• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.187-187
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• 2022

최근 선박의 자율운항기술이 활발하게 연구되어 오면서, 경로추종 제어 및 충돌회피 등의 자율운항 기술 연구가 많이 진행되고 있으며 그에 따른 시뮬레이션과 실해역 시험 등도 활발하게 수행되고 있다. 이러한 자율운항기술 중 본 연구에서는 AUV(Autonomous Underwater Vehicle) 진회수 시 모함에 활용되며 쌍동선형을 갖는 쌍동형 무인수상선을 대상으로 경로추종 제어에 대한 실해역 시험을 수행한 내용을 소개한다. 대상선인 쌍동형 무인수상선은 배수량이 약 10ton, 최대속도 10knots를 기준으로 설계된 선형이며 Sail drive 타입의 쌍축 추진기를 탑재하고 있으며 Fig. 1에 나타내었다. 실해역 시험은 경기도 화성시에 위치한 제부마리나 전면 해역에서 여러 속도에 대해 Fig. 2의 경로(빨간색)를 활용하여 수행되었다. 해당 경로는 변침각이 45도까지 이루어져 있다. 경로추종 제어 알고리즘은 목표경유점을 향하기 위해 선수각을 제어하는 부분과 목표속도로 추진하기 위해 속도를 제어하는 부분으로 나뉘어져 있다. 선수각 제어 시 경로와 무인선과의 위치 오차를 줄이는 방향으로 선수각이 향할 수 있도록 알고리즘이 설계되었다. 속도 제어의 경우 RPM 별로 실제 속도를 계측하여 데이터화 한 후, 실제 속도가 명령 속도와 다를 경우 RPM을 가감하여 명령 속도로 추진하기 위해 제어할 수 있도록 하였다. Fig. 2에서 파란색 선은 설계한 알고리즘을 활용하여 경로추종 제어를 한 결과의 궤적을 보여준다.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.5
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• pp.416-422
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• 2001

The BLDC(Brushless DC) Motor is characterized by linear torque to current and speed to voltage. It has low acoustic noise and fast dynamic response. Moreover, it has high power density with high proportion of torque to inertia in spite of small size drive. However, when armature current is commutated, the current ripple is generated by the motor inductance components in stator windings and back-EMF. This current ripple caused to torque ripple. Therefore, it is difficult to apply the BLDC motor to a precision servo drive system. In this paper, a new current control algorithm using fourier series coefficients is proposed. This proposed algorithm can minimize torque ripple due to the phase current commutation of BLDC motor. Simulation and Experimental results prove the effectiveness at the Proposed algorithm through comparison with the conventional unipolar PWM method.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.1-8
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• 2013

This paper implements an integrated vehicle chassis system of ACC(Adaptive Cruise Control) and LKS(Lane Keeping System) based on OSEK OS to vehicle operating system and analyzes its performance through experiments. In recent years active safety and advanced driver assistance system has discussed to improve safety of vehicle. Among the rest, We integrate ACC that controls longitudinal velocity of vehicle and LKS that assists a vehicle in maintaing its driving lane, then implement integrated control system in vehicle. Implemented control system uses OSEK/VDX proposed standard, which is aiming at reusability and safety of software for vehicle and removal hardware dependence of application software. Redesigned control system based on OSEK OS, which is supported by OSEK/VDX, can manage real-time task, process interrupt and manage shared resource. We show by results performed EILS(ECU-In-the-Loop Simulation) that OSEK OS-based integrated controller of ACC and LKS is equivalent conventional integrated controller of ACC and LKS.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.6 no.2
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• pp.56-61
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• 1992

This paper is reported on the simulation and test results of a constant flux vector control scheme of an induction motor without any speed detecting eqiupment, in which the adaptive current PWM inverter is used. The rotor speed is estimated form stator voltage, current and parameters of motor, and control algorithm in the system is performed with by micro processor. By comparing the waveform of input current of this system with that of the case with taco-generator, good agreement is observed except small ripple component. Experimental results which are acquired at start up and during acceleration/deceleration are quite similar to those of the simulation results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.71-81
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• 2000

This paper describers a look ahead algorithm of PC-NC(personal computer numerical control). The algorithm is based on acceleration/deceleration before interpolation which doesn\`t include a command error and determines a feedrate value at the end point of each block(or start point of each block). The algorithm is represented as following; 1) calculating two maximum arrival feedrates(F$_1$,F$_2$) by an acceleration value, a command feedrate, and the distance of a NC block, 2) getting a tangent feedrate (F$_3$) of the adjacent blocks, 3) choosing a minimum value among these three feedrates, and 4) setting the value to a feedrate of a start point of the next block(or a end point of the previous block). The proposed look ahead algorithm was implemented and tested by using a commercial TROS(real time operation system) on the MS-Windows NT 4.0 in a PC platform. For interfacing to a machine, a counter board, a DAC board and a DIO board were used. The result of the algorithm increased a machining precision and a machining speed in many short blocks.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.363-372
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• 2018

