• Journal of Biosystems Engineering
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• 제25권5호
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• pp.369-378
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• 2000

The purpose of this study is to developed high-efficient rotary tillage system for a power tiller by improving the rotary blade. A kind of the rotary blade with single-edged blade(DS) was developed that requires lower tillage energy than conventional double-edged blade(CD) on the design theory for Japanese rotary blade. In order to find out the tillage characteristics between the single-edged blade and the double-edged blade for power tiller, experiments were performed in soil-bins which were filled up clay loam, loam and sandy loam, and then analyzed the effects of the factors such as soil texture, travelling speed, rotational speed, and tillage depth to each of the blades. And field tests were carried out to compare tillage performances of the two blades using rotary cultivator driven by conventional power tiller. The results of this study were summarized as follows; 1) On the soil bin experiment, it was found that tillage torque of the single-edged blade was less than the ones of the double-edged blade. The decreasing ratios of maximum tillage torque of the single-edged blade to the ones of the double-edged blade were 1 to 8% at clay loam, 5 to 20% at loam and 9 to 31% at sandy loam, respectively. 2) By the field tests, that the tillage performances with the single-edged blade compared with the double-edged blade was improved about 19% in field capacity, about 34% in fuel consumption, and 12.5% in soil breaking ratio. Furthermore, the fluctuation of engine speed, the variation of exhaust gas temperature, and the amount of soil clogging on the blade and straw wound on the rotary shaft showed lower values with the developed blade than the conventional blade. So, it may be concluded that tillage performance by the developed single-edged blade was improved compared with the one by the conventional double-edged blade.

• Journal of Biosystems Engineering
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• 제9권2호
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• pp.37-47
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• 1984

Using the soil bin systems, this study was carried out to analyze the effects of the angular and tilling speed of the rotary shaft with the edge curves which were $30^{\circ}$ and $40^{\circ}$, and the edged blade which were single and double, on the torque requirement of rotary tillage. In the analyses, we developed the mathematical models for the torque requirments of rotary tillage, and analyzed the optimum conditions of each variable for the minimum tillage torque requriements. The results of the study were summarized as follows. 1. The required tilling torque by one rotary blade has the minimum value when the tilling speed of the rotary blade was low, and the revolution of the rotary blade was fast, in general. 2. The torque requirements of single edged blade was decreased to about 81% in comparing with that of double edged blade of which the edge curved angle was $40^{\circ}$ and the tilling speed was 29.40 cm/sec. But, for the mean values, the maximum torque requirements were decreased to 45%, and the mean torque requirements were decreased to 35%. 3. For the edge curved angle, the torque requirements of ${\theta}=40^{\circ}$ were 48% more than that of ${\theta}=30^{\circ}$ in the maximum tilling torque in case that the rotary blade were double edged blade. but, there was not a difference when the rotary blades were single edged blade. The mean tilling torques of ${\theta}=40^{\circ}$ were 6% more when the rotary blade was double edged blade, and were 11% less at single edged blade, than that of ${\theta}=30^{\circ}$. 4. In order to reduce the torque requirements for tilling, the optimum revolutions of the rotary shaft were analyzed as that 204-240 rpm for the double edged blade and 280-320 rpm for the single edged blade.

• International Journal of Fluid Machinery and Systems
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• 제8권4호
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• pp.311-317
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• 2015

It is difficulty to calculate velocity circulation in centrifugal pump impeller outlet accurately. Velocity circulations of a double-blade pump impeller outlet were calculated with Stodola formula, Weisner formula and Stechkin formula. Simultaneously, the internal flow of impeller for the double-blade pump were measured with PIV technology and average velocity circulations at the 0.8, 1.0 and 1.2 times of design flow were obtained. All the experimental values were compared with the above calculation values at the three conditions. The results show that calculation values of velocity circulations with Weisner formula is close to the experimental values. On the basis of the above, velocity circulations of impeller outlet were corrected. The results of experimental verification show that the corrected calculation errors, whose maximum error is 3.65%, are greatly reduced than the uncorrected calculation errors. The research results could provide good references for establishment of theoretical head and multi-condition hydraulic optimization of double-blade pumps.

