• 로봇학회논문지
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• 제6권4호
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• pp.344-352
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• 2011

A mobile manipulator is a system with a robotic manipulator mounted on top of a mobile base. It has both indoor and outdoor applications for transporting or transferring materials. When a user gives commands, they are usually at high levels such as "move the object to the table," or "tidy the room." By intelligently decomposing these complex commands into several subtasks, the mobile manipulator can perform the tasks with a greater efficiency. One of the crucial subtasks for these commands is the pick-and-place task. For the mobile manipulator, selection of a good base position and orientation is essential to accomplishing this task. This paper presents an algorithm that determines one of the position and orientation of a mobile manipulator in order to complete the pick-and-place task without human intervention. Its effectiveness are shown for a mobile manipulator with 9 degrees-of-freedom in simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1841-1846
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• 2003

The mobile platform-manipulator discussed in this paper is a three link manipulator mounted on a mobile platform. This mobile manipulator is used for welding operation and it is able to operate in a narrow space. The task of the torch, which is mounted at the end effector of the manipulator, is to track along the seam line and the task of the mobile platform is to move the origin point of the manipulator in order to go away from the singularity of the manipulator’s configuration. In this paper, the path planning for the motion of two subsystems (i.e., the manipulator and the mobile platform) was presented by the decentralized control method. Two controllers for the mobile platform and the manipulator were designed, and the relationship between the independent controllers is its state information. The simulation results are also presented to demonstrate the effectiveness of the control method.

• Journal of information and communication convergence engineering
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• 제3권1호
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• pp.33-37
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• 2005

One of the most important feature of the Mobile Manipulator is redundant freedom. Using the redundant freedom, Mobile Manipulator can move various mode, perform dexterous motion. In this paper, to improve robot job ability, as two robots perform a job in co-operation control, we studied optimal position and posture of Mobile Manipulator with minimum movement of each robot joint. Kinematics of mobile robot and task robot is solved. Using mobility of Mobile robot, weight vector of robots is determined. Using Gradient methode, global motion trajectory is minimized. so the job which Mobile Manipulator perform is optimized. The proposed algorithm is verified with PURL-II which is Mobile Manipulator combined Mobile robot and task robot. and discussed the result.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.401-401
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• 2000

A mobile manipulator-a serial connection of a mobile robot and a task robot is redundant by itself. Using its redundant freedom, a mobile manipulator can move in various modes, and perform dexterous tasks. An interesting question,

• 한국정밀공학회지
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• 제22권5호
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• pp.95-102
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• 2005

The coordination of locomotion and manipulation has been the typical and main issue for a mobile manipulator. This is particularly because the solution for the control parameters is redundant and the accuracies of controlling the each joints are different. This paper presents a motion planning method for which the mobile base locomotion is less precise than the manipulator control. In such a case, it is appropriate to move the mobile base to discrete poses and then to move the manipulator to track a prescribed path of the end effector, while the base is stationary. It uses a variant of the conventional manipulability measure that is developed for the trajectory control of the end effector of the mobile manipulator along an arbitrary path in the three dimensional space. The proposed method was implemented on the simulation and the experiments of a mobile manipulator and showed its effectiveness.

• Journal of Mechanical Science and Technology
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• 제14권6호
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• pp.605-621
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• 2000

A mobile manipulator-a serial connection of a mobile platform and a task robot-is redundant by itself. Using its redundant freedom, a mobile manipulator can move in various modes, i. e., can perform dexterous tasks. In this paper, to improve task execution efficiency utilizing redundancy, optimal configurations of the mobile manipulator are maintained while it is moving to a new task point. Assuming that a task robot can perform the new task by itself, a desired configuration for the task robot can be pre-determined. Therefore, a cost function for optimality can be defined as a combination of the square errors of the desired and actual configurations of the mobile platform and of the task robot. In the combination of the two square errors, a newly defined mobility of a mobile platform is utilized as a weighting index. With the aid of the gradient method, the cost function is minimized, so the tasle that the mobile manipulator performs is optimized. The proposed algorithm is experimentally verified and discussed with a mobile manipulator, PURL-II.

