Abstract
This paper presents the Robust Generalized Dynamic Inversion (RGDI) control system for Autonomous Underwater Vehicles (AUV)s. The outer (position) and the inner (attitude) loops of the control system utilize Generalized Dynamic Inversion (GDI) of two pre specified asymptotically stable dynamics of the inertial position coordinates and the attitude angles, respectively. The outer loop provides the pitch and yaw tilting commands to the inner loop, which in turns generates values of the corresponding control surface deflections by which the vehicle's position is controlled. Sliding mode control-based elements are included in the particular parts of the two GDI control loops, and they work to robustify the GDI control system against instabilities and performance deterioration due to unmodeled nonlinearities, parametric variations, and unknown bounded disturbances. A Lyapunov stability analysis of the proposed RGDI control law is presented, and a detailed six degrees of freedom mathematical model of the Monterey Bay Aquarium Research Institute AUV is used to evaluate the controller performance. Numerical simulations are conducted under both nominal and perturbed conditions to demonstrate robustness of the control design. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.