• Journal of Chest Surgery
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• v.38 no.5 s.250
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• pp.366-370
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• 2005

Background: In general, cardiac surgery has been performed via median sternotomy. During the past decade, improvements in endoscopic equipment and operative techniques have resulted in development of minimally invasive cardiac operation using small incisions. With the advent of a voice controlled camera-holding robotic arm (AESOP 3000, Automated Endoscope System for Optimal Positioning), cardiac surgery entered the robotic age. Material and Method: Between April 2004 and December 2004, a total of seventy eight patients underwent robotic cardiac surgery, of whom sixty four patients underwent robot-assisted minimally invasive cardiac surgery via 5cm right lateral minithoracotomy using voice controlled robotic arm, femoral vessels cannulation, percutaneous internal jugular cannulation, transthoracic aortic cross clamp. Other fourteen patients underwent MIDCAB via internal mammary artery harvesting using AESOP. Result: Robotic cardiac surgery were mitral valve repair in 37 cases, mitral valve replacement in 10 cases, aortic valve replacement in 1 case, MIDCAB in 14 cases, ASD operation in 9 cases, and isolated Maze procedure in 1 case. In mitral operation, mean CPB time was $165.3\pm43.1$ minutes and mean ACC time was $110.4\pm48.2$ minutes. Median length of hospital stay was 6 days (range 3 to 30) in mitral operation, 4 days (range 2 to 7) in MIDCAB, and 4 days (range 2 to 6) in ASD operation. For complications, 3 patients were required by reoperation for bleeding. There was no hospital mortality. Conclusion: Our experience of robot cardiac surgery suggests that many cardiovascular surgeons will be able to perform minimally invasive cardiac operations through small incisions with robot-assisted video-direction. Well-designed studies and close long-term follow-up will be required to analyze the benefits of robot-assisted operation.

• Advances in robotics research
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• v.2 no.2
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• pp.113-127
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• 2018

Robotics and automation are rapidly growing in the industries replacing human labor. The idea of robots replacing humans is positively influencing the business thereby increasing its scope of research. This paper discusses the development of an experimental platform controlled by a robotic arm through Robot Operating System (ROS). ROS is an open source platform over an existing operating system providing various types of robots with advanced capabilities from an operating system to low-level control. We aim in this work to control a 7-DOF manipulator arm (Robai Cyton Gamma 300) equipped with an external vision camera system through ROS and demonstrate the task of balancing a ball on a plate-type end effector. In order to perform feedback control of the balancing task, the ball is designed to be tracked using a camera (Sony PlayStation Eye) through a tracking algorithm written in C++ using OpenCV libraries. The joint actuators of the robot are servo motors (Dynamixel) and these motors are directly controlled through a low-level control algorithm. To simplify the control, the system is modeled such that the plate has two-axis linearized motion. The developed system along with the proposed approaches could be used for more complicated tasks requiring more number of joint control as well as for a testbed for students to learn ROS with control theories in robotics.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.3
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• pp.136-148
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• 2017

The paper presents dual arm ROV manipulation using deep reinforcement learning. The purpose of this underwater manipulator is to investigate and excavate natural resources in ocean, finding lost aircraft blackboxes and for performing other extremely dangerous tasks without endangering humans. This research work emphasizes on a self-learning approach using Deep Reinforcement Learning (DRL). DRL technique allows ROV to learn the policy of performing manipulation task directly, from raw image data. Our proposed architecture maps the visual inputs (images) to control actions (output) and get reward after each action, which allows an agent to learn manipulation skill through trial and error method. We have trained our network in simulation. The raw images and rewards are directly provided by our simple Lua simulator. Our simulator achieve accuracy by considering underwater dynamic environmental conditions. Major goal of this research is to provide a smart self-learning way to achieve manipulation in highly dynamic underwater environment. The results showed that a dual robotic arm trained for a 3DOF movement successfully achieved target reaching task in a 2D space by considering real environmental factor.

