The goal of this research was to analyze the load and safety of the transplanting device of the 4-bar link type semi-automatic vegetable transplanter under different workload conditions. To measure the strain at the transplanting device, a load measurement system was developed using 15 strain gauges. Field tests were conducted at 4 levels of engine speeds (750, 1000, 1250, and 1500 rpm) and 10 levels of the planting distance (0.29–0.47 m). The static safety factor was defined as the ratio between the strength of the material and the maximum stress in the transplanting device. The calculated stress data were converted from the time domain to the frequency domain using the rain-flow counting methods and Goodman’s Equation. The sum of fatigue damage was acquired based on the Palmgren–Miner’s rule. It was observed that the stresses increased with increasing engine speed and planting distance. The results show the higher engine speed and the longer planting distance will decrease the static safety factor and fatigue life. The static safety factor value was more than 1.0 for all locations and all working conditions. The minimum fatigue life was 49,153.3 h at link A (S_14), under the working condition of engine speed 750 rpm and planting distance of 0.35 m.

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The objective of this study was to present the development of GPS-based tracking system to evaluate the effectiveness of tillage using a four-wheel tractor. The system is composed of a location acquisition, using GPS (iGPSport), and data analysis for estimating the tractor trajectories and effectiveness of tillage by measuring the overlap during the tillage. The laboratory stage experiment was conducted to validate the system by measuring the specified size of the field and tractor trajectories. The performance evaluation of the system was done by measuring the displacement error of actual trajectories and the estimated one. The system was also tested for the actual tillage operation using a four-wheel tractor, Daedong Kioti RX7210, in two locations in Yogyakarta: Pajangan, and Moyudan. The tractor tracking system was developed based on GPS for estimating the tractor trajectory path and operation width distance (l) after the operation as tillage effectiveness evaluation by the evaluation of overlap and untillage land systematically using the tracking system. The system performance evaluation in the actual field for tillage operation using the four-wheel tractor in Moyudan and Pajangan shows that the RMSE < 50 cm, and the MAPE < 24% with R2 > 0.7. Overall performance of the tracking system, it could be used to estimate the behavior of tillage operation.