• 한국정보통신학회논문지
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• 제21권10호
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• pp.1879-1885
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• 2017

본 논문에서는 시간에 따라 방향 속도와 위치가 변하는 무인자동차의 궤적 추적 제어시스템에 대해 논한다. 무인자동차는 운전자의 도움이 없어도 스스로 주위환경을 인식하여 지정된 도로를 주행할 수 있는 자동차로 올바른 주행을 위해 고려해야 할 변수가 다양하다. 무인자동차의 궤적 추적 시스템에서 인식한 정보는 이산적인 값을 가지므로 센스 간의 간격으로 인하여 비연속성 및 비선형성을 가지고 있다. 이로 인하여 목표 궤적을 정확하게 추적하는 것 어렵다. 본 논문은 차량의 운동학 모델링을 통하여 선형오차, 제약 조건, 제어 목표함수의 세 가지 조건을 갖는 무인자동차 궤적 추적시스템을 제안한다. 제안된 궤적 추적시스템을 기반으로 동적 시뮬레이션 소프트웨어-카심(Dynamic Simulation Software-CarSim)의 결합시뮬레이션을 통해 시스템의 성능을 평가하였고, 그 결과로 더욱 정밀하게 목표 궤적을 추적할 수 있음을 확인하였다.

• 로봇학회논문지
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• 제13권4호
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• pp.256-264
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• 2018

Unlike normal wheels, the Mecanum wheel enables omni-directional movement regardless of the orientation of a mobile robot. In this paper, a robust trajectory tracking control method is developed based on the dynamic model of the Mecanum wheel mobile robot in order that the mobile robot can move along the given path in the environment with disturbance. The method is designed using the impedance control to make the mobile robot to track the path, and the integral sliding mode control for robustness to disturbance. The good performance of the proposed method is verified using the MATLAB /Simulink simulation and also through the experiment on an actual Mecanum wheel mobile robot. In both the simulation and the experimentation, we make the mobile robot move along a reference trajectory while maintaining the robot's orientation at a constant angle to see the characteristics of the Mecanum wheel.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2390-2392
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• 2003

ILC(Iterative Learning Control: 이하 ILC)는 현재 기계, 전기, 화학 등 많은 분야에 널리 적용되고 있다. ILC는 특히 반복적인 trajectory tracking Control 문제에 아주 효과적인 방법 중의 하나이다. 하지만 ILC는 메모리 기반의 scheme로서 trajectory tracking을 위해서는 많은 메모리를 요구하게 된다. 한편, 자세한 관찰에 의하면 인간의 팔, 다리 등의 관절의 움직임은 아주 정확하지가 않다. 이러한 사실로 미루어 인간이 정화한 모션을 취하는데 드는 비용을 줄이고자 모션 명령을 간단히 한다는 가정을 추론 해 낼 수 있다. 이러한 가정에 기초하여 우리는 ILC 명령을 간단히 하기 위해서 약간의 trajectory tracking의 정확성을 회생하는 메커니즘을 제안한다. 간단해진 ILC 명령은 적은 메모리 공간에 저장될 것이다. 또한, 로봇의 trajectory tracking을 위한 기존의 방법들은 아주 복잡할 뿐만 아니라 하나의 task의 수행만이 가능할 뿐 어떤 일반화의 방법도 제시하지 못하고 있다. 그래서 본 논문에서는 ILC 명령의 scaling에 대한 메커니즘을 제공하여 하나의 trajectory에 대해서 비슷한 모양이지만 다른 크기와 속도를 가지는 trajectory를 구현 할 수 있도록 하였다.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.252-257
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• 2005

In this work, we propose a simple but efficient method to design a target temperature trajectory for pulling speed tracking control of the crystal grower in the Czochralski crystallization process. In the suggested method, the model predictive control strategy is used to incorporate the complex dynamic effect of the heater temperature on the pulling speed into the temperature trajectory design quantitatively. The feedforward trajectories designed by the proposed method were implemented on 200 mm and 300 mm silicon crystal growers in the commercial Czochralski process. The application results have demonstrated its excellent and consistent tracking performance of pulling speed along whole bulk crystal growth.