• 드라이브 ㆍ 컨트롤
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• 제21권1호
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• pp.53-58
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• 2024

With the recent development of intelligence and automation technologies for construction machinery, the demand for safety and efficiency of road-cutting operations has continued to increase. In response to this, a double-blade road cutter has been developed that can automatically cut roads. However, a double-blade road cutter has a load difference between the two blades due to the ground and wear conditions of the cutting blades. The difference in load between the two blades distorts the direction of travel of the cutter. In this study, a vision sensor-based driving guide technology was developed to correct the driving path of road cutters. In addition, we developed a load-sensing technology that detects blade loads in real-time and controls driving speed in the event of overload.

• Journal of Biosystems Engineering
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• 제29권3호
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• pp.281-286
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• 2004

The end-effector is the one of the important factors on development of the cucumber robot to harvester a cucumber. Three end-effectors were designed the single blade end-effector with one blade, the double blade end-effector with two blades and the triple blade end-effector with three blades. Performance tests of the end-effector, the fully integrated system, were conducted to determine the cutting rate by using two different kinds of cucumber. The success rates of cucumber cutting ratio of single end-effector, double end-effector and triple end-effector in laboratory. were 61.7%, 95%, 86.7%, respectively. The cutting rate of single blade or double blade was a little difference with respect to the different diameters of cucumber stem. However, the success cutting rate of the end-effector with triple blade was 61.7% under 29mm diameter of a grabbing stem section. The triple end-effector was not suitable for harvesting a cucumber, but was considered to be suitable for harvesting a grape, an apple and a tomato. The success rate of cucumber cutting ratio of triple end-effectors in greenhouse was 84%. The failure cutting rate was 16% which are due to abnormal shape of cucumber fruit.

• 한국유체기계학회 논문집
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• 제18권1호
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• pp.51-58
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• 2015

This paper presents a study on Vane Tidal Turbine (VTT) focusing on analysis of two types of blade arrangement originated from the previous studies where the original design was examined and performance-tested for different numbers of blades (six, eight and twelve). Compared to conventional tidal turbines, VTT has several special features and potential advantages which have been being thoroughly developed. The purpose of this study is to analyze VTT's capability of extracting and converting the hydrokinetic energy of tidal currents into electricity at given arrangement of blades (single and double rows, six and twelve blades) using CFD. From the calculation results, the six-blade single row turbine shows the best performance, in which the highest power and torque coefficients reach up to about 34 % and 36 %, respectively, at TSR=0.94. However, despite of lower power coefficient, by adding more blades, the torque's extraction of twelve-blade turbine, especially the double row type, is less fluctuate than that of the six-blade setups.

• 드라이브 ㆍ 컨트롤
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• 제20권1호
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• pp.8-15
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• 2023

With the recent trend of intelligence and automation of construction work, a double-blade road cutter is being developed that automatically enables cutting along the cutting line marked on the road using a vision system. The road cutter can recognize the cutting line through the camera and correct the driving route in real-time, and it detects the load of the cutting blade in real-time to control the driving speed in case of overload to protect workers and cutting blades. In this study, a vision system mounted on a double-blade road cutter was developed. A cutting route recognition technology was developed to stably recognize cutting lines displayed on non-uniform road surfaces, and performance was verified in similar environments. In addition, a vision sensor protection module was developed to prevent foreign substances (dust, water, etc.) generated during cutting from being attached to the camera.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.423-430
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• 2001

The purpose of this study is to develop high-speed rotary tillage system for a power tiller by improving the rotary blade and the power train of transmission. Mechanical structure of gear train of rotary drive of conventional power tiller was simplified so that power can be transmitted directly from second shaft to tilling speed change shaft by rotating freely the transfer gear which changes the direction of rotation of shafts using needle bearing installed into middle shaft. A new gear train suitable for the single-edged rotary blade and high-speed rotary drive was developed with the rotational speed of rotary shaft faster than 7.5% at 1st-speed and 1.4% at 2nd-speed the one of conventional system by changing the numbers of teeth of gears of middle shaft, tilling speed change shaft and PTO shaft. Using the developed gear train for high-speed rotary drive, field tests were performed to compare tillage performances by the developed single-edged blade and by the conventional double-edged blade. The results showed that the performances by the single-edged blade compared with the one by the double-edged blade was improved about 18% in field capacity, about 34% in fuel consumption, and 9.4% in soil crushing ratio. Therefore, it may be concluded that tillage performance by the single-edged blade was improved compared to the one by the conventional blade. Evaluation of the developed system consisting of single-edged blade and gear train for high-speed rotary drive in field revealed that tillage performance of the developed system was similar to the one of field test conducted using the system consisting of single-edged blade and gear train for rotary drive of conventional power tiller However, considering the higher cone index of the upland field where evaluation was carried out compare to the one of the ordinary paddy field, it may be concluded that tillage performance of the developed rotary tilling system better than the one of conventional system.

