install minimum retroreflectivity)를 조사하여 차선의 시인성 확보를 위한 최소한의 관리 수치를 규명하였으며 아울러 국내기존 차선 재료의 물리적 특성 그리고 재귀반사도의 시험을 통하여 우천 시 야간 재귀반사도 향상 방안을 마련하였다.

• 전기학회논문지P
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• 제51권4호
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• pp.175-185
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• 2002

In this paper, a new fully digital current control method of UPS inverter, which is based on an internal model control, is proposed. In the proposed control system, overshoots and oscillations due to the computation time-delay are compensated by explicit incorporation of the time-delay in the current control loop transfer function. The internal model controller is adopted to a second order deadbeat reference-to-output response which means that its response reaches the reference in two sampling time including computational time-delays. That is, the average current of filter capacitor is been exactly equal to the reference current with a time lag of two sampling intervals. Therefore, this method has an essentially overshoot free reference-to-output response with a minimum possible rise time. The effectiveness of the proposed control system has been verified by the simulation and experimental respectively. From the simulation and experimental results, the proposed system is achieved the robust characteristics to the calculation time delay and parameter variation as well as very fast dynamic performance, thus it can be effectively applied to the power supply for the critical load.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.303-308
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• 2004

The acquisition of many control points for SAR data processing is very difficult and time_consuming steps. For resolving the problem about control points, this paper describes satellite orbit refinement method using minimum control point. Accuracy of geocoding according to distribution and number of control points are analyzed and geocoded RADARSAT image was produced in the paper.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.166.6-166
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• 2001

An attitude control of an air vehicle based on the variable structure control is proposed. For an air vehicle, minimum weight is required. Thus, it is desired to reduce the input energy. The optimal state portrait curve using time-varying sliding surface is proposed to reduce the control energy. Tracking performance of the closed loop system is guaranteed under the existence of parameter variation and external disturbances.

• 제어로봇시스템학회논문지
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• 제6권12호
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• pp.1099-1105
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• 2000

The interactive bicycle simulator presented in this paper consists of a Stewart platform manipulator, magneto-rheological steering and braking devices, and a visual simulator. To provide a rider with reality, these devices should be controlled in real-time and motions of the devices and the visual should be also synchronized. If any of the devices and the visual gets unsynchronized due to significant blocking of control signals, the reality of the simulator is no longer secured. This paper presents communication protocols that minimize the blocked time of the control processes to guarantee the synchronization. The protocols are designed based on IPC (InterProcess Communications) of QNX, TCP/IP, and serial communication. The performance of the designed communication protocols is evaluated with the implemented bicycle simulator, and found satisfactory.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.52-55
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• 1996

In order to establish the robust current controller design technique of series wound motor driver system. This paper proposes a method of compensated Bang-Bang current control using a series wound motor driver system under improperly variable load. To get minimum time torque control. A compensated Bang-Bang current controller structure is simpler than the structure of PID plus Bang-Bang controller. This paper shows that a general 8 bits microprocessor be used efficiently implementing such an algorithm. The calculation time of software is extremely small when compared with conventional PID plus Bang-Bang a controller. Both nonlinear operating characteristics of Digital switching elements and Describing Function methods are used for the analysis and synthesis. Real time implementation of compensated Bang-Bang current is achieved. Concept design strategy of the control and PWM waveform generation algorithms are presented in the paper.

• 대한전기학회논문지
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• 제33권5호
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• pp.193-199
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• 1984

This paper presents a direct adaptive pole placement control scheme which is applicable to discretetime non-minimum phase systems. It is proved that by this scheme the poles can be placed at the desired locations and the overall state vector of the system is uniformly bounded if the reference input is sufficiently rich, and also proved that in case of insufficiently rich reference input the overall system can still be stabilized though the poles may not be placed exactly at the desired locations. The effectiveness of this scheme is verified by digital computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.434-439
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• 1993

This paper present a sensor based obstacle avoidance method which is based on a VFH(Vector Field Histogram) method. The basic idea of obstacle avoidance is to find a minimum obstacle direction and distance. From the minimum sonar index and the target direction high level system determine steering angle of mobile robot. The sonar sensor system consists of 12 ultra sonic sensor, and each sensor have its direction and safety value. This method has advantage on calculation speed and small memory. This method is implemented on indoor autonomous vehicle'ALiVE-2'.

• 제어로봇시스템학회논문지
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• 제13권10호
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• pp.990-999
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• 2007

We deal with second order NMP(Non-Minimum Phase) systems which are difficult to control with conventional methods because of their inherent characteristics of undershoot. In such systems, reducing the undesirable undershoot phenomenon makes the response time of the systems much longer. Moreover, it is impossible to control the magnitude of undershoot in a direct way and to predict the response time. In this paper, we propose a novel two sliding mode control scheme which is capable of determining the magnitude of undershoot and thus the response time of NMP systems a priori. To do this, we introduce two sliding lines which are in charge of control in turn. One is used to stabilize the system and achieve asymptotic regulation eventually like the conventional sliding mode methods and the other to stably control the magnitude of undershoot from the beginning of control until the state meets the first sliding line. This control scheme will be proved to have an asymptotic regulation property. The computer simulation shows that the proposed control scheme is very effective and suitable for controlling the second order NMP system because it can decide the magnitude of undershoot in a direct and stable way and reduce the response time compared with the conventional ones.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.405-409
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• 2020

This paper proposes time management system for unmanned aerial vehicle (UAV) network. The computers of the UAVs need time synchronization that time offset does not exceed the minimum interval of data samples for errorless data blending between the computers. The proposed time management system is composed of time synchronization and general management systems for UAV control. The systems communicate each other for time information and control signals. The synchronization system uses improved version of existing time offset estimation that network time protocol (NTP) uses. The time synchronization is operated when the time offset of any UAV exceeds threshold that preconfigured by the general management system. The demonstration of prototype shows stable time synchronization satisfying preconfigured threshold.