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This paper deals with the stabilization problem of an underactuated quadrotor UAV system in presence of actuator and sensor faults. The dynamical model of quadrotor while taking into account various physical phenomena, which can influence the dynamics of a flying structure is presented. Subsequently, a new control strategy based on backstepping approach, taking into account the actuator and sensor faults is developed. Lyapunov based stability analysis shows that the proposed control strategy design keeps the stability of the closed loop dynamics of quadrotor UAV even after the presence of these faults. Simulations of the controlled system, illustrate that the proposed control strategy is able to maintain performance levels and to preserve stability under the occurrence of actuator and sensor faults.

This paper presents an adaptive fault tolerant control (FTC) scheme for a class of multiple-input multiple-output (MIMO) nonlinear systems against sensor faults, modeling errors and external disturbances. Four kinds of sensor faults including bias, drift, loss of accuracy and loss of effectiveness can be tolerated by the proposed FTC system. Within this scheme, dynamic surface control (DSC) technique, robust adaptation laws and adaptive nonlinear filters are combined for designing an adaptive dynamic surface control (ADSC)-based FTC system in order to compensate for the effects of sensor faults and system uncertainties (including external disturbances, modeling errors and unexpected nonlinear functions caused by sensor faults). Lyapunov approach is used to prove that all the signals in the closed-loop system are bounded and the tracking-errors can be forced to converge into a small neighborhood of zero. The feasibility and the effectiveness of the proposed FTC controller are demonstrated through two simulation examples.

This paper is concerned with the adaptive fault-tolerant control (FTC) problem for a class of multivariable nonlinear systems with external disturbances, modeling errors and time-varying sensor faults. The bias, drift, loss of accuracy and loss of effectiveness faults can be effectively accommodated by this scheme. The dynamic surface control (DSC) technique and adaptive first-order filters are brought together to design an adaptive FTC scheme which can reduce significantly the computational burden and improve further the control performance. The adaptation laws are constructed using novel low-pass filter based modification terms which enable under high learning or modification gains to achieve robust, fast and high-accuracy estimation without incurring undesired high-frequency oscillations. It is proved that all signals in the closed-loop system are uniformly ultimately bounded and the tracking-errors can be made arbitrary close to zero. Simulation results are provided to verify the effectiveness and superiority of the proposed FTC method.

This paper deals with the active fault tolerant control (AFTC) problem for a class of multiple-input multiple-output (MIMO) uncertain nonlinear systems subject to sensor faults and external disturbances. The proposed AFTC method can tolerate three additive (bias, drift and loss of accuracy) and one multiplicative (loss of effectiveness) sensor faults. By employing backstepping technique, a novel adaptive backstepping-based AFTC scheme is developed using the fact that sensor faults and system uncertainties (including external disturbances and unexpected nonlinear functions caused by sensor faults) can be on-line estimated and compensated via robust adaptive schemes. The stability analysis of the closed-loop system is rigorously proven using a Lyapunov approach. The effectiveness of the proposed controller is illustrated by two simulation examples.

In this paper we present a Takagi-Sugeno (T-S) model for Quadrotor modelling. This model is developed using multiple model approach, composed of three locally accurate models valid in different region of the operating space. It enables us to model the global nonlinear system with some degree of accuracy. Once the T-S model has been defined it is claimed to be relatively straightforward to design a controller with the same strategy of T-S model. A nonlinear state feedback controller based on Linear Matrix Inequality (LMI), and PDC technique with pole placement constraint is synthesized. The requirements of stability and poleplacement in LMI region are formulated based on the Lyapunov direct method. By recasting these constraints into LMIs, we formulate an LMI feasibility problem for the design of the nonlinear state feedback controller. This controller is applied to a nonlinear Quadrotor system, which is one of the most complex flying systems that exist. A comparative study between controller with stability constraints and controller with pole placement constrains is made. Simulation results show that the controller with pole placement constrains yields good tracking performance. The designed T-S model is validated using Matlab Simulink.

This paper considers the stabilization problem of an underactuated quadrotor UAV systemin presence of actuator faults. The dynamic model of quadrotor while takinginto account various physical phenomena, which can influence the dynamics of a flying structureis presented. Subsequently, a new control strategy based on backstepping approach andtaking into account the actuator faults is developed. Lyapunov based stability analysis shows that the proposed control strategy design keep s the stability of the closed loop dynamics of quadrotor UAVeven after the presence of actuator faults. Numerical simulation results are provided to show the good tracking performance ofproposed control laws.

The work proposed in this paper aims to design a robust stabilization of an underactuated quadrotor UAV system in presence of sensor failures. The dynamical model of quadrotor while taking into account various physical phenomena, which can influence the dynamics of a flying structure is presented. Subsequently, a new control strategy based on backstepping approach is developed. Lyapunov based stability analysis shows that the proposed control strategy design keep the stability of the closed loop dynamics of the quadrotor UAV even after the presence of sensor failures. Numerical simulation results are provided to show the good tracking performance of proposed control laws.