• Title/Summary/Keyword: PTO

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Comparison of Tillage and Loads Characteristics of Three Types of Rotavators: Rotary-type, Crank-type, and Plow-type

  • Kim, Myoung-Ho;Nam, Ju-Seok;Kim, Dae-Cheol
    • Journal of Biosystems Engineering
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    • v.38 no.2
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    • pp.73-80
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    • 2013
  • Purpose: This study was conducted to compare tillage and loads characteristics of three types of rotavators in farmland working condition of Korea. Methods: Tillage operations using three types of rotavators, i.e. rotary-type, crank-type and plow-type, were carried out in a dry field of Korea. The same prime mover tractor was used for driving three types of rotavators, and under several operational conditions, tillage characteristics such as actual working speed, rotavating depth, rotavating width, actual field capacity, flow of tilled soil, soil inversion ratio, and pulverizing ratio were measured. In addition, loads characteristics like torque and required power of Power Take-Off (PTO) shaft were calculated. Results: The average rotavating depth was smaller than the nominal value for all rotavators, and the difference was the greatest in the plow-type rotavator. Nevertheless, the plow-type rotavator showed the largest rotavating depth. The rotavating width was the same as the nominal value of all rotavators. The flow of tilled soil at the same operational conditions was the greatest in the plow-type rotavator and was the smallest in the rotary-type rotavator. In the most commonly used gear conditions of L2 and L3, the average soil pulverizing ratio was the greatest in the rotary-type rotavator, and followed by crank-type and plow-type rotavators in order. In the gear L2 and L3, the plow-type rotavator also had the lowest average soil inversion ratio while the rotary-type and crank-type rotavators had the same soil inversion ratio each other. The average torque and power of PTO shaft in the gear L2 and L3 were the highest in the plow-type rotavator. The load spectra of PTO shaft applying rain flow counting method and Smith-Waston-Topper equation to the measured torque showed that the modified torque amplitude was the greatest in the crank-type rotavator. This may come from the large torque fluctuation of crank-type rotavator during tillage operations. Conclusions: The three types of rotavators had different tillage and loads characteristics. The plow-type rotavator had the deepest rotavating depth, the smallest soil inversion ratio, the largest soil pulverizing ratio and required PTO power. Also, the crank-type rotavator showed a large torque fluctuation because of their unique operational mechanism. This study will help the farmers choose a suitable type of rotavator for effective tillage operations.

3-Dimensional Numerical Analysis of Air Flow inside OWC Type WEC Equipped with Channel of Seawater Exchange and Wave Characteristics around Its Structure (in Case of Irregular Waves) (해수소통구를 구비한 진동수주형 파력발전구조물 내 공기흐름과 구조물 주변에서 파랑특성에 관한 3차원수치해석(불규칙파의 경우))

  • Lee, Kwang Ho;Lee, Jun Hyeong;Jeong, Ik Han;Kim, Do Sam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.30 no.6
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    • pp.253-262
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    • 2018
  • Oscillating Water Column (OWC) Wave Energy Converters (WEC) harness electricity through a Power-Take-Off (PTO) system from the induced-airflow by seawater oscillating inside a chamber. In general, an air chamber with a relatively small cross-sectional area is required compared to seawater chamber to obtain high-velocity air in the PTO system, and in order to simulate an accurate air flow rate in the air chamber, a three-dimensional study is required. In this study, the dynamic response of OWC-WEC that is equipped with the channel of seawater exchange for the case of irregular waves has been numerically studied. The open source CFD software, OLAFLOW for the simulation of wave dynamics to the openFOAM and FOAM-extend communities, was used to simulate the interaction between the device and irregular waves. Based on the numerical simulation results, we discussed the fluctuation characteristics of three dimensional air flow in the air-chamber, wave deformation around the structure and the seawater flow inside the channel of seawater exchange. The numerical results the maximum air flow velocity in the air-chamber increases as the Ursell value of the significant wave increases, and the velocity of airflow flowing out from the inside of air chamber to the outside is greater than the speed of flowing into the air chamber from the outside.

