• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.271-272
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• 2013

• 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 of Manufacturing Technology Engineers
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• v.22 no.3_1spc
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• pp.587-592
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• 2013

Until recently, the primary users of wheelchairs were people with lower body disabilities. However, the number of patients recovering from accidents or surgery, as well as the number of elderly people using wheelchairs, is constantly increasing. This study examined the design and manufacture of standing and gait assist wheelchairs that assist temporary gait disturbed patients to take rehabilitation training and elderly people to engage in walking exercise. A kinematic analysis was used to select a drive motor and design a four-bar linkage mechanism for lifting the backrest vertically. Using a multibody dynamic simulation, detailed design was performed taking into consideration the spatial motion and partial interference, and the necessary push force and stroke of the linear actuator were also calculated. To ensure structural safety, the von-Mises equivalent stresses of the upper and lower brackets of the linear actuator were verified through a finite element analysis. The manufactured wheelchair was shown to operate successfully as intended, using the developed controller for the drive motors and linear actuator.

• Journal of the Korean Society of Industry Convergence
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• v.16 no.4
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• pp.141-145
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• 2013

This paper is the development of industrial robotic hand system and the design methods of industrial robot hand that can mimic human fingers motion. In order to overcome problems incurred during the reduction of the mobility, this study focuses on analyzing human hand structure and finger movements from an anatomical point of view. As a result, distinctive features that improve the discovered stability in constraints for range of motion in the fingers is reflected in this design concept. A 4-bar Linkage is used in robot finger structure. Lastly, there were experiments to inspect the developed robot hands performance. The developed robot hand has many potential applications and can be in many different fields.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.737-752
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• 1992

Analysis of elasto-dynamic deformation of flexible linkage mechanism is conducted using the finite element method. The equations of motion of the system are derived from the static structural problem in which dynamic inertia, gravitational and driving forces are treated as external loads. Linear spring model is included in the formulation of equation of motions to represent the effects of deformation of elastic bearings of revolute joints on the system behavior. A computer program is constructed and applied to analyze a specific crank-lever 4-bar mechanism. The algorithm of the program is as follows. First, the natural frequencies and the mode shapes of the system are calculated by solving the eigenproblem of the mechanism system which can be considered as a static structure by assuming the input shaft (crank shaft) to be fixed at any given configuration of mechanism. And finally, the elasto-dynamic deformation of the whole system is obtained using mode superposition method for the case of constant input speed. The effect of geometric stiffness on the mechamism is included in the program with the axial forces of links obtained through the quasi-static displacement analysis. It is found that the geometric stiffness exerts an important effect upon the elasto-dynamic behavior of the flexible linkage mechanism. Elastic deformation of bearing lowers the natural frequencies of the system, resulting smaller elastic displacement at the mid-point of the links and bigger elestic displacement at the ends of the links than rigid bearing. The above investigation of flexible linkage mechanism shows that the effects of the elastic deformation of bearing on the mechanism should be considered to design the mechanism which satisfies more preciously the purpose and the condition of design.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.4
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• pp.307-314
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• 2016

Recently, demands on the tapping machine are increased due to the case of a cell phone is changed to metal such as aluminum. The automatic tool changer (ATC) is one of the most important devices for the tapping machine related to the speed and energy consumption of the machine. To reduce the consumed energy and vibration, the dynamic modeling is essential for the ATC. In this paper, inverse dynamic modeling of a novel ATC mechanism is introduced. The proposed ATC mechanism is composed of a double four-bar mechanism with a circular tablet to generate continuous rotation of the tablet. The dynamic modeling is performed based on the Lagrange equation with a modeling for the contact between the four-bar and the tablet. Simulation results for various working conditions are proposed and analyzed for the prototype design. The dynamic modeling can be applied to determine the proper actuator and to reduce the vibration and consumed energy for the ATC machine.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.42-47
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• 2021

