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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Biosystems Engineering
Journal Basic Information
Journal DOI :
Korean Society for Agricultural Machinery
Editor in Chief :
Volume & Issues
Volume 18, Issue 4 - Dec 1993
Volume 18, Issue 3 - Sep 1993
Volume 18, Issue 2 - Jun 1993
Volume 18, Issue 1 - Mar 1993
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Automatic Control of Engine Speed and Transmission Ratio for Efficient Tractor Operations(I) -Control Systems for Engine Speed and Transmission Ratio-
Kang, S.B. ; Ryu, K.H. ; Oh, K.K. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 305~316
Fuel efficiency in tractor operations dep6nds on the selection of transmission gears and upon the engine being operated at or near maximum torque much of time. The objective of this study was to develop automatic control systems for tractor transmission ratio and governor setting so that the engine is operated at or near maximum torque as much of time as possible. An indoor test unit, which can be used to simulate tractor operation, was built in order to investigate the system design parameters and test the performance of the control system designed. The test-unit consists of engine, gear-type transmission, dynamometer, and control systems for transmission ratio and engine speed. Governor setting lever was controlled by a step motor, and the clutch and transmission levers were controlled by hydraulic cylinders and solenoid valves. The control systems showed good time responses which are assumed to be suitable for optimal tractor operation. The time required for shifting gears from clutch disengagement to engagement was about 1 second, which is almost the same as that for manual shift. And the settling time for engine speed control system was about 5 to 6 seconds.
Development of Measurement System and Analysis Program for Engine Vibration using Microcomputer
Myung, B.S. ; Kim, S.R. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 317~327
This study was carried out to develop a microcomputer-based data acquisition system and software for analysis of engine vibration. Due to this development of system and software, studies on the vibration of engine was able to conduct efficiently. From the display of color monitor, the outputs of test were compared and analysed on zero-base monitoring. The results obtained are summarized as follows : 1. Data acquisition system in microcomputer was designed and programmed and operated accurately. 2. The results of test were easily compared in monitoring of zero-base at color monitor. 3. The system and program developed was able to control the measuring intervals, number of channels, and number of data.
Automatic Depth Control System for Tractor Implement
Choi, C.H. ; Na, K.W. ; Kim, J.M. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 328~343
To control depth of tractor implement, an automatic depth control system based upon microcomputer was developed. This system consists of data aquisition system to measure and to record travel speed, draft and depth of the implement, hydraulic system to control the implement depth and 3-point hitch to attach the implement. Program, written in C language, was able to select position control, draft control and mixed control. To analyze parameters affecting this system, the performance of the system was evaluated through use of computer simulation and verified in soil bin experiments. 3-point hitch was lifted by hydraulic pressure and lowered by implement weight. Dead band was one of the important factors which affect the stability and the accuracy of the system. The system became unstable when the flow rate was increased or when the dead band was decreased. The position control mode with on-off control showed the great ability to control the implement at the given plowing depth. With the draft control, the tractor load could be reduced, however the plowing depth was changed unexpectedly when the soil was hard and inconsistent. The mixed control could improve the performance of the system to maintain the plowing depth without overload of the tractor.
Tractor Design for Rotary Tillage Considering Lift Resistance
Sakai, J. ; Yoon, Y.D. ; Choe, J.S. ; Chung, C.J. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 344~350
The purpose of this study is to develop design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage. The main results of this study are as follows. 1. A wheel-lug ought to receive a special resistance in downward direction which resists the lug's upward motion on wet sticky soil surface. The authors introduce a new academic name of the "lift resistance(上昇抵抗力, 상승저항력)" for such a force which resists retraction of a wheel lug from the soil in the upward trochoidal motion. This force is composed of the frictional force acting on the trailing and the leading lug side, and the "perpendicular adhesion(鉛直付着力, 연직부착력)" acting on the lug face and the undertread face on adhesive soil. 2. The "lift resistance ratio(上昇抵抗力係數, 상승저항력계수)" and the "perpendicular adhesion ratio(鉛直付着力係數, 연직부착력계수)" were defined, which are something similar to the definition of the motion resistance ratio, the traction coefficient, etc. 3. The design equation of the optimum weight of a rotary tiller mounted on the tractor derived by calaulating the forces acting on the rotary blades. 4. The design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage were derived. It becomes clear that the optimum weight of a rotary tiller and a tractor can be estimated in planning design by means of putting about 21 design factors of the target into the equation. These equations are useful for planning design to estimate the optimum dimensions and specifications of a rotary tiller as well as a tractor by the use of known and/or unknown design parameters.
Analysis of Performance of an Air-Type Garlic Peeler for its Optimum Design
Cho, Y.J. ; Kim, C.J. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 351~357
Recently, a garlic peeler with high performance is being demanded due to increase of consumption of peeled garlic. Although the air type out of various types of garlic peelers is recommended to remove effectively skin of garlic, it has an important problem of large energy consumption. This study was performed to analyze performance of an air-type garlic peeler for its optimum design. Performance indices to represent performance of garlic peeler include peeling ratio, energy efficiency and peeling performance. The factors such as aperture of nozzle, angle and position of air injection, charge rate of garlic, peeling time and so on must be considered to design optimally an air-type garlic peeler.
