Hydraulic Control System Using a Feedback Linearization Controller and Disturbance Observer - Sensitivity of System Parameters -

Tae-hyung Kim,Ill-yeong Lee,Ji-seong Jang 유공압건설기계학회 2019 드라이브·컨트롤 Vol.16 No.2

Hydraulic systems have severe nonlinearity inherently compared to other systems like electric control systems. Hence, precise modeling and analysis of the hydraulic control systems are not easy. In this study, the control performance of a hydraulic control system with a feedback linearization compensator and a disturbance observer was analyzed through experiments and numerical simulations. This study mainly focuses on the quantitative investigation of sensitivity on system uncertainties in the hydraulic control system. First, the sensitivity on the system uncertainty of the hydraulic control system with a Feedback Linearization - State Feedback Controller (FL-SFC) was quantitatively analyzed. In addition, the efficacy of a disturbance observer coupled with the FL-SFC for the hydraulic control system was verified in terms of overcoming the control performances deterioration owing to system uncertainty.

동료피드백 시스템 개발 연구: 프로젝트기반학습에서의 팀간 피드백 도구 설계 사례

김영주,임규연 한국교육정보미디어학회 2019 교육정보미디어연구 Vol.25 No.4

This study aims to develop a peer feedback system that supports successful project-based learning. Peer feedback is an activity that exchanges opinions among learners about the tasks performed by colleagues, which attracts attention in the education field where the active participation of learners is important. There are examples of peer feedback systems that have already been developed as a result of efforts to incorporate technology, but they mostly focus on providing an opportunity to reflect on their own team's work within the team. This study integrates between-team peer feedback in the context of project-based learning. Overall, the study followed the procedures of development studies proposed by Richey, Klein, and Nelson (2004). First we reviewed the literature and analyzed the needs of learners, and derived design principles based on the analysis implications. Key features of the suggested peer feedback system are as follows: First, pre-training for the procedure of peer feedback was embedded in the system to ensure the quality of peer feedback. Second, between-team feedback on the other teams’ drafts as well as final outcomes were provided, and shared within the given team. Third, the complexity of the peer feedback activity in terms of logistics is minimized, for example, by assigning feedback providers using the online system. Lastly, the suggested system considered that most of the project-based learning is conducted in the long term, which may require repeated feedback sharing and storing the feedback for later use. Interviews on the usability of the prototype revealed that the learners recognized the system not only useful to improve their project work but also efficient to reduce unnecessary steps. 본 연구에서는 학습자의 성공적인 프로젝트기반학습을 지원하는 동료피드백 시스템을 개발하였다. 동료피드백은 동료가 수행한 과제에 대해 학습자 간 의견을 교환하는 활동으로 학습자의 적극적인 참여를 중요시하는 교육현장에서 꾸준히 주목받는 학습 활동이다. 테크놀로지를 교육현장에 접목하려는 노력의 결과로 이미 개발된 동료피드백 시스템 사례가 존재하나, 프로젝트기반학습에 최적화되어 팀 간 동료피드백 활동을 지원함으로써 자신의 팀이 수행한 과제에 대해 성찰할 수 있는 기회를 제공하는 시스템은 찾아보기 어렵다. 본 연구에서는 우선 동료피드백 관련 문헌검토 및 학습자를 대상으로 한 요구분석을 실시하였고, 그 결과를 바탕으로 설계원리를 도출하여 Richey, Klein과 Nelson(2004)이 제안한 개발연구의 일련의 절차에 따라 동료피드백 시스템을 설계 및 개발하였다. 개발된 동료피드백 시스템의 대표적 특징은 첫째, 동료피드백 활동에 대한 사전훈련을 시스템에 탑재하여 동료피드백의 품질을 확보하고자 하였으며, 둘째, 다른 팀이 도출한 중간/최종산출물에 대해 팀간 피드백을 주고받을 수 있는 기능 및 제공받은 피드백의 팀 내 공유 기능 등을 제공하여 팀간 및 팀내 상호작용을 촉진하였고, 셋째, 피드백 제공자의 지정 방식 등을 설계에 고려함으로써 동료피드백 활동의 절차적 복잡도를 최소화하였다. 또한 이전에 작성했던 모든 피드백에 대한 검토를 가능하게 하는 등 프로젝트기반학습이 대부분이 장기적으로 진행된다는 점을 고려하였다. 개발된 동료피드백 시스템의 사용성을 파악하기 위해 프로젝트기반으로 진행되는 대학원 수업에서 이를 활용한 결과, 학습자들은 편리성, 효과성 측면에서 긍정적으로 인식하였다.

