M. Rahmatian; S. H. Karparvarfard; M. A. Nematollahi; A. Sharifi Malvajerdi
Abstract
All over the world, farmers choose different implements for tillage, which depend on crop type, soil type, the amount of plant residue from the previous crop, etc. Tillage implement selection is also affected by the availability of implements, power consumption, labor costs, and fund. In this research, ...
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All over the world, farmers choose different implements for tillage, which depend on crop type, soil type, the amount of plant residue from the previous crop, etc. Tillage implement selection is also affected by the availability of implements, power consumption, labor costs, and fund. In this research, the draft force, soil disturbance area, soil cone index, and fuel consumption were considered. The effects of rake angle, forward speed, and soil moisture content on the above-mentioned parameters were investigated. In this research, a comparison between the performance of a Fiber Reinforced Polymer (FRP) composite blade and a conventional steel blade was carried out. Tests were based on the split-split plot in a completely randomized design. The factors of soil moisture content, rake angle, and forward speed were included in three levels. Three levels for the soil moisture content (9.3, 13, 16.7 %), rake angle (20°, 30°, 40°), and forward speed (3, 5, 7 km.h-1), were considered. The FRP composite blade (on average in the desired range for variables) has reduced the draft force, fuel consumption, and soil cone index, 14.97%, 16.63%, and 35.08%, respectively, than the steel blade. Also, the soil disturbance area created by the FRP composite blade was 4.93% higher than the steel blade. Based on the results of this study, it is clear that the FRP composite blade has better performance rather than the conventional steel blade for the aforementioned test variables. The FRP composite is inexpensive than the steel, this leads to remarkable save money in the production of the FRP composite blade used in the chisel and combined tillage tools that is economical for the farmer and manufacturer.
B. Souri Damirchi Sofla; S. H. Karparvarfard; A. Ranjbar Karim Abadi; H. Azimi-Nejadian; A. Moazni Kalat
Abstract
IntroductionTillage is one of the most important field operations to improve soil structure and physical conditions and provide the proper plant site. Conservation tillage is one of the methods of tillage that reduces tillage costs. The blade is one of the most important consumed components of tillage ...
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IntroductionTillage is one of the most important field operations to improve soil structure and physical conditions and provide the proper plant site. Conservation tillage is one of the methods of tillage that reduces tillage costs. The blade is one of the most important consumed components of tillage tools in the conservation tillage, which is very important for how it is adjusted and its effect on the quality of tillage and energy required of tillage tools. According to the research conducted on the importance of optimizing tillage implements, the aim of this study was oriented to determine the optimum rake angle of a narrow-modified winged and non-winged blade in the field soil.Materials and MethodsThe tests were conducted in the 22nd part of farms in Agriculture School (Bajgah zone) of Shiraz University. Three levels of blade rake angles (20, 25, and 30 degrees), two levels of tillage depth (15 and 20 cm), and two levels of forward speed (2 and 3 km h-1) were the treatments of this study. Draft, fuel consumption, slippage, soil disturbance area, soil upheaving area, and specific draft were the measured parameters and they were measured for each combination of the treatments. The RNAM test code was then used to measure the draft force. In order to measure fuel consumption, two flow meters were used in the round way as a closed-loop. The encoder and the fifth wheel were also employed to measure the slippage. The profilometer and laser meter were applied to measure the soil upheaving and disturbance areas. The split-split plot on randomized complete block design was used to do the field experiments in three replication and the data analysis was performed by SAS software (9.4 edition). Multivariate linear regression was used to determine the optimum values of the mentioned parameters. For this purpose, the lowest value of draft, fuel consumption, specific draft, tractor driver wheel slip, and the highest soil disturbance and upheaving areas was considered.Results and DiscusionThe results showed that the magnitude of draft increased with rake angle, therefore, the minimum draft was obtained in the rake angle of 20°. As the blade rake angle increased, the amount of soil disturbance area was increased and the maximum soil disturbance was obtained in the rake angle of 30°. The mean slip values of the tractor driver wheels when using non-winged blade were not significant for three levels of blade rake angles and it was significant for two velocity levels. With increasing in rake angle from 20 to 25°, the mean values of specific draft were increased, but with changeing the rake angle from 25 to 30°, there was not significant difference between specific draft values. The difference between the magnitude of tractor driver wheels slip for three levels of rake angle was not significant. Increasing the rake angle had a significant effect on tractor fuel consomption, such that it increased by increasing the rake angle values.ConclusionThe optimum rake angle for the non-winged blade mode was 20° with R2 of 0.73 and for the winged blade mode was 30° with R2 of 0.90. The optimum depth for the non-winged blade was 19.98 cm with R2 of 0.99 and for the winged blade was 20 cm with R2 of 0.97. Also, the optimum forward speed values for the non-winged blade was 2.21 km h-1 with R2 of 0.43 and for the winged blade was 2.03 km h-1 with R2 of 0.84.
