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Korean farms for dryland crops are usually disordered and uneven. Thus, 43.4% of major farm machinery accidents occur due to instability and sharp turning conditions. Therefore, the objective of this study is to analyze the stability of a tractor-mounted Chinese cabbage collector using a simulation program and validate it via experiments. In the static condition, the ground slope angle was increased by 1° to obtain the overturning angle. In the dynamic condition, 10 cm high rigid obstacles were located to investigate the stability of the equipment with an approach angle of 135°. The simulation was conducted at four tractor forward speeds (0.15 m/s, 0.20 m/s, 0.25 m/s and 0.30 m/s). Additionally, the motion trajectory of the front wheel and rear axle were predicted for loaded and unloaded conditions. Furthermore, vibration sensors were placed at four locations to determine the vibration level of the Chinese cabbage collector, and the load condition and conveyor speed were considered the factors affecting the vibration level. The static overturning simulation suggested that the collector could reach critical angles of 45.6° and 33.2° and overturn at 52° and 36.1° on the right and left sides, respectively. In dynamic stability analysis, it was observed that the center of gravity could change and separate from the ground when the forward speed was more than 0.30 m/s. Apart from the first point, the maximum vibration level exceeded 1.15 m/s2 at the remaining three points. Furthermore, the vibration level increased with an increase in the speed of the conveyor.

Deflection and fatigue damage in a tractor-mounted Chinese cabbage collector might occur due to continuous operation. Therefore, the objective of this study is to predict the service life of the material used for the hydraulic motor shaft and conveyor joints based on stress and fatigue analysis. The torque produced by the motor was measured using the torque sensor for various tractor forward speeds and rotational speeds under unloaded and loaded conditions with three iterations. The relevant shear stress with the S – N curve on fatigue life was determined using the Smith – Watson – Topper equation and rain flow cycle counting method. Additionally, the severity level was investigated using Miner’s rule. Design variables of the shaft diameter and conveyor’s joints were incrementally increased by 0.02 m. The experimental results of deflection and shear stress of the components were found to be negligible. The result of fatigue lifecycles was also generated over 107. The maximum severity level of the motor shaft, conveyor joints 1 and 2 were 4.27 and 4.48, 4.26 and 5.58, and 4.12 and 4.46, respectively under unloaded and loaded conditions. When the values of design variable components were increased incrementally, shear stress and deflection decreased gradually but the fatigue life increased. Nevertheless, the results indicated that this machine could be safely used in the field.