다각적인 학습을 위한 피드백 시스템 디자인 연구 -게이미피케이션의 배지 보상 시스템을 적용하여-

정새해(주저자) ( Sae Hae Chung ),이현진(교신저자) ( Hyun Jean Lee ) 디자인융복합학회 2015 디자인융복합연구 Vol.14 No.6

본 연구는 게이미피케이션 설계방식을 도입한 학습 관리가 학습자의 몰입과다각적 학습에 영향을 끼치는지 그 효과를 알아보고자 진행하였다. 먼저 선행 연구를 통해 게이미피케이션에서 활용되는 배지 보상 시스템을 검토하고, 이를 바탕으로 교육 현장에서 활용할 수 있는 통합적 피드백 방식과 분석적 피드백 방식의 스티커 보상 시스템을 설계하였다. 그 후 설계된 피드백 시스템을 다각적 학습의 효과성을 검증하기 위하여, 초, 중등 학생을 대상으로 한 프로그래밍, 그래픽, 사운드, 기획 등의 다각적이고 통합적인 학습을 요하는 스크래치(Scratch) 수업의 숙제관리에 적용하는 실험을 진행하였다. 그리고 피험자들의 학습 내용에 대한 이해와 몰입, 숙제 수행도가 어떠한 변화를 보이는지 분석하였다. 본 연구는 두 가지 피드백 시스템이 학생들에게 학습 동기를 높인다는 점과, 특히 분석적 피드백 시스템의 경우다각적 학습에 긍정적인 영향을 끼친다는 것을 확인하였다. 더불어 본 피드백 시스템이 교사에게도 학습자의 성취도와 이해와 개인적 적성과 관심 등의 변화를 파악하는 도구로서 사용될 수 있음도 파악할 수 있었다. 본 연구는 게이미피케이션과 교육의 접목에 대한 구체적 방법론과 방향성에 대하여보다 세부적 논의를 이끌어 내며, 특히 다각적 학습을 위한 피드백 설계 연구에 유의미한 실천이 될 수 있기를 기대한다. This article presents a study of feedback system in integrative learning environment applying gamification’s badge reward system. Especially this focuses on gamified feedback interface design, examining the effects for learners’ immersion, flow, and homework performance in their learning experience. First, the badge reward mechanism in gamification is examined as literature review, and then, based on such, two different sticker reward feedback interfaces.a synthetic feedback and an analytic feedback-are designed. With the designed feedback systems, we experiment these with a group of elementary and middle school students who are in Scratch class. Scratch requires integrative learnings including programming, graphic design, sound design, and idea planning. Our experiment examined how the sticker reward feedback system aroused their motivation and leaded them to a helpful immersion status. Also we discovered that the analytic feedback system can not only enrich thediversified education for learners but also became a useful tool for teachers, guiding their students’ current knowledge, talents/interests, and their achievements. We hope this research nourishes the study of gamification methodologies, and particularly of a feedback system interface designing for diversified and integrative education.

