A Fuzzy Skyhook Algorithm Using Piecewise Linear Inverse Model

Jeongmok Cho,Bong Soo Yoo,Jeongseon Joh 한국지능시스템학회 2006 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.6 No.3

In this paper, the nonlinear damping force model is made to identify the properties of the ER damper using higher order spectrum. The higher order spectral analysis is used to investigate the nonlinear frequency coupling phenomena with the damping force signal according to the sinusoidal excitation of the damper. Also, this paper presents an inverse model of the ER damper, i.e., the model can predict the required voltage so that the ER damper can produce the desired force for the requirement of vibration control of vehicle suspension systems. The inverse model has been constructed by using piecewise linear damping force model. In this paper, the fuzzy logic control based on heuristic knowledge is combined with the skyhook control. And it is simulated for a quarter car model. The acceleration of the sprung mass is included in the premise part of the fuzzy rules to reduce the vertical acceleration RMS value of the sprung mass. Then scaling factors and membership functions are tuned using genetic algorithm to obtain optimal performance.

Occlusion Filling in Dynamic Programming with Simple Index Treatment

JeongMok HA,Hong JEONG 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

One of the problems in stereo matching algorithm is that it is impossible to estimate the most left positioned pixels with left reference system or the most right positioned pixels with right reference system because of the characteristic of stereo vision. That means in stereo matching algorithm, it cannot estimate disparity in occlusion parts. We used very simple index treatment to solve this problem, to compare original DP algorithm exactly, and to make not complex system. We could see that occlusion areas are filled when we used improved DP. If we add more techniques that are used frequently to other stereo matching algorithm, we could get more exact and reliable results.

Fuzzy Skyhook Control of A Semi-active Suspension System

Jeongmok Cho,Taegeun Jung,Joongseon Joh 한국지능시스템학회 2006 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.6 No.2

In the recent years, the development of computer-controlled suspension dampers and actuators has improved the trade-off between the vehicle handling and ride comfort, and has led to the development of various damper control policies. The skyhook control is an effective control strategy for suppressing vehicle vibration. In this study, a fuzzy skyhook control is proposed and tuned by a genetic algorithm to improve ride comfort. The proposed fuzzy skyhook control is applied to a quarter-car model in order to compare its performance with continuous skyhook suspensions. To obtain optimized fuzzy skyhook control, scale factors and in-out membership functions are tuned by a genetic algorithm. The simulation results show that the fuzzy skyhook control offers more effective suspension performance over the continuous skyhook control.

Inverse Model Control of An ER Damper System

Jeongmok Cho,Taegeun Jung,Dong-Hyeon Kim,Joongseon Joh 한국지능시스템학회 2006 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.6 No.1

바나듐 레독스 흐름전지 양극 반응 향상을 위한 코발트 산화물 전극 개질법 연구

박정목(Jeongmok Park),고민성(Minseong Ko) 한국표면공학회 2019 한국표면공학회지 Vol.52 No.3

The demands to improve the performance of the vanadium redox flow battery have attracted an intense research on modifying the carbon-based electrode. In this study, the surface of graphite felt was reformed, using cobalt oxide. The cobalt oxide was implanted into graphite felt during hydrothermal and two step heat treatments. The cobalt was deposited by hydrothermal method and the two step heat treatments made lots of holes on the graphite felt surface which is called as porous surface. The porous surface acts as an electrochemically active site for the cathodic reaction of vanadium redox flow battery. The reformed electrode shows the electrochemically improved performance compared with the pristine electrode.

회전형 MR 댐퍼를 이용한 반능동 현가장치의 퍼지 스카이-훅 제어

조정목(Jeongmok Cho),조중선(Joongseon Joh) 한국지능시스템학회 2007 한국지능시스템학회논문지 Vol.17 No.5

최근 고층건물의 방진시스템 및 자동차의 현가장치 분야에 MR 유체를 이용한 반능동 진동제어에 관한 연구가 활발히 진행되면서 MR 유체의 밸브모드 특성을 이용한 선형 MR 댐퍼가 널리 사용되고 있다. 그러나 전단모드를 이용한 회전형 MR 댐퍼에 관한 연구는 초기단계에 머물고 있다. 본 연구에서는, 주행로봇의 무한회전형 액츄에이터용 회전형 댐퍼의 진동제어에 관한 연구를 수행하였으며, 퍼지 로직을 기반으로한 회전형 MR 댐퍼용 진동제어 알고리즘을 제안하였다. 퍼지제어기의 입출력 이득과 멤버쉽 함수의 모양은 유전자 알고리즘을 이용하여 조정하였다. 시뮬레이션 결과는 MR 댐퍼에 충격력이 가해질 때 퍼지 스카이-훅 제어 성능을 보여준다. Recently, a number of researches about linear magnetorheological(MR) damper using valve-mode characteristics of MR fluid have sufficiently undertaken, but researches about rotary MR damper using shear-mode characteristics of MR fluid are not enough. In this paper, we performed vibration control of shear-mode MR damper for unlimited rotating actuator of mobile robot. Also fuzzy logic based vibration control for shear-mode MR damper is suggested. The parameters, like scaling factor of input/output and center of the triangular membership functions associated with the different Linguistic variables, are tuned by genetic algorithm. Simulation results demonstrate the effectiveness of the fuzzy-skyhook controller for vibration control of shear-mode MR damper under impact force.

