Nonlinear control of aerial manipulation systems

This paper presents four effective control algorithms to overcome challenges in controlling Aerial Manipulation Systems (AMSs). Interaction with the environment, nonlinear couplings, and structural and non-structural uncertainties are some issues that make the AMS controller difficult to develop and implement. Because of the complexity in the control design process, many research studies employed simplified AMS dynamics in the design of the controller. In this study, all the proposed control algorithms, with the exception of the hierarchical LQR method, are designed considering complete dynamics of the system without any need for simplification. Proposed control methods include (i) inverse dynamic, (ii) hierarchical LQR, (iii) sliding mode, and (iv) semi-optimal nonlinear control, which show appropriate behavior in the presence of some of the above-mentioned challenges. In order to assess the effectiveness of the control methods, coupled dynamics of a quadcopter endowed with a robotic manipulator is modeled. These controllers are compared to identify their effectiveness in simultaneous control of the quadcopter and its manipulator in the context of control accuracy and control effort. Additionally, sensitivity of the proposed approaches to an increase in the uncertainty levels are determined. (C) 2020 Elsevier Masson SAS. All rights reserved.