• 제어로봇시스템학회논문지
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• 제13권9호
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• pp.875-882
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• 2007

In order for a vehicle to follow a predetermined trajectory accurately, its position must be estimated accurately and reliably. In this thesis, we propose trajectory tracking control methods for unmanned vehicle and a positioning system using ultrasonic wave. The positioning problem is an important part of control problem for unmanned navigation of a vehicle. Dead Reckoning is widely used for positioning of vehicle. However this method has problems because it accumulates estimation errors. We propose a new method to increase the accuracy of position estimation using the Ultrasonic Satellite System (USAT). It is shown that we will be able to estimate the position of vehicle precisely, in which errors are not accumulated. And proposed trajectory tracking control methods include both a new path planning method and a lateral control method for vehicle. The experimental results show that the proposed methods enables exact vehicle trajectory tracking even under various environmental factors.

• 한국공작기계학회논문집
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• 제13권3호
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• pp.126-132
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• 2004

This paper proposed trajectory tracking control based on genetic algorithm. Trajectory tracking control scheme are real coding genetic algorithm(RCGA) and back-propagation algorithm(BPA). Control scheme ability experience proposed simulation. Stable tracking control problem of mobile robots have been studied in recent years. These studies have guaranteed stability of controller, but the performance of transient state has not been guaranteed. In some situations, constant gain controller shows overshoots and oscillations. So we introduce better control scheme using real coding genetic algorithm and neural network. Using RCGA, we can find proper gains in several situations and these gains are generalized by neural network. The generalization power of neural network will give proper gain in untrained situation. Performance of proposed controller will verity numerical simulations and the results show better performance than constant gain controller.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권3호
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• pp.143-148
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• 2001

A lot of robot trajectory tracking methods are proposed to enhance the tracking error, but irregular tracking errors are always accompanied and very hard to reduce it. Up to now, these irregular tracking errors are reduced by introducing more complicated control algorithms. But, it is intuitively obvious to reduce only the big errors selectively in the irregular ones for the better performance instead of using more complicated control algorithms. By the characteristics of the robot, big tracking errors of the end-effector are generated mostly due to the fast moving of joint. So, in this paper, we introduce a new method which reduce the big tracking errors by clippings the joint velocity with the constraint of given path. Using this method, desired trajectory tracking is obtained within the far reduced error bound. Also, this method is successfully applied to generate the path-constrained error reducing trajectories for 2-axis SCARA type robot.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1172-1177
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• 2003

In this paper, we propose an obstacle avoidance technique in trajectory tracking of nonholonomic wheeled mobile robots. Input-output linearized backstepping controller is used in trajectory tracking, and repulsive type control input for obstacle avoidance is added to it. The added input is generated by fuzzy logic. And we do not add the two inputs directly but combine them via fuzzy logic, which determines the ratings of each input. Some simulations are performed to show that with the proposed algorithm, the mobile robot can track its reference trajectory even if there are multiple obstacles on the trajectory of robot.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.449-452
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• 1996

In this paper, a robust.adaptive control scheme is presented for precise trajectory tracking of nonholonomic mobile robots. In the controller, a set of desired trajectory is defined and used in constructing the control input which constitutes the main part of the proposed controller. The stable operating characteristics such as precise trajectory tracking, parameter estimation, disturbance suppression, tec., are shown through experiments as well as computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.642-646
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• 1992

Trajectory tracking control problems are described for a two-link robot manipulator with artificial rubber muscle actuators. Under the assumption that the so-called independent joint control is applied to the control system, the dynamic model for each link is identified as a linear second-order system with time-lag by the step response. Two control laws such as the feedforward and the computed torque control methods, are experimentally applied for controlling the circular trajectory of an actual robot manipulator.