Sliding Mode Attitude Control Research Articles

Adaptive sliding mode attitude control of two-wheeled robots for planetary auxiliary: From theory to applications

The value of two-wheeled robots in planetary auxiliary is significant, but their attitude control presents challenges due to their inherent characteristics and external environment conditions. To address this issue, this paper presents an adaptive sliding mode (SMC) control scheme of two-wheeled robots for planetary auxiliary. Firstly, a motion model specifically for two-wheeled robots that focuses on attitude control is established. Secondly, an adaptive reaching law was proposed based on the study (Wang et al. 2014). It improves upon the previous adaptive gain, and it can ensure stable operation when the improved adaptive gain converges to a small neighborhood of the origin. This effectively avoids the chattering phenomenon and guarantees that the sliding mode surface converges within a finite time. On this basis, an adaptive SMC attitude controller is developed, and its stability is proven using Lyapunov stability theory. Finally, comparative simulation experiments are conducted to verify the effectiveness, adaptability, superiority and robustness of the proposed control scheme. (A virtual simulation video generated by Simulink 3D Animation can be viewed onhttps://pan.baidu.com/s/1JxRR7vMyq9Cm-23YHFPnYA?pwd=5lf1)

Fractional-order super-twisting sliding mode attitude control for elastic refueling boom with exogenous disturbances

Fractional-order super-twisting sliding mode attitude control for elastic refueling boom with exogenous disturbances

An Attitude Adaptive Integral Sliding Mode Control Algorithm with Disturbance Observer for Microsatellites to Track High-Speed Moving Targets

Gaze tracking of high-speed moving targets is a novel application mode for low Earth orbit microsatellites. In this mode, small satellites are equipped with high-resolution, narrow-field-of-view video cameras for stable gaze-tracking imaging of high-speed moving targets. This paper proposes a high-precision attitude adaptive integral sliding mode control method with a feedforward compensation disturbance observer to enhance the capability of a microsatellite attitude control system for gaze tracking of high-speed moving targets. Specifically, first, we present the attitude control system model for microsatellites and the calculation method for the desired attitude of target tracking based on image feedback. Then, an adaptive integral sliding mode attitude control algorithm with a feedforward compensation disturbance observer, which meets the requirements of high-precision tracking control, is designed. The developed algorithm utilizes the disturbance observer to observe the friction torque of the flywheel and compensates for it through feedforward control. It also employs the adaptive integral sliding mode control algorithm to reduce the impact of uncertain disturbances, decrease the steady-state error of the system, and enhance attitude control precision. Simulation experiments demonstrated that the designed disturbance observer can successfully observe the frictional disturbance torque of the flywheel. The attitude Euler angle control precision for high-speed moving target tracking reached 0.03°, and the angular velocity control precision reached 0.005°/s, validating the effectiveness of the proposed approach.

Design and real-time implementation of a robust backstepping non-singular integral terminal sliding mode attitude control for a quadrotor aircraft

This paper concerns the problem of robust attitude control of a quadrotor aircraft subjected to modeling inaccuracies and wind disturbances. First, the model dynamics and state space representation of the quadrotor system are designed by considering the impact of disturbances and uncertainties. Then, a novel robust backstepping non-singular integral terminal sliding mode control (BNITSMC) is synthesized for the quadrotor attitude with the aim of enhancing the tracking accuracy. To strengthen the system’s robustness and guarantee the reachability of the sliding surface while reducing chattering, the supertwisting algorithm (ST) is used. Closed-loop stability and state convergence are guaranteed via the Lyapunov theory. Some experimental flight tests have been executed to validate the workability of the developed flight control. The obtained results prove that the recommended technique can provide improved performance in terms of stabilization and tracking precision.

