• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.827-829
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• 2014

This paper presents a design methodology for improving dynamic stiffness of an inspection robot frame to prevent resonance. Finite element models of robot frame are developed for natural frequency analysis. Natural frequency analysis of robot frame is conducted to compare with sub-span oscillation which is excitation frequency. Reinforcement beams are applied to the sensitive parts of the robot frame to improve dynamic stiffness using case study. To reduce mass of the robot frame, thickness optimization of the robot frame is carried out by utilizing response surface method. The result of optimization show that dynamic stiffness of robot frame is increased. As a result, natural frequency of an optimal model is not included in range of frequencies of the sub-span oscillation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.44.3-44
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• 2001

This articles describes a novel design elastic joint manipulator for a mobile robot, which works in an office environment with humans. The primary goal of this manipulator design is safeness on collision and contact. To achieve this, each joint is made of an elastic element and this is driver with a high ratio gear tram. The performance was verified, however, it has a serious drawback. It produce vibration, due to the elastic joints and high ratio gear train. We found that a sliding mode controller has an excellent performance for reducing such vibration. Results of computer simulation and experiments are shown.

• Journal of Information Technology Services
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• v.19 no.3
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• pp.1-15
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• 2020

This study applies the Delphi method to design services with convergence characteristics in the financial sector. In designing a service robot for practical deployment that can support and replace bank teller, the opinions and judgments of various expert groups were extracted and a consensus process was made through feedback. A total of six dimensions and thirty service elements were derived over three rounds. Coefficient of Variation and content validity were used to verify the suitability and reliability of the selected service elements. As a result, the essential service element of robots was interaction with customers, followed by basic and professional financial services. Based on these service factors, we proposed two types of service models. support mode to assist employees during business hours and alternative mode on behalf of employees outside business hours. It is hoped that this study will use the Delphi technique in the design of IT convergence services.

• Journal of Magnetics
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• v.15 no.3
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• pp.128-131
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• 2010

In this paper, we propose a new design of the permanent magnet reluctance wheel which will make it possible to attach the robot to a vertical plane and move it. In the newly suggested design, a permanent magnet is utilized to enhance the adhesive force during attachment, and an electromagnet is produced to weaken the magnetic field of the permanent magnet and reduce the adhesive force for easier detachment of wheels from steel plates. To characterize the performance of this new wheel design, a 3-D finite element analysis is executed using a commercial FE program. The results show that the adhesive force is reduced effectively by the electromagnet which flows in the reverse direction of the magnetic loop of the permanent magnet when the current is supplied to the coil.

• Journal of Sensor Science and Technology
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• v.26 no.5
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• pp.353-359
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• 2017

This paper describes the design and manufacture of a ankle two-axis force sensor of a walking assist robot for hemiplegic leg patient. The walking assist robot for the hemiplegic leg patient can safely control the robot by detecting whether the foot wearing the walking assist robot is in contact with the obstacle or not. To do so, a two-axis force sensor should be attached to the robot's ankle. The sensor is used to measure the force of a patient's ankle lower part. The two-axis force sensor is composed of a Fx force sensor, a Fy force sensor and a pulley, and they detect the x and y direction forces, respectively. The two-axis force sensor was designed using by FEM(Finite Element Method), and manufactured using by strain-gages. The characteristics experiment of the two-axis force sensor was carried out respectively. The test results indicated that the interference error of the two-axis force sensor was less than 1.2%, the repeatability error and the non-linearity of the two-axis force sensor was less than 0.04% respectively. Therefore, the fabricated two-axis force sensor can be used to measure the force of ankle lower part in the walking assist robot.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.633-641
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• 2008