H. Balanian; S. H. Karparvarfard; A. Mousavi Khanghah; M. H. Raoufat; H. Azimi-Nejadian
Abstract
In this study, a model was developed for predicting the seeding rate of corn seeds of a typical row-crop planter equipped with a multi-slot feeding device. To this, nine multi-slot rotors (with 4, 5 and 6 slots in three angles of mouth including 23°, 25° and 27°) were designed and manufactured. ...
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In this study, a model was developed for predicting the seeding rate of corn seeds of a typical row-crop planter equipped with a multi-slot feeding device. To this, nine multi-slot rotors (with 4, 5 and 6 slots in three angles of mouth including 23°, 25° and 27°) were designed and manufactured. Tests were carried out at four levels of angular velocity of 40, 52, 62 and 78 rpm on grease belt moving at constant speed of 3.5 km h-1. Tests were completed in three replications. Discharge flow rate was measured and recorded for each treatment. The data were used to develop a model which can be used for predicting the seeding rate under various numbers of slot, mouth angle and rotor angular velocity. According to the results, angle mouth of slots, number of slots, angular velocity and the dual interaction between them showed increasing effects on weight flow rate of seeds (P-value<0.01). In the next step, raw data were used to develop the two desired models: based on the dimensional analysis technique and response surface methodology (RSM). The models outputs were compared to experimental data. The standard error of estimate for flow rate for dimensional analysis and response surface methodology (RSM) were 68.13 mm3 s-1 and 475.59 mm3 s-1, respectively. The dimensional analysis model was closer to experimental data rather than the RSM method. Thus, to predict the volume flow rate of seed, the dimensional analysis model is recommended.
M. Mohammadi; S. H. Karparvarfard; S. Kamgar; M. Rahmatian
Abstract
Introduction Due to problems such as water resources constraints, poor soil and soil organic matter, and the problems related conventional tillage, the attention paid to protective tillage equipment should be taken into consideration by farmers. Today, agricultural machinery designers and manufacturers ...
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Introduction Due to problems such as water resources constraints, poor soil and soil organic matter, and the problems related conventional tillage, the attention paid to protective tillage equipment should be taken into consideration by farmers. Today, agricultural machinery designers and manufacturers are looking for ways to resolve the problems due to the lack of water and soil resources and the reduction in fuel resources. One of these solutions is the optimization of agricultural machinery. The blade is one of the most important consumed components of tillage tools, which is very important for how it is adjusted and its effect on soil. According to research conducted on the importance of optimizing tillage implements, this study was carried out with the aim of optimizing the operating conditions for combined tillage with a new narrow blade. Materials and Methods The tests were taken place in the 10th section of farms in Agriculture school (Bajgah zone) of Shiraz University. Those tests were arranged as the split-split plot based on a completely randomized design. The treatments included the tillage depth, tilt angle and forward speed. The levels for the tillage depth, tilt angle and forward speed were 15, 20 cm and 0, 10, 15, 20, 25 degree and 3, 4, 5 km h-1 respectively. The experiments were performed in three replications. The test variables were draft, soil upheaving and disturbance areas, specific draft, fuel consumption and tractor wheel slippage. The CK 45 steel was used to make blades. The blades were made of the same dimensions and the difference between the blades was only at their tilt angle. Before starting the field tests, some properties of soil such as soil moisture content, soil texture and soil bulk density were measured. The RNAM test code was then used for measuring the draft force. The encoder and the fifth wheel were also employed to measure the slippage. For measuring the fuel consumption, two flow meters were used in the round way. The profilometer was applied for measuring the soil upheaving and disturbance areas. The specific draft was also computed. The data analysis was performed by SAS software (9.4 edition). Multiple regression method was used for modeling the desired treatments. Results and Discussion The results of multivariate regression method for optimizing forward speed, tillage depth and tilt angle for the blades including winged were 3.3 km h-1, 20 cm and 25°, respectively, and for the non-winged, 3.5 km h-1, 20 cm and 24.8°. Providing the tilt angle on the blade surface is considered as an innovation in this research, therefore, it can be seen from the results that with increasing this angle, the draft of the tillage was decreased. This could be due to the increased surface of the blade in the face of the soil on the diagonal surface. This increase was proportional to the cosine tilt angle at the initial surface of the blade. Therefore, the shear strength of the soil was decreased with increasing of this surface and ultimately decreased the amount of draft of the tillage. This variable had a