This paper investigates the design of a robust controller for the trajectory tracking problem of an under-actuated quadrotor UAV subject to the modeling uncertainties and unknown external disturbances. A new robust nonlinear adaptive controller is proposed for orientation and translation tracking by using the Adaptive Nonsingular Fast Terminal Sliding-Mode Control (ANFTSMC) algorithms. The ANFTSM control law: (i) ensures fast convergence, i.e. the quadrotor outputs achieve to the original values in a short finite-time; ( i i ) avoids singularities; ( i i i ) solves the chattering effect; ( i v ) offers robustness against the unknown external disturbances and uncertainties. Furthermore, the system unknown uncertainty and external disturbances upper bound are coped by the proposed control approach. Online estimation of these upper bounds is only introduced by velocity and position measurements. In addition, the control law applies the Lyapunov theory, guarantees the closed-loop stability of the quadrotor system. Finally, various simulations under different scenarios in terms of external disturbances and parametric uncertainties are carried out to evaluate/emphasize the effectiveness of the ANFTSMC strategy proposed in this work. Moreover, a comparative study is accomplished at the end of the present paper and shows clearly the outperformance of the proposed control scheme.

Robust adaptive nonsingular fast terminal sliding-mode tracking control for an uncertain quadrotor UAV subjected to disturbances

The finite-time attitude control of quadrotor unmanned aerial vehicles (UAVs) subject to external disturbances with unknown bound is investigated in this paper. First, an adaptive multivariable finite-time stabilizing control algorithm for second-order multivariable systems is developed based on the improved supertwisting and the equivalent control algorithms. Furthermore, the finite-time stability conditions are derived via the Lyapunov technique. The remarkable feature of the developed algorithm is to eliminate the overestimation of the control gains without loss of the sliding motion. Then, the proposed algorithm is applied for quadrotor UAVs to solve the finite-time attitude-tracking problem. Finally, a comparison of the proposed multivariable algorithm with its scalar counterpart is presented and validated both by simulation and experiment results.

Adaptive Finite-Time Attitude Tracking of Quadrotors With Experiments and Comparisons

Position and attitude control of multi-rotor aerial vehicles: A survey

High-order ESO based output feedback dynamic surface control for quadrotors under position constraints and uncertainties

In this article, a composite disturbance rejection control method is proposed for attitude control of quadrotor using an inner–outer loop control framework, which can effectively improve the angular tracking performance of the quadrotor and achieve the active disturbance rejection. In the inner loop, a novel nonlinear extended state observer (NESO) is designed to estimate the disturbance and nonlinear part of the system model, then a robust control law is embedded in inner-loop controller to attenuate the effect of the estimation error. In the outer loop, a composite nonlinear feedback (CNF) controller is designed to improve the transient performance. Moreover, the stability of two loops are also analyzed, respectively. Numerical simulation and platform experiment are carried out to verify the efficiency of the proposed method.

Composite Disturbance Rejection Attitude Control for Quadrotor With Unknown Disturbance

The design of robust tracking control for quadrotors is an important and challenging problem nowadays. In this paper, a robust tracking output-control strategy is proposed for a quadrotor under the influence of external disturbances and uncertainties. Such a strategy is composed of a finite-time sliding-mode observer, which estimates the full state from the measurable output and identifies some types of disturbances. It is also composed of a combination of PID controllers and continuous sliding-modes controllers that robustly track a desired time-varying trajectory with exponential convergence despite the influence of external disturbances and uncertainties. The closed-loop stability is provided based on the input-to-state stability (ISS) and finite-time ISS properties. Finally, experimental results in real time show the performance of the proposed control strategy.

Continuous Sliding-Mode Control Strategies for Quadrotor Robust Tracking: Real-Time Application

The design of robust tracking control for Quad-Rotors is an important and challenging problem nowadays. In this paper a robust tracking output-control strategy is proposed for a Quad-Rotor under the influence of external disturbances and uncertainties. Such a strategy is composed of a Finite-Time Sliding-Mode Observer (FT-SMO) which estimates the full state from the measurable output and identifies some type of disturbances; and also of a combination between PID controllers and a Continuous Sliding-Modes Controller (Continuous-SMC), that exponentially robustly track a desired time-varying trajectory and despite the influence of external disturbances and uncertainties. The closed-loop stability is provided based on Input-to-State Stability (ISS) and Finite-Time ISS (FT-ISS) properties. Finally, some experimental results in real-time show the performance of the proposed control strategy.

Oscar A. Gonzalez

Papers

Continuous Sliding-Mode Control Strategies for Quadrotor Robust Tracking: Real-Time Application

Quad-Rotor Robust Tracking: A Continuous Sliding-Mode Control Strategy