Simulator is used to verifying the function and performance of train control system before verifying with actual train. In this case, it is important that the simulation result should be coincide with the result with actual train. In this paper, the process of the development of automatic train operation (ATO) is described. ATO is in charge of automatic train control such as speed regulation and precision stop control. Identical interfaces from the ATO to the actual train was made in the simulator. Therefore ATO communicates to the simulator in the same way to the actual train. Futhermore, the train dynamic properties was measured by experiments and these were applied to the train model. Hence the response of the train in the simulator to the acceleration command is similar to that of the actual train. The simulation result of precision stop control is compared with the result in the actual train test to show the fidelity of the train model derived in the study and the superiority of this simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.344-351
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• 2016

In the point of view of a train operator, the main concern with a train operation is not only to maintain a time schedule, but also to decrease the energy consumption as much as possible. Generally for a manual drive, a train conductor controls the train acceleration and deceleration by controlling the notches not to exceed the regulation velocity by considering the given maximum velocity profile for an operation route. For this case, the guideline for a conductor is needed to choose the proper notches by applying the notch optimization so as to drive at the regulation velocity and minimize energy consumption simultaneously. In this paper, the real-time notch optimization plan is suggested using a genetic algorithm that optimizes the notches for the remaining route in real time when the event occurs that track information or regulation velocity profile of the remaining route changes during train operation as well as a normal operation situation. An energy saving effect and the convergence behavior of the optimal solution obtained was analyzed in a genetic algorithm.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.5
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• pp.15-28
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• 1998

Recently may investigations have been studied on the high-speed machining by using machine tools. A CNC machine tool makes some tool path errors caused by software acceleration/deceleration. The faster a cutting feedrate is, the bigger the tool path errors are. Some known methods reduce these kinds of errors, but they make the total cutting time increased. This paper presents a feed-forward algorithm that can be generated by distorting the original tool path, and reduces the tool path errors and the total cutting time. The algorithm to generate a new tool path is represented as following; 1)calculating each distance of software acceleration/deceleration between two adjacent blocks, 2) estimating the distorted distance which is the adjacent-ratio-constant(k1, k2) multiply the distance of software acceleration/deceleration, 3) generating a 3-degree Bezier curve approximating the distorted tool path, 4) symmetrically transforming the Bezier curve about the intersection point between two blocks, and 5) connecting the transformed Bezier curve with the original tool path. The algorithm is applied to FANUC 0M. The study is to promote the high-precision machining and to reduce the total cutting time.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.208-214
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• 2014

Vehicle dynamic states used in various advanced driving safety systems are influenced by road geometry. Among the road geometry information, the vehicle pitch angle influenced by road slope and acceleration-deceleration is essential parameter used in pose estimation including the navigation system, advanced adaptive cruise control and others on sag road. Although the road slope data is essential parameter, the method measuring the parameter is not commercialized. The digital map including the road geometry data and high-precision DGPS system such as DGPS(Differential Global Positioning System) based RTK(Real-Time Kinematics) are used unusually. In this paper, low-cost cascade extended Kalman filter(CEKF) based road slope estimation method is proposed. It use cascade two EKFs. The EKFs use several measured vehicle states such as yaw rate, longitudinal acceleration, lateral acceleration and wheel speed of the rear tires and 3 D.O.F(Degree Of Freedom) vehicle dynamics model. The performance of proposed estimation algorithm is evaluated by simulation based on Carsim dynamics tool and T-car based experiment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.599-607
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• 2011

In this paper, a reaction-force compensation system for an XY linear motion stage, without an additional external isolation structure or extra motors, is developed. This system consists of a movable magnet track, a spring, a dummy weight, and a dedicated sensor module that measures the relative positions of the movable magnet track with respect to the motor coil. The reaction force compensation system is modeled, and simulations are carried out to optimize design parameters such as the moving distance of the magnet track, the transmission force, the dummy weight, and the allowed size of the mechanism. An XY linear motion stage is built, incorporating the reaction force compensation system, and the performance of the system is verified experimentally. For acceleration and deceleration values of 10 m/$s^2$, 85% of the reaction force is absorbed by the reaction force compensation system.