A method based on second order sliding mode control (2-SMC) is proposed to design controllers for a small quadrotor UAV. For the switching sliding manifold design, the selection of the coefficients of the switching sliding manifold is in general a sophisticated issue because the coefficients are nonlinear. In this work, in order to perform the position and attitude tracking control of the quadrotor perfectly, the dynamical model of the quadrotor is divided into two subsystems, i.e., a fully actuated subsystem and an underactuated subsystem. For the former, a sliding manifold is defined by combining the position and velocity tracking errors of one state variable, i.e., the sliding manifold has two coefficients. For the latter, a sliding manifold is constructed via a linear combination of position and velocity tracking errors of two state variables, i.e., the sliding manifold has four coefficients. In order to further obtain the nonlinear coefficients of the sliding manifold, Hurwitz stability analysis is used to the solving process. In addition, the flight controllers are derived by using Lyapunov theory, which guarantees that all system state trajectories reach and stay on the sliding surfaces. Extensive simulation results are given to illustrate the effectiveness of the proposed control method.

Second order sliding mode control for a quadrotor UAV.

Adaptive control methods are developed for stability and tracking control of flight systems in the presence of parametric uncertainties. This paper offers a design technique of adaptive sliding mode control (ASMC) for finite-time stabilization of unmanned aerial vehicle (UAV) systems with parametric uncertainties. Applying the Lyapunov stability concept and finite-time convergence idea, the recommended control method guarantees that the states of the quad-rotor UAV are converged to the origin with a finite-time convergence rate. Furthermore, an adaptive-tuning scheme is advised to guesstimate the unknown parameters of the quad-rotor UAV at any moment. Finally, simulation results are presented to exhibit the helpfulness of the offered technique compared to the previous methods.

Adaptive sliding mode control for finite-time stability of quad-rotor UAVs with parametric uncertainties.

A control method based on global fast dynamic terminal sliding mode control (TSMC) technique is proposed to design the flight controller for performing the finite-time position and attitude tracking control of a small quadrotor UAV. Firstly, the dynamic model of the quadrotor is divided into two subsystems, i.e., a fully actuated subsystem and an underactuated subsystem. Secondly, the dynamic flight controllers of the quadrotor are formulated based on global fast dynamic TSMC, which is able to guarantee that the position and velocity tracking errors of all system state variables converge to zero in finite-time. Moreover, the global fast dynamic TSMC is also able to eliminate the chattering phenomenon caused by the switching control action and realize the high precision performance. In addition, the stabilities of two subsystems are demonstrated by Lyapunov theory, respectively. Lastly, the simulation results are given to illustrate the effectiveness and robustness of the proposed control method in the presence of external disturbances.

Global fast dynamic terminal sliding mode control for a quadrotor UAV

This paper develops a novel integral sliding mode controller (ISMC) for a general type of underwater robots based on multiple-input and multiple-output extended-state-observer (MIMO-ESO). The difficulties associated with the unmeasured velocities, unknown disturbances, and uncertain hydrodynamics of the robot have been successfully solved in the control design. An adaptive MIMO-ESO is designed not only to estimate the unmeasurable linear and angular velocities, but also to estimate the unknown external disturbances. An ISMC is then designed using Lyapunov synthesis, and an adaptive gain update algorithm is introduced to estimate the upper bound of the uncertainties. Rigorous theoretical analysis is performed to show that the proposed control method is able to achieve asymptotical tracking performance for the underwater robot. Experimental studies are also carried out to validate the effectiveness of the proposed control, and to show that the proposed approach performs better than a conventional potential difference (PD) control approach.

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Corrections to “Extended State Observer-Based Integral Sliding Mode Control for an Underwater Robot With Unknown Disturbances and Uncertain Nonlinearities”

Robust adaptive backstepping fast terminal sliding mode controller for uncertain quadrotor UAV

A Parallel-Structure-Based Sliding Mode Control for Trajectory Tracking of a Quadrotor UAV

For the problem of tracking control of a class of dynamic systems, an extended state observer based nonsingular terminal sliding mode control is proposed by sufficiently considering nonlinear characteristics and external disturbance. Firstly, in order to estimate and compensate the unknown total disturbance item of dynamic systems, the extended state observer is designed. Secondly, the nonsingular terminal sliding mode controller is designed to ensure that the tracking error converges to zero in finite time. Finally, abundant simulation results validate the effectiveness of the proposed control method.

Extended State Observer Based Nonsingular Terminal Sliding Mode Control for a Class of Dynamic Systems

In this paper, an extended state observer based continuous finite-time sliding mode control (CFTSMC) method is developed for an uncertain coaxial octorotor unmanned aerial vehicle (COUVA) under the influence of model parametric uncertainties, unknown external disturbances and unmodeled aerodynamics. Such a method is composed of a finite-time convergent extended state observer (FTCESO), which not only estimates the linear and angular velocities, but also estimates the lumped disturbances, which include model parametric uncertainties, unknown external disturbances and unmodeled aerodynamics. It is also composed of a continuous finite-time sliding mode controller, which are utilized to robustly track a desired time-varying trajectory with finite time convergence. Corresponding theoretical analysis is provided to prove the closed-loop stability of the proposed control method. Finally, the effectiveness of the proposed control method is verified by comparing the simulation results.

Continuous Finite-Time Sliding Mode Control for an Uncertain Coaxial Octorotor UAV

This paper mainly investigates the robust problem of sliding mode trajectory tracking control of a quadrotor unmanned aerial vehicle (UAV) with input constraints. A sliding mode control approach that considers input constraints is developed to address it. To deal with the control input constraints, an auxiliary system is presented to compensate the control inputs via using its state variables. Simultaneously, the trajectory tracking errors that include the state variables of auxiliary system are defined. Then, according to Lyapunov stability theory and sliding mode control theory, suitable sliding mode surfaces are constructed and corresponding controllers are designed such that the system is asymptotically stable. Finally, the simulation results are given to confirm the availability of the developed sliding mode control approach.

Robust Trajectory Tracking Control for a Quadrotor UAV with Input Constraints

The adaptive trajectory tracking control issue of a small quadrotor unmanned aerial vehicle (UAV) is preliminarily concerned and studied in this paper. The mathematic model of quadrotor UAV is firstly expressed in a simple form such that the model uncertainties and unknown external disturbances can be conveniently taken into account. Then, an adaptive sliding mode controller is developed for estimating model uncertainties and unknown external disturbances such that the robust and adaptive controller is obtained to enhance the robustness of the flight controller. It is found that the trajectories will asymptotically track the corresponding desired position and attitude values even under uncertainties and unknown disturbances. Finally, simulations based on the developed control scheme are conducted to demonstrate the effectiveness while faced with the uncertainties and unknown disturbances.

Jing-Jing Xiong

Papers

A Parallel-Structure-Based Sliding Mode Control for Trajectory Tracking of a Quadrotor UAV

Extended State Observer Based Nonsingular Terminal Sliding Mode Control for a Class of Dynamic Systems

Continuous Finite-Time Sliding Mode Control for an Uncertain Coaxial Octorotor UAV

Robust Trajectory Tracking Control for a Quadrotor UAV with Input Constraints

Adaptive Position and Attitude Trajectory Tracking Control for a Quadrotor UAV