The consumed power and safety of cam and four-bar-link semi-automatic vegetable transplanters were analyzed and compared according to the engine speed and planting distances. A measurement system was constructed to obtain the torque, rotational speed, and strain at the corresponding locations of both transplanters. Field tests were conducted at three engine speeds and three planting distances for each type of transplanter. The torque and rotational speed data of the input shaft of the transplanting devices were used to calculate the power consumed during transplanting. The strain data were converted into stress values to calculate the static safety factor and fatigue life. The results show that the torque and consumed power of the cam transplanter were greater than those of the four-bar-link transplanter under similar operational conditions, owing to its rigid and heavier design. The consumed power increased as the engine speed increased for both types. The static safety factor and fatigue life exhibited different values depending on the measurement location with a sufficient safety margin. Although more skill is required in planting distance control owing to its manual adjustment, the four-bar-link type is more economical under similar operating conditions because of its smaller power requirement.

In this study, we have conducted a quasi-static lateral overturning test and derived a static falling down sidelong angle by using a miniature tractor model. We analyzed the lateral overturning condition of tractors theoretically by literature review and derived a method to manufacture a miniature model based on the analysis result. A miniature model was manufactured using a 3D printer at a scale of 1/20, relative to the actual dimension of a tractor. In addition, a test platform was constructed to perform lateral overturning tests. The miniature model was placed on the test platform, and the inclination angle of the ground was gradually increased. Then the static falling down sidelong angle, that is the inclination angle at the moment of lateral overturning occurred, was measured. The test result indicated that the difference of average static falling down sidelong angle was 1.0%. comparing to the accredited certification test result of the original tractor. Therefore, by utilizing the method applied in this study, the static falling down sidelong angle of tractors could be derived quickly and conveniently from a miniature model. As future research, the in-depth verification for the developed method is required by applying to a variety of agricultural machines.