Robotic systems: optimization of stiffness characteristics

Abstract

Optimization methods of structure are considered. Methods have been developed for modeling robotic structure made of a multilayer composite material, including a three-layer one, consisting of external bearing layers and lightweight aggregate between the bearing layers. It is necessary to arrange the basis of the composite material along the lines of maximum stresses to obtain the most stiffness composite structure. The structure of a homogeneous material under operating loads was calculated to determine the lines of maximum stresses at the first stage, and the trajectories of the maximum tensile and compressive stresses were determined. The structure was modeled by composite materials at the second stage, and the basis of the composite material was located along the found paths of maximum stresses. The trajectories arrangement of the basis of the composite material were adjusted according to the results of the composite structure calculation at the third stage. The process continued until the true location of the composite base along the maximum stress paths was achieved. A multi-stage dynamic stand was considered as a robotic system designed for semi-natural modeling. The technique is proposed for approximating parts of robotic systems containing ring gears, motors, reduction gear, and bearing supports. The essence of the method was to determine the stiffness of ring gears, motors, reduction gear, bearing supports based on analytical methods. The resulting stiffness were assigned to the rod systems in the future, replacing the elements under consideration. Methods and algorithms for the frequency analysis and the optimization of the semi-natural modeling stands designed to simulate the flight characteristics in laboratory conditions have been developed. The developed methodology and algorithms allow you the following: to determine the frequency characteristics of the stand; to optimize the stands’ characteristics of various structures that have great technical, scientific and applied value. The analysis was carried out using finite element and analytical methods. The convergence of the calculation results was checked by increasing the number of finite elements, i.e. the thickening of the approximation grid. The last partition was considered sufficient to obtain reliable calculation results when the partition results of the previous and subsequent, the smaller ones do not differ by more than 3%. The data obtained as a result of the study for test problems were compared with the available experimental data. The good agreement was observed between theoretical and experimental results. The discrepancy was not more than 10%. The good agreement between theoretical and experimental results was observed. The discrepancy was not more than 10%.