무선 가속도센서 시스템을 이용한 건축물의 실시간 피드백 진동제어 : 시스템 구축 및 기초성능 평가

전준용,박기태,이진옥,허광희,이우상 한국구조물진단유지관리공학회 2013 한국구조물진단유지관리공학회 논문집 Vol.17 No.2

본 논문에서는 건축물의 실시간 피드백 진동제어를 위한 기초연구로써, 자체 기술력을 바탕으로 개발된 무선 가속도센서 시스템 및 프로토타입 (Prototype) AMD 시스템을 결합하여 피드백 진동제어 시스템을 구성하고, 모형 건축물을 대상으로 구성된 제어시스템의 기초성능을 평가하고자 하였다. 이를 위하여 본 논문에서는 우선 MEMS 센서 소자 및 블루투스 통신 모듈 기반의 무선 가속도 센서 유닛, 실시간 가속도 응답획득 및 제어법칙에 근거한 제어출력을 구현하도록 구성한 운영프로그램 등을 개발하였다. 또한 AC 서보모터를 이용해 기동되도록 설계한 프로토타입 AMD 및 모터 드라이버 시스템을 구성하였다. 마지막으로 이를 이용해 실시간 피드백 진동제어 시스템을 구성하였고, 2층 모형 건축물을 대상으로 실험실 규모의 진동제어 실험을 수행하여 목적된 구조물의 진동저감 효과를 정량적으로 분석하였다. 실험의 결과, 모형 구조물의 1차 및 2차 공진주파수 그리고 랜덤주파수 등의 실험조건에서 명확한 진동저감의 효과를 확인할 수 있었으며, 종국적으로 본 논문에서 개발한 무선 가속도센서 시스템 및 AMD 시스템이 향후 여타 구조물의 진동제어를 위한 효과적인 수단으로 응용될 수 있는 가능성을 확인하였다. This is a preliminary study for the real-time feedback vibration control of building structures. The study developed a wireless acceleration sensor system based on authentic technology capacities, to integrate with the Prototype AMD system and ultimately construct the feedback vibration control system. These systems were used to evaluate the basic performance levels of the control systems within model building structures. For this purpose, the study first developed a wireless acceleration sensor unit that integrates an MEMS sensor device and bluetooth communication module. Also, the study developed an operating program that enables control output based on real-time acceleration response measurement and control law. Furthermore, the Prototype AMD and motor driver system were constructed to be maneuvered by the AC servo-motor. Eventually, all these compositions were used to evaluate the real-time feedback vibration control system of a 2-story model building, and qualitatively measure the extent of vibrational reduction of the target structure within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within 1st and 2nd resonance frequency as well as the random frequency of the model building structure. Ultimately, this study confirmed the potential of its wireless acceleration sensor system and AMD system as an effective tool that can be applied to the active vibration control of other structures.

지식관리시스템의 성공요인에 관한 탐색적 연구: 지각된 피드백을 중심으로

김승운 ( Seung Woon Kim ),강희택 ( Hee Taek Kang ) (주)엘지씨엔에스(구 LGCNS 엔트루정보기술연구소) 2011 Entrue Journal of Information Technology Vol.10 No.2

본 연구는 피드백 이론과 정보시스템 성공모형을 토대로 사용자가 등록한 지식에 대하여 받은 피드백(등록지식에 대한 피드백) 및 지식요청에 대하여 받은 피드백(요청지식에 대한 피드백)과 시스템 요인(시스템품질, 지식품질), 사용(지식기여, 지식수집), 사용자만족, 개인성과간의 관계를 탐색하기 위한 것이다. 분석결과, 등록지식에 대한 피드백은 지식기여에 영향을 미친 반면에 지식요청에 대한 피드백은 지식기여와 지식수집에 모두 영향을 미치는 것으로 나타났다. 사용자 만족은 지각된 피드백보다는 시스템 품질과 지식품질에 의해 결정되는 것으로 나타났으며, 지식품질은 지식기여와 지식수집에 영향을 미치는 것으로 나타났다. 사용자 만족은 지식기여, 지식수집, 개인성과에 영향을 미치고, 지식수집은 개인성과에 영향을 미치는 것으로 밝혀졌다. Based on feedback related theories and Information system success model, this study explores the relationship among feedback which donators receive on their knowledge (Feedback on Posted Knowledge), feedback which collectors receive from other users when they ask for knowledge (Feedback on Knowledge Request Postings), system characteristics (System Quality and Knowledge Quality), user satisfaction, use (Knowledge Donating, Knowledge Collecting), and individuall outcome. The results show, firstly, that feedback on posted knowledge affects knowledge donating only, while feedback on knowledge request postings influences both knowledge donating and know ledge collecting. Secondly, user satisfaction is determined by system quality and knowledge quality rather than perceived feedback, and knowledge quality, in turn, is positively related to both knowledge donating and knowledge collecting. Thirdly, user satisfaction has a significant impact on knowledge donating, knowledge collecting, and individual outcome, and knowledge collecting affects individual outcome.