significant difference with the depth of tillage and the forward speed of tractor and fuel consumption for the winged new narrow blade. Although the interactions of the above mentioned variables on the fuel consumption for the new blade condition were not significantly different, the minimum fuel consumption for the non-winged blade condition was also obtained at the same tilt angle as the winged new blade. In general, considering all of factors, the 25 degree inclination angle was proposed for both conditions. The interaction of this factor (tilt angle) on the wheel slip rate was also significant. The effect of the angle of inclination for both blades was significant on the slip of the wheel drive, so that the increase in the tilt angle reduced the amount of wheel slip. However, if the amount of slip of the tractor's wheel for an optimum angle of 25° was considered, according to the graph which representing the relationship between tractive efficiency vs. wheel slip and for Cn = 50, the tractive efficiency will be determined by calculation. It should be noted that the tractor's tractive efficiency was equivalent to 82%. This value reflects the effect of the tilt angle on the amount of tractor output power according to the definition of the tractive efficiency of the tractor. Conclusion Considering the increasing growth of using combined tillage tools in dry soil and its low moisture content, and considering the necessity of replacing the custom chisel blades with new blades which resistance to the soil reaction forces upon them, the non- winged blades with the tilt angle about 25° for working depth of 20 cm and forward speed of 3.5 km h-1 can increase the tractive efficiency of tractors to 82% and also decrease the fuel consumption by 34% compared to conventional tillage blades.
H. Rahmanian- Koushkaki; S. H. Karparvarfard
Abstract
Introduction Pneumatic conveying is a continuous and flexible material handling method which uses positive or negative air pressure to convey materials in pipe. This conveying system is generally divided into two groups of dilute and dense phase. The purpose of this research was to create spiral grooves ...
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Introduction Pneumatic conveying is a continuous and flexible material handling method which uses positive or negative air pressure to convey materials in pipe. This conveying system is generally divided into two groups of dilute and dense phase. The purpose of this research was to create spiral grooves inside horizontal pipes which transfer granular materials under dense phase. Also, the performance of these pipes was compared with control pipes. Finally, friction factors obtained in this research were compared to the previous study. Materials and Methods To create spiral grooves inside the pipes, a broaching machine was designed and developed. Then, by connecting the broached pipes to a pneumatic conveying test- rig of granular materials, the performance of these pipes was compared with control pipes. The specifications of the broaching machine and test-rig were as follow. Broaching machine: The machine included chassis, an electromotor with one hp power, a reduction gearbox, a ball screw for converting rotational motion to linear motion, a spiral shaft, a guide with three bolls, broaches and inverter. Cutting operations and creating grooves inside the pipes were done using broaches. These broaches had two angles, attack angle of 15 degrees and a clearance angle of 10 degrees. The spiral angle of broaches was 30 degrees, the spiral pitch was 260 mm, the width of each groove was 1.5 mm, and a number of teeth were 20. Test- rig: The main components of the test- rig were the air compressor, blow tank, conveying pipes, solid discharge control valve (SDCV), receiving hopper, orifice plate flow meter, pressure transducers, and single point load cell. The compressor was a piston- type, the air flow rate was 405 L min-1 and maximum pressure was 12 bar. For a continuous flow of air and material mixture into conveying pipes, a blow tank was used. To transfer material from blow tank to pipes, a 90-degree bend with a radius of 250 mm and an inner diameter of 40 mm was used. The inner diameter of pips was 40 mm, the thickness was 5 mm and was selected from ABS. In order to measure static pressure of air along the pipes, 10 holes of one mm diameter were drilled on the surroundings of the pipes at intervals of one meter. Then, on each of these holes, a polyethylene bushing was placed. Pressure transducers were threaded on the top of these bushings. A solid discharge control valve was placed at the end of the flow line to control the flow of materials in a dense and continuous phase and to prevent material acceleration. The materials were introduced into the receiving hopper after leaving the valve. To measure the volume flow rate of air, an orifice plate with D and D/2 tapping was used. The pressure transducers were Hogller. For measuring the mass of the materials entering the receiving hopper, a single point load cell (Zemic L6G) was installed under the hopper. A data acquisition system based on ARM microcontroller was used to record output signals from transducers. The treatments were four levels of groove depth (0, 0.35, 0.55 and 0.9 mm), three levels of air pressure (1, 2 and 3 bar) and three levels of pipe length (3, 6 and 9 m). The transferred