• 한국전자통신학회논문지
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• 제6권1호
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• pp.142-147
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• 2011

본 연구에서는 로봇 미들웨어 기술 중 국제표준으로 채택된 RTM을 이용하여 7자유도 매니퓰레이터 협업로봇의 구성 요소를 RT 컴포넌트로 만들었다. 또한 미들웨어 네트워크를 기반으로 로봇 구성 요소의 RT 컴포넌트를 서로 연결하여 하나의 로봇 시스템을 구현하였으며, 실제 제작된 7자유도 매니퓰레이터를 이용하여 구현 시스템의 동작을 테스트하였다.

• 한국정밀공학회지
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• 제32권2호
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• pp.191-198
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• 2015

In this paper, six-degree-of-freedom (DoF). Displacement measurement technique using a compact stereo-vision system is proposed. The measuring system consists of a camera, an optical prism, two plane mirrors, and a planar marker on a target. The target was attached on an object so that its six-DoF displacement can be calculated using a proposed coordinates estimating algorithm and stereo images of the marker. A prototype was designed and fabricated for performance test. From the test results, it can be confirmed that the proposed measuring technique can be applied to monitoring and control of various manipulators.

• International Journal of Precision Engineering and Manufacturing
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• 제8권2호
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• pp.3-8
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• 2007

A machining system that generates accurate relative motions between the tool and workpiece is required to realize ultra precise machining or measurements. Accuracy improvements for each element of the machine are also required. This paper proposes a machining system that uses a compensation device for the six-degree-of-freedom (6-DOF) motion error between the tool and workpiece. The compensation device eliminates elastic and thermal errors of the joints and links due to temperature fluctuations and external forces. A hexapod parallel kinematics mechanism installed between the tool spindle and surface plate is passively actuated by a conventional machine. Then the parallel mechanism measures the 6-DOF motions. We describe the conception and fundamentals of the system and test a passively extensible strut with a compensation device for the joint errors.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.888-893
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• 1998

In this paper, we present a magnetic levitation system which has not a gap sensor with sensor-less realization and stabilizing controller design. For measuring gap between magnet and levitated object we propose a gap sensorless method and adop two-degree-of-freedom controller for robust-ness and performence of the magnetic levitation system. From time responeses we confirm that the proposed sensorless method which can be applied to magnetic levitation system. Also the designed stabilizing controller has good disturbance rejection and reference tracking performance.

• 로봇학회논문지
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• 제19권2호
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• pp.176-187
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• 2024

Recently, automated solutions using collaborative robots have been emerging in various industries. Their primary functions include Pick & Place, Peg in the Hole, fastening and assembly, welding, and more, which are being utilized and researched in various fields. The application of these robots varies depending on the characteristics of the grippers attached to the end of the collaborative robots. To grasp a variety of objects, a gripper with a high degree of freedom is required. In this paper, we propose a service automation system using a multi-degree-of-freedom gripper, collaborative robots, and vision sensors. Assuming various products are placed at a checkout counter, we use three cameras to recognize the objects, estimate their pose, and create grasping points for grasping. The grasping points are grasped by the multi-degree-of-freedom gripper, and experiments are conducted to recognize barcodes, a key task in service automation. To recognize objects, we used a CNN (Convolutional Neural Network) based algorithm and point cloud to estimate the object's 6D pose. Using the recognized object's 6d pose information, we create grasping points for the multi-degree-of-freedom gripper and perform re-grasping in a direction that facilitates barcode scanning. The experiment was conducted with four selected objects, progressing through identification, 6D pose estimation, and grasping, recording the success and failure of barcode recognition to prove the effectiveness of the proposed system.

• 대한산업공학회지
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• 제23권4호
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• pp.779-791
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• 1997

The purpose of this study is to measure a perceived joint discomfort in the seated and standing position, and to provide ranking systems of perceived joint discomfort. Nineteen mole subjects with no history of musculo-skeletal disorders participated in the experiment. Their physical characteristics were: age $-25.4{\pm}2.7$years, stature $-171.9{\pm}6.0cm$, and body weight $-67.1{\pm}7.0kg$. The results showed that the perceived joint discomforts were different depending upon the joints involved in motion and their movement directions (degree of freedom of motions), which implied that the human body motions and their degrees of freedom should be classified into several distinct classes that need to be assigned different weights of postural stress. Therefore, three ranking systems based on the perceived joint discomforts were suggested, which were classified by the degree of freedom of motions and joints, by only degree of freedom motions, and by joints involved in motion, respectively. In the seated position, the hip movement was the most stressful, the bock was the second, and the shoulder was the third. Likewise, in the standing postures, the hip was the most, the bock was the second, and the ankle was the third. It was expected that these joint motion ranking systems could be used by practitioners of health and safety to improve the comfort of working postures in industry.

