• 제목/요약/키워드: variable platform

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가변형 병렬기구에 대한 작업공간과 힘/모멘트 전달 특성 해석 (Workspace and Force-Moment Transmission of a Parallel Manipulator with Variable Platform)

  • 김병창;이세한
    • 제어로봇시스템학회논문지
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    • 제12권2호
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    • pp.138-144
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    • 2006
  • Kinematic and dynamic characteristics of a Stewart platform based parallel manipulators are fixed once they are constructed. Thus parallel manipulators with various configurations are required to meet a variety of applications. In this research a parallel manipulator with variable platform (PMVP) has been developed, in which the length of the arm linking the platform center to the platform-leg contact point can be varied by an actuator. The workspace of the PMVP is larger than that of a traditional Stewart platform and especially the range in which the maximum orientation angles can be maintained is significantly expanded. Furthermore, the characteristics of force and moment transmission between the legs and platform can be adjusted to meet the requirements of various tasks. Kinematic and dynamics analysis was performed to verify the usefulness of the PMVP and the actual hardware was built to demonstrate the feasibility.

화력발전소 보일러 수퍼히트부 안전발판 개발 연구 (A Development of Platforms for Boiler of Thermal Power Plant)

  • 이정석;이동락;김희경;정병용;오태근
    • 한국안전학회지
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    • 제32권3호
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    • pp.34-40
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    • 2017
  • The catastrophic collapse of the in-boiler scaffolding system in the two thermal power plants occurred in March and April 2012. After site investigation and document review, it was found that the specialized scaffolding system was imported for overhaul & maintenance and that the system did not get the safety certification at the import. In this regard, this study developed & proposed an access platform and a support for the vertical tube section of the super heat as well as a variable-length platform for the horizontal tube section, satisfying the domestic certification standards. The access platform was developed to be easy to handle by the worker with a weight of about 0.069 kN, which could reduce the risk of falling accidents and workers' musculoskeletal diseases. For the variable-length platform, it is possible to cope with various changes in length between the horizontal tubes associated with the increase of rigidity in the overlapping and the elimination of the protrusion.

블록체인을 이용한 뉴스 미디어 플랫폼 사용에 영향을 미치는 요인 분석 (Analyses of Factors Affecting the Use of News Media Platforms with Blockchain Technology)

  • 허광호;김인재
    • 한국정보시스템학회지:정보시스템연구
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    • 제31권3호
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    • pp.131-152
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    • 2022
  • Purpose The purpose of this study was to investigate the intention of using a news media platform using block chain through media company workers in a situation where various platform services using block chain are being newly released in the media industry. Therefore, in this paper, we intend to explore the development direction of the news media platform service using the block chain in the future by deriving implications through the characteristics of the block chain, user characteristics, and self-determination factors. Design/methodology/approach This study conducted a survey on the main characteristics of blockchain, user characteristics, self-determination, resistance to innovation, etc., and designed a research model by integrating factors on the continuity of intention to use the news media platform. Findings According to the empirical analysis result, in this study, it was confirmed that the intention to use the blockchain news media platform is significantly related to decentralization, which is a characteristic variable of the blockchain, perceived risk, which is a user characteristic variable, and competence and relationship, which is a self-determination variable. In addition, it was confirmed that it affects the perceived ease of use with respect to the intention to use. In addition, in this study, news writers write more careful articles as they cannot edit articles once written, which can contribute to improving the quality of news content.

밭 노지 환경 주행을 위한 모듈형 농업 로봇 플랫폼에 대한 연구 (A Study on Modular Agricultural Robotic Platform for Upland)

  • 조용준;우성용;송수환;홍형길;윤해룡;오장석;김준성;김동우;서갑호;김대희
    • 로봇학회논문지
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    • 제15권2호
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    • pp.124-130
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    • 2020
  • This paper designed modular agricultural robotic platform capable of a variety of agricultural tasks to address the problems caused by a decline in agricultural populations and an increase in average age. We propose a modular robotic platform that can perform many tasks required in field farming by replacing only work modules with common robotic platforms. This platform is capable of steering while driving on four wheels in an upland environment where farm work is performed, and an attitude control module is attached to each drive module to control the attitude of the platform. In addition, the width of the platform is designed to be variable in order to operate in various ridges according to the crop cultivation method. Finally, we evaluated five items: variable width, gradient, attitude control angle, step and road speed in order to carry out the farming industry while maintaining a stable posture.

농업용 무한궤도형 자율주행 플랫폼의 경로 추종 및 추종 성능 향상을 위한 가변형 전방 주시거리 알고리즘 개발 (Development of Path Tracking Algorithm and Variable Look Ahead Distance Algorithm to Improve the Path-Following Performance of Autonomous Tracked Platform for Agriculture)

  • 이규호;김봉상;최효혁;문희창
    • 로봇학회논문지
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    • 제17권2호
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    • pp.142-151
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    • 2022
  • With the advent of the 4th industrial revolution, autonomous driving technology is being commercialized in various industries. However, research on autonomous driving so far has focused on platforms with wheel-type platform. Research on a tracked platform is at a relatively inadequate step. Since the tracked platform has a different driving and steering method from the wheel-type platform, the existing research cannot be applied as it is. Therefore, a path-tracking algorithm suitable for a tracked platform is required. In this paper, we studied a path-tracking algorithm for a tracked platform based on a GPS sensor. The existing Pure Pursuit algorithm was applied in consideration of the characteristics of the tracked platform. And to compensate for "Cutting Corner", which is a disadvantage of the existing Pure Pursuit algorithm, an algorithm that changes the LAD according to the curvature of the path was developed. In the existing pure pursuit algorithm that used a tracked platform to drive a path including a right-angle turn, the RMS path error in the straight section was 0.1034 m and the RMS error in the turning section was measured to be 0.2787 m. On the other hand, in the variable LAD algorithm, the RMS path error in the straight section was 0.0987 m, and the RMS path error in the turning section was measured to be 0.1396 m. In the turning section, the RMS path error was reduced by 48.8971%. The validity of the algorithm was verified by measuring the path error by tracking the path using a tracked robot platform.

