Attitude Tracking Of Rigid Spacecraft Research Articles

Output-Constrained Attitude Tracking Control for Spacecraft with Adaptive Inertia and Disturbance Identifications

In this paper, we present an adaptive control strategy for the output-constrained attitude tracking of rigid spacecraft under unknown inertia and disturbances. The designed controller is recursively constructed under the framework of the backstepping method, which involves an auxiliary stabilizing law and a practical control law. In the auxiliary stabilizing law design, the log-type barrier Lyapunov function (BLF) is embedded to tackle the time-varying output constraints. In addition, in the practical control law design, the element-wise parametric adaptive laws are adopted to identify the unknown inertia and disturbances by introducing a linear mapping operator. The stability evaluation indicates that the overall closed-loop system is semi-globally uniformly ultimately bounded (SGUUB) and all error variables can eventually regulate to the minor fields about zero. Meanwhile, the spacecraft attitude tracking errors can be preserved in the preassigned output constraints. Lastly, the efficiency and strong robustness of the presented control strategy are demonstrated through competitive simulations.

Anti-unwinding terminal sliding mode attitude tracking control for rigid spacecraft

In this paper, terminal sliding mode attitude tracking control without unwinding for rigid spacecraft is investigated. In order to guarantee the finite-time convergence of the system states and unwinding-free performance of the system on the sliding surface, a novel switching function is constructed by a hyperbolic sine function such that the obtained terminal sliding surface contains two equilibria. Then, a terminal attitude tracking control law is developed to ensure that the system states are driven to the sliding surface in a finite time. Moreover, a boundary layer is introduced to solve the chattering problem of the designed controller. The convergence of the system states within the boundary layer is guaranteed by imposing a constraint for the parameter of the developed switching function. Furthermore, the subsets of attraction domains of the two equilibria are given by designing a dynamic parameter for the proposed control law. The simulation results illustrate that the attitude tracking of rigid spacecraft without unwinding is realized by adopting the proposed attitude control law.

All state constrained decentralized adaptive implicit inversion control for a class of large scale nonlinear hysteretic systems with time-delays

This paper proposes an all state constrained decentralized adaptive implicit inversion control scheme for a class of large scale nonlinear systems with unknown time delays and asymmetric saturated hysteresis. First, to address the states constrained problem, the asymmetric barrier Lyapunov function is introduced to keep the error surface within an appropriate range from the view of engineering practice to ensure the performance and safety, such as for attitude tracking of rigid spacecraft, for spacecraft approach and intersection. Second, the transmission delays between different subsystems are considered and approximated through the incorporation of the neural-network approximators and the finite coverage lemma. Third, a new hysteresis implicit inverse algorithm is designed to effectively mitigate asymmetric and saturated hysteresis nonlinearities. It should be noted that the implicit inverse implies that the analytical inverse of the asymmetric and saturated hysteresis is not required. Instead, the decoupling algorithms are designed to extract the actual control signal from the temporarily hysteretic control signal , which reduces the preliminary work of the control algorithm. Finally, all of the signals in the closed-loop system are proved to be semi-globally ultimately uniformly bounded and the tracking errors converge to an arbitrarily small residual set. The experimental results on two-machine excitation power systems in the hardware-in-loop system are presented to illustrate the effectiveness of the proposed scheme.

Neural adaptive attitude tracking control for uncertain spacecraft with preassigned performance guarantees

In this article, two novel neural adaptive attitude control strategies are presented for the attitude tracking of rigid spacecraft affected by inertia uncertainty, external disturbance, and torque saturation with guaranteed prescribed performance. Under the backstepping framework, a neural adaptive state feedback controller is designed first by utilizing the neural network (NN) approximation and barrier Lyapunov function (BLF). Then, on the basis of the state feedback controller, a neural adaptive output feedback controller is exploited by integrating with a high-gain observer. Lyapunov stability analysis shows that all the closed-loop error signals are uniformly ultimately bounded under the both proposed neural adaptive attitude controllers. In comparisons with the most existing researches, the distinctive advantages of the proposed neural adaptive attitude controllers are threefold. (1) With the help of NN approximation, the proposed attitude controllers are model-independent and still applicable even when the spacecraft attitude dynamics are completely unknown. (2) Benefiting from the BLF, the proposed attitude controllers can guarantee the attitude tracking error always satisfies the preassigned performance. (3) Both the state feedback control and output feedback control are considered. The angular velocity information of the spacecraft is not required for the output feedback control design. At last, numerical simulations and comparisons are conducted to verify and highlight the proposed neural adaptive attitude control strategies.

