Precise Dynamic Modeling and Control of a Net-Throwing Aerial Vehicle in Capturing Flying Objects

The purpose of this paper is to provide a comprehensive mathematical model and control strategy for a Net-Throwing Aerial Vehicle (NTAV) to grab flying objects with high reliability. To achieve this goal, by describing the flight phases of the mission and the overall dynamics of flying objects, the process of extracting equations of motion is expressed in tensor form. Then, a control strategy for this multi-step mission is introduced. Due to the nonlinear nature of the aerial vehicle and the presence of intense time-varying loads and uncertainties after capturing the unknown target, a robust control system based on generalized super-twisting sliding mode control (GSTSMC) approach is designed for this under-actuated system. The controller is able to estimate the target inertia precisely, which effectively leads to a reduction of tracking error without deteriorating transient response. In this regard, the performance of the designed controller compared with the generalized and super-twisting sliding mode controllers (GSMC and STSMC) is evaluated based on some standard metrics such as integral absolute error and control input. The results show the validity of the proposed model and the desired performance of the control system without expending more control effort.