Design of a non-circular planetary-gear-train system to generate an optimal trajectory in a rice transplanter

Bae, Kang-Yul,Yang, Young-Soo Taylor Francis 2007 Journal of engineering design Vol.18 No.4

<P> The transplanting accuracy of a rice transplanter for picking, conveying and transplanting seedlings mainly depends on the trajectory as well as the return motion of the hoe. The trajectory of the hoe has to be optimized in treating seedlings for a prevailing soil condition. For better transplanting accuracy, a planetary-gear-train system, instead of the four-bar linkage system is used to design a transplanting mechanism. This study proposes a theoretical design method for a transplanting mechanism; the method designs non-circular gears of a planetary-gear-train system for the hoe to trace a prescribed trajectory. An optimization method was used to determine the arm length and tool length; inverse kinematics to determine the configuration angles of the two links and the roll contact condition in transmitting motion between the gears; and a linearization approach to obtain the shapes of the gears. Based on the proposed method, the shapes of the gears and the lengths of the tools of the planetary-gear-train system are determined for three prescribed trajectories. A commercialized package program (ADAMS) is used to carry out a kinematic simulation to confirm that the gear-train system configured from the proposed method is adequate for the transplanting mechanism.</P>

하이브리드 자동차의 변속기 유형에 따른 모드 변환 시 응답특성 해석

안정근(Jeong-Keun Ahn),김동현(Dong-Hyun Kim),정기화(Ki-Hwa Jung),진한별(Han-Byeol Jin),구본용(Bon-Yong Koo),김현수(Hyun-Soo Kim),황성호(Sung-Ho Hwang) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

In this paper, the modelling of AMT-HEV(automated manual transmission hybrid electric vehicle) and Planetary-HEV is performed, and a modified shift control algorithm is proposed to improve the shifting performance at changing mode. The driving simulation in carried out with various driving conditions in order to investigate the response characteristics of HEV with respect to transmission type. HEV powertrain model consists of the internal combustion engine, electric motor, battery, planetary gear, automated manual transmission and the regenerative braking system using MATLAB. In addition, a regenerative control algorithm is suggested considering the battery SOC. In this paper, the modelling of AMT-HEV and Planetary-HEV is performed by using MATLAB, the response characteristics of AMT-HEV is compared with the response characteristics of Planetary-HEV at changing mode.

A study on the design of a new power transmission for wind turbines

김성걸 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.3

The single-rotor wind turbine remains the dominant design for energy production. However, this design requires improvements toovercome some of its limitations. The introduction of the dual rotor system regarded as improvement over the single-rotor system inKorea due to its high efficiency, despite Korea’s low wind quality. Many researchers have attempted to devise different dual rotor machinesand assess their power production capabilities under similar wind conditions to those in Korea. Existing power transmissions fordual-rotor wind turbines have issues with the complexity of design, difficulty in manufacturing, high costs and low efficiencies. Therefore,the aim of this study was to design a new power transmission for the dual-rotor wind turbine with an alternative to the bevelplanetarysystem by using a planetary system. This new method is dependent on the torque ratio and not the gear ratio as in common gearsystems. The design and analysis of each part, such as the gears, shafts, bearings and control mechanisms are included in this study. Thedesign is based on the power transmission of a motor vehicle. A prototype of the design is manufactured to verify the proposed method. The experimental results show that the new planetary-type gear box incurs fewer energy losses, has a high efficiency and low manufacturingcosts. It is anticipated that the proposed design might be suitable for use with commercial wind turbines.

궤도차량용 유성기어 감속기의 역설계 기법에 관한 연구

정성교(S.G. Jung),홍상렬(S.R. Hong),허도은(D.E. Heo),황영진(Y.J. Hwang),이석순(S.S. Lee) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

In this study, the reverse engineering method of planetary-gear reducer for track vehicles is investigated. A important factor in this study (Reverse engineering method of a planetary-gear reducer) is shift-coefficient and backlash. Therefore, a backlash was defined by gear class 4 of the KS(Korean Industrial Standard) and tolerance of base tangent length was defined by backlash. Center-distance of sun-gear, planet-gear, planet-gear and ring-gear is used to get sum of the shift-coefficient. The sum of the shift-coefficient is divided into gears properly. Shift-coefficient and backlash is applied to planetary-gear reducer degisn. A calculated gears tooth is checked by application program for a planetary gear.