material was considered as mung bean. Results and Discussion The results of ANOVA showed that the main effects of groove depth, pipe length, and air pressure were significant on the mass flow rate of transmitted mung bean and solid friction factor at 1% probability level. The results indicated that the maximum mass flow rate and minimum friction factor were observed at a pipe length of 3 m, the groove depth of 0.90 mm and air pressure of 3 bar. Minimum mass flow rate and maximum friction factor were observed at pipe length of 9 m, the groove depth of 0 mm (smooth pipe) and air pressure of 1 bar. Conclusion The results showed that the existence of spiral grooves within horizontal conveying pipes would increase the mass flow rate of the mung bean and reduce the solid friction factor of the mung bean and inner wall of pipes.
R. Karmulla Chaab; S. H. Karparvarfard; M. Edalat; H. Rahmanian- Koushkaki
Abstract
Introduction One of the problems which considered in recent years for grain harvesting is loss of wheat during production until consumption and tenders the offers for prevention of its especially in harvesting times by combine harvesting machine. Grain harvesting combines are good examples of an operation ...
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Introduction One of the problems which considered in recent years for grain harvesting is loss of wheat during production until consumption and tenders the offers for prevention of its especially in harvesting times by combine harvesting machine. Grain harvesting combines are good examples of an operation where a compromise must be made. One would expect increased costs because of natural loss before harvesting, because of cutter bar loss, because of threshing loss, because of greater losses over the sieve and because of the reduced forward speed necessary to permit the through put material to feed passed the cylinder. The ability to recognize and evaluate compromise solutions and be able to predict the loosed grain is a valuable trait of the harvesting machine manager. By understanding the detailed operation of machines, be able to check their performance, and then arrive at adjustments or operating producers which produce the greatest economic return. Voicu et al. (2007) predicted the grain loss in cleaning part of the combine harvester by using the laboratory simulator based on dimensional analysis method. The obtained model was capable to predict the grain loss perfectly. Soleimani and Kasraei (2012) designed and developed a header simulator to optimize the combine header in rapeseed harvesting. Parameters of interest were: forward speed, cutter bar speed and reel index. The results showed that all the factors were significant in 5% probability. Also in the case of forward speed was 2 km h-1, cutter bar speed was 1400 rpm and reel index was 1.5, the grain loss had minimum quantity. The main purpose of this research was to develop an equation for predicting grain loss in combine header simulator. Modeling of the header grain loss was conducted using dimensional analysis approach. Effective factors on grain loss in combine header unit were: forward speed, reel speed and cutter bar height. Materials and Methods For studying the effective parameters on head loss in grain combine harvester, a header simulator with the following components was built in Biosystems Engineering Department of Shiraz University. Reel unit The reel size was 120 cm length and 100 cm diameter. This reel was removed from an old combine header and installed on a fixed bed. For changing the rotational speed of the reel, an electrical inverter (N50-007SF, Korea) was used. Cutter bar unit The cutter bar length was 120 cm. Knifes were installed on this section. Reciprocating motion was transmitted to the cutter bar through a slider crank attached to a variable speed electric motor (1.5kw, 1400 rpm, Poland). The motor was fixed on the bed. Feeder unit This section was consisted of a rail and a virtual ground. This ground was a tray that the wheat stems were staying on it manually. The rail was the path of virtual ground. Treatments consisted of three levels of rotational speed of reel (21, 25 and 30 rpm), three levels of forward speed of virtual ground (2, 3 and 4 km h-1), three levels of cutter bar height (15, 25 and 35 cm) and three replications. In other words, 81 tests were done. The basis of choosing levels of treatments was combine harvester manuals and driver’s experiences. The dependent variable (H.L) was calculated as below: (1) Where L.G is the mass of loss grains and H.G is the mass of harvested grains. Results and Discussion Generally results of ANOVA test showed that the cutter bar height, rotational speed of reel and forward speed had significant effect on head loss. Also interaction of rotational speed and forward speed, cutter bar height and forward speed had significant effect on head loss. These findings were based on Soleimani and Kasraei (2012) research. Therefore, the cutter bar height, rotational speed of reel and forward speed were three independent parameters on head loss as a dependent parameter. By results of laboratory data, the equation for predicting grain loss by header simulator was obtained. Conclusion The statistical results of F- test in 5% probability showed that there were no significant difference between measured and predicted amounts for laboratory data.