Development of Weight Sensing Unit of Fruit Weight Grader Using Load Cell
Kim, H.S. ; Koh, H.K. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 358~370
In Korea, fruit grading has been mainly done manually, and manual grading depends on human sense. Thus it is subjected to human error and is not always as consistent as would be desired. Therefore, a study on the development of fruit grader was initiated to improve the consistency of fruit grading. The sensitivity for fruit weight of the conventional spring type weight grader has a tendency to decrease by physical characteristics of spring which is used as a weight sensing unit. This study was carried out to develop weight measuring device for establishing the base of weight sensing unit of electronic weight grader. This device consists of a weight sensor using load cell, data acquisition system, and a microcomputer containing program to calculate fruit weight. The weight measuring device using load cell was developed to increase sensitivity of fruit weight. The result of this study showed that the weight sensing unit of electronic weight grader contributed to the improvement of performance of weight measuring device.
A Study on the Threshing Mechanism of Rasp-Bar Type Thresher -Dynamic Analysis of Threshing Process-
Park, K.J. ; Clark, S.J. ; Dwyer, S.V. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 371~381
Threshing operation is performed by impact, compression and friction forces inside the thresher. These values should be appropriate to the crop condition to enhance the threshing and separating efficiency and to decrease the grain damage. To analyze the threshing process inside the rasp-bar type thresher, impact, friction and compression forces were measured using transducers with strain gage circuits. To measure the impact forces and friction forces between the rasp-bar and crop, full bridge strain gage circuit was built on the rasp-bar holder. To measure the compression forces and circumferential friction forces between the concave and crop, two sets of full bridge strain gage circuits were built on the T-type concave transducer. Threshing work of wheat crop with 12% of moisture content was performed at 3 levels of compression ratio and with 3 replications. Each transducer could not measure the exact forces continuously because the transducer oscillates with the forces. However they could measure maximum forces and force distribution according to the time. Average friction coefficients between crop and concave was 0.61 not showing any significant difference according to the compression ratio. Average acceleration of the crop in the cylinder appeared from
according to the compression ratio. The velocity of the crop at the exit of the cylinder appeared from 10.7m/s to 15.0m/s according to the compression ratio.
Evaluation of Surface Color of Apples and Tomatoes by Using Color Sensors
Bae, Y.H. ; Joo, C. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 382~389
In this research, the surface color of 'Fuji' apples and tomatoes were measured by using Sharp PD 151 semiconductor color sensors. The measurements were compared with color-difference-meter readings and with visual sensory test scores. A negative exponential function was developed which describe the relationship between the dominant wavelength of the surface color of 'Fuji' apples and the ratio of the photoelectric currents of the color sensor. Also a linear relationship was found for the surface color of tomatoes and the color sensor output. There were good correlations between the visual test scores and the color sensor output for both 'Fuji' apples and tomatoes.
The Analysis of Optimum Locations of Rice Processing Complex
Chang, H.H. ; Chang, D.I. ; Kim, D.C. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 390~401
This study was conducted to analyze the optimum capacity of Rice Processing Complex (RPC) and to select the optimum location of RPC based on the analysis of rice production and its commercializing rate for each county of major area of paddy field nationally. The study results showed that 500 of RPC having a drying capacity of 3,000 tons of rice would be needed nationally based on the selection analysis.
Study on the Mechanical Properties of the Rice Plants Subjected to Radial Load -Analysis of Relaxation Behavior-
Huh, Y.K. ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 402~409
During all mechanical processes rice plants are subjected to verious forces such as natural load of wind and mechanical load of agricultural machines. A force is always accompanied by deformation, which must be either sufficiently great for pressing or sufficiently slight in order to avoid damage. The mechanical behavior of the rice plants is determined by three variables : force, deformation and time. And they must be studied using rheological methods to determine their viscoelastic properties. This study is conducted to experimentally determine the mechanical and rheological properties of the rice stalks subjected to radial load. The force relaxation tests are performed under constant deformation, during which the reduction of forces over time is measured. The mechanical models were developed from the abtained data. The results were as follows : 1. The relaxation behavior of a rice stalk in radial compession may be described by a generalized Maxwell model consisting of 3 Maxwell elements in parallel. 2. Relaxatiom intensity always decreased with increased time of relaxation. 3. The rate of deformation has a significant effect on the relaxation behavior. having increasing pattern with an increase in rate of deformation. 4. The relaxation intensity and residual deformation increased with increased initial load. 5. The relaxtion of the intermediate portion of stalk was bigger tham that of the upper and lower portions.
환경공해(環境公害)와 신(新) 농업기술(農業技術)
Hong, Ji-Hyeong ;
Journal of Biosystems Engineering, volume 18, issue 4, 1993, Pages 410~418