Velocity-free attitude tracking for rigid spacecraft via bounded control

This article investigates the attitude tracking control problem for a rigid spacecraft without angular velocity feedback, in which external disturbances, parametric uncertainties, and input saturation are considered. Initially, an angular velocity observer is developed incorporated with adaptive technique, which could tackle the unmeasurable angular velocity and system uncertainties simultaneously. By introducing adaptive updating law into the proposed observer, the synchronized uncertainties are handled such that robustness of the observer is enhanced, even in the presence of external disturbances. Further, for solving the input constraints problem, command filter and backstepping method are utilized; thus, a bounded attitude tracking control law is derived. Finally, the attitude tracking performance is evaluated by numerical examples.

Event-triggered integral sliding mode controller for rigid spacecraft attitude tracking with angular velocity constraint

This paper investigates the attitude trajectory tracking problem of a rigid spacecraft subject to external disturbances and full-state constraint under the event-triggered scheme. By incorporating a barrier Lyapunov function (BLF) into the dynamic surface technique, we develop a coordinate-free integral sliding mode controller which cannot only deal with the state constraint but also enforce the tracking error converge into a vicinity of the origin. To save the computation and communication resources, a modified integral sliding mode-based robust event-triggered controller is proposed, in which the control torque generation and the information transmission of attitude and control signal only need to be implemented at some discrete time when the predefined measurement error exceeds a constant threshold. Furthermore, a lower bound estimation on the inter-execution intervals is also given to show that Zeno behaviour can be avoided. Finally, numerical simulations are presented to demonstrate the effectiveness and robustness of the proposed controller.

Attitude Tracking of Rigid Spacecraft with Actuator Saturation and Fault Based on a Compound Control

A compound control based on active disturbance rejection control (ADRC) scheme and slide mode control (SMC) is proposed to investigate the attitude tracking problem for a spacecraft with modeling uncertainties, external disturbances, actuator failures, and actuator saturations simultaneously. A positive term including control input is separated from the system, and then, the active disturbance rejection concept and the extended state observer (ESO) are applied to deal with the general uncertain item caused by uncertainties, external disturbances, actuator failures, and actuator saturations. The sliding mode surface is designed to transform the attitude tracking problem into attitude stabilization problem. In order to deal with the actuator saturations, a saturation degree coefficient and its corresponding adaptive law are introduced. Compared to other existing references, the proposed scheme does not need to know the structure or upper bound information of the inertial matrix uncertainties and external disturbances. Finally, the stability of the closed-loop system is analyzed by using input to state stability theory. Simulation results are given to verify the effectiveness of the proposed scheme. More importantly, the proposed technique can also be applied to the attitude stabilization of other aircraft, such as the attitude of unmanned aerial vehicle and helicopter in maritime rescue.

Finite-time fault tolerant attitude tracking control of spacecraft using robust nonlinear disturbance observer with anti-unwinding approach

This paper investigates the composite control scheme of robust nonlinear disturbance observer (RNDO) with adaptive non-singular fast terminal sliding mode control (NSFTSMC) technique for the attitude tracking of rigid spacecraft. The spacecraft is subjected to the parametric uncertainties, external disturbances, and actuator faults. The proposed RNDO estimates the overall lumped disturbance (combination of faults and disturbances) in finite-time. Moreover, it improves the disturbance rejection property of the composite control by feedforward compensation. An adaptive law is also employed in the composite control to enhance the robustness against the cases where RNDO takes some time for estimation, e.g., when there is a sudden change in the lumped disturbance. Further, the proposed controller is also enriched with anti-unwinding property to tackle the problem of unwinding in the quaternion based attitude representation. The stability analysis of the closed-loop system under the composite control scheme guarantees the finite-time convergence of relative state variables using the Lyapunov stability theory. The simulation analysis with the comparative study illustrates the effectiveness of the proposed strategy in terms of better disturbance rejection ability, higher accuracy, faster convergence, and better steady-state performance.

Fixed‐time attitude tracking control for rigid spacecraft

This study addresses the fixed-time attitude tracking for rigid spacecraft with inertia uncertainties and external disturbances. Firstly, a new fixed-time sliding surface based on the bi-limit homogeneous theory is proposed. Secondly, a non-singular sliding mode control is designed to solve the robust fixed-time attitude tracking problem. It is proved that the proposed control can ensure that the sliding surface and attitude tracking errors converge to zero within fixed time. The appealing features of the proposed control are exact fixed-time tracking stability with fast convergence, high precision, strong robustness and easy implementation. Simulations verify the effectiveness and improved performance of the proposed approach.

