• Transactions on Control, Automation and Systems Engineering
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• 제4권4호
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• pp.347-355
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• 2002

Obstacle avoidance of underactuated robot manipulators using switching computed torque method (SCTM) is presented. One fundamental feature of this novel method is to use partly stable controllers (PSCs) in order to fulfill the ultimate control objective. Here, we use genetic algorithms (GAs) to acquire the optimum switching sequence of the control actions for a given time frame with the available set of elemental controllers, depending on which links/variables are controlled. The effectiveness of the concept is illustrated by taking a three-degrees-of-freedom (DOF) manipulator and showing enhanced performance of the proposed control methodology.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1949-1954
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• 2005

One of control methods for underactuated manipulators is known as a switching control which selects a partially-stable controller using a prespecified switching rule. A switching computed torque control with a fuzzy energy region method was proposed. In this approach, some partly stable controllers are designed by the computed torque method, and a switching rule is based on fuzzy energy regions. Design parameters related to boundary curves of fuzzy energy regions are optimized offline by a genetic algorithm (GA). In this paper, we discuss on parameters obtained by GA. The effectiveness of the switching fuzzy energy method is demonstrated with some simulations.

• 조명전기설비학회논문지
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• 제13권1호
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• pp.31-38
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• 1999

본 논문에서는 수동 관절을 지니는 로봇 매니퓰레이터의 제어를 위하여 퍼지 슬라이딩 모드 기법을 제안하였다. 구동기가 정착되어 있지 않은 수동 관절을 지니는 로봇 매니퓰레이터는 언더액츄에이티트(Underactuated) 시스템의 일종이며 이러한 매니퓰레이터의 제어에 비해 어려운 측면이 있다. 여기서는 불확실성 및 외란이 존재하는 매니퓰레이터 시스템에 대하여 퍼지 슬라이딩 모드 제어를 적용함으로써, 불확실성을 극복하며 채터링 현상이 없는 제어가 가능함을 시뮬레이션을 통해 확인하였다.

• 제어로봇시스템학회논문지
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• 제9권10호
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• pp.755-767
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• 2003

This paper proposes a robust fault-tolerant control framework for robot manipulators to maintain the required performance and achieve task completion in the presence of both partial joint failures and complete joint failures and uncertainties. In the case of a complete joint failure or free-swinging joint failure causing the complete loss of torque on a joint, a fully-actuated robot manipulator can be viewed as an underactuated robot manipulator. To detect and identify a complete actuator failure, an on-line fault detection operation is also presented. The proposed fault-tolerant control system contains a robust adaptive controller overcoming partial joint failures based on robust adaptive control methodology, an on-line fault detector detecting and identifying complete joint failures, and a robust adaptive controller overcoming partial and complete joint failures, and so eventually it can face and overcome joint failures and uncertainties. Numerical simulations are conducted to validate the proposed robust fault-tolerant control scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.44.2-44
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• 2001

This paper presents a new concept for controlling of under actuated robot manipulators with avoiding obstacles using switching computed torque method (SCTM). One fundamental approach of this algorithm is to use the partly stable controllers (PSCs) in order to fulfill the ultimate control objective. Here, we use genetic algorithms (GA)in order to employ the optimum control action for a given time frame with the available set of elemental controllers, depending on which links/variables are controlled, i.e. the selection of optimum switching sequence of the control actions. The proposed approach models links of the robot using evolving ellipses and then introduces a penalty scheme for the objective function of GA when it detects collisions. An under actuated robot manipulator, which has three detrees-of-freedom is taken into consideration so as to illustrate the design procedure. Simulation results show the e.ectiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.513-518
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• 1998

In this paper, a robust fault-tolerant control scheme for robot manipulators overcoming actuator failures is presented. The joint(or actuator) fault considered in this paper is the free-swinging joint failure and causes the loss of torque on a joint. The presented fault-tolerant control framework includes a normal control with normal(non-failed) operation, a fault detection and a fault-tolerant control to achieve task completion. For both no uncertainty case and uncertainty case, a stable normal con-troller and an on-line fault detection scheme are presented. After the detection and identification of joint failures, the robot manipulator becomes the underactuated robot system with failed actuators. A robust adaptive control scheme of robot manipulators with the detected failed-actuators using the brakes equipped at the failed(passive) joints is proposed in the presence of parametric uncertainty and external disturbances. To illustrate the feasibility and validity of the proposed fault-tolerant control scheme, simulation results for a three-link planar robot arm with a failed joint are presented.

• 대한기계학회논문집A
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• 제36권11호
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• pp.1405-1411
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• 2012

위험지역에서의 작업을 위하여 전세계적으로 원격조작기가 널리 활용되고 있다. 특히 원격 시스템의 경우, 운영되는 환경의 특징상 안정적인 성능이 담보되어야만 하며, 조작기 몸체의 경량화 및 운용환경 외부에서의 유지보수 편리성을 위하여 구동부를 시스템의 기저부에 집중시킬 수 있는 장력구동방식 메커니즘이 주로 활용되고 있다. 본 연구에서는 장력구동 방식 원격조작기에 적용하기 위한 그리퍼 탄성 구동부의 설계를 위해 시도된 접근법을 소개하고자 한다. 제시된 그리퍼 시스템은 기본적으로 스프링 메커니즘에 기반을 둔 4 절 링크형 구조를 가지고 있으며 마스터 조작자에 의해 동작되는 슬레이브 조작기의 말단부에 결합되는 구조를 가진다. 본 논문에서는 이러한 조작기의 요구사항에 맞는 그리퍼의 파지력 및 복원력을 재현하기 위하여 그리퍼 상에서의 적정 스프링 결합위치 및 요구강성과 그에 따른 운동학적 영향계수 등을 분석 및 고찰하였다. 최종적으로는 이러한 분석내용들을 바탕으로, 실제 그리퍼 시스템에 적용함으로써 타당성을 검증하였다.