• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.2
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• pp.414-430
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• 1996

In this paper, a new kinematic structure of a parallel manipulator with six Cartesian degrees of freedom is proposed. It consists of a platform which is connected to a fixed base by means of 3-PPSP(parameters P, S denote the prismatic, spherical joints) subchains. Each subchain has a link which is concected to a passive prismatic joint at the one end and a passive spherical joint at the other. The spherical joint is then attached to perpendicularly arranged prismatic actuators which are fixed at the base. The spherical joint is then attached to perpendicularly arranged prismatic actuators which are fixed at the base. This arrangement provides a basis to control all six Cartesian degrees of motion of the platform in space. Due to its efficient architecture, the colsed-form solutions of the inverse and forward kinematics can be obtained. As a consequence, this new kinematic structure can be servo controlled using simple inverse kinematics becaese forward kinematics allows for measuring the platform's position and orientation in Cartesian space. Furthermore, the proposed structure provides an effective functional workspace. Series of simulations are performed to verify the results of the kinematics analyses.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.611-616
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• 1994

Most of Commercial Remote Center Compliance(RCC) devices have been designed using deforma ble structures. In this work, we propose another type of assembly devices which generate the compliance effec ts by attaching the compliances (or spring) at the prismatic joints of the griven mechainsm. First, the kinematic analysis for a parallel-type planar 3-degree-of-freedom mechanism is performed using modified transfer method of generalized coordinate. Then, compliance characteristics for the mechanism using prismatic joint compliances are investigated. In particular, when the system maintains its symmetric configuration, the mechanism is show n to have RCC points at the center of the workspace. Finally, sensitivity analysis around RCC points is perfor med.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.363-368
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• 1995

A general method of solving inverse kinematics of three-joint manipulator composed of revolute joints or prismatic joints or combinations of those joints is presented in this study. In completing real-time control, it is very important to obtain the closed form solutions of inverse kinematics rather than iterative numerical solutions, because iterative numerical solutions are generally much slower than the corresponding closed form solutions. If it is possible to obtain the inverse kinematic solutions for general cases of considering twist anlges and offsets, the manipulator work space can be designed and enlarged more effciently for specific task. Moreover, in idustrial manipulators, the effect of main three joints is larger than that of the other three joints related to orientation in the view of work space. Therfore the solutions of manin three-joint are considered. Even The inverse kinematic equations are complicatedly coupled, the systematical solving process by using symbolic calculation is presented.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.613-617
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• 1992

The tracking control problem of a flexible manipulator with a prismatic joint along a given path is discussed. The nondimensionalization of the elastic part of the manipulator makes it possible to model such a flexible manipulator. For a discontinuous velocity trajectory, an optimal control theory has been applied to formulate the problem. The optimal scheme is given to find the input commands(e.g., joint torques) necessary to produce a, specified end effector motion. Simulated results show the potential use of this scheme for a discontinuous velocity trajectory control.

• Journal of Korean Society of Steel Construction
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• v.16 no.6 s.73
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• pp.833-846
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• 2004

This study presents a non-prismatic beam element for modeling the elastic behavior of steel beams, which have the post-Northridge connections in steel moment frames. The elastic stiffness matrix, including the shear effects for non-prismatic members with reduced beam section (RBS) connection, is in closed form. A simplified approach is also suggested, which uses a prismatic beam element to model beams with the RBS connection. This method can estimate quiteexactly the maximum story drift ratios of frames with the RBS connection. The effects of reduced beam section connection on the elastic stiffness of steel moment frames were investigated. The selection of a proper model to account for deformations at the joint might have a more important role in estimating the maximum story drift ratios of frames with better accuracy than the RBS cutouts.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.131-137
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• 1989

The effect of kinematic model choice on robot calibration is examined. This paper presents a complete formulation to identify the actual robot kinematic parameters directly from position data. The method presented in this paper applies to any serial link manipulator with arbitrary order and combination of revolute and prismatic joint.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.51.4-51
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• 2002

$\textbullet$ A noval haptic mouse system is developed for human computer interface. $\textbullet$ Five bar mechanism is adapted for 2 dof force feedback with virtual environment. $\textbullet$ Double prismatic joint type mechanism is adapted to reflect 1 dof grabbing force feedback. $\textbullet$ Cable driven mechansim is used for actuation to reduce backlash and endow backdrivability. $\textbullet$ Virtual wall perception experiment is conducted to obtain force specification for haptic mouse. $\textbullet$ Average mouse workspace is measured using magnetic position tracker.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.1
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• pp.144-153
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• 1997

The determination of the direct kinematics of the parallel mechanism is a difficult problem but has to be solved for any practical use. This paper presents the efficient formulation of the direct kinematics for double parallel robot arm. The robot arm consists of two parallel mechanism, which generate positional and orientational motions, respectively. These motions are decoupled by a passive central axis which is composed of four revolute joints and one prismatic joint. For a set of given lengths of linear actuators, the direct kinematics will find the joint displacements of th central axis from geometric constraints in each parallel mechanism. Then the joint displacements will be converted into the position and the orientation of the end effector of the robot arm. The proposed formulation is decoupled and compacted so that it will be implemented as a real-time direct kinematics. With the proposed formulation, we analyze the motion of the double parallel robot and show its characteristics. Specially, we investigate the workspace in terms of positional space as well as orientational space.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1482-1487
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• 2003

This paper presents a new family of 4-DoF parallel mechanism with two platforms. The new mechanism is composed of front and rear platforms, and three limbs. Two limbs with 6dof joint (P-P-S-P) are attached to the each platform and are perpendicular to baseplate, while the middle limb with 4-Dof joints (R-R-R-P or R-R-P-P) is attached to the revolute joint that connect front and rear platform. The two-DoF-driving mechanism at the middle limb with two base-fixed prismatic actuators can generate the heaving and roll motions or two translational motions. Therefore, Therefore, the new 4-Dof parallel mechanism (1T-3R) can generate pitch motions at each platforms, roll, and heaving motions, while another type of new 4-Dof parallel mechanism (2T-2R) can generate pitch motions at each platforms, x and z translational motions. For 1T-3R mechanism, kinematic analyses including inverse, forward kinematics, and Jacobian are performed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.43-44
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• 2018

본 논문에서는 로봇 매니퓰레이터의 순방향 기구학 학습에 있어서 로봇의 비용적인 측면으로 인하여 실재 로봇 매니퓰레이터를 교보재로 사용하여 실습을 하기에 제한되는 환경과 교재만으로 학습하는 제한된 환경에서 학생들이 이해하는 것 뿐만 아니라 검증이나 실험을 하기가 어려운 점을 개선하기 위해서 증강현실 기반의 시뮬레이터를 제안한다 로봇 기구학에서는 주로 교재를 사용하는데 실재로 존재하는 모델보다 회전 관절(revolute joint)과 병진 관절(prismatic joint) 모형의 조합으로 모델링한다 관절의 모형을 일종의 증강현실의 마커로 사용하여 교재에서 제안하는 모델에 더해서 개인이 조합한 모델 또한 실습이 가능하도록 하는 증강현실 시뮬레이터를 제안한다.