• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.180-185
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• 2004

Unlike industrial manipulators, the manipulators mounted on the service robots are interacting with humans in various aspects. Therefore, safety has been the important design issue. Many compliant robot arm designs have been introduced for safety. It is known that passive compliance method has faster response and higher reliability than active ones. In this paper, a new safe mechanism based on passive compliance has been proposed. Passive mechanical elements, specifically transmission angle of the 4-bar linkage, springs and shock absorbing modules are incorporated into this safe mechanism. This mechanism works only when the robot arm exerts contact force much more than the human pain tolerance. Validity of the safe mechanism is verified by simulations and experiments. In this research, it is shown that the manipulator using this mechanism provides higher performance and safety than those using other passive compliance mechanisms.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.851-858
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• 2011

Nanopositioning technologies play an important role in the progress of electronics, optics, bio-engineering and various nano-scale technologies. As a result, various practical nanopositioning methods have been successfully introduced. Flexure mechanism is a valuable method in nanopositioning because of smooth and friction-free motion and the infinitesimal movement near to sub-nm. In this study a modularized nanopositioner based on parallelogram four-bar linkage structure with right-circular flexure hinge was developed. The positioning performance of a single axis nanopositioner and a XY nanopositioner which was extended from single axis one were demonstrated using control experiments. Consequently, it was shown that the developed single axis nanopositioner possessed high performance and could be extended to various multi-axis nanopositioners.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1534-1541
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• 2005

Unlike industrial manipulators, the manipulators mounted on service robots are interacting with humans in various aspects. Therefore, safety has been one of the most important design issues. Many compliant robot arms have been introduced for safety. It is known that passive compliance method has faster response and higher reliability than active ones. In this paper, a new safety mechanism based on passive compliance is proposed. Passive mechanical elements, specifically transmission angle of the 4-bar linkage, springs and shock absorbing modules are incorporated into this safety mechanism. This mechanism works only when the robot arm exerts contact force much more than the human pain tolerance. Validity of this mechanism is verified by simulations and experiments. It is shown that the manipulator using this mechanism provides higher performance and safety than those using other passive compliance mechanisms or active methods.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.384-388
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• 2016

This paper proposed a m.Sketch to search the optimal link lengths for a legged walking robot. In order to apply the m.Sketch for the proposed, set the design parameters of the constraints and use the m.Skecth to get optimal GL(Groud Length) and GAC(Ground Angle Coefficient). The legged robot designed based on four-bar linkage theory and Theo Jansen mechanism. The stride length of the legged walking robot was defined based on the proposed kinematic analysis. Use the Edison Design m.Sketch simulate and find the optimal link length having the best of the Ground Length (GL) and Ground Angle Coefficient(GAC). And use these length implemented the Theo Jansen mechanism both in Science box parts and acrylic. In addition to the further expansion of the legs to reach the goaltranslating heavy objects or person.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.18-25
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• 2003

A haptic hand controller (HHC) operated by the user’s hand can receive information on position and orientation of the hand and display force and moment generated in the virtual environment to the hand. In this paper, a 3-DOF hand controller is first presented, in which all the actuators are mounted on the fixed base by combining a 5-bar linkage and a gimbal mechanism. The 6-DOF HHC is then designed by connecting these two 3-DOF devices through a handle which consists of a screw and nut. Analysis using performance index is carried out to determine the dimensions of the device. The HHC control system consists of the high-level controller for kinematic and static analysis and the low-level controller for position sensing and motor control. The HHC used as a user interface to control the mobile robot in the virtual environment is given as a simple application.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.107-115
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• 2017

In this paper, four-bar linkage mechanism for the knee joint is developed which is used in prosthetics. But unlike the prosthetics, the feature of this mechanism is that the instantaneous center of rotation of the four-bar linkages can be moved behind the ground reaction force vector so that it can be passively supported without any external power. In addition, this mechanism is developed similar to the structure of the human knee joint for eliminating the sense of heterogeneity of the wearer. In order to design the mechanism with these two objectives, optimization design process is done using the PIAnO tool and detailed design is carried out through optimized variable values. The developed mechanism is attached to the robot which can assist the hip and ankle joints. In order to verify the operation of the developed knee mechanism, an insole type sensor was attached to the shoes to compare data values before and after wearing the robot. Result data showed that wearer wearing the exoskeleton robot with the knee mechanism was the same value regardless of whether the heavy tool is loaded or not.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1508-1515
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• 1996

The method of utilizing sensitivity linkages for the analysis of mechanical errors are proposed. As sources of the mechanical error, tolerances in the link length and clearances in thejoints are considered. It is demonstrated that the problem of calculating mechanical errors of a 4-bar mechanism can be transformed into a problem of conventeional velocity analysis of a sensitivity linkage. As a result of the present study, it is found and proved that the mechanical error of the output angle in the 4-Bar mechaism is represented as a simple harmonic function with respect to the relative position of the pin on the clearance circle. Also the vector representing the mechanical error of a coupler point makes, in general, an ellipse as the relative angle varies on the clearance circle. With these results we can better identify the characteristic of the mechanical errors in linkages.

• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.193-204
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• 2016

This paper presents an anthropomorphic finger prosthesis for amputees whose proximal phalanx is mutilated. The finger prosthesis to be proposed is able to make the amputees to perform the natural motion such as flexion/extension as well as self-adaptive grasping motion as if normal human finger does. The mechanism of finger prosthesis with three degrees-of-freedom (DOFs) consists of two five-bar and one four-bar linkages. Two passive components composed of torsional spring and mechanical stopper and only one active joint are employed in order to realize an underactuation. Each passive component is installed into the five-bar linkage. In order to activate the finger prosthesis, it is required for the user to flex and extend the remaining proximal phalanx on the metacarpophalangeal (MCP) joint, not an electric motor. Thus the finger prosthesis conducts not only the natural motion according to his/her intention but also the grasping motion through the deformation of springs by the object for human finger-like behavior. In order to reveal the operation principle of the proposed mechanism, kinematic analysis is performed for the linkage design. Finally both simulations and experiments are conducted in order to reveal the design feasibility of the proposed finger mechanism.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1045-1046
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.502-503
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• 2014