• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.26-34
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• 2015

In this paper, a fuzzy compensated PID control system is proposed for formation control of mobile robots. The control system consists of a kinematic controller based on the leader-follower approach and a dynamic controller to handle dynamics effects of mobile robots. To maintain the desired formation of mobile robots, the dynamic controller is equipped with a PID controller; however, the PID controller has poor performance in nonlinear and changing environments. In order to improve these problem, we applied the additional fuzzy compensator. Finally, the proposed control system has been evaluated through computer simulation to demonstrate the improved results.

• Structural Engineering and Mechanics
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• v.57 no.5
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• pp.809-821
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• 2016

Concentric-tube continuum robots have formed an active field of research in robotics because of their manipulative exquisiteness essential to facilitate delicate surgical procedures. A set of concentric tubes with designed initial curvatures comprises a robot whose workspace can be controlled by relative translations and rotations of the tubes. Kinematic models have been widely used to predict the movement of the robot, but they are incapable of describing its time-dependent hysteretic behaviors accurately particularly when snapping occurs. To overcome this limitation, here we present a finite element modeling approach to investigating the dynamics of concentric-tube continuum robots. In our model, each tube is discretized using MITC shell elements and its transient responses are computed implicitly using the Bathe time integration method. Inter-tube contacts, the key actuation mechanism of this robot, are modeled using the constraint function method with contact damping to capture the hysteresis in robot trajectories. Performance of the proposed method is demonstrated by analyzing three specifications of two-tube robots including the one exhibiting snapping phenomena while the method can be applied to multiple-tube robots as well.

• International journal of advanced smart convergence
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• v.8 no.3
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• pp.138-144
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• 2019

Understanding teachers in the early childhood education is crucial as it can not only affect the quality of children's education but also cause many critical problems such as child abuse. A significant amount of research work has been made on the use of robots in childcare classrooms. The finding from the research has shown many advantages such as the improvement of learning performance, social/emotional skills, creativity, concentration period, physical and cognitive development. However, most of the study has been implemented at the K-12 classrooms but not much has been focused on the education at the early childhood classrooms. Importantly, it is very crucial to understand teachers' perception, demands and technical competence about the new teaching tool, in order to maximize its educational effect. This paper investigates some critical issues existing in both teaching and managing in the early childhood education. It will also explore teachers' perceptions and expectations on the use of robots to identify some dilemmas that exist in their working and teaching environment. A survey study was conducted with 119 early childhood educators in South Korea. It analyzed the educators' perception of using robots to improve their teaching performance and to make better outcomes for children, investigated job satisfaction and difficulties that they have in the current work environment. This paper concludes with several guidelines for integrating and setting robotics in the early childhood environment, in order to engender productive outcomes for the future early childhood education.

• Journal of Power Electronics
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• v.19 no.3
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• pp.691-701
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• 2019

To solve the problems in the contact charging of inspection robots, a wireless charging system for inspection robots and a control strategy are introduced in this paper. Circuit models of a wireless power system with a compound compensation circuit and a three-phase Class-D resonant inverter are set up based on circuit theory. An output voltage control method based on the equal spread regulation of the phase difference between adjacent phases and the parameter correction method in the primary compound compensation circuit are proposed. The dynamic characteristics of the key parameters varying with the secondary coil position are obtained to further investigate the adaptive location scheme during the access and exit processes of moving robots. Combining the output voltage control method and the adaptive location scheme, a transition control strategy for the standby and operation modes of the wireless charging systems for inspection robots is put forward to realize the system characteristics including the low standby power in the standby mode and the high receiving power in the operation mode. Finally, experiments are designed and conducted to verify the correctness of the theoretical research.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.6
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• pp.1004-1016
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• 2021

This study aims to derive the design requirements for functional clothing worn with military wearable robots using a survey of people with military experience. Specifically, 982 adult males with military and muscular exercise experience were surveyed for their demands for the clothing worn with wearable robots during military activities. The study showed that it is necessary to develop functional clothing worn inside robots suitable for frequent movements of soldiers to improve their comfort level of wearable robots. The surveyed soldiers indicated that they preferred the top and bottom clothing with high-pressure levels because the upper body felt fatigued during transportation, while both the upper and lower body got exhausted during marches. The survey of design requirements revealed that the participants preferred a top with long sleeves and a bottom with ankle-length leggings in color similar to current military uniforms. We conclude that it is important to design functional clothing worn inside wearable robots in different forms depending on frequent movements, e.g., with differentiated pressures and material placements.