Adaptive sliding mode attitude control for multirotor aerial vehicles with experimental evaluation

Adaptive sliding mode attitude control for multirotor aerial vehicles with experimental evaluation

Predefined-time sliding mode attitude control for liquid-filled spacecraft with large amplitude sloshing

In the present study, a predefined-time attitude stabilization for liquid-filled spacecraft with large liquid sloshing is investigated under input saturation and external disturbance. First, the large slosh of the liquid is equivalent to the motion pulsating ball model (MPBM), and the dynamic model of the rigid-liquid coupling system is established. Then, liquid sloshing state quantity-related items and external disturbances are combined to form a lumped disturbance. A predefined-time disturbance observer is proposed to accurately reconstruct the lumped disturbance within a predefined-time regardless of the initial estimated state. Based on the proposed predefined-time disturbance observer, a predefined-time sliding mode surface is designed. The predefined-time stability of the proposed observer and controller is proved using the Lyapunov function. Finally, a variable-speed reaching law and exponential reaching law are combined to suppress the chattering caused by sliding mode control. To this end, a new auxiliary function is developed to consider the effects of input saturation. The simulation results show that the proposed controller can effectively stabilize the attitude stability of the liquid-filled spacecraft.

Finite-time attitude tracking control of stratospheric airship in the presence of multiple disturbances

Abstract This paper proposes a composite non-singular fast terminal sliding mode attitude control scheme based on a reduced-order extended state observer for the stratospheric airship’s attitude system affected by multiple disturbances. First, the feedback linearisation method is applied to address the nonlinearity of the attitude motion model and achieve decoupling of the model in three channels. Second, the overall disturbances, encompassing airship parameter perturbations and external disturbances, are treated as an aggregate. A reduced-order extended state observer is designed for each channel to formulate a composite non-singular fast terminal sliding mode surface. In the control design phase, the hyperbolic sine function is adopted as replacement for the sign function to ensure the continuity of the control signal. The estimated disturbances are incorporated in the control law design to directly offset the effects of multiple disturbances on the attitude motion of the airship. Third, based on Lyapunov theory, it has been proven that the control law can drive the attitude tracking error to converge to zero within a finite time. Simulation results demonstrate that the proposed control scheme exhibits favorable disturbance rejection capability, as well as higher tracking accuracy and faster response speed.

Formation tracking control for an air–ground system under position deviations and wind disturbances

AbstractIn this paper, a formation tracking control strategy based on a leader–follower structure is investigated under position deviations and wind disturbances for an air–ground system. A backstepping controller is designed to achieve the expected trajectory‐tracking performance for the leader which is a car‐like vehicle. A robust nonsingular integral terminal sliding mode formation controller based on leader–follower formation errors is presented to provide desired positions under the influence of position deviation for the follower which is a quadrotor. A backstepping‐based adaptive recursive sliding mode position controller is proposed for the follower to ensure tracking accuracy under wind disturbances. Comparison experiments with existing studies show superior performances and effectiveness of the proposed control method for the air–ground system.

Output-Constrained Adaptive Composite Nonsingular Terminal Sliding Mode Attitude Control for a Class of Spacecraft Systems with Mismatched Disturbances and Input Uncertainties

Output-Constrained Adaptive Composite Nonsingular Terminal Sliding Mode Attitude Control for a Class of Spacecraft Systems with Mismatched Disturbances and Input Uncertainties

Robust Fixed-Time Sliding Mode Attitude Control for a 2-DOF Helicopter Subject to Input Saturation and Prescribed Performance

Robust Fixed-Time Sliding Mode Attitude Control for a 2-DOF Helicopter Subject to Input Saturation and Prescribed Performance

Adaptive sliding mode attitude control of 2-degrees-of-freedom helicopter system with actuator saturation and disturbances

The modelling uncertainties, external disturbance and actuator saturation issues will degrade the performance and even the safety of flight. To improve control performance, this study proposes an adaptive U-model based double sliding control (UDSMC) algorithm combined with a radial basis function neural network (RBFNN) for a nonlinear two-degrees-of-freedom (2-DOF) helicopter system. Firstly, the adaptive RBFNN is designed to approximate the system dynamics with unknown uncertainties. Furthermore, two adaptive laws are designed to deal with unknown external disturbances and actuator saturation errors. The global stability of the proposed helicopter control system is rigorously guaranteed by the Lyapunov stability analysis, realizing precise attitude tracking control. Finally, the comparative experiments with conventional SMC and adaptive SMC algorithms conducted on the Quanser Aero2 platform demonstrate the effectiveness and feasibility of the proposed 2-DOF helicopter control algorithm.