Modeling
M. R. Salar; S. H. Karparvarfard
Abstract
Introduction The dynamic response of soil on tillage tools, is an important factor in determining their performance. For a tractor with a certain size, a reduction in draft force, the working width and speed of tools can rise and result in increasing performance and reduce costs. Researches carried out ...
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Introduction The dynamic response of soil on tillage tools, is an important factor in determining their performance. For a tractor with a certain size, a reduction in draft force, the working width and speed of tools can rise and result in increasing performance and reduce costs. Researches carried out in order to reduce the draft force led to design and build new tillage tools called Bent Leg and Parra plows. The dual bent blade sub-surface tillage tool was built and examined inspired by the shape of a bent leg. The researches indicated that the combination of a dual bent blade sub-surface tillage tool and chisel plow could be used in order to reduce draft force, loosen the seed bed by the chisel plow and wings, increase in soil disturbance area by the wings, and create a suitable space for root growth by chisel plow. Since the fuel consumption and traction power of tractor are the limiting factors for pulling tools in the soil. The rake angle of tillage tools is the penetration factor of the tools to the soil. It is necessary to determine the optimized rake and bend angles according to their effect on draft force and better penetration in soil. In this research, the Response Surface Methodology (RSM) was utilized to determine the optimized points of wing geometry of winged chisel plow in order to minimize the draft and vertical forces of tillage tool. Materials and Methods Using the properties of dual bent blade subsurface tillage implement and chisel plow, the winged chisel plow was designed by Catia V5R20 software and was built in the workshop of mechanics of biosystems engineering department at Shiraz University. The effect of three factors of working depth of wing (5, 10, and 15 cm), bend angle (10, 20, and 30 degree), and rake angle (7.5, 15, and 22.5 degree) were analyzed on draft and vertical forces of wined chisel plow in soil bin of Karaj Agricultural Engineering Research Institute. The length, width, and depth of the soil bin were 24 m, 1.7 m, and 1 m, respectively. The most important issue was to study the main effects and interactions of factors. So, the Response Surface Methodology was selected. With the help of this statistical design, the numbers of experiments were reduced and all coefficients of quadratic regression and interaction factors were estimated. The experiments were conducted based on the central composite design considering three main surface including central and axial points for each factors. For each response the quadratic polynomial models were obtained using the multiple linear regression. Results and Discussion The results indicated that fitted quadratic model for draft force corresponded with the experimental data by determination coefficient of up to 94% (R2 ˃ 0.94). Increasing the depth of wing, the contact with loosened soil decreased that led to failure in unloosened soil around the chisel blade and increase in pressure to the blade. The results showed that the effect of bend angle was significant on draft force and increasing the bend angle, the tip of wing located in deeper place so, the draft force was increased that was in line with previous researches. The effect of rake angle was not significant on the draft force and its effect on the model was positive and negligible which was reported positive and significant in previous works. The fitted quadratic model for vertical force corresponded with the test data by determination coefficient of up to 93% (R2 ˃ 0.93). The effects of wing depth and bend angle were positively significant on the vertical force of the tool but the effect of rake angle was negligible. The increase in vertical force with increasing bend angle was further in deeper wing position. However, the impact of rake angle was seen in vertical force and the effect of bend angle was not significant in vertical force in rake angles of 7.5° and 15°, but it was significant in rake angle of 22.5°. Conclusion The draft and vertical forces were determined 3.43 and 1.31 kN, respectively, at optimum condition (wing depth of 5cm, bend angle of 11.1°, and rake angle of 19.46°). The proposed model to predict the dependent variables were very close to the results of obtained experimental findings. The wing depth and bend angle had positive and significant effects on draft and vertical forces but the effect of rake angle was positive and insignificant on both measured traits.