The Experiment of the Robust Multi-Variable Controller and the LQG/LTR Controller for the Stewart Platform

  • Joon, Heo-Seong;Woo, Ko-Dong;Chul, Han-Myung
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.147.4-147
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    • 2001
  • This work presents the robust controller and the LQG/LTR controller for the stewart platform. To simplify the dynamics we combine equation of the stewart platform and linearized one of hydraulic actuators not considered condensability of the fluid. Through the connection of two dynamic equations we can omit force feedback process of actuators and design controllers for the whole system. We applied two controllers on the stewart platform and show the adequacy controllers through the result of simulation and experiment.

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Layout optimization for multi-platform offshore wind farm composed of spar-type floating wind turbines

  • Choi, E.H.;Cho, J.R.;Lim, O.K.
    • Wind and Structures
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    • 제20권6호
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    • pp.751-761
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    • 2015
  • A multi-platform offshore wind farm is receiving the worldwide attention for the sake of maximizing the wind power capacity and the dynamic stability at sea. But, its wind power efficiency is inherently affected by the interference of wake disturbed by the rotating blades, so its layout should be appropriately designed to minimize such wake interference. In this context, the purpose of this paper is to introduce a layout optimization for multi-platform offshore wind farm consisted of 2.5MW spar-type floating wind turbines. The layout is characterized by the arrangement type of wind turbines, the spacing between wind turbines and the orientation of wind farm to the wind direction, but the current study is concerned with the spacing for a square-type wind farm oriented with the specific angle. The design variable and the objective function are defined by the platform length and the total material volume of the wind farm. The maximum torque loss and overlapping section area are taken as the constraints, and their meta-models expressed in terms of the design variable are approximated using the existing experimental data and the geometry interpretation of wake flow.

Relevant Analysis on User Choice Tendency of Intelligent Tourism Platform under the Background of Text mining

  • Liu, Zi-Yang;Liao, Kai;Guo, Zi-Han
    • 한국컴퓨터정보학회논문지
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    • 제24권9호
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    • pp.119-125
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    • 2019
  • The purpose of this study is to find out the relevant factors of the choice tendency of tourism users to Intelligent Tourism platform through big data analysis, which will help enterprises to make accurate positioning and improvement according to user information feedback in the tourism market in the future, so as to gain the favor of users' choice and achieve long-term market competitiveness. This study takes the Intelligent Tourism platform as the independent variable and the user choice tendency as the dependent variable, and explores the related factors between the Intelligent Tourism platform and the user choice tendency. This study make use of text mining and R language text analysis, and uses SPSS and AMOS statistical analysis tools to carry out empirical analysis. According to the analysis results, the conclusions are as follows: service quality has a significant positive correlation with user choice tendency; service quality has a significant positive correlation with tourism trust; Tourism Trust has a significant positive correlation with user choice tendency; service quality has a significant positive correlation with user experience; user experience has a significant positive correlation with user choice tendency Positive correlation effect.

가변형상 트러스구조물의 자세제어 (Configuration Control of Vaiable-Geometry Truss Structures)

  • 노태환;김태익;박현철;권영두
    • 대한기계학회논문집A
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    • 제20권9호
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    • pp.2854-2865
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    • 1996
  • The concept of variable-geometry truss structure(VGTS) is introduced as a class of actively controlled adaptive structure. VGTS can purposefully vary its geometric configurations by changing the lengths of some members of the structure. General kinematics and inverse kinematics of a statically determinate VGTS(variable geometry truss structure) are studied. The solution technique is based on the Jacobian matrix obtained via joint equilibrium equations. Pseudoinverse control method is applied to resolve the redundancy of a large VGTS. two types of actuator layout of octahedral type VGTS, VG truss and Stewart platform, are compared. Introducing the concept of performance index, Stewart platform based layout was found to has less consumption energy and manipulation time. A functional VGTS model with 3 octahedral modules is designed and manufactured for the labaratory demonstration. Six vertically located length-variable members are used to create general 6 d.o.f. motions.

스튜어트 플랫폼의 견실제어를 위한 슬라이딩 섭동 관측기를 갖는 슬라이딩 모드 제어기 개발 (The Design of Sliding Mode Controller with Sliding Perturbation Observer for a Robust Control of Stewart Platform Manipulator)

  • 유기성;박민규;이민철
    • 제어로봇시스템학회논문지
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    • 제8권8호
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    • pp.639-648
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    • 2002
  • The stewart platform manipulator is a manipulator that has the closed-loop structure with an upper plate end-effector and a base frame. The stewart platform manipulator has the merit of high working accuracy and high stiffness compared with a serial manipulator. However, this is a complex structure, so controllability of the system is not so good. In this paper, we introduce a new robust motion control algorithm using partial state feedback for a class of nonlinear systems in the presence of modelling uncertainties and external disturbances. The major contribution of this work introduces the development and design of robust observer for the state and the perturbation, which is integrated into a variable structure controller(VSC) structure. The combination of controller/observer improves the control performance, because of the robust routine called sliding mode control with sliding perturbation observer(SMCSPO). Simulation and experiment are performed to apply to the manipulator. And their results show a high accuracy and a good performance.