Event-triggered attitude tracking for rigid spacecraft

This study aims to investigate the problem of attitude control for a spacecraft with inertial uncertainties, external disturbances, and communication restrictions. An event-triggered active disturbance rejection control approach is proposed for attitude tracking of the spacecraft. An event-triggered mechanism is introduced together with an extended state observer to jointly monitor the system states and total disturbances. The observation error is proved to be uniformly bounded. Based on the proposed control scheme, the integrated tracking system is shown to be asymptotically stable, implying successful attitude tracking of the spacecraft for the desired motion. Numerical results illustrate the effectiveness of the control strategy in achieving satisfactory tracking performance with a reduced data-transmission cost.

Full‐order sliding mode control for finite‐time attitude tracking of rigid spacecraft

This study addresses an attitude tracking problem for a rigid spacecraft with bounded external disturbances. Attitude dynamics of the rigid spacecraft is modelled by a unit quaternion for global representation. Based on this representation, a novel continuous controller is proposed based on the full-order terminal sliding mode method. The finite-time stability of the closed-loop system is assured by Lyapunov and homogeneous finite-time stability theorems. Moreover, the singularity term in the terminal sliding surface is compensated by an identical item in the feedback control law, and this makes the closed-loop system trajectories converge to the equilibrium in finite-time, and hence a high precision is obtained. Finally, simulation results are presented to illustrate the effectiveness of the proposed controller.

A New Nonsingular Terminal Sliding Mode Control for Rigid Spacecraft Attitude Tracking

This paper addresses the finite time attitude tracking for rigid spacecraft with inertia uncertainties and external disturbances. First, a new nonsingular terminal sliding mode (NTSM) surface is proposed for singularity elimination. Second, a robust controller based on NTSM is designed to solve the attitude tracking problem. It is proved that the new NTSM can converge to zero within finite time, and the attitude tracking errors converge to an arbitrary small bound centered on equilibrium point within finite time and then go to equilibrium point asymptotically. The appealing features of the proposed control are fast convergence, high precision, strong robustness, and easy implementation. Simulations verify the effectiveness of the proposed approach.

Nonlinear disturbance observer-based robust control of attitude tracking of rigid spacecraft

Robust control of attitude tracking system between two rigid spacecraft is addressed using nonlinear disturbance observer-based control technique. A relative attitude dynamics model is derived for spacecraft tracking maneuver, where parameter uncertainty and environmental disturbances are considered as disturbance torques. A composite control technique is proposed for robust attitude tracking of a rigid spacecraft about a spacecraft under multiple disturbances by combining a nonlinear disturbance observer with an asymptotic tracking control. The proposed nonlinear disturbance observer is used to enhance the disturbance attenuation ability and robustness performance against uncertain inertia parameter and disturbances by estimating and compensating for the disturbances through feedforward. Stability and tracking performance of the nonlinear disturbance observer are analyzed. Furthermore, the stability of the composed control approach consisting of the asymptotic tracking control and nonlinear disturbance observer is established through Lyapunov method. Simulation results show that the composite control technique can significantly enhance disturbance attenuation ability, robust dynamics performance and the desired relative attitude tracking accuracy of a rigid spacecraft under external disturbances and uncertain inertia matrix.

Robust attitude tracking for rigid spacecraft with prescribed transient performance

ABSTRACTThis paper investigates the prescribed performance attitude tracking control problem of a rigid spacecraft with uncertain dynamics and bounded disturbances. By suitable selection of the configuration error function, the trajectory tracking problem on SO(3) is transformed into a point stabilisation problem of an error dynamic system in the associated Lie algebra. The predefined transient performance indexes, which include the maximum steady-state error and overshoot, and the minimum convergence rate of the attitude error vector, are characterised as the inequality constraints. For the tracking controller design, the error transformation technique is utilised to transform the attitude error dynamics with inequality constraints to an equivalent ‘unconstrained’ error one. Then, a coordinate-free robust tracking controller is designed for the ‘unconstrained’ error dynamics to solve the prescribed performance attitude tracking control problem. A rigorous mathematical stability proof is given. Finally, numerical simulations are presented to demonstrate the effectiveness and robustness of the proposed controller.

