• 한국정밀공학회지
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• 제13권4호
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• pp.109-121
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• 1996

This paper presents how the input forces along the prismatic joints of a parallel manipulator are transmitted to the upper platform. In order to consider force transmission and moment transmission seperately the Jacobian matrix for parallel manipulators is splitted into two parts. Magnitudes of input forces on the six actuators at a given manipulator configuration which generate maximum/minimum output force with no moment generated on the platform are obtained through the singular value decomposition of a matrix involving the Jacobian. Similarly the directions of the input forces to obtain only the rotation of the platform have been analyzed. Using the singular values a simple equation for the volume of ellipsoid which is a good tool for manipulability measure is provided. Obtained results could be useful in determinimg design parameters like radius of plaform, angles between joints, etc. Simulations are porvided.

• 로봇학회논문지
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• 제7권1호
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• pp.9-19
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• 2012

This paper proposes a performance index for the multiple shape object handling of dual arm manipulator to determine whether a robot is good or not. When the dual-arm manipulator grasps a fixed object and is posed, the dual-arm manipulator should procure a space to freely control the manipulator. As a performance evaluation parameter, each joint torque from current sensor signal is utilized. From the current information, torque and energy for each joint are estimated. In this paper an performance index for an unstructured object is defined by an energy-cost function, and stability analysis for each motion is derived by the maximum force to the object. The maximum force to the object is computed by the inertia of object and acceleration information of end-effector. The acceleration data are derived by the double derivation of each encoder signal. Manipulability measure which implies how efficiently the dual-arm manipulator can move with the grasped object, can be represented by the intersection of the two manipulability ellipsoids for the left and right arms. Effectiveness of the proposed algorithm has been verified through the practical simulations and real experiments.

• 한국정보통신학회논문지
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• 제5권4호
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• pp.756-765
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• 2001

An effective dexterous motion control method of redundant robot manipulators based on neural optimization network is proposed to satisfy multi-criteria such as singularity avoidance, minimizing energy consumption, and avoiding physical limits of actuator, while performing a given task. The method employs a neural optimization network with parallel processing capability, where only a simple geometric analysis for resolved motion of each joint is required instead of computing of the Jacobian and its pseudo inverse matrix. For dexterous motion, a joint geometric manipulability measure(JGMM) is proposed. JGMM evaluates a contribution of each joint differential motion in enlarging the length of the shortest axis among principal axes of the manipulability ellipsoid volume approximately obtained by a geometric analysis. Redundant robot manipulators is then controlled by neural optimization networks in such a way that 1) linear combination of the resolved motion by each joint differential motion should be equal to the desired velocity, 2) physical limits of joints are not violated, and 3) weighted sum of the square of each differential joint motion is minimized where weightings are adjusted by JGMM. To show the validity of the proposed method, several numerical examples are illustrated.

• 한국정밀공학회지
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• 제14권1호
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• pp.52-57
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• 1997

The paper deals with kinematic evaluation of performance of a hydraulic shovel arm for deburrinhg task. First, a new criteria for evaluation is derived to evaluate accuracy of an ene-effector at each position with- in the movable area of the hydraulic shovel arm. Secondly a graphic evaluation system that displays a map of the criteria for evaluation and a map of the manupulability measure is build. Thirdly, by using by using the sas- tem, a hydraulic shovel arm is kinematically evaluated. Finally, from the comparison of the result obtained from the computer simulation and an experimental result, it is indicated that the derived criteria for evalu- ation and the graphic system are useful.

• 한국정보통신학회논문지
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• 제9권6호
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• pp.1395-1401
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• 2005

이동매니퓰레이터란 이동로봇과 작업로봇을 직렬로 결합하여 이동능력과 작업능력을 가지는 로봇이다. 이동매니퓰레이터의 중요한 특징중의 하나는 잉여의 자유도를 가진다는 것이다. 이를 이용하여 이동매니퓰레이터는 여러 가지 모드로 이동이 가능하고 다양한 작업을 수행할 수 있다. 이동매니퓰레이터는 고정베이스 구조의 로봇에 비해 넓은 작업공간과 특이자세 회피 및 장애물 회피에서 더 좋은 성능을 가진다. 두 대의 로봇이 협동하여 작업을 수행할 때 주어진 작업공간에서 여유자유도를 가지고 있는 이점을 이용하여 작업의 성능을 향상시킬 수 있다. 본 논문은 이동매니퓰레이터가 수행되어질 작업을 세분화 시키고 로봇의 작업 성능 지수를 사용하여 로봇이 최적자세로 작업을 수행할 수 있는 연구를 하였다. 제안된 알고리즘을 검증하기위해 이동매니퓰레이터를 제작하였고, 실험에 사용한 이동매니퓰레이터 PURL-II는 3자유도를 가지는 이동로봇과 5자유도를 가지는 작업로봇으로 구성되어 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1545-1548
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• 1997

