• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.6
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• pp.831-836
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• 2010

In real system application, the path planning and following system for the coordinated control of heterogeneous marine robots based on the underwater acoustic communication has the following problems: surface and underwater robots have different maneuvering properties, an underwater robot requires more effective operating, it has a limited communication range because of the transmission loss (TL) of acoustic wave, it has a communication error because of the Doppler distortion of acoustic wave, and further, it requires an easy design procedure in terms of its structures and parameters. To solve these problems, an intelligent path planning algorithm using the evolution strategy (ES) and the fuzzy logic controller (FLC) based on system modeling, is proposed. To verify the performance of the proposed algorithm, the path planning and following of an underwater robot is performed according to the maneuvering of a surface robot. Simulation results show that the proposed algorithm effectively solves the problems.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1217-1224
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• 2009

A simple and effective guidance and control scheme that enables autonomous three-dimensional path-following for a fixed wing aircraft is presented. The method utilizes the nonlinear path-following guidance law for the outer loop that creates steering acceleration command based on the desired flight path and the current position and velocity of the vehicle. The scheme considers the gravity in the guidance level, where it is subtracted from the acceleration command to form the specific force acceleration command which the aircraft is better suited to follow than the total acceleration command in the inner-loop. A roll attitude control scheme is also presented that enables inverted flight or sideslip maneuvers such as slow roll and knife-edge. A series of aerobatic maneuvers are demonstrated through simulations to show the potential of the proposed scheme.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.401-407
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• 2016

This paper introduces 3-dimensional path planning and guidance including power model for high altitude long endurance (HALE) UAV using solar energy. Dubins curve used in this paper has advantage of being directly available to apply path planning. However, most of the path planning problems using Dubins curve are defined in a two-dimensional plan. So, we used 3-dimensional Dubins path generation algorithm which was studied by Randal W. Beard. The aircraft model which used in this paper does not have an aileron. So we designed lateral controller by using a rudder. And then, we were conducted path tracking simulations by using a nonlinear path tracking algorithm. We generate examples according to altitude conditions. From the path tracking simulation results, we confirm that the path tracking is well on the flight path. Finally, we were modeling the power system of HALE UAVs and conducting path tracking simulation during 48hours. Modeling the amount of power generated by the solar cell through the calculation of the solar energy yield. And, we show the 48hours path tracking simulation results.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2329-2331
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• 2004

본 논문에서는 이동 로봇의 경로 추종 제어를 위해 웨이블릿 신경 회로망에 기반한 예측 제어기의 설계 방법을 제안하고자 한다. 제안한 방법에 의해 설계된 제어기는 이동 로봇의 동특성을 예측하기 위한 웨이블릿 신경회로망 기반 예측기와 예측 제어기로 구성된다. 제안한 방법에서 모델링 및 제어기로 적용되는 신경 회로망의 장점과 우수한 해석 능력을 가진 웨이블릿 변환의 장점을 결합한 웨이블릿 신경 회로망을 이용하여 이동 로븟의 동특성을 모델링하여 예측 제어기에서의 비용 함수 최소화에 적용한다. 경로 추종 제어의 목적인 이동 로봇의 실제 출력과 예측기의 출력 오차를 최소화하기 위해 웨이블릿 신경 회로망의 파라미터 동정 및 예측 제어기는 경사 하강법을 이용하여 학습한다. 마지막으로 컴퓨터 모의 실험을 통하여 제안한 예측 제어 시스템의 적용가능성 및 효율성을 검증하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.530-533
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• 2017

이 연구는 센서와 자율주행 자동차의 경로 추종의 효율성에 관한 연구이다. 자율주행 자동차의 '기술 현황'과 '주요 사용 센서 현황'을 통해 사용센서를 선정하였고, 선정한 센서들의 특성을 분석하였다. 초음파, 적외선, 조도 센서를 이용해 환경 변수가 제한된 상황에서 경로 추종 주행 연구를 실시하였다. 이 연구를 통해 동일 환경이라도 센서의 값이 상이한 것을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.906-912
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• 2014

The study of fish robot is a main subject that are related with the propulsive force comparison using a varying amplitude and frequency for body and tail motion trajectory, and the quick turn using a proper trajectory function. In this study, when a fish robot thrusts forward, feedback control is difficult to apply for a fish robot, because body and tail joints as a sine wave are rolled. Therefore, we detect the virtual position based on the path of the fish robot, define the angle errors using the detected position and the look-ahead point on the given path, and design a controller to track given path. We have found that the proposed method is useful through the computer simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.532-535
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• 2022

Path following algorithms have been intensively studied for various mobile platforms such as planetary exploration, unmanned delivery, and autonomous driving. However, ensuring high accuracy in practical applications is challenging due to enormous uncertainty inherent in real environment. In this paper, we aim to reveal the guideline for the design and implementation by investigating the path following performance of mobile robot controlled by the pure pursuit algorithm. To this end, we evaluate the accuracy of the pure pursuit algorithm when tuning the look ahead distance and deploying erroneous actuator.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.1-9
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• 2009

A parking-assist system is defined that a driver adjusts vehicle velocity through brake pedal operation and parking-assist system controls the motion of the vehicle to follow a collision-free path. In this study, a motion control algorithm using Fuzzy inference is proposed to track a maneuvering clothoid parallel path. Simulations are performed under SIMULINK environments using MATLAB and CarSim for a vehicle model. As the vehicle model in MATLAB a bicycle model is used including lateral dynamics. The simulation results show that the path tracking performance is satisfactory under various driving and initial conditions.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.121-128
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• 2000

In this paper, the control algorithm fur an autonomous vehicle is studied and applied to an actual 2 wheel-driven vehicle system. In order to control a nonholonomic system, the kinematic model for an autonomous vehicle is constructed by relative velocity relationship about the virtual point at distance from the vehicle's frame. And the optimal controller that based on the kinematic model is operated on purpose to track a reference vehicle's path. The actual system is designed with named 'HYAVI' and the system controller is applied. Because all the results of simulation don't satisfy the driving conditions of HYAVI, a reformed control algorithm that satisfies an actual autonomous vehicle is applied at HYAVI. At the results of actual experiments, the path tracking works very well by the reformed control algorithm. An autonomous vehicle that applied this control algorithm can be easily used for a path generation algorithm.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.448-449
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• 2008

본 논문에서는 이동 로봇의 경로 추종을 위해서, 비선형 모델 예측 슬라이딩 모드 제어(nonlinear model predictive strung mode control) 기법을 제안한다. 본 논문에서 제안한 방법에서는 미래의 슬라이딩 평면을 예측하고, 이에 따른 최적화된 제어기를 유도함으로써 슬라이딩 모드 제어기 단독으로 사용하는 제언 시스템에 비해 성능을 향상시킬 수 있다. 마지막으로 컴퓨터 시뮬레이션을 통해 본 논문에서 제안한 제어기의 성능을 검증하고자한다.