하수도 시스템의 효율적인 운영 및 유지관리를 위한 시스템다이내믹스 모형의 개발

박수완,이태근,김봉재,김태영 한국수자원학회 2012 한국수자원학회논문집 Vol.45 No.1

본 논문에서는 시스템 다이내믹스(System Dynamics, SD) 방법론에 입각하여 하수도 시스템의 운영지표들과 이에 영향을 미치는 외부변수들로 구성된 피드백 루프 메커니즘(Feedback Loop Mechanism)을 관로유지관리와 연관하여 규명하고, 외부변수의 변화에 따른 운영지표의 변화를 예측함으로써 하수도 시스템의 효율적인 운영 및 유지관리 방안을 모색할 수 있는 SD 컴퓨터 모의 모형(Computer Simulation Model)을 개발하였다. 개발된 모형에 부산광역시 하수도 시스템의 과거 운영 자료를 적용함으로써 모형을 검증하였고, 미래의 운영 상황을 예측하였다. 그 결과, 하수도보급률은 이미 목표치에 거의 도달하여 큰 변동이 없을 것으로 예측되었으며, 하수처리효율과 하수처리량, 요금현실화율은 점차 증가할 것으로 예측되었다. 또한 정책 지렛대의 발견을 위해 시스템에 큰 영향을 미치는 주요 운영지표를 선정하여 외부변수의 변화에 대한 민감도 분석을 수행하였는데, 그 결과 관로 유지관리와 연관된 외부변수는 하수처리효율의 변화뿐만 아니라 시설이용률, 하수처리량 등의 변화에도 큰 영향을 미치는 것으로 분석되었다. In this paper, the feedback loop mechanisms among the operational indices and exogenous variables of a sewerage system that are inherent in the operation and maintenance of a sewerage system were identified using the System Dynamics (SD) modeling methodology. The identified feedback loops were used to develop a SD computer simulation model that can be used to predict future operational conditions of a sewerage system and identified the efficient ways of operation. The data of Busan metropolitan city sewerage system was applied to verify the developed SD model and predict future operational conditions of the system. As a result, it was predicted that sewage treatment efficiency, volume of sewage treatment and cost recovery rate will be gradually increased, whereas service rate which was already very close to the target will remain almost the same as the current value. Furthermore, sensitivity analysis concerning some operational indices was performed in order to discover the policy leverage. As a result, it was found that the exogenous variables related to the pipe maintenance had a great effect on facility using rate, volume of sewage treatment as well as sewage treatment efficiency.

Hydraulic Control System Using a Feedback Linearization Controller and Disturbance Observer - Sensitivity of System Parameters -

Kim, Tae-hyung,Lee, Ill-yeong,Jang, Ji-seong The Korean Society for Fluid Power and Constructio 2019 드라이브·컨트롤 Vol.16 No.2

Hydraulic systems have severe nonlinearity inherently compared to other systems like electric control systems. Hence, precise modeling and analysis of the hydraulic control systems are not easy. In this study, the control performance of a hydraulic control system with a feedback linearization compensator and a disturbance observer was analyzed through experiments and numerical simulations. This study mainly focuses on the quantitative investigation of sensitivity on system uncertainties in the hydraulic control system. First, the sensitivity on the system uncertainty of the hydraulic control system with a Feedback Linearization - State Feedback Controller (FL-SFC) was quantitatively analyzed. In addition, the efficacy of a disturbance observer coupled with the FL-SFC for the hydraulic control system was verified in terms of overcoming the control performances deterioration owing to system uncertainty.

