Saturated adaptive backstepping control of uncertain nonlinear systems with validation using twin rotor system

This work investigates the semi-global tracking control of a class of uncertain nonlinear systems with input saturation, using adaptive backstepping controller and tuning function design. The control input has been represented as a product of a positive constant and a generalized saturation function of unit magnitude, where the constant parameter represents the saturation bound of the available input signal. It has been shown that the overall saturation problem can be realized as an equivalent problem involving no saturation if the system satisfies a sufficient condition. The condition represents a relationship between the saturation bound of the input signal and the upper bounds of tracking errors, disturbances, and uncertainties. To realize this fact physically, the proposed control algorithm has been implemented on a Twin Rotor Multi Input Multi Output System (TRMS). Experimental and simulation outcomes illustrate the validation of the derived control methodology along with robustness and performance analysis. (C) 2020 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.