• The Journal of Korea Robotics Society
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• v.17 no.1
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• pp.1-7
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• 2022

Robots are widely used in industries and services. Traditional robots have been used to perform repetitive tasks in a fixed environment, and it is very difficult to solve a problem in which the physical interaction of the surrounding environment or other objects is complicated with the existing control method. Reinforcement learning has been actively studied as a method of machine learning to solve such problems, and provides answers to problems that robots have not solved in the conventional way. Studies on the learning of all physical robots are commonly affected by noise. Complex noises, such as control errors of robots, limitations in performance of measurement equipment, and complexity of physical interactions with surrounding environments and objects, can act as factors that degrade learning. A learning method that works well in a virtual environment may not very effective in a real robot. Therefore, this paper proposes a weighted sum method and a linear regression method as an effective and accurate learning method in a noisy environment. In addition, the bottle flipping was trained on a robot and compared with the existing learning method, the validity of the proposed method was verified.

• The Korean Journal of Food & Health Convergence
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• v.8 no.1
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• pp.9-16
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• 2022

Recently, the use of serving robots has been increasing due to the increase in preference for non-face-to-face services and the rise in the minimum wage due to the coronavirus. When analyzing previous studies related to serving robots, it was confirmed that most of the studies on the functions and technologies of serving robots were conducted. Therefore, this study analyzed the factors affecting the attitude and customer satisfaction of restaurant consumers toward serving robots by adding performance expectations, effort expectations, and speed factors among the UTAUT2 models. The survey period was conducted from July 28, 2021 to September 9, 2021, and 306 out of a total of 310 surveys were used for analysis, excluding 4 unfaithful surveys. For the analysis, exploratory factor analysis, reliability analysis, confirmatory factor analysis, and hypothesis test were performed using SPSS 20.0 and AMOS 20.0, and the research results are as follows. First, it was found that performance expectation, effort expectation, and speed had a significant positive (+) effect on attitudes. Second, it was found that attitude had a significant positive (+) effect on customer satisfaction. This study researched customer selection attributes of robot service restaurants using the UTAUT2 model, and also provided academic and practical implications.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.164-169
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• 1998

Complex "lifelike" behaviors are composed of local interactions of individuals under fundamental rules of artificial life. In this paper, fundamental rules for cooperative group behaviors, "flocking" and "arrangement", of multiple autonomous mobile robots are represented by a small number of fuzzy rules. Fuzzy rules in Sugeno type and their related paramenters are automatically generated from clustering input-output data obtained from the algorithms the group behaviors. Simulations demonstrate the fuzzy rules successfully realize group intelligence of mobile robots.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.759-762
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• 1991

In this paper an algorithm is presented which serves for collision avoidance between robots with working space. The method is based on the concept of a hierarchical coordinator and permits an on-line application. Computing possible collision points a collision_free trajectory for the robot with no right_of_way precedence is generated. The computations are based on the states of the robots concerned including their practicable accelerations and velocities.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.4
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• pp.201-204
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• 2004

In this paper, a direct adaptive tracking controller based Lyapunov method is designed for a wheeled mobile robots. A wheeled mobile robots have three degrees of freedom and two control variables. Therefore, it is difficult to control a mobile robot using the general linear control. We introduce two kinds of Lyapunov function for the design of the controller and verify the controller. A mobile robots using the designed adaptive direct tracking controller is well-behaved and is easily implemented.