Analysis of Rollover Angle According to Arrangement of Main Parts of Electric Tractor Using Dynamic Simulation (시뮬레이션을 이용한 전기 트랙터 주요 부품 배치에 따른 전도각 분석)

  • Jin Ho Son;Yeong Su Kim;Yu Shin Ha
    • Journal of the Korea Society for Simulation
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    • v.32 no.4
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    • pp.77-84
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    • 2023
  • In the agricultural sector, power sources are being developed that use alternative energy sources such as electric tractors and hydrogen tractors, away from internal combustion engine tractors. As parts such as engines and transmissions used in conventional internal combustion engine tractors are replaced with motors and batteries, the center of gravity changes, and thus the risk of rollover should be considered. The purpose of this study is to analyze the overturn angle of the main parts of the electric tractor through dynamic simulation to minimize the overturn accident and to derive the optimal arrangement of parts to improve stability. A total of nine dynamics simulations were conducted by designing three components of the PTO motor, drive motor and the battery pack, and three factors of the arrangement method. As a result of the experiment, it was confirmed that Type3 Level3, in which the drive motor and the PTO motor are located at the front and rear of the tractor, and two battery packs are located in the middle of the tractor, has a high rollover angle. As a result of this study, the stability increased as the center of gravity was placed backward and located below. Future research needs to be done to find the optimal location of parts considering their performance and placement efficiency.

PTO 시스템과 비선형 탄성커플링을 갖는 어선용 기관축계의 비틀림 자유진동해석

  • Kim, Won-Rae
    • Journal of Korea Ship Safrty Technology Authority
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    • v.16
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    • pp.26-37
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    • 2004
  • 선박 추진축계의 진동은 크랭크축, 추력축 등의 이상마멸을 초래할 뿐 아니라 과도하면 선체진동을 유발시키기도 한다. 이러한 추진축계의 진동중에서 가장 빈번히 문제가 되는 것이 비틀림 진동이므로 축계의 초기설계 단계부터 이에 대한 신중한 검토가 필요하다 .

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Fatigue Life Prediction of Crank-type Rotavator

  • Kim, Dae-Chun;Park, Young-Jun;Lee, Geun-Ho
    • Journal of Biosystems Engineering
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    • v.40 no.4
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    • pp.305-313
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    • 2015
  • Purpose: This study was performed to predict the fatigue life of a crank-type rotavator operated in domestic soil conditions using Recurdyn$^{(R)}$, a dynamic analysis program. Methods: Torque on the PTO shaft was measured using experiments conducted on the uplands and paddy fields in Korea. On the basis of the experimental and analytical results, the fatigue life of the crank-type rotavator was predicted by constructing an S-N curve according to the GL (Germanischer Lloyd Wind Energie GmbH) guideline. Results: The torques experienced by the PTO shaft in the paddy soil and the uplands were in the range of 472~797 N m and 313~430 N m, respectively, for every condition. In case of load condition, the peak torques (846 N m, 770 N m) were applied for severe conditions, resulting in a maximum (von Mises) stress of 75 MPa at the crank arm. The fatigue life of the crank-type rotavator was predicted to be 1,167 h that satisfies the target value of 1,110 h, by substituting the analysis results into an S-N curve of crank arm. Conclusions: The fatigue life of the crank-type rotavator was within the target life for the studied soil conditions; however, further field experiments for various soil conditions would be required to verify the prediction results.

Latching Control Technology for Improvement of Extracted Power from Wave Energy Converter (파력발전기 추출파워 향상을 위한 래칭 제어기법)

  • Cho, Il Hyoung
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.18 no.4
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    • pp.282-290
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    • 2015
  • In this study, a latching control technology, proposed by Sheng et al.(2015), was applied in order to maximize the extraction efficiency of WEC (Wave Energy Converter), which is the heaving buoy coupled with linear electric generator. The latching control is the phase-control technique for improving the wave energy conversion with appropriate latching duration of keeping the buoy fixed. From the time-domain analysis in regular waves, the latching control technology can significantly improve the heave velocity and extracted power, even though the resonance condition is not satisfied. By using the latching control technology, the draft of buoy as well as the required PTO damping force can be significantly reduced along with increased extracted power, which is a big advantage in manufacturing the WEC.

