Attitude Stabilization Of Spacecraft Research Articles

Memory sampled-data control design for attitude stabilization of uncertain spacecraft with randomly missing measurements

This paper focuses on stabilizing the attitude of the rigid spacecraft under the sampled-data control design technique with constant communication delay. The system dynamics with model uncertainty (perturbation) and missing measurements are considered. The aim is to design a desirable attitude control that ensures the stabilization of the rigid spacecraft with an optimal H∞ performance level. A novel Lyapunov–Krasovskii functional is developed, incorporating looped characteristics, for the proposed study on the rigid spacecraft model by developing relevant new terms. Making use of the Lyapunov function as well as free-matrix-based integral inequality, sufficient stability criteria are established to assure the stability of the rigid spacecraft model. Furthermore, the desired sampled-data control gain matrices are acquired through the solution of linear matrix inequalities, which guarantees the asymptotic stability of the rigid spacecraft model. Finally, the numerical simulation demonstrates the efficacy of the theoretical study proposed for the rigid spacecraft model.

Negative-imaginary-based spacecraft attitude tracking control using modified Rodrigues parameters

This paper investigates a counter-clock-wise input-output map about spacecraft attitude dynamics and kinematics using Modified Rodrigues Parameters. A gyro-free attitude control scheme is established by constructing a negative imaginary system for spacecraft attitude stabilization. Attitude tracking control scheme is also explored where the negative-imaginary-based controller has no need on the angular velocity measurements. Numerical simulations are presented to show the effectiveness of the proposed attitude control scheme.

Predefined-Time Observer-Based Nonsingular Sliding-Mode Control for Spacecraft Attitude Stabilization

Predefined-Time Observer-Based Nonsingular Sliding-Mode Control for Spacecraft Attitude Stabilization

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.

Extended state