Finite-time terminal sliding mode attitude control for tailless full-wing configuration UAVs based on extended state observers and auxiliary compensators

Considering the sensitivity of the tailless full-wing configuration unmanned aerial vehicle to disturbance and the strong nonlinearity and coupling caused by the manipulation combining the propeller and rudder, a finite-time terminal sliding mode controller with compound compensation is proposed in this paper to ensure stable attitude control. Based on singular perturbation theory, the inner loop sliding mode controller is designed so that the supremum of the convergence time of the rotational angular velocity tracking error in the sliding phase can be directly determined by the control parameters without requiring the initial state, and the outer loop sliding mode controller is designed so that the sliding surface function of the attitude angle tracking error has a fast convergence speed when it is far from and close to the origin. The compound compensation design further addresses the manipulation nonlinearity and disturbance sensitivity of the research object. Based on the minimum Euclidean norm optimization, the designed control allocator achieves command decoupling and reduces the desired control command. Through comprehensive verification, the proposed controller shows superior control performance and low energy consumption and exhibits strong robustness in the cruising flight envelope.

Logic-based gimbal compensator for the double-gimbal scissored-pair control moment gyroscope using magnetic torquers

Control Moment Gyroscopes (CMGs) are effective torque-producing actuators for satellite missions requiring agile maneuvering and accurate pointing. CMGs can develop relatively large torques compared to other momentum storage actuators like reaction wheels; however, using CMGs for three-axis attitude control is complicated by inherent mechanical singularities associated with CMGs. The singularity effect is worsened by common disturbances, such as aerodynamic or magnetic torques, which influence the CMG momentum state. A recent CMG design known as the Double-Gimbal Scissor-Pair CMG (DGSPCMG) has shown promise for use in small satellites because it has manageable singular conditions and has the potential to achieve three axis control using only two flywheels. This paper proposes a novel extension of the DGSPCMG control law and supplements it with a classical sliding-mode attitude controller to allow for the DGSPCMG momentum to be managed such that the gimbals may be restored to desirable positions by way of magnetic torques. The proposed solution achieves agile maneuvering by differentiating when singularity escape is possible through a steering control law and when magnetic torques are necessary for gimbal compensation in the DGSPCMG. The effectiveness of the control scheme is demonstrated by numerical simulations in MATLAB which subject the design to a detailed space environment. For the simulation conditions used in this research, the results indicate that the proposed control scheme would be an effective solution for attitude control of small satellites using a DGSPCMG in Low-Earth Orbit.

Robust Collision-Free Guidance and Control for Underactuated Multirotor Aerial Vehicles

This paper is concerned with the robust collision-free guidance and control of underactuated multirotor aerial vehicles in the presence of moving obstacles capable of accelerating, linear velocity and rotor thrust constraints, and matched model uncertainties and disturbances. We address this problem by using a hierarchical flight control architecture composed of a supervisory outer-loop guidance module and an inner-loop stabilizing control one. The inner loop is designed using a typical hierarchical control scheme that nests the attitude control loop inside the position one. The effectiveness of this scheme relies on proper time-scale separation (TSS) between the closed-loop (faster) rotational and (slower) translational dynamics, which is not straightforward to enforce in practice. However, by combining an integral sliding mode attitude control law, which guarantees instantaneous tracking of the attitude commands, with a smooth and robust position control one, we enforce, by construction, the satisfaction of the TSS, thus avoiding the loss of robustness and use of a dull trial-and-error tweak of gains. On the other hand, the outer-loop guidance is built upon the continuous-control-obstacles method, which is incremented to respect the velocity and actuator constraints and avoid multiple moving obstacles that can accelerate. The overall method is evaluated using a numerical Monte Carlo simulation and is shown to be effective in providing satisfactory tracking performance, collision-free guidance, and the satisfaction of linear velocity and actuator constraints.

Adaptive Robust Time-Varying Formation Control of Quadrotors under Switching Topologies: Theory and Experiment

This paper investigates a practical time-varying formation control method for quadrotors subjected to disturbances, uncertainties, and switching-directed topologies. A fully distributed formation control scheme is proposed using a linear-velocity independent position controller (LVIPC) and a nonsingular terminal sliding mode attitude controller (NTSMAC). A distributed observer is adopted to eliminate the measurement of linear-velocity states, and only local neighbor states are needed to realize formation flight. A time-varying nonsingular terminal sliding mode manifold is designed to suppress the reaching phase and ensure the finite-time convergence. Adaptive estimators are employed to remove the reliance on the prior knowledge of the upper bound of lumped uncertainties. It is then proven that all the closed-loop signals are bounded under the proposed method. Comparative experimental results based on a practical outdoor hardware solution are presented to confirm the effectiveness of the suggested control algorithm.