Heaving displacement amplification characteristics of a power buoy in shoaling water with insufficient draft

  • Kweon, Hyuck-Min;Cho, Il-Hyoung;Cho, Hong-Yeon
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.4
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    • pp.614-624
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    • 2013
  • The resonance power buoy is a convincing tool that can increase the extraction efficiency of wave energy. The buoy needs a corresponding draft, to move in resonance with waves within the peak frequency band where wave energy is concentrated. However, it must still be clarified if the buoy acts as an effective displacement amplifier, when there is insufficient water depth. In this study, the vertical displacement of a circular cylinder-type buoy was calculated, with the spectrum data observed in a real shallow sea as the external wave force, and with the corresponding draft, according to the mode frequency of normal waves. Such numerical investigation result, without considering Power Take-Off (PTO) damping, confirmed that the area of the heave responses spectrum can be amplified by up to about tenfold, compared with the wave energy spectrum, if the draft corresponds to the peak frequency, even with insufficient water depth. Moreover, the amplification factor of the buoy varied, according to the seasonal changes in the wave spectra.

Declutching control of a point absorber with direct linear electric PTO systems

  • Zhang, Xian-Tao;Yang, Jian-Min;Xiao, Long-Fei
    • Ocean Systems Engineering
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    • v.4 no.1
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    • pp.63-82
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    • 2014
  • Declutching control is applied to a hemispherical wave energy converter with direct linear electric Power-Take-Off systems oscillating in heave direction in both regular and irregular waves. The direct linear Power-Take-Off system can be simplified as a mechanical spring and damper system. Time domain model is applied to dynamics of the hemispherical wave energy converter in both regular and irregular waves. And state space model is used to replace the convolution term in time domain equation of the heave oscillation of the converter due to its inconvenience in analyzing the controlled motion of the converters. The declutching control strategy is conducted by optimal command theory based on Pontryagin's maximum principle to gain the controlled optimum sequence of Power-Take-Off forces. The results show that the wave energy converter with declutching control captures more energy than that without control and the former's amplitude and velocity is relatively larger. However, the amplification ratio of the absorbed power by declutching control is only slightly larger than 1. This may indicate that declutching control method may be inapplicable for oscillating wave energy converters with direct linear Power-Take-Off systems in real random sea state, considering the error of prediction of the wave excitation force.

The Influence of Unstable Bridge Exercise With Abdominal Drawing-In on Posture of the University Female Students (불안정한 지지면에서 복부 드로잉 인을 이용한 브릿지 운동이 여대생의 자세에 미치는 영향)

  • Gong, Won-Tae;Jung, Yeon-Woo;Kwon, Hyeok-Soo
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.19 no.1
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    • pp.63-68
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    • 2013
  • Background: The purpose of this study is to examine the effects of unstable bridge exercise on the posture of female university students. Methods: The subjects of this study were 30 female university students who were equally and randomly allocated to a unstable bridge exercise group, an experimental group, and a stable bridge exercise group, a control group. Both did so for 30 minutes three times per week over a six-week period. Using BackMapper, their trunk inclination (TIN), trunk imbalance (TIM), pelvic position (PPO), pelvic torsion (PTO), pelvic rotation (PRO), and the position of their scapulae (PSA) were evaluated. Results: The unstable bridge exercise group obtained significant results in TIN, TIM, PPO, PTO and PSA, while the stable bridge exercise group obtained significant results in TIN, PPO. Conclusion: unstable bridge exercise may be applied as a method to correct the posture of average adults.

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FFT analysis of load data during field operations using a 75-kW agricultural tractor

  • Ryu, Myong-Jin;Chung, Sun-Ok;Kim, Yong-Joo;Lee, Dae-Hyun;Choi, Chang-Hyun;Lee, Kyeong-Hwan
    • Korean Journal of Agricultural Science
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    • v.40 no.1
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    • pp.53-59
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    • 2013
  • Analysis of load data during field operations is highly important for optimum design of power drive lines for agricultural tractor. Objective of the paper was to analyze field load data using FFT to determine frequency and the energy levels of meaningful cyclic patterns. Rotary tillage, plowing, baling, and wrapping operations were selected as major field operations of agricultural tractor. An agricultural tractor with power measurement system was used. The tractor was equipped with strain-gauge sensors to measure torque of four driving axles and a PTO axle, speed sensors to measure rotational speed of the driving axles and an engine shaft, pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to calculate power requirement. In rotary tillage, calculated frequency was decreased as travel speed increased. In baler operation, calculated frequency was increased as PTO speed was increased. The calculated peak frequency levels and expected levels were similar. Results of the study would provide information on power utilization patterns and on better design of power drive lines.