• Bulletin of the Korean Mathematical Society
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• v.54 no.6
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• pp.2183-2210
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• 2017

We construct a completed version $\hat{\varrho}({\Gamma})$ of the configuration space of a linkage ${\Gamma}$ in $\mathbb{R}^3$, which takes into account the ways one link can touch another. We also describe a simplified version $\underline{\varrho}({\Gamma})$ which is a blow-up of the space of immersions of ${\Gamma}$ in $\mathbb{R}^3$. A number of simple detailed examples are given.

• Advances in Computational Design
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• v.7 no.3
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• pp.189-210
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• 2022

Deployable structures have the ability to shift from a compact state to an expanded functional configuration. By extension, reconfigurability is another function that relies on embedded computation and actuators. Linkage-based mechanisms constitute promising systems in the development of deployable and reconfigurable structures with high flexibility and controllability. The present paper investigates the deployment and reconfigurability of modular linkage structures with a pin and a sliding support, the latter connected to a linear motion actuator. An appropriate control sequence consists of stepwise reconfigurations that involve the selective releasing of one intermediate joint in each closed-loop linkage, effectively reducing it to a 1-DOF "effective crank-slider" mechanism. This approach enables low self-weight and reduced energy consumption. A kinematics and finite-element analysis of different linkage systems, in all intermediate reconfiguration steps of a sequence, have been conducted for different lengths and geometrical characteristics of the members, as well as different actuation methods, i.e., direct and cable-driven actuation. The study provides insight into the impact of various structural typological and geometrical factors on the systems' behavior.

• 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.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.161-172
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• 2017

Foot mechanisms play the role of interface between the main body of robotic systems and the ground. Biomimetic design of the foot mechanism is proposed in the paper. Specifically, multi-chained and multiple contact characteristics of general foot mechanisms are analyzed and their advantages are highlighted in terms of impulse. Using Newton-Euler based closed-form external and internal impulse models, characteristics of multiple contact cases are investigated through landing simulation of an articulated leg model with three kinds of foot. It is shown that in comparison to single chain and less articulated linkage system, multi-chain and articulated linkage system has superior characteristic in terms of impulse absorption as well as stability after collision. The effectiveness of the simulation result is verified through comparison to the simulation result of a commercialized software.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2065-2073
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• 2000

In this paper, we present a wall climbing robot whose gate pattern takes after those of specialized climbing animals such as spiders. Characteristic features of the biological locomotion are partly realized in the design of the mechanism. The robot has two legs and a trunk. Each one-dof leg with suction pads is driven by a motor which employs a closed loop linkage mechanism, and the trunk with suction pads steers the whole body of the robot using a motor. By generating adequate trajectories of the leg and simultaneously alternating the suction pattern between the legs and the trunk, we can achieve the spider like motion. The proposed idea is implemented in a robot and some tests are performed to evaluate its performance.

• 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

• International Journal of Automotive Technology
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• v.6 no.4
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• pp.403-411
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• 2005

The bus is regarded as one of the most frequently used public transportation systems, the research and development on driving stability, safety, and convenience for drivers and passengers has tremendously increased in recent days. This paper investigated the design of the bus door mechanism composed of an actuator (or motor) and linkages. The bus door mechanism is divided into many types according to the coupling of the linkages and the driving system. The mathematical models of all types of door mechanism have been constructed for computer simulation. To design the bus door mechanism, we developed a simulation program, which automates the kinematic and dynamic analysis according to the input parameters of each linkage and the driving system. Using this program, we investigated the design parameters that affect the kinematic and dynamic characteristics of the bus door mechanism under various simulation conditions. In addition, simple examples are examined to validate the developed program.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.489-496
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• 2005

In this paper, the feasibility of the high-performance damping device vibration suppression of stay cables has been investigated. The proposed damping system consists of a linear viscous damper and a scissor-jack-type toggle linkage. Since the mechanism of the scissor-jack-type toggle linkage amplifies the relative displacement of the linear viscous damper, it is expected that the capacity of the viscous damper used in the scissor-jack-damper energy dissipation system can be reduced without the loss of the control performance. Numerical simulation results demonstrate the efficacy of the damping system employing the scissor-jack-type toggle linkage. Therefore, the proposed damping system could be considered as one of the promising candidates for suppressing vibration of stay cable.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.833-839
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• 2010

In this paper, a novel 1 DOF hand rehabilitation robot is proposed in consideration of ADL training for stroke patients. To perform several ADL trainings, the proposed robot can move the thumb part and the part of 4 fingers simultaneously and realize the full ROM (Range of Motion) in grasp. Based on these characteristics, the proposed robot realizes several types of grasp such as cylindrical grasp, lateral grasp, and pinch grasp by using a passive revolute joint that can change the thumb movement direction. The movement of the thumb is driven by a cable mechanism and the part of 4 fingers is moved by a four-bar linkage mechanism.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.9
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• pp.961-968
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• 2013

In this paper, we propose an optimal design for starfish capturing manipulator module with four-bar linkage mechanism. A tool link with compliance is attached on the four-bar linkage, and the tool repeats detaching starfish from the ground and putting it into the storage box. Since the tool is not rigid and the manipulator is operating underwater, the trajectory of the tool tip is determined by its dynamics as well as kinematics. We analyzed the trajectory of the manipulator tool tip by quasi-static analysis considering both kinematics and dynamics. In optimization, the lengths of each link and the tool stiffness are considered as control variables. To maximize the capturing ability, capturing stroke of the four-bar manipulator trajectory is maximized. Reaction force and reaction moment, and other kinematic constraints were considered as inequality constraints.