행성 시대 공통장의 한계: 강원도 원주시 인공빙장 사례 연구

오영훈 한국문화인류학회 2024 韓國文化人類學 Vol.57 No.2

본 논문은 인간적 지평 너머의 행성으로서의 지구적 면모를 공통장(commons)이 어느 정도까지 포착하고 수용할 수 있는지에 관한 민족지적 연구다. 자본과 국가 권력으로부터의 대안이자 동시에 수탈 대상으로도 논의되고 있는 공통장은 그 해방적이고 민주적인 성격이 다소 이상화되어, 각종 사회구조적 문제는 물론 기후위기까지 헤쳐나갈수 있는 대안으로까지 지목되면서 그 생성과 보존이 바람직하다는 규범적 틀이 종종 전제되고 있다. 그러나 공통장은 여러 국면에서 자본/국가의 재생산에 유용되기도 한다. 본 연구는 강원도 원주시에서 2003년 이래로 현재까지 조성⋅운영되어 온 인공빙벽등반장 판대아이스파크를 지구 행성성과의 접점이 잘 드러나는 공통장의 사례로 간주하고, 1년여에 걸친 민족지적 현장조사를 통해 그 구성과 작동, 한계를 검토했다. 본 논문은 다음 세 가지를 주장한다. 첫째, 공통적인 것의 지향점은 자연으로의 회귀나 인간성의 복원이 아니라 그 자신의 생산과 복제다. 둘째, 현대사회의 공통장은 자본/국가에대한 저항이자 보완이라는 두 가지 성격을 동시에 갖는다. 셋째, 공통장은 지구의 행성성을 잠재된 공통장(latent commons)의 형태로 조우하지만, 두 공통장이 서로 제휴하고 연대할 분명한 가능성은 발견되지 않았다. In this anthropological essay I investigate the extent to which the perspective of the planetary conceptualized under the discourses of climate crisis may be explored from the perspective of the human. I critically review the often-idealized notion of the commons, which is viewed as both an alternative to and an object exploited by the strategies o f capitalism and the natio n-state, idealized as the most probable candidate for the solution of climate crisis as well as the variety of extant social-structural issues. In the following, I ethnographically examine the construction, operation, and limitations of the commoning practices surrounding the Pandae Ice-Park, an artificially created ice wall structure for climbing constructed annually since 2003 in Pandae, Wonju of the Gangwon Province in South Korea. I argue the fo llowing: first, the general aim o f the common is the production and replication of itself instead of a return to the ‘nature’ or a restoration of the humanity; second, the commons in contemporary societies will exhibit the two seemingly mutually incompatible features o f the resistance to and the supplementatio n o f the capital and nation-state combination and; finally, while the co mmo ns may find itself being in co nfro ntatio n with the planetary Earth in the fo rm o f latent co mmo ns, no clear evidence fo r the formation of alliance and solidarity between the two commons is found.

서스펜션 플라즈마 용사를 이용한 이트리아 안정화 지르코니아 (7.5 wt% Y₂O₃-ZrO₂) 코팅 증착 및 특성

이원준,권창섭,김성원,오윤석,김형태,임대순,Lee, Won-Jun,Kwon, Chang-Sup,Kim, Seongwon,Oh, Yoon-Suk,Kim, Hyung-Tae,Lim, Dae-Soon 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.6

Yttria-stabilized zirconia (YSZ) coatings are fabricated via suspension plasma spray (SPS) for thermal barrier applications. Three different suspension sets are prepared by using a planetary mill as well as ball mill in order to examine the effect of starting suspension on the phase evolution and the microstructure of SPS prepared coatings. In the case of planetary-milled commercial YSZ powder, a deposited thick coating turns out to have a dense, vertically-cracked microstructure. In addition, a dense YSZ coating with fully developed phase can be obtained via suspension plasma spray with suspension from planetary-milled mixture of $Y_2O_3$ and $ZrO_2$.

전달행렬법을 이용한 유성기어형 반공진 진동 절연기 특성 연구

윤종환(Jong-Hwan Yun),곽규빈(Gyubin Kwak),이형일(Hyeongill Lee) 한국소음진동공학회 2019 한국소음진동공학회 논문집 Vol.29 No.1

As a follow-up to a previous study on the transfer matrix for a lever-type anti-resonance vibration isolator (L-DAVI), a transfer matrix for a planetary-gear-type dynamic anti-resonance vibration isolator (PG-DAVI) is defined by the vector-type four pole parameter method. Both the system’s angular acceleration determined using the transfer matrix method (TMM) and the derived matrix are compared with those from the conventional method to validate the use of the transfer matrix for the PG-DAVI. Then, TMM is used to calculate the angular displacement transmissibility of a 3-DOF target system, and to study the application of the PG-DAVI to improve the transmissibility of a target system. The optimal configuration of the PG-DAVI is investigated using the transfer matrix derived in the first step. The displacement transmissibility of the modified system is compared with that of the original system to determine the effect of the PG-DAVI. Finally, the displacement transmissibility of a system modified by the PG-DAVI is compared with that of a system that uses a classical dynamic absorber. Results indicate that the PG-DAVI is more effective than the classical absorber in improving the displacement transmissibility of the target system.