• Proceedings of The KACE
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• 2017.08a
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• pp.189-192
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• 2017

던지기는 시간 효율이 높은 물체 수송 방법이나 그 정확성을 위해서는 다양한 물리적인 변인들을 고려해야 한다. 따라서 본 연구에서는 정확한 던지기에 영향을 주는 변인들을 설정하여 물체를 정확하게 던지는 해를 찾는 유전 알고리즘을 설계하고, 이를 4자유도 로봇팔에 적용시켰다. 하드웨어는 TETRIX와 EV3 플랫폼을 이용하여 설계하였고, 소프트웨어는 LabVIEW 2014를 이용하여 구현하였다. 또한 물체가 던져질 때마다 위치와 각 변인들의 값을 수집하고, 이를 통계적으로 분석하여 던지기의 정확성에 대한 각 관절의 기여도를 분석하였다. 본 연구의 결과는 물체를 정확히 던지는 기계를 설계하거나 사람의 던지는 동작을 이해하는 데 도움이 될 것으로 기대된다.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.119-128
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• 2015

In this paper, we propose a new motion control technology to design robust control system of industrial robot. The system modeling of robotic manipulation tasks with constraints is presented, and the control architecture for unconstrained and constrained motion system with parametric uncertainties is synthesized. The optimal reference of robot manipulator is generated by the reference controller as a discrete state system and the control behavior of constrained system which has poor modeling information and time-invariant constraint function is improved motion control system is successfully evaluated by experiment to the desired tasks.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.233-238
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• 2001

In the design and operation of robot arms with flexible links, the equations of motion are required to exactly model the interaction between rigid motion and elastic motion and to be formulated efficiently. Thus, the flexible link is represented on the basis of the D-H rigid link represented to measure the elastic deformation. The equations of motion of robot arms, which are configured by the generalized coordinates of elastic and rigid degrees of freedom, are formulated by using F.E.M to model complex shaped links systematically and by eleminating elastic mode of higher order that does not largely affect option to reduce the number of elastic degree of freedom. Finally presented is the result of simulation to flexible robotic arm whose joints are controlled by direct or PD control.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.645-652
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• 2010

For free motions, vibration suppression of single flexible manipulators has been one of the hottest research topics. However, for cooperative motions of multiple flexible manipulators, a little effort has been devoted for the vibration suppression control. So, the aim of this paper is to develop a hybrid force/position control and vibration suppression control scheme for multiple cooperation flexible manipulators handling a rigid object. In order to clarify the discussion, the motions of dual-arm experimental flexible manipulator are considered. Using the developed model, we control a robotic system with hybrid position/force control scheme. Finally, Experiments are performed, and a comparison of experimental results is given to clarify the validity of our control scheme.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.123-129
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• 1996

Computed torque method has been used for precise trajectory control of the robotic system that involves nonlinear dynamics. It is hard to know exact values of robot system parameters, and the robot arm receives umpredictable interference from the working environment. These disturbances, especially in a direct drive robot, are directly transmitted to actuating motor without reduction. Modelling error and distrubance can cause significant errors in a trajectory tracking problem. In this paper, we propose a new controller that $H_{\infty}$controller is conbined to robot system linearized by computed torque. Simula- tions are made for comparing the performance of the proposed controller with that of a nonlinear $H_{\infty}$ controller proposed by Chen and also computed torque method.hod.

• The Journal of Korea Robotics Society
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• v.15 no.4
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• pp.398-403
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• 2020

Robot's throwing control is difficult to accurately calculate because of air resistance and rotational inertia, etc. This complexity can be solved by using machine learning. Reinforcement learning using reward function puts limit on adapting to new environment for robots. Therefore, this paper applied deep reinforcement learning using neural network without reward function. Throwing is evaluated as a success or failure. AI network learns by taking the target position and control policy as input and yielding the evaluation as output. Then, the task is carried out by predicting the success probability according to the target location and control policy and searching the policy with the highest probability. Repeating this task can result in performance improvements as data accumulates. And this model can even predict tasks that were not previously attempted which means it is an universally applicable learning model for any new environment. According to the data results from 520 experiments, this learning model guarantees 75% success rate.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.898-904
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• 1987

A new control algorithm using the VSS theory is developed for accurate trajectory control of robot manipulators. This paper focuses on the implementation of VSS controller with smoothing laws in the design of effective tracking control for robotic arms. The VSS controller for multi-linkage robot arm is realized using balance condition and its simplification which possesses powerful smoothing capability to reduce or even remove undesirable chattering and meanwhile keep the robust characteristic to reject system uncertainties. The design principle of selecting different smoothing methods, which aims at achieving trade-off between smoothing and robust behaviors while considering the actual system constraints, is also given and further confirmed through experimental results.