Features of the spectra of loads on the units of mobile agricultural machines in the field when delay in external influences

Abstract

The problem of choosing the oscillatory parameters of mobile combine harvesters leads to the development of dynamic models that ensure the normal functioning of machines, as well as to consider these parameters in the probabilistic aspect and, consequently, to assess their dispersion. The main type of impact is the impact created by the unevenness of the path of the mobile machine and the change in the physical and mechanical characteristics of the soil. Such problems are solved with sufficient accuracy for practice in the linear formulation. In the article, external influences in multidimensional dynamic systems are presented in matrix form. Matrix of spectral densities when calculation of statistical characteristics in the presence of mutual relationships lead to the need to calculate the elements of both the main and secondary diagonals, which leads to the complication of calculations. Calculation of correlations between impacts determines the form of the matrix of spectral densities of external influences. When calculating statistical characteristics, relations taken into account lead to a complication of calculations. Therefore, it is advisable to bring the matrix of external influences to a diagonal form in order to obtain matrices of uncorrelated influences. The calculations of the spectral densities and vibrational intensities for mobile machines of the agroindustrial complex made it possible to establish that the same results are obtained only for vehicles with weak functional connections, when moving along a field micro profile creating an uncorrelated external influence. Recommendations on the practical use of calculation formulas are given.