• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.173-177
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• 2002

This paper describes the algorithm for WMR (Wheeled Mobile Robot) to follow the preceding object using stereo vision. The center point of object existing in each image is calculate. From the distance and variation of two center points, we calculates the distance from WMR to preceding object and the relative velocity of WMR. And we use the Lyapunov theory to design controller.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.265-270
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• 1998

In this paper we introduce a modeling of wheeled mobile robot with a differential drive derived by R.M. DeSantis and using the dynamics model-ing with some disturbance term we control the wheeled mobile robot using fuzzy sliding mode control(FSMC) method. In a fuzzy control approach it is very difficult to prove the stability of the fuzzy controller. Therefore, to overcome that difficult proof of the stability in a fuzzy control method, we first propose a sliding mode controller and prove the stability of the proposed controller. Next, transforming the proposed sliding mode controller into a fuzzy sliding mode controller without changing the basic structure of the sliding mode con-troller, we easily obtain a fuzzy sliding mode con-troller(FSMC) whose stability is guaranteed with-out difficult stability proof procedure of the proposed FSMC.

• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1235-1240
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• 2006

Previous isotropy analysis of a caster wheeled omnidirectional mobile robot(COMR) has been made under the assumption that the steering link offset is equal to the caster wheel radius. Nevertheless, many practical COMR's in use take advantage of the steering link offset different from the wheel radius, mainly because of improved stability. This paper presents the isotropy analysis of a fully actuated COMR with variable steering link offset, which can be considered as the generalization of the previous analysis. First, the kinematic model of a COMR under full actuation is obtained based on the orthogonal decomposition of the wheel velocities. Second, the necessary and sufficient conditions for the isotropy of a COMR are derived and examined to categorize three different groups, each of which can be dealt with in a similar way. Third, for each group, the isotropy conditions are further explored so as to identify all possible isotropic configurations completely.

• 융합신호처리학회논문지
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• 제7권4호
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• pp.214-220
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• 2006

This paper presents the systematic isotropy analysis of a fully actuated caster wheeled omnidirectional mobile robot (COMR) with the steering link offset different from the wheel radius, which can be considered as the generalization of the previous analysis. First with the characteristic length introduced, the kinematic model of a COMR is obtained based on the orthogonal decomposition of the wheel velocities. Second, the necessary and sufficient conditions for the isotropy of a COMR are derived and examined to categorize there different groups, each of which can be dealt with in a similar way. Third, for each group, the isotropy conditions are further explored so as to identify four different sets of all possible isotropic configurations. Fourth, for each set the expressions of the isotropic characteristic length required for the isotropy of a COMR are elaborated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.50-52
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• 2004

Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and the floor decreases suddenly, the robot has slip state. First of all, this paper models adhesion characteristics and slip in wheeled robot. Secondly, the paper proposes estimation method of adhesion force coefficient according to slip velocity. In oder to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. The paper proposes an anti-slip control system based on an ordinary disturbance observer, that is, the anti-slip control is achieved by reducing the driving torque enough to give maximum adhesion force coefficient. These procedure is implemented using a Pioneer 2-DXE parameter.

• 전기학회논문지
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• 제65권12호
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• pp.2053-2056
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• 2016

In this paper, we propose an output feedback tracking control method for the wheeled mobile robots with kinematic disturbances. The kinematic disturbances should be compensated to avoid the performance degradation. Also, the unavailable velocity of the mobile robot should be estimated. These should be estimated together by designing the nonlinear observer. Based on these estimates, the output feedback controller can be designed. The stability of the mobile robot control systems using the proposed method is rigorously analyzed and the simulation results are also provided to validate the proposed method.

• 로봇학회논문지
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• 제4권4호
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• pp.289-297
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• 2009

This paper presents the development and control of a two wheeled car-like mobile robot using balancing mechanism whose heading control is done by turning the handle. The mobile inverted pendulum is a combined system of a mobile robot and an inverted pendulum system. A sensor fusion technique of low cost sensors such as a gyro sensor and a tilt sensor to measure the balancing angle of the inverted pendulum robot system accurately is implemented. Experimental studies of the trajectory following control task has been conducted by command of steering wheel while balancing.

• 로봇학회논문지
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• 제2권3호
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• pp.212-220
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• 2007

This paper proposes a method of avoiding obstacles and tracking a moving object continuously and simultaneously by using new concepts of virtual tow point and fuzzy danger factor for differential wheeled mobile robots. Since differential wheeled mobile robot has smaller degree of freedom to control and are non-holonomic systems, there exist multiple solutions (trajectories) to control and reach a target position. The paper proposes 'fuzzy danger factor' for obstacles avoidance, 'virtual tow point' to solve non-holonomic object tracking control problem for unique solution and three kinds of fuzzy logic controller. The fuzzy logic controller is policy decision controller with fuzzy danger factor to decide which controller's result is more valuable when the mobile robot is tracking a moving object with obstacles to be avoided.

• 융합신호처리학회논문지
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• 제23권1호
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• pp.21-27
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• 2022

전통적인 자동차 또는 전통적인 두 바퀴형 차동 구동 로봇은 기구적인 구조 때문에 이동 동작에 제한이 있을 수밖에 없다. 자동차 산업에서 내연기관 자동차가 전기차로 빠르게 전환되면서 자동차에 로봇 공학 기술의 적용이 활발하게 모색되고 있다. 로봇 공학 분야에서는 이동체의 자세를 변화시키지 않고도 다양한 방향으로 이동할 수 있는 전방향 이동로봇에 대한 연구가 활발히 진행되어 왔으며 주목할 만한 연구 결과들도 많다. 하지만 대부분의 연구에서 이와 같은 전방향 이동을 구현하기 위해서는 메카넘휠 등과 같은 특수한 형태의 바퀴를 사용해야 하는 제한점이 있다. 우리는 전방향 이동을 위한 특수한 바퀴를 사용하지 않고도 전방향성을 구현할 수 있는 두 바퀴를 갖는 모듈형 로봇을 제안하였었다. 본 논문에서는 모듈형 로봇 2대를 전후로 결합하여 네 바퀴를 갖는 전방향 이동로봇을 새로이 제안하였다. 제안된 로봇은 차동 구동 방식의 이동로봇으로 전자브레이크를 사용하여 바퀴부와 로봇 몸체부를 선택적으로 분리, 결합하는 방식을 사용하며 두 개의 절대치형 엔코더와 네 개의 증분형 엔코더를 사용하여 로봇 바퀴부의 위치와 로봇 바퀴의 속도를 제어한다. 제안된 로봇은 일반적인 타이어 바퀴를 채택하고도 전방향 이동이 가능하다. 로봇을 실 제작하여 대각선 궤적과 정사각형 궤적에서의 주행 실험을 통하여 제안된 로봇의 유용성과 안정성을 검증하였다.

• 한국항행학회논문지
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• 제16권4호
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• pp.703-708
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• 2012

본 논문은 비선형성이 내재된 모바일 역진자형 로봇 시스템의 제어기 성능을 개선하고, 위치와 속도제어를 위하여 두 개의 다룬 휠로 구동되는 역진자형 타입의 모바일 로봇으로 모델링하였다. 이 시스템은 파라미터의 변화를 실시간으로 체크하고. 제어신호는 여러 상황에서 시스템이 원하는 상태를 유지하도록 변화하게 구성하였고, PI 제어기로 설계하였다. 시스템이 불안정하므로 시스템의 안전성 판별을 통하여 PI 제어기의 게인 값을 설계하였다. 위 실험 결과로서 수동 튜딩 방법 보다 터 좋은 적절한 방법의 성능을 얻을 수 있었다.