Study of the influence of oscillatory processes in a mobile vehicle on the running smoothness characteristics
The issue of optimizing the dynamic characteristics of a mobile vehicle depending on the operating conditions is considered. The optimization problems were solved taking into account the random nature of dynamic loads. The task of transforming the input effect on the elements of the mobile machine was solved in a deterministic aspect using integrated criteria. As a measure of the accuracy of the introduced criteria, the standard deviation was used. The minimum values of vertical reactions on the header shoes were determined by the dispersion of its oscillations, taking into account the spectral density of the irregularities of the agricultural background. It was found that the frequency characteristics of the header shoes also depend on the vertical and longitudinal-angular vibrations of the combine separator. Optimality criteria are presented for assessing the dispersion of vibrational parameters of vehicles from external influences. The general optimization criterion was determined based on the independence of the objective functions and the maximum quantile of the normal distribution, which allowed, in a probabilistic aspect, to evaluate the optimization efficiency for agricultural machinery with a wide range of applications. The local optimum was determined by the expression of objective functions in terms of elementary functions, taking into account statistical parameters and the nature of the distribution of a random variable. The optimal transfer function was determined based on the minimum value of the standard deviation of the objective function taking into account the Fourier variables. The determination of the local optimum was carried out graphoanalytically by the objective function of smoothness and by the probabilistic criterion. The optimal value of the relative attenuation coefficient of vertical oscillations of the separator body was determined, the reason for its minimization and the probability of exceeding the permissible vibration level were established. A method for determining the transfer function to predict the smoothness of the combine is presented. The possibilities of the proposed optimization method are estimated.