Development of a Plow Tillage Cycle for an Agricultural Tractor

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<abstract> <b><sc>Abstract.</sc></b> Various field tests are needed to improve agricultural tractor performance; however, field tests require expenditures for constructing an experiment system and time for conducting the tests repeatedly. In addition, it is difficult to acquire reliable data because field tests depend on environmental conditions. For this reason, indoor tests using dynamometers have been used in the automotive industry instead of field tests. To ensure the reliability of indoor tests, standardized driving cycles are needed as input data for the dynamometer. Therefore, this study aimed to develop a standardized plow tillage cycle for agricultural tractors using real field data. A load measurement system was installed on a tractor to collect real field data from loads acting on the four driving axles and the hydraulic pumps. Plow tillage was conducted on ten farmlands of similar size (3000 m²; 100 m x 30 m) at three sites (A, B, and C). The plow tillage cycles for each site were developed using the driving cycle construction method for conventional vehicles with the measured load data. At one site, the entire dataset from the ten farmlands was first classified into micro-trips, which were the minimum patterns of plow tillage including plowing, three-point hitch ascending, and tractor turning. The arbitrary working cycles were generated by combining micro-trips, and less than 5% absolute percentage error was achieved between the entire dataset and the generated arbitrary working cycle. Second, the plow tillage cycle was determined considering the sum square difference (SSD) with a torque and torque variation probability distribution. The selected working cycle with the lowest SSD was determined as the plow tillage cycle. Third, the performance values (PVs) of the plow tillage cycles of agricultural tractors and the driving cycles of conventional vehicles were compared to evaluate the performance of the plow tillage cycle. The results showed that the ranges of absolute percentage error relative to the entire dataset were 1.0% to 4.9% for all sites. The SSDs of the plow tillage cycles were 1195.96, 958.77, and 1202.50, and the PVs of the plow tillage cycles were 99.60, 77.90, and 84.15 for sites A, B, and C, respectively. The PVs of the commonly used driving cycles were low, at 60% to 125% of the plow tillage cycles. The plow tillage cycles had especially higher performance than some of the international standard driving cycles by 104% to 125% for site B. The results showed that the developed plow tillage cycles can be applied to indoor tests for performance evaluation of agricultural tractors.