Toshio Konaka

Prediction of soil reaction forces on a moldboard plow surface

Abstract Using mathematical models, approximate trajectories of soil furrow subslices were determined and the forces occurring on the moldboard surface were calculated. The various components of the normal force along the trajectory line of the middle section of the furrow slice were analysed in relation to the velocity of plowing operation and the curvature of the path. The soil reaction forces encountered by the share portion of the plow were also determined by a model which used the method of trial wedges to determine the angle of the failure surface with the horizontal. The sum of the calculated forces was compared with that obtained by actual plowing experiments performed in the laboratory.

Compaction characteristics for the towed and driven conditions of a wheel operating in an agricultural soil

Abstract High axle loads, duration of strain as well as strain rate due to applied stresses, and field moisture condition have been found to contribute to compaction in the field. Numerous previous investigations on agricultural soil compaction were carried out with relatively dry soil. The aim of this study was to investigate the interrelationships between compaction, applied load, vehicle speed and a certain practical range of soil moisture content through a soil bin investigation of the compaction which results from the passage of a towed and a driven wheel. Soil pressure and the corresponding bulk density were analysed using a model proposed by Bailey et al. ( J. agric Engng Res. 33 , 257–262 (1986)) and ANOVA techniques. The results showed that compaction was higher at the higher moisture content level for both towed and driven conditions of the wheel, and that it was applied load that had the greatest contributory effect. Also, compaction was higher in the case of the driven wheel as compared to the towed wheel due to the phenomenon of slip sinkage. Baileys model, it appears, can be utilized in the field for a practical estimation of compaction resulting from the passage of a towed wheel.

A model to determine the trajectory of soil motion on a moldbroad plow surface

Abstract A mathematical model was developed to determine the soil trajectory of motion on the moldboard plow surface. With the use of the model, trajectory lines of soil particle travel were calculated based on the shape of the moldboard plow surface. Also, with the use of the values of soil properties, soil-metal coefficient of friction, the travel speed of plow and the soil modulus of elasticity, equations of forces were solved for equilibrium condition of the furrow slice passing over the moldboard surface. The use of the model can be xtended to the approximation of the soil reaction forces occurring the plowing operation. Laboratory experiments were conducted to verify the validity of the model. the moldboard shape factors used were derived from the coordinates of points describing the contours of the plow surface as measured by a profilograph.

Triaxial force measurement at specific positions on a soil-cutting blade

Abstract In order to create a mathematical model of a soil-cutting blade, it is necessary to understand thoroughly the behavior of a soil slice and its interaction with the blade surface. The triaxial force transducer was developed to serve as one of the various tools to verify the proposed mathematical model. The prototype model transducer was fabricated, calibrated and tested with a soil slice on a flat cutting blade. The calibration results have indicated high sensitivity and the capability of simultaneous measurement in three directions. As a technological refinement, the detecting part of this triaxial force transducer was tapered to solve the problem of soil clogging in the opening clearance. Furthermore, the effects of the clearance configurations between the bore on the soil-cutting blade and the detecting part which is embedded in this bore were investigated to determine the most desirable configuration. The comparative results indicated that by tapering both the detecting part and the bore, the tangential stress measurement gained the highest value, and provided the most satisfactory condition for three-dimensional stress management.

Basic Studies on the Application of Fuzzy Theory to Farm Work Planning III. Calculation of Coverage Area by Using Fuzzy Linear Programming.

In order to improve the agricultual production efficiency, it is necessary to design the oprimum scheduling of farm work operation under the condition of farm scale, machine power, working period, and working capacity etc.In recent years, some decision support systems for agricultural optimization planning have been developed. However, the present system cannot deal with uncertain information such as “approximately 10ha”, “about 8 hours” and other fuzzy data.In this study, to calculate coverage when puddling and rice transplanting working periods are partially overlapped, we have formulated it as fuzzy linear programming problems.Membership function of fuzzy constraints and fuzzy goal was determined from answers on the questionarie on puddling and rice transplanting. For example, the target coverage is assumed to be approximately more than 2.4ha because the owned rice paddies have 2.4ha. And the limitation of the working hours is assumed to be approximately less than 44 hours in the working period, and so on. By using membership functions which were obtained in the way described above, each working hours and coverage for multi farm operations in the typical 4 cases were to be found as a fuzzy solution and discussed.