Design and Construction
A. Mondani; S. H. Karparvarfard
Abstract
IntroductionMaximum efficiency of natural resources, reduced risk of production, improved fertility of soil, and increased production per area enjoyment have made intercropping a preferential practice compared with cropping. One of the fundamental problems in this kind of cropping is non-existence of ...
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IntroductionMaximum efficiency of natural resources, reduced risk of production, improved fertility of soil, and increased production per area enjoyment have made intercropping a preferential practice compared with cropping. One of the fundamental problems in this kind of cropping is non-existence of suitable machines. In this research, a new intercropping machine has been designed and built for intercropping of corn and bean with precise ratios and different planting patterns. Materials and MethodsThe experiments were conducted at the Badjgah Research Station, Shiraz University, located in NW Shiraz, Iran. The soil texture was clay loam (16% sand, 48% silt, and 35% clay). The plot size was 9 m wide and 12 m long. The total number of the plots were 9. The basic components of intercropping machine were an adjustable frame to adjust row spacing for each unit planter about 550 mm horizontally independently (the row spacing between corn and bean planting lines was considered 375 mm), a hinged frame for adjustment of seeding depth and possible poor emergence of plants due to very deep or shallow planting, metering case frames for installing the vacuum metering disk units around which the seed drums have a row of 36 holes of 4.5 and 5.5 mm diameter for corn and bean, respectively, seed delivery tubes, a suction fan, shovel openers used for bedder planting for corn and lister planting for bean, a knife covering attachment, seed-firming wheels, interchangeable gears which are mechanical chain drives for 43 varying seeding rates driven by carrying wheel drives, two metal seed hoppers whose lower side walls’ slope can be adjust at a maximum level of 45 . A front wheel assist, Massey Ferguson tractor (MF-399) (ITM, Tabriz, Iran) with a maximum engine power of 81 kW was used for field test of intercropping machine. Moldboard plow was used for primary tillage and the depth of plowing was 25 cm. Next, by an offset disk harrow, the field was disked twice for pulverizing lumps, mulching the surface and firming the underneath soil to provide a smooth uniform seedbed. In this study, the common bean seed (var. Derakhshan) and corn hybrid seed (SC-704) with 93 and 83 percent of germination and 97 and 98 percent of purity, respectively, were used. This machine was operated in five different distance patterns between corn and bean seeds on each row: 55 mm and 215 mm in the first pattern, 85 mm and 185 mm in the second pattern, 110 mm and 150 mm in the third pattern, 130 mm and 120 mm in the fourth pattern, and 160 mm and 100 mm in the fifth pattern for corn and bean, respectively. For all patterns, the depth of planting for corn and bean seeds was chosen as 20, 40, and 60 mm. In addition, the forward speed was assumed to be constant (4 km h-1). By using split plots with three replicates and SAS software (2002), the results were analyzed. Results and DiscussionThe multiple index, miss index, precision index, and quality of feed index was evaluated. The analysis of variance for bean planting unit showed that difference distance between seeds and various planting depth were significantly higher for multiple index (P< 0.01), but their interactions were not significant (P 0.05). Also, with decreasing the seeds distances, the multiple index was increased (P< 0.05). Moreover, comparing the results of the average multiple index in different levels of planting depth indicated that the multiple index was decreased when at higher depths of planting (P< 0.05). The seeds distance and planting depth were significantly higher for miss index and quality of feed index (P< 0.01), but their interactions were not significant for either index (P> 0.05). The precision index was significant was affected by different levels of seeds distance (P< 0.05) and was higher for different levels of seeds planting depths (P< 0.01), but their interactions were not significant. In corn planting unit, the results showed that the different distances between seeds and planting depths were significantly higher for multiple index, miss index, quality of feed index, and precision index (P< 0.01). Also their interactions were significant for multiple index (P< 0.05), but the other indices showed no significant interactions (P> 0.05). ConclusionsThe data suggested a higher quality index once corn and bean were respectively plated at 160 and 215 mm seed distance with a planting depth of 60 mm being optimum for each corn and bean.