Finite‐Time Sliding Mode Trajectory Tracking Control of Uncertain Mechanical Systems

AbstractThe problem of finite‐time tracking control is studied for uncertain nonlinear mechanical systems. To achieve finite‐time convergence of tracking errors, a simple linear sliding surface based on polynomial reference trajectory is proposed to enable the trajectory tracking errors to converge to zero in a finite time, which is assigned arbitrarily in advance. The sliding mode control technique is employed in the development of the finite‐time controller to guarantee the excellent robustness of the closed‐loop system. The proposed sliding mode scheme eliminates the reaching phase problem, so that the closed‐loop system always holds the invariance property to parametric uncertainties and external disturbances. Lyapunov stability analysis is performed to show the global finite‐time convergence of the tracking errors. A numerical example of a rigid spacecraft attitude tracking problem demonstrates the effectiveness of the proposed controller.

Adaptive Finite-Time Control for Attitude Tracking of Rigid Spacecraft

AbstractThis paper investigates the attitude tracking control problem for rigid spacecraft with inertia uncertainties and external perturbations. Spacecraft attitude dynamics and kinematics are initially converted into Lagrange-like model and formulated as a state-space form described by the modified Rodrigues parameters (MRPs). Robust controllers contain two parts and use geometric homogeneity, integral sliding mode (ISM) technique, and adaptive laws. One part proposes a class of feedback controllers to accomplish finite-time stabilization of the second order dynamics without the lumped uncertainties. The other part rejects bounded uncertainties based on ISM associated with adaptive laws. Moreover, a rigorous proof of finite-time convergence is developed. The proposed control laws provide finite-time convergence, robustness, and faster and higher control precision, and these algorithms require no information about inertia uncertainties and external disturbances, which cannot be obtained in practical syst...

Comments on “Controller design for rigid spacecraft attitude tracking with actuator saturation”

In 2013, Lu, Xia and Fu proposed three robust controllers for rigid spacecraft attitude tracking with inertia uncertainties, external disturbances and actuator saturations. In this comment, we point out several flaws occurred through the paper, leading to the ineffectiveness of the proposed controllers.

Improved Adaptive Sliding Mode Control for Rigid Spacecraft Attitude Tracking

AbstractThis paper considers the attitude tracking problem of a rigid spacecraft involving inertia matrix uncertainty and external disturbance. First, an adaptive integral sliding mode control (ISMC) is proposed for when the upper bound on the lumped uncertainty is unknown in advance. It is shown that such a combination can produce a much smaller switching gain than the current adaptive sliding mode control (ASMC); hence, the overadaptation problem in existing ASMC design is effectively solved. Additionally, the system performance is improved by virtue of the global sliding mode feature of ISMC. A similar, but more flexible, ASMC design is introduced to further enhance the results; this design is developed on the basis of the reference trajectory scheme. The validity of the proposed strategies is verified by both theoretical analysis and simulation results.

Controller design for rigid spacecraft attitude tracking with actuator saturation

This paper investigates the attitude tracking control problem for rigid spacecraft with actuator saturations, inertia uncertainties and external disturbances. First, based on adaptive algorithm, a sliding mode control (SMC) law is designed to achieve accurate attitude tracking, and asymptotic convergence is guaranteed by means of the Barbalat lemma. Then, the spacecraft dynamic equation is optimized, and a novel method plays a crucial role toward ensuring stability robustness to actuator saturations in the control design. Using backstepping technique (BT) associated with extended state observer (ESO) or modified differentiator (MD), the corresponding SMC approaches are appropriately designed, which not only achieve a faster and more accurate response, better transient performance, but also afford stronger capability of resistance to inertia uncertainties, external disturbances and control input saturations. Finally, simulation results are presented to illustrate effectiveness of the control strategies.

Sliding mode attitude tracking of rigid spacecraft with disturbances

The attitude tracking control problem of a spacecraft nonlinear model with external disturbances and inertia uncertainties is addressed in this paper. First, a new sliding mode controller is designed to ensure the asymptotic convergence of the attitude and angular velocity tracking errors against external disturbances and inertia uncertainties by using a modified differentiator to estimate the total disturbances. Second, an adaptive algorithm is applied to compensating the disturbances, by which another sliding mode controller is successfully designed to achieve a high performance on the attitude tracking in the presence of the inertia uncertainties, external disturbances and actuator saturations. Finally, simulation results are presented to illustrate effectiveness of the control strategies.