Modelo matemático simplificado para previsão do esforço de tração em ferramentas estreitas de mobilização do solo

Abstract

Equipment such as scarifiers and subsoilers, due to their lower soil mobilization, have been increasingly used in the initial soil mobilization tasks for crop establishment. Sizing this type of equipment based on technical parameters contributes to the rationalization of its use. The estimation of the force required for the traction of a specific piece of equipment can be performed through field tests and mathematical modeling. In Brazil, there are few studies on the use of mathematical models to obtain the traction effort of narrow soil mobilization tools, such as scarifiers, subsoilers, and furrow openers for no-till seeders. There are several mathematical models that allow for the estimation of both the traction effort and the mobilization caused by these tools in the soil. The main objective of this work was to study different mathematical models in order to identify, among them, the most promising ones for Brazilian conditions. Subsequently, efforts were made to simplify them and incorporate them into a mobile application, in order to enable the calculation of the required effort per shank and the power needed for the tractor, in a simple, fast, and accurate manner. The methodology of this work was divided into three phases: the first phase involved systematic research, the second phase involved simplification and comparison, and the third phase involved the development of a mobile application. The selected models were: Reece (1965); Hettiaratchi & Reece (1967); Godwin & Spoor (1977), McKyes & Ali (1977); Grisso et al. (1980) and Perumpral et al. (1983). To apply them, studies from various Brazilian authors' fieldwork were used. The simplification process of the models was based on excluding features that were more difficult to obtain and also had little interference in the final result. The obtained results were then compared, and the model proposed by Hettiaratchi & Reece (1967), in its simplified form, showed the highest approximation for most of the field comparison results. This model was selected for insertion into the application, which was developed for the Android platform, providing traction effort results in Kgf and power in CV; KW and HP, with a variability level of ten percent plus or minus. Validation tests were conducted comparing field data between the unsimplified model, the simplified model, and the calculation by the application, obtaining results that demonstrate that the application adequately fulfills the objective of assisting in the calculation of traction effort in a simple, fast, and efficient manner.