A Force-refecting hand controller can provide the kinesthetic information obtained from a slave manipulator to the operator of a teleoperation system. This thesis presents the desgn and the analysis of a 6-degree-of-freedom force-reflecting hand controller using fivebar parallel mechanism. The goal of this thesis is to construct a superior hand controller that can provide large workspace and good force-reflecting ability. The forward kinematics of the fivebar paprallel mechanism has been calculated in real-time using three pin-joint sensors in addition to six actuator position sensors. A force decomposition approach is used to comput the Jacobin. To analyze the characteristics of the fivebar parallel mechanism, it has been compared with the other three parallel mechanisms in terms with workspace and manipulability measure. The force-reflecting hand controller using the fivebar parallel mechanism has been constructed and tested to verify the feasibility of the design concept.

• 제어로봇시스템학회논문지
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• 제5권3호
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• pp.288-296
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• 1999

A force-reflecting hand controller can provide the kinesthetic information obtained from a slave manipulator to the operator of a teleoperation system. The goal is to construct a compact hand controller that can provide large workspace and good force-reflecting capability. This paper presents the design and the analysis of a 6-degree-of-freedom force-reflecting hand controller using fivebar parallel mechanism. The forward kinematics of the fivebar parallel mechanism has been calculated in real-time using three pin-joint sensors in addition to six actuator position sensors. A force decomposition approach is used to compute the Jacobian. To evaluate the characteristics of the fivebar parallel mechanism, it has been compared with the other three parallel mechanisms in terms with workspace and manipulability measure. The hand controller using the fivebar parallel mechanism has been constructed and tested to verify the feasibility of the design concept.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.386-390
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• 1992

Algorithmic or kinematic singularities are inevitably a introduced if optimality criteria or augmented kinematic equations are used to resolve the redundancy of almost any manipulator with rotary joints. In this paper, a sufficient condition for a singularity-free optimal solution of the kinematic control of a redundant manipulator is derived and, specifically, algorithmic singularities are analyzed for optimality-based methods. A singularity-free space (SFS) to characterize the performance of a secondary task for a redundant manipulator using the sufficient condition for a redundant manipulator is defined. The SFS is a set of regions classified by the loci of configurations satisfying the inflection condition for manipulability measure in the Configuration space. Using SFS, the topological property of the Configuration space and the invertible workspace without singularities are analyzed.

• 전자공학회논문지B
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• 제31B권9호
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• pp.47-56
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• 1994

In this paper, we demonstrate how to design a redundant robot which is suitable for the multiple task execution without any constraints on the work space. The implementation is possible by the rigid connection of a cacro-robot and a micro-robot. A 5 d.o.f. articulated robor designed for commercial purpose is utilized as a micro-robot which can perform a general task with the appropriate adjustment of its base location. The base of a micro-robot is located at a suitable position by the macro-robot designed and implemented through this research. A task assigned to this redundant robot is performed mainly by the micro-robot. However, when the micro-robot cannot perform the task by itself or when the micro-robot has difficulties in performing the task, the coordination of the macro-robot is requited. To monitor the task execution efficiency of the micro-robot, we used the 'Manipulability Measure' as a cost function. The coordination between the two robots are verified both by the simulation and the experiment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1587-1592
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• 2003

There are three kinds of singularity in controlling redundant manipulators. Kinematic, algorithmic and representation singularities are those. If manipulators fall into any singularity without proper action to avoid it, the control system must go away from our desire, and we can meet a dangerous situation. Hence, we have to deal the singularities very carefully. In this paper, we describe an on-line solution for avoiding the occurrence of both algorithmic and kinematic singularities in task-priority based kinematic controllers of robotic manipulators. Representation singularity can be easily avoided by using proper representation algorithm, so, in this paper, we only consider kinematic and algorithmic singularities. The proposed approach uses a desired task reconstruction and a successive task projection in order to maintain the measure for singularity over a user defined minimum value. It shows a gain in performance and a better task error especially when working in proximity of singular configurations. It is particularly suitable for autonomous systems where an off-line trajectory control scheme is often not applicable. The advantage and performance of the proposed controller is verified by simulation works. And, the experiment with real manipulator is remaining for the future works.