A one-touch descending lifeline that can easily be installed and rapidly evacuated in the event of a fire accident in high-rise buildings was proposed to overcome difficulties of conventional descending lifeline such as complex installation methods and procedures. However, this lifeline exhibits limitations such as restrictions in installation location and large apparatus size. Therefore, this paper proposes a sliding-type descending lifeline, which has a similar operation to that of current one-touch descending lifeline and solves the aforementioned limitations. A double square link mechanism including a sliding four-bar linkage is proposed and the descending lifeline support is redesigned to unfold in two different planes, allowing 3D movement. Additionally, the shape of the support frame is designed to obtain two attachment surfaces that can be attached to a wall, irrespective of the angle between the window and the inner wall. FEA analysis using ABAQUS is performed to ensure that the robustness of the presented support complies with the Fire Control Act Enforcement Decree. Finally, the feasibility of the proposed sliding one-touch descending lifeline is verified through fabrication.

• Journal of Astronomy and Space Sciences
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• v.29 no.4
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• pp.381-387
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• 2012

The planetary exploration rover executes various missions after moving to the target point in an unknown environment in the shortest distance. Such missions include the researches for geological and climatic conditions as well as the existence of water or living creatures. If there is any obstacle on the way, it is detected by such sensors as ultrasonic sensor, infrared light sensor, stereo vision, and laser ranger finder. After the obtained data is transferred to the main controller of the rover, decisions can be made to either overcome or avoid the obstacle on the way based on the operating algorithm of the rover. All the planetary exploration rovers which have been developed until now receive the information of the height or width of the obstacle from such sensors before analyzing it in order to find out whether it is possible to overcome the obstacle or not. If it is decided to be better to overcome the obstacle in terms of the operating safety and the electric consumption of the rover, it is generally made to overcome it. Therefore, for the purpose of carrying out the planetary exploration task, it is necessary to design the proper suspension system of the rover which enables it to safely overcome any obstacle on the way on the surface in any unknown environment. This study focuses on the design of the new double 4-bar linkage type of suspension system applied to the Korea Aerospace Research Institute rover (a tentatively name) that is currently in the process of development by our institute in order to develop the planetary exploration rover which absolutely requires the capacity of overcoming any obstacle. Throughout this study, the negative moment which harms the capacity of the rover for overcoming an obstacle was induced through the dynamical modeling process for the rocker-bogie applied to the Mars exploration rover of the US and the improved version of rocker-bogie as well as the suggested double 4-bar linkage type of suspension system. Also, based on the height of the obstacle, a simulation was carried out for the negative moment of the suspension system before the excellence of the suspension system suggested through the comparison of responding characteristics was proved.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1285-1288
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• 1997

The basic technology of virtual reality can be described as the cognition of the condition change in virtual world by stimulating the visual, auditory, kinesthetic and tactile sensation. Among these, the kinesthetic and tactile sensation is one of the most important things to recognize the interaction. In this paper, it is addressed the haptic device which help the human feel the sense of the operator, and is designed in modular type to expand for five fingers later. the haptic device is driven by tendon and ultrasonic motors located in the wrist part. Each joint is actuated by coupled tendons and adopts more actrator by one than the number of the joints, called 'N+1 type'. The haptic device adopts metamorphic 4-bar linkage structure and the length of linkages, shape and the location of joint displacement sensor are optimized through the analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.12
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• pp.2527-2534
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• 2002

An efficient method is proposed for the design of six-bar function generators with complex design tasks. Especially, the desired functions are defined for the entire motion ranges of the input variables. The design problem is defined as a nonlinear optimization problem. A concept of a weighted structural error is introduced for the definition of the objective function. Also simple branch identifiers are incorporated to eliminate the branch problems commonly encountered in a typical linkage synthesis problem. Two example problems of designing a Watt-II type double dwell mechanism and a Stephenson-III type double beat-up mechanism are demonstrated with numerical results. Constraints such as on the Grashof conditions and on the transmission angles are included for practical solutions.