Robustness to Disturbances of Ellipsoid-Shape Underwater Vehicle with Multi-Link Manipulator

This article is devoted to the issue of analyzing the influence of external disturbances on the underwater vehicle in the form of a flattened ellipsoid body with a multilink manipulator when performing technological operations. The relevance of the study is related to the automation of such operations as underwater welding, transfer of objects, twisting, bending, etc., performed underwater. For this purpose, we have built a mathematical model of the underwater apparatus with an ellipsoid shape, indicated the ways of influence of moments and forces arising in the manipulator on the apparatus body. It was found out that this influence leads to nonlinear effects in transients. This influence is different, depending on the axis in which the motion of the apparatus is performed. Since the body is flattened in the horizontal axis, the most unpleasant effect occurs in the vertical motion, due to the increased hydrodynamic resistance. The model is considered without a control loop in the apparatus, and it is the effect of the housing on the accuracy of movements of a multilink manipulator with a standard control system in the form of PID controllers that is important to us.