• 한국가시화정보학회지
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• 제8권2호
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• pp.23-30
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• 2010

Regarding the aircrafts with a rotor blade system, the miniaturization of them is limited due to the rotor blade length and the tail rotor system. To miniaturize an aircraft, an equipment is required that increases thrust and also shortens the length of the rotor blade. The present study will conduct the flow analysis for miniaturizing the aircraft by applying a duct to the coaxial rotor blade system without tail rotor. First, the verification on the calculated results was conducted through the computational flow analysis on the coaxial rotor blade system without a duct. Then, the flow analysis for the coaxial rotor blade systems was performed including Ka-60 duct, Single duct, Twin duct, and Double duct, respectively. From the numerical results, the thrust coefficient appeared higher with the duct than without a duct for the coaxial rotor blade system. Especially, in the case of Double duct, the thrust was improved due to the increase of incoming flow and the extension of the wake area. These results will be used as the basic concepts for miniaturizing the aircraft with the rotor blade system. The flow analysis on the coaxial rotor blade system including the fuselage remains as a future work.

• 농업과학연구
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• 제11권2호
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• pp.264-269
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• 1984

단면(單面)의 로우터리 경운(耕耘)날이 양면(兩面)보다 경운소요(耕耘所要)토오크를 절감(節減)시키는 데 효과적(效果的)이란 결과(結果)에 대(對)하여는 앞서의 연구(硏究)에서 보고(報告)한 바 있으며, 본(本) 연구(硏究)는 경운작업(耕耘作業)에 의(依)한 날의 마모과정중(磨耗過程中) 양(兩), 단면(單面) 형상(形狀)의 경운(耕耘)날이 경운소요(耕耘所要)토오크의 절감효과(節減效果)가 지속(持續)되는가를 구명(究明)하기 위(爲)하여 포장실험(圃場實驗)을 실시(實施)하였다. 양(兩), 단면(單面)의 공시(供試)날은 동일(同一) 로우터리 축(軸)에 부착(附着)시켜 미경운토양(未耕耘土壤)에서 포장작업(圃場作業)을 실시(實施)하여 매(每) 3시간(時間)마다 마모량(磨耗量)을 측정(測定)하였으며, 계량(計量)한 날의 경운소요(耕耘所要)토오크는 실험실(實驗室)에서 Soil bin system 을 이용(利用)하여 측정(測定)하였으며, 분석(分析) 결과(結果)를 요약(要約)하면 다음과 같다. 1. 로우터리 경운작업(耕耘作業)을 실시(實施)하는 동안 날의 단면형상(斷面形狀)의 원형(原形)은 변화(變化)하지 않았으며, 단면(單面)인 날이 양면(兩面)보다 전(全) 내용시간(耐用時間) 동안 최대경운소요(最大耕耘所要)토오크는 5~10%, 평균경운소요(平均耕耘所要)토오크는 3~15% 절감(節減)하는 것으로 분석(分析)되었다. 2. 일반적(一般的)으로, 경운소요(耕耘所要)토오크는 경운(耕耘)날의 형상(形狀)이 유지(維持)되는 12시간(時間)까지는 감소(減少)하였으나, 그 후(後)에는 날의 tip형상(形狀)의 변형(變形)에 의(依)하여 증가(增加)하는 것으로 나타났다. 이것은 날의 tip형상(形狀)이 경운소요(耕耘所要)토오크에 영향(影響)을 미치는 요인(要因)이라고 분석(分析)할 수 있으며, 이에 대(對)한 연구(硏究)는 계속(繼續)되어져야 할 것으로 사료(思料)된다.