MF-UF 분리막 복합공정에 의한 염색가공 폐수처리

양정목(Jeongmok Yang),박철환(Chulhwan Park),이병환(Byunghwan Lee),김상용(Sangyong Kim) 한국청정기술학회 2006 청정기술 Vol.12 No.3

광촉매반응에 의한 Reactive Black 5의 색도제거 연구

양정목(Jeongmok Yang),송진수(Jinsu Song),박철환(Chulhwan Park),김상용(Sangyong Kim) 한국청정기술학회 2008 청정기술 Vol.14 No.3

본 연구에서는 광촉매 산화반응을 이용한 반응성염료(Reactive Black 5)의 오염부하 저감율(TOC, 색도제거율)을 조사하였다. 광촉매 반응활성의 주요한 인자로서 염료농도, TiO₂ 주입량 및 pH 조건을 최적화하였으며, 실험에 적용된 최적의 조건은 각각 100 ㎎/L, 2 g/L, pH 4.9였다. 용존산소의 경우에는 산소의 농도가 증가함에 따라 처리속도도 함께 증가하였다. 새로운 TiO₂를 적용한 경우와 MF 세라믹 분리막에 의해 재생된 TiO₂를 각각 적용하여 실험한 결과 색도제거율과 처리속도에는 약간의 차이를 보였으나, 반응 전반에는 영향을 주지 않았다. We investigated the reduction of pollutants such as TOC (total organic carbon) and decolorization of Reactive Black 5 (RB5) by photocatalytic oxidation. The optimal values of major parameters for the reaction were obtained including the concentration of RB5, the amount of TiO₂ dosage and pH of solution. The values were 100 ㎎/L, 2 g/L and 4.9, respectively. As the concentration of oxygen increased, removal rate of pollutants increased. After TiO₂ was regenerated and used again by micro filtration (MF) ceramic membrane, the removal efficiency of color and removal rate of pollutants did not decrease significantly.

[산ㆍ학ㆍ연 논단] Biocide로서 이산화염소의 식품산업에 응용

김정목(Jeongmok Kim) 한국식품영양과학회 2001 식품산업과 영양 Vol.6 No.2

다층신경망을 이용한 전단모드 회전형 MR 댐퍼의 모델링

조정목(Jeongmok Cho),허남(Nam Huh),조중선(Joongseon Joh) 한국지능시스템학회 2007 한국지능시스템학회논문지 Vol.17 No.7

자기변성유체(magnetorheological fluid)에 관한 연구는 MR 장치의 개발, MR 장치의 수학적 모델링 및 시뮬레이션, 그리고 MR 장치를 채용한 시스템의 제어 알고리즘 개발에 관한 연구로 구분된다. 시뮬레이션을 통한 제어 알고리즘 개발을 위해서는 MR 장치의 비선형 응답을 예상하기 위한 신뢰성 높은 수학적 모델이 요구된다. 또한 MR 장치 시스템을 제어하기 위해서는 제어기에서 요구하는 댐핑력을 출력하기 위한 MR 장치의 전류(또는 전압) 입력 값이 필요하며, 이 입력값을 얻기 위해서는 역댐퍼 모델이 필요하다. 이러한 이유로 MR 장치의 모델링 및 역댐퍼 모델링은 MR 장치개발의 중요한 역할을 담당하며 이에 관한 많은 연구가 요구되고 있다. 본 연구에서는 전단모드 회전형 MR 댐퍼의 모델링을 위해 개발된 MR 댐퍼를 이용하여 동특성 시험기를 제작하였으며, 전단모드 회전형 MR 댐퍼의 특성을 연구하기 위한 실험을 수행하였다. 시험기 시험결과를 통해 모델링에 필요한 시험 데이터들을 획득하였으며 다층신경망을 이용하여 전단모드 회전형 MR 댐퍼의 모델 및 역모델을 구하였다. Scientific challenges in the field of MR(magnetorheological) fluids and devices consist in the development of MR devices, the mathematical modeling and simulation of MR devices, and the development of (optimal) control algorithm for MR device systems. To take a maximum advantage of MR fluids in control applications a reliable mathematical model, which predicts their nonlinear characteristics, is needed. A inverse model of the MR device is required to calculate current(or voltage) input of MR damper, which generates required damping force. In this paper, we implemented test a bench for shear mode rotary MR damper and laboratory tests were performed to study the characteristics of the prototype shear-mode rotary MR damper. The direct identification and inverse dynamics modeling for shear mode rotary MR dampers using multi-layer neural networks are studied.