Backstepping and Robust Control for a Quadrotor in Outdoors Environments: An Experimental Approach

Abstract

This paper addresses the tracking control of quadrotors flying outdoors. Two control laws are combined and tested in real-time experiments. The aircraft attitude and the translational displacement are controlled using the backstepping approach, while the altitude is controlled using the sliding mode control strategy. In both cases, new modifications are introduced with respect to the existing classical algorithms. Concerning the backstepping algorithm, we introduce the dynamical model of the quadrotor in the controller design and this guarantees that the virtual input is bounded. On the other hand, the proposed sliding mode control assures that the vehicle's altitude converges in finite time to the desired reference, even when uncertainties are considered in the system. The proposed controller is tested in an outdoor environment and the experiments highlighted the controllers' reliability. Additionally, the performance of the closed-loop plant with the proposed controllers is compared with the performance given by a proportional-derivative controller.INDEX TERMS Backstepping control, sliding mode control, nonlinear systems, quadrotor.

Robust Adaptive Multilevel Control of a Quadrotor

“…T is the vector of desired attitude angles. The NFTSMC surface is expressed as [56] S = e η + sgn q (e η ) + sgn r (ė ) (43) where (47) for reaching and staying on the surface (43), and supposed that the parameters of the FDO (39) are properly selected so that the disturbances can be exactly estimated, then the attitude signals track the desired angles in finite time. u = u e + u d + u r (44)…”

“…In [42], a backstepping controller and a chattering-free backstepping SMC have been presented for the quadrotor rotational and translational subsystems respectively. In [43], a backstepping control method was designed for the displacement subsystem, while a SMC strategy was utilised to control the attitude. In [44], a RBFNN based SMC was developed for the position subsystem and a robust integral of the signum error (RISE) was designed for the orientation subsystem.…”

“…The proposed control strategy is divided into into three subcontrollers: ADIFTSMC for altitude control, RBFNNBC for horizontal position control, and FDOBNFTSMC for rotational angle control. The main contributions of the proposed method are presented as follows 1) Contrary to [37]- [43], [45] where the quadrotor control design is divided into two subcontrollers, we divided the proposed control scheme into three subcontrollers: the altitude, the horizontal position and the attitude controllers. 2) Unlike the adaptive NFTSMC [33], ADRC [38], backstepping FTSMC [40], RISE [44], backstepping SMC [45] implemented for the attitude control, in this paper, a backstepping is combined with NFTSMC and FDO (FDONFTSMC) to control the attitude angles.…”

“…The advantage of this scheme is that the disturbances are exactly estimated and guarantees the robust trajectory following in finite time. 3) In contrast to Adaptive backstepping [40], backstepping [43], RBFNN based SMC [44], integral SMC [45] developed for the position subsystem, a RBFNN based backstepping is devised to stabilised the horizontal position subsystem and produce the desired Euler angles. The RBFNN identify the uncertain functions together with the external disturbances and the time derivative of the virtual control laws.…”

Fixed-TimeBackstepping Control of Quadrotor Trajectory Tracking Based On Neural Network

“…In [8], the quadrotor system is considered as two interrelated subsystems, and a proportional integral-derivative H ∞ controller is presented. In addition, other control methods, including hierarchical control strategy [9], robust output feedback [10], [11] and integral sliding mode method [12], [13], are utilized to design the trajectory tracking controller for a quadrotor.…”