Design and Construction
S. Dehghani; S. H. Karparvarfard; H. Rahmanian- Koushkaki
Abstract
Introduction: Automatic guidance of tractors in the mechanized farming practice has taken the attention of agricultural engineers in the last two decades. For this to be truly practical on the farm, it should be economical, simple to operate and entirely contained on the vehicle. Different types of steering ...
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Introduction: Automatic guidance of tractors in the mechanized farming practice has taken the attention of agricultural engineers in the last two decades. For this to be truly practical on the farm, it should be economical, simple to operate and entirely contained on the vehicle. Different types of steering systems such as leader- cable, laser- controlled, radio- operated and contactor- type have been developed for automatic guidance. The automatic leveling system is used on hillside machines to keep the separator level when operating on hillsides. This system has three parts: fluid level system, electrical system and hydraulic system. The fluid level system consists of fluid reservoir and a leveling control switch box. The fluid level system actuates the electrical system of the leveling unit. The electrical system which actuated by the fluid system consist of four micro switches in the leveling control switch box, two micro switches in the limit control box, a solenoid in the hydraulic control level, manual leveling control switch, and a leveling limit warning light. The hydraulic system maintains the level of the separator when the machine is operating on a hillside. The present study was aimed to develop a reliable, versatile and easy to maintain system to fit our economy and low technology level of farmers for hillside- range development or fallow farming. The automatic guidance system has been implemented successfully on agricultural vehicles on the basis of three components, i.e. sensors, processors and actuator elements. The study site (N, latitude; E, longitude; and 1810 m above sea level) was located at the Agricultural Research Center, Shiraz University, 15 km northwest of Shiraz, Fars Province, Iran. MF-399 agricultural tractor manufactured by ITMCO, Tabriz, Iran was used for doing the experiments.Materials and Methods:The Level Sensing System: The biaxial tilt industrial sensor (ZCT245AL- China) with digital output can be connected to the computer and received angular position in x and y coordinates. An assumed degree could be considered as basis degree and the measured frequency was adjustable. The tilt sensor located along the axial length of tractor and leads the angles which are created by longitudinal axle transverse axle of the tractor in related to horizontal level. It was used for contour lines detecting. The potentiometer located on the steering wheel of the tractor and pressure sensor which used with goniometer sensor used keeping uniformly of leveling points in tractor motion. The pressure sensor (SN-SCP1000- South Korea) which is used in leveling system can detect the elevation changes. In this way, by defining a limitation of altitude for system, it would be able to stop steering turning motor which was coupled to tractor steering rod automatically. By resetting, the tractor could be able to live in a new level position. To avoid excessive left and right steering wheels deviation and interfering with other lines of travel, potentiometer was used. The deviation degree for steering rod from center to left or right was selected 120 degrees. Accordingly, the wheels would not be able to move more than 10 degrees to each direction. The Processing System: The electrical circuit graphically designed and simulated by software (Altium Designer, 2009) and installed on the tractor. The components of this circuit are as follows: Electrical board, two relays which control the electrical pathway in both directions, a battery with 12 volts of electric potential as electrical power supply, ATmeGA32 microcontroller which was made by Atmel company as main core for information processing, RS232 protocol was used for making correlation between serial port (COM) and the microcontroller and two capacitors for reducing noises. The Actuator System: The output signals from the a processing system, were lead in the actuator system would order and indicative of left- turn or right- turn command, were introduced to actuator- units include an electric- gearbox motor that stimulate the steering wheel shaft of the tractor by chain and sprocket and conduct the tractor in leveling traces at the desired speed. Before hitching any implements such as row planter behind the tractor, the system was successfully tested on average slopes of 14.5% using a tracing powder. Results and Discussion: A plot of the average elevation of each 12 lines traced for a length of about 50 meters, H0, versus the actual elevation of 12 to 16 equally spaced points of each trace, H, produced the following relationship: H0= 0.142+ 0.990 H Indicating a reasonably acceptable performance with standard error and R2 0.048 and 99.3% respectively. Conclusions:The row planting in various slopes coincided with the contour lines of ground (Duncan’s Multiple Range Test p ≤ 0.05). Also, no significant difference was observed among the slopes and index of length and dry weight of root and shoot. The percentage of the emergence index in the high slopes (18-21%) showed significant differences. Hence by increasing slopes, the percentage of seed emergence was decreased.