Properties of the planetary caustic perturbation

Chung, Sun‐,Ju,Lee, Chung‐,Uk Blackwell Publishing Ltd 2011 Monthly notices of the Royal Astronomical Society Vol.411 No.1

<P><B>ABSTRACT</B></P><P>Just two of 10 extrasolar planets found by microlensing have been detected by the planetary caustic, despite the higher probability of planet detection relative to the central caustic, which has been responsible for four extrasolar planet detections. This is because the perturbations induced by the planetary caustic are unpredictable, thus making it difficult to carry out strategic observations. However, if future high‐cadence monitoring surveys are conducted, the majority of planetary caustic events including the events by free‐floating planets and wide‐separation planets would be detected. Hence, understanding the planetary caustic perturbations becomes important. In this paper, we investigate in detail the pattern of the planetary caustic perturbations. From this study, we find three properties of the planetary caustic perturbations. First, planetary systems with the same star–planet separation (<I>s</I>) basically produce perturbations of constant strength, regardless of the planet‐to‐star mass ratio (<I>q</I>), but the duration of each perturbation scales with <IMG src='/wiley-blackwell_img/equation/MNR_17664_mu1.gif' alt ='inline image'/>. Secondly, close planetary systems with the same separation produce essentially the same negative perturbations between two triangular‐shaped caustics, regardless of <I>q</I>, but the duration of the perturbations scales with <IMG src='/wiley-blackwell_img/equation/MNR_17664_mu2.gif' alt ='inline image'/>. Thirdly, the positive perturbations for planetary systems with the same mass ratio become stronger as the caustic shrinks with the increasing |log <I>s</I>|, while the negative perturbations become weaker. We estimate the degeneracy in the determination of <I>q</I> that occurs in planetary caustic events. From this, we find that the mass ratio can be more precisely determined as <I>q</I> increases and |log <I>s</I>| decreases. We also find that the degeneracy range of events for which the source star passes close to the planetary caustic is usually very narrow, and thus it would not significantly affect the determination of <I>q</I>.</P>

Influence of the Carrier Pinhole Position Errors on the Load Sharing of a Planetary Gear Train

Kim, Jeong-Gil,Park, Young-Jun,Lee, Sang-Dae,Oh, Joo-young,Kim, Jae-Hoon,Lee, Geun-Ho Korean Society for Precision Engineering 2018 International Journal of Precision Engineering and Vol.19 No.4

Load sharing among planetary gears, one of the design variables, has a significant influence on the performance and service life of a gearbox. This study involved simulating and testing the design parameters related to load sharing among planetary gears. In this regard, the influence of errors in the carrier pinhole position on the load sharing among the planetary gears was analyzed. The results showed that the difference between the simulation results using the model and the laboratory test results was less than 10%. Furthermore, similar tendencies were observed according to the magnitude of the load applied to the planetary gears. As for the design parameters affecting load sharing, the service life of a gearbox containing planetary gears can be extended by using a floating system as opposed to a non-floating system. In addition, reduced planetary pin diameter and increased planetary bearing clearance leads to appropriate load sharing among the planetary gears and increases the service life and floating effect of the gearbox.

자동변속기 유성기어 소음을 고려한 시스템 분석용 프로그램 개발 및 적용에 관한 연구

이현구(Hyun Ku Lee),이상화(Sang Hwa Lee),김무석(Moo Suk Kim),홍사만(Sa Man Hong),김시웅(Si Woong Kim),유동규(Dong Kyu Yoo),권현식(Hyun Sik Kwon),아멧칼만(Ahmet Kahraman) 한국소음진동공학회 2015 한국소음진동공학회 논문집 Vol.25 No.7

A generalized special program called planetary transmission analysis(here in after PTA) is developed to improve planetary gear noise in automatic transmission. PTA is capable of analyzing any typical one-degree-of-freedom automatic transmission gear train containing any number of simple, compound or complex-compound planetary gear sets. The kinematics module in PTA can compute the rotational speeds of gears and carriers and calculate the order frequencies to predict the planetary noise components. The power flow analysis module performs a complete static force analysis providing forces, moments, or torques of gears, bearings, clutches and connections. Based on the given type and number of planetary gear sets, the search algorithm determines all possible kinematic configurations and gear tooth combinations in a required set of gear ratios, while eliminating whole kinematic redundancies and unfavorable clutching sequences. By using PTA program, planetary internal speeds of new developed automatic transmission are early obtained; therefore, possibility of the noise problem could be predicted in early design stage. As implementing PTA in planetary gear NVH development procedure, planetary gear noise was successfully reduced by 10 dBA.