Recently, the necessity for diagnosis and management of pipes has emerged as the issue due to contamination of water supply generated by corrosion of pipes. Although inspection has been performed with industrial endoscopes, the method has limits for full diagnosis of pipes due to the lack of working range. As a solution for this problem, many locomotive mechanisms for a micro robot with endoscope functions were proposed. In this paper, we analyze the locomotive mechanism of crawling robot proposed as locomotive device for pipe inspection. Based on a mechanical modeling of motor and micro robot inside small pipe, the theoretical formula for velocity is obtained. This derived theoretical formula is demonstrated the feasibility through the comparison with experimental result. Also, we could find the most important element influencing the moving velocity of micro robot when the robot operates in small pipe. Consequently, it is expected that this study can supply useful information to design of crawling robot to move in small pipe.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.30-33
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• 1991

The natural frequency of an one-link flexible robot manipulator may be varied due to many kinds of causes and this natural frequency is regarded as the uncertain element. Utilizing measured state the robust controller is designed for bounding every system response within a certain neighborhood of the zero state.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.4
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• pp.320-328
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• 2007

This paper presents a stiffness modeling of a low-DOF parallel robot, which takes into account of elastic deformations of joints and links, A low-DOF parallel robot is defined as a spatial parallel robot which has less than six degrees of freedom. Differently from serial chains in a full 6-DOF parallel robot, some of those in a low-DOF parallel robot may be subject to constraint forces as well as actuation forces. The reaction forces due to actuations and constraints in each serial chain can be determined by making use of the theory of reciprocal screws. It is shown that the stiffness of an F-DOF parallel robot can be modeled such that the moving platform is supported by 6 springs related to the reciprocal screws of actuations (F) and constraints (6-F). A general $6{\times}6$ stiffness matrix is derived, which is the sum of the stiffness matrices of actuations and constraints, The compliance of each spring can be precisely determined by modeling the compliance of joints and links in a serial chain as follows; a link is modeled as an Euler beam and the compliance matrix of rotational or prismatic joint is modeled as a $6{\times}6$ diagonal matrix, where one diagonal element about the rotation axis or along the sliding direction is infinite. By summing joint and link compliance matrices with respect to a reference frame and applying unit reciprocal screw to the resulting compliance matrix of a serial chain, the compliance of a spring is determined by the resulting infinitesimal displacement. In order to illustrate this methodology, the stiffness of a Tricept parallel robot has been analyzed. Finally, a numerical example of the optimal design to maximize stiffness in a specified box-shape workspace is presented.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.4
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• pp.457-467
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• 2004

In this paper, a robot is considered as an agent, a structure of robot is presented which consisted by multi-subagents and they have diverse capacity such as perception, intelligence, action etc., required for robot. Also, subagents are consisted by micro-agent($\mu$agent) charged for elementary action required. The structure of robot control have two sub-agents, the one is behavior based reactive controller and action selection sub agent, and action selection sub-agent select a action based on the high label action and high performance, and which have a learning mechanism based on the reinforcement learning. For presented robot structure, it is easy to give intelligence to each element of action and a new approach of multi robot control. Presented robot is simulated for two goals: chaotic exploration and obstacle avoidance, and fabricated by using 8bit microcontroller, and experimented.

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.1
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• pp.66-70
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• 2001

This paper describes the design of a two-axis force sensor for robots finger. In detects the x-direction force Fx and y-direction force Fy simultaneously. In order to safely grasp an unknown object using the robots fingers, they should detect the force or gripping direction and the force of gravity direction, and perform the force control using the forces detected. Therefore, the robots hand should be made by the robots finger with tow-axis force sensor that can detect the x-direction force and y-direction force si-multaneously. Thus, in this paper, the two-axis force sensor for robots finger is designed using several parallel-plate beams. The equations to calculate the strain of the beams according to the force in order to design the sensing element of the force sensor are derived and these equations are used to design the aize of two-axis force sensor sensing element. The reliability of the derive equa-tions is verified buy performing a finite element analysis of the sensing element. The strain obtained through this process is compared to that obtained through the theory analysis and a characteristics test of the fabricated sensor. It reveals that the rated strains calculated from the derive equations make a good agreement with the results from the Finite Element Method analysis and from the character-istic test.