• 한국멀티미디어학회논문지
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• 제20권6호
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• pp.927-934
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• 2017

As the technology of drone develops, the use of drone is increasing, In addition, the types of sensors that are inside of smart phones are becoming various and the accuracy is enhancing day by day. Various of researches are being progressed. Therefore, we need to control drone by using smart phone's sensors. In this paper, we propose the most suitable machine learning model that matches the gyro sensor data with drone's moving. First, we classified drone by it's moving of the gyro sensor value of 4 and 8 degree of freedom. After that, we made it to study machine learning. For the method of machine learning, we applied the One-Rule, Neural Network, Decision Tree, and Navie Bayesian. According to the result of experiment that we designated the value from gyro sensor as the attribute, we had the 97.3 percent of highest accuracy that came out from Naive Bayesian method using 2 attributes in 4 degree of freedom. On and the same, in 8 degree of freedom, Naive Bayesian method using 2 attributes showed the highest accuracy of 93.1 percent.

• 제어로봇시스템학회논문지
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• 제5권3호
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• pp.324-337
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• 1999

In this work, a new 3-PSP type spatial 3-degree-of-freedom parallel mechanism is proposed. And a 6 DOF hybrid manipulator which consists of a 3-PPR type planar 3 DOF parallel mechanism and a new 3-PSP type spatial 3-degree-of-freedom parallel mechanism is proposed. Both 3 DOF mechanism modules have closed-form forward position solutions and particularly, 3-PSP spatial module has unique forward position solution. Firstly, the closed-form position analysis and first-order kinematic analysis for the proposed 3-PSP type module are carried out, and the first-order kinematic characteristics are examined via maximum singular value and the isotropic index of the mechanism. It is shown through these analyses that the mechanism has excellent isotrpic property throughout the workspace. Secondly, position and kinematic analysis of the 3-PPR planar module are briefly described. Thirdly, the forward position analysis for the 3-PPR 3-PSP type 6 degree-of-freedom hybrid mechanism consisting of a 3-PPR planar module and a 3-PSP spatial module is performed along with the analysis of the workspace size and first-order kinematic characteristics. The kinematic characteristics of the proposed hybrid manipulator are compared to those of geometrically similar Stewart manipulator.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2301-2309
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• 2018

In a field-oriented vector-controlled permanent magnet synchronous motor (PMSM) control system, the d-axis current control loop can offer a free degree of freedom which can be used to improve control performances. However, in the industry the desired d-axis current command is usually set as zero without using the free degree of freedom. This paper proposes a method to use the degree of freedom for control performance improvement. It is assumed that both the inner loop proportional-integral (PI) current controller and the q-axis outer loop PI speed controller are tuned by the well-known tuning rules. This paper gives an optimal d-axis reference current command generator such that some useful performance indexes are minimized and/or a tradeoff between conflicting performance criteria is made. This paper uses a differential evolution algorithm to autotune the parameter values of the optimal d-axis reference current command generator. This paper implements the proposed control system in real time on a Texas Instruments TMS320F28335 floating-point DSP. This paper also gives experimental results showing the practicality and feasibility of the proposed control system, along with simulation results.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 춘계학술발표대회
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• pp.600-603
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• 2020

360 영상은 시청자가 시야방향을 결정하는 3DoF(3 Degree of Freedom)를 지원한다. 본 연구에서는 다수의 360 영상에서 깊이 정보를 획득하고, 이를 DIBR (Depth -based Image Rendering) 기법을 사용하여 임의 시점 시청기능을 제공하는 6DoF(6 Degree of Freedom) 영상제작 기법을 제안한다. 이를 위하여 기존의 평면 다시점 영상기법을 확장하여 360 ERP 투영 영상으로부터 카메라의 파라미터 예측을 하는 방법과 깊이영상 추출 방법을 설계 및 구현하고 그 성능을 조사하였으며, OpenGL 그래픽스기반의 RVS(Reference View Synthesizer) 라이브러리를 사용하여 DIBR을 적용하였다.