The Effect of Visual Feedback on One-hand Gesture Performance in Vision-based Gesture Recognition System

Junho Kim,Ji Hyoun Lim,Sung Hyun Moon 대한인간공학회 2012 大韓人間工學會誌 Vol.31 No.4

Objective: This study presents the effect of visual feedback on one-hand gesture performance in vision-based gesture recognition system when people use gestures to control a screen device remotely. Backgroud: gesture interaction receives growing attention because it uses advanced sensor technology and it allows users natural interaction using their own body motion. In generating motion, visual feedback has been to considered critical factor affect speed and accuracy. Method: three types of visual feedback(arrow, star, and animation) were selected and 20 gestures were listed. 12 participants perform each 20 gestures while given 3 types of visual feedback in turn. Results: People made longer hand trace and take longer time to make a gesture when they were given arrow shape feedback than star-shape feedback. The animation type feedback was most preferred. Conclusion: The type of visual feedback showed statistically significant effect on the length of hand trace, elapsed time, and speed of motion in performing a gesture. Application: This study could be applied to any device that needs visual feedback for device control. A big feedback generate shorter length of motion trace, less time, faster than smaller one when people performs gestures to control a device. So the big size of visual feedback would be recommended for a situation requiring fast actions. On the other hand, the smaller visual feedback would be recommended for a situation requiring elaborated actions.

Hydraulic Control System Using a Feedback Linearization Controller and Disturbance Observer - Sensitivity of System Parameters -

김태형,이일영,장지성 사단법인 유공압건설기계학회 2019 드라이브·컨트롤 Vol.16 No.2

Hydraulic systems have severe nonlinearity inherently compared to other systems like electric control systems. Hence, precise modeling and analysis of the hydraulic control systems are not easy. In this study, the control performance of a hydraulic control system with a feedback linearization compensator and a disturbance observer was analyzed through experiments and numerical simulations. This study mainly focuses on the quantitative investigation of sensitivity on system uncertainties in the hydraulic control system. First, the sensitivity on the system uncertainty of the hydraulic control system with a Feedback Linearization - State Feedback Controller (FL-SFC) was quantitatively analyzed. In addition, the efficacy of a disturbance observer coupled with the FL-SFC for the hydraulic control system was verified in terms of overcoming the control performances deterioration owing to system uncertainty.

Effects of Feedback Conditions on Involuntary Positional Shifts Reduction in a Virtual Environment Navigation Task

Yong Min Kim(김용민) 대한인간공학회 2021 대한인간공학회 학술대회논문집 Vol.2021 No.11

Objective: This study aims to investigate the effects of feedback conditions on users’ involuntary positional shift (IPS) when performing navigation tasks in a virtual environment using motion-based repositioning locomotion techniques. Background: Users should be able to safely experience virtual reality (VR) without leaving the designated play area. However, a significant amount of IPS may occur when using certain locomotion techniques. In particular, the IPS is more likely to occur when using leg motion-based locomotion techniques than controller-based techniques. The consequences of IPS can cause critical safety problems such as collisions with walls and physical injuries. Method: Twenty-six participants were recruited in this experiment (Male = 16, Female = 10), and an HTC Vive Pro, a head-mounted display (HMD)-based VR device, was used. Participants were asked to perform a navigation task and feedback was provided when the participants were outside the boundaries of the safe area. There were four feedback conditions: visual feedback, auditory feedback, visual-auditory feedback, and no feedback. Real-time log data was recorded, and the data includes three-dimensional coordinate values for the positions of HMD and virtual objects, collision events with virtual walls, and warning feedback presentation events. Results: Providing feedback was effective in reducing IPS. The bounding box area and the convex hull area were significantly smaller in the conditions in which the feedback was provided compared to the case in which no feedback was provided. In addition, among the feedback conditions, the visual-auditory feedback was evaluated as the most useful and satisfactory. Conclusion: The feedback system for IPS reduction designed in this study was proved to be effective for IPS reduction regardless of the feedback conditions. Application: It is expected that the feedback system for IPS reduction could help users perform navigation tasks more safely when using motion-based locomotion techniques. Also, the findings of this study are expected to contribute to safer VR content design.