• 한국해양공학회지
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• 제23권2호
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• pp.8-17
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• 2009

This paper presents an adaptive tracking control method for a welding mobile manipulator with several unknown parameters such as the last length of the manipulator, the wheel radius and the distance from the center to the wheel. The mobile manipulator consisted of the manipulator and the mobile-platform. Kinematic modelings for the manipulator and the mobile-platform with several unknown parameters were produced. The tracking error vectors for the manipulator and the mobile-platform were defined. These adaptive controllers were designed based on the Lyapunov function to guarantee the stability of the whole system when the mobile manipulator performs a welding task. Update laws were also designed to estimate the unknown dimensional parameters. To implement the designed controllers, a control system integrated with PIC16F877 microprocessors and a TMS320C32 DSP was developed. Simulation and experimental results are presented to show the effectiveness of the proposed controllers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.120.2-120
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• 2001

This paper presents the analysis on the manipulability of a wheeled mobile manipulator which consists of a wheeled mobile platform and a manipulator atop. It is assumed that the mobile platform is a deficient system and the manipulator is a nonredundant system, but the mobile manipulators as a whole is a redundant system. First Yoshikawa´s definition of the manipulability ellipsoid for a redundant/nonredundant system is extended to a deficient system. Second, the effects of the nonholonomic constraint of the mobile platform and the location the mobile platform and the manipulator is analyzed.

• 한국컴퓨터정보학회논문지
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• 제13권3호
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• pp.153-160
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• 2008

이동매니퓰레이터의 중요한 특징은 잉여의 자유도가 부과되므로 여러 모드의 이동을 가능하게 하고 다양한 작업을 수행할 수 있다. 본 논문에서는 이동로봇과 작업로봇이 결합된 형태를 이동매니퓰레이터라 정의하고 두 로봇이 협동하여 연속적인 하나의 작업을 수행할 때 최적의 자세를 유지할 수 있도록 한다. 이를 위하여 이동 로봇과 작업로봇의 기구학을 해석하고 이를 바탕으로 이동로봇의 Mobility를 이용하여 이동로봇의 가중치를 조정하였다. 또한 이동매니퓰레이터의 최적의 위치와 자세를 조인트 변위량의 최소화 충분조건으로 정의할 때 움직임을 최소화시키는 방법으로 Gradient Method를 이용하여 작업의 최적화 기준을 검토하였다. 이동로봇과 결합된 매니퓰레이터는 PURL-II를 이용하여 제시한 알고리즘 실현과 결과가 논의된다.

• 전자공학회논문지SC
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• 제42권5호
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• pp.1-12
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• 2005

이동로봇과 작업로봇의 직결연결 형태인 이동매니퓰레이터는 원자로 내부와 같은 위험한 작업환경에서 다양한 일한 처리하기위해 유용한 시스템이라 할 수 있다. 하부의 이동로봇은 non-holonomic 시스템이고 상부의 작업로봇의 결합으로 인하여 기구학적 잉여자유도를 갖고 있다. 그러나 주행 중 작업공간 확보로 인하여 고정식 매니퓰레이터보다 더 효율적인 작업이 가능 하다고 할 수 있다. 본 논문에서는 영상정보에 의한 물체인식 및 최적주행을 수행하기 위하여 이동로봇에 장착된 능동카메라에 인식된 영상과 실제 물체간의 기하학적 관계를 이용하여 직교좌표상의 물체의 위치를 추정할 수 있도록 하였다. 두 번째로 시스템의 위치변위 및 영상정보를 이용하여 물체위치를 추정하고 동차행렬을 이용하여 이동매니퓰레이터의 현 위치와 물체간의 최적경로를 결정하는 방법을 제시하였다. 제시한 방법을 시뮬레이션과 이동매니퓰레이터를 이용한 실험데이터분석을 통하여 유효성을 제시하였다.