Adaptive sliding mode attitude control of quaternion model for aircraft based on neural network minimum parameter learning method

AbstractThis paper studied the back-stepping adaptive sliding mode control (SMC) attitude problem of quaternion aircraft model based on radial basis function (RBF) network approximation. Firstly, a sliding mode controller is designed based on the back-stepping method (BSM) for the nonlinear aircraft model. Secondly, a RBF network algorithm is designed to compensate for the unknown and uncertain parts of the aircraft system. RBF network has simple network structure and good generalisation ability, avoids lengthy and unnecessary calculations, realises adaptive approximation of unknown parts in the aircraft model, and through the adjustment of adaptive weights, the convergence and stability of the entire closed-loop system (CLS) are guaranteed. Finally, the anti-interference performance of the controller is verified by simulation of the actuator fault model. Our proposed method has all-right control performance indicated by the simulation results.

Hybrid adaptive sliding mode attitude control for earth pointing nanosatellites

Hybrid adaptive sliding mode attitude control for earth pointing nanosatellites

Finite-time sliding mode attitude control design for a coaxial tilt-rotor UAV

In this article, a finite-time sliding mode controller (FTSMC) is designed with the aim of attitude tracking of the coaxial tilt-rotor UAV (CTRUAV) under external disturbance. The CTRUAV is a multi-input multi-output (MIMO) and highly coupled system, which leads to the complexity of the controller design. Based on the dynamic model of the CTRUAV, an FTSMC is designed to improve the tracking performance of attitude control and robustness under uncertain disturbance, the stability of FTSMC is proved based on Lyapunov theory, and the power distribution is adjusted to solve the control-allocation problem of the CTRUAV. At last, simulation results are provided to show the effectiveness of FTSMC.

Performance evaluation of an improved non-singular sliding mode attitude control of a perturbed quadrotor: Experimental validation

In this paper, a new control scheme, that combines the Super-Twisting (ST) algorithm with the Nonsingular Terminal Sliding Mode Control (NTSMC), is adopted to robustly stabilize the quadrotor attitude while compensating for the impact of uncertainties/perturbations. The main merit of the proposed ST-NTSMC is to take advantage of the robustness and chattering avoidance allowed by the ST algorithm and the finite-time convergence, the fast transitions, and the high trajectory tracking accuracy allowed by the NTSMC algorithm. Lyapunov criterion is used to analyze the closed-loop stability of the proposed ST-NTSMC controller. Experimental tests are conducted on a quadrotor prototype under various flight conditions in order to test and evaluate the performance of the new controller. Comparisons with multiple linear and nonlinear controllers are also performed to highlight the outperformance of the suggested approach. Experimental results demonstrate the high performance of the developed controller in terms of tracking accuracy, robustness, and chattering reduction.

Constrained Nonsingular Terminal Sliding Mode Attitude Control for Spacecraft: A Funnel Control Approach

This paper presents an adaptive constrained attitude control for uncertain spacecraft. Inspired by the concept of nonsingular terminal sliding mode control and funnel control for nonlinear systems, a novel adaptive attitude control is introduced which contains a time-varying gain to handle the constraints imposed on the spacecraft attitude. Indeed, when the attitude trajectory approaches the boundary of the constraint set, the control effort as well as the time-varying gain will increase in order to preclude the trajectory from intersecting the boundary. Then, it is analytically proved that the system trajectories converge to an arbitrary small region around the origin within a fixed time where the smallest upper bound of the convergence time is determined as an independent parameter in the controller. Further, the proposed control scheme is nonsingular without having to use any piecewise continuous function which simplifies stability analysis. These properties distinguish the proposed control scheme from the existing finite/fixed-time attitude controls. Finally, several simulation results confirm the robustness and performance of the proposed control framework.