H. Mehregan; Sh. Ghavami Jolandan; M. E. Khorasani Ferdavani
Abstract
Introduction Today, in modern agriculture, the use of agricultural machines is inevitable. the tire is the last part of the power transmission system, which plays an essential role in controlling the tractor and transferring the tractor's reaction to the soil. Tires used in agricultural implements and ...
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Introduction Today, in modern agriculture, the use of agricultural machines is inevitable. the tire is the last part of the power transmission system, which plays an essential role in controlling the tractor and transferring the tractor's reaction to the soil. Tires used in agricultural implements and tractors should be able to transport appropriately and have sufficient adhesion and slip. Several parameters affect these abilities, including tire diameter and width, tire shape, tire tread modulus, tire pressure and load on the tire, with the last two parameters, tire pressure and load on the tire two very important factor is the tire and surface contact, the tire's contact between the tire and the ground, the tire's involvement in the direction of travel, as well as the tensile and fuel consumption of cars and motor vehicles. Given the fact that the tire pressures/load of agricultural machinery are less attractive to the users, Due to the many benefits that the use of electronic control systems. Due to the many benefits that the use of electronic control systems, Today, the use of electronic control technologies is considered as an innovation. the automatic tire pressure control system could ensure the pressure stability. Tire pressure drop is detected, and the system automatically refills the tire according to the tire pressure requirements. Therefore, the main aim of this paper is to set the tire pressure at the optimal value by designing an electronic control system for measuring and controlling tire pressure and evaluating the response speed of the system. Materials and Methods This research work is mainly aimed at designing a tire pressure control the tire pressure. BD pressure sensor, Arduino board, voltage/pressure regulator, 5-volt double-channel relay module was utilized. Moreover, Solenoid valve, rotary joint along with compressor and reservoir was employed for controlling tire pressure. In this paper, a laboratory tire pressure control system was designed which can operate in both manual and automatic modes. In automatic mode, a series of ideal pressure (P1) is defined as the soil type, and the driver selects an ideal pressure for the system. If the tire pressure (P0) differs from the set pressure point (P1), then the control unit determines a time duration (T1) for the decrease/increase the pressure level to achieve the optimal setpoint. Besides, a manual mode allows the system to provide a wide range of pressure for the driver depending on the terrain encountered. It is worthy of mentioning that the operation of the system in manual mode is the same as that of automatic mode. In this work, experiments were performed at three levels of output pressure (43.5, 65.2, 87 psi), two tire pressure reduction levels (20- 16 and 16 -12 psi), and two tire pressure increase levels (8 -12 and 12 -16 psi). The tests were laid out as a factorial in a completely randomized design with three replicates. Results and Discussion The ANOVA results indicated that the effect of reservoir outlet pressure on the timing function and tire pressure was significant at the level of 1% (p-value <0.01), while the dual and triple impacts of the factors were not significant. The results also illustrated an increase in the speed of the system response at the output pressure of the reservoir of 87 psi. Also, two different scheduling functions were conducted to evaluate the speed of the system response to reduce the tire two levels of 20 to 16 and 16 to 12 psi. For this reason, two different scheduling functions were used. The ANOVA results indicate that the timing function and tire pressure level had a significant effect on the output parameters at the level of 1%. Furthermore, an increase in the speed of the system response in the second-order scheduling function was observed. Comparison of system performance with first and second time estimation functions at different reservoir pressures, as shown in Fig. 9, showed that the use of the second-order estimation function in all cases reduced the number of steps to reaching the desired pressure significantly. Conclusion According to the obtained results, it can be concluded that the replacement of the second-order scheduling function to control tire pressure, increased the speed of the system’s response, which results in keeping the right pressure at all times very accurately.
Fatemeh Afsharnia; Mohammad Asoodar; Abbas Abdeshahi
Volume 1.32, مجموعه مقالات منتشر شده در حوزه مهندسی زراعی قبل از تفکیک مجله علمی کشاورزی در سالهای 1354 تا 1388 , February 1976, , Pages 49-58
Abstract
Effective operation of a system is related to acceptable programming of repair and service activities. Efficient managerial programming is associated with accurate estimation of maintenance system parameters. In this study, four tractors failure rate was investigated by completing 300 questionnaires ...
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Effective operation of a system is related to acceptable programming of repair and service activities. Efficient managerial programming is associated with accurate estimation of maintenance system parameters. In this study, four tractors failure rate was investigated by completing 300 questionnaires from tractor operators in Khuzestan Province. The operators were interviewed in four regions of the province. Under study variables included driver experience, level of education, driving license, skill training course, work location (region and city), type of service and maintenance, storage conditions, distance to first workshop, distance from shelter to farm, machine age, annual use hours and number of failure. Regression analysis by estimating an exponential function showed that the variables such as age of tractor, annual hours used and type of service and maintenance affected the failure rate of each four type tractors. For one percent increase in age of tractor and annual use hours, failure rate increased about 0.6% and 0.24%, respectively. Also, failure rate in MF285, MF399 and U650 tractors was about 0.383, 0.453 and 0.143 percent more than JD3140 tractor, respectively. The preventive maintenance causes 0.252 percent decrease in failure rate.
Abbas Rohani; Hasan Masoudi
Volume 1.32, مجموعه مقالات منتشر شده در حوزه مهندسی زراعی قبل از تفکیک مجله علمی کشاورزی در سالهای 1354 تا 1388 , February 1976, , Pages 59-68
Abstract
Replacement of tractors is a very difficult task. Farm managers often need to make such economic decisions about their machines. Repair and maintenance expenditures can have significant impacts on these economic decisions and forecasts. The purpose of this research was to identify a regression model ...
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Replacement of tractors is a very difficult task. Farm managers often need to make such economic decisions about their machines. Repair and maintenance expenditures can have significant impacts on these economic decisions and forecasts. The purpose of this research was to identify a regression model that can determine economic life of two-wheel drive tractors. The study was conducted using empirical data on 60 two-wheel drive tractors from Astan Ghodse Razavi agro-industry during the years 1988 to 2005. A power model was selected as the best model for prediction of repair and maintenance costs. Based on the power model, the cumulative cost model (CCM) was used to predict the tractors economic life. 29025 hours was predicted as the economic life of the tractor by the CCM model, while according to cost minimization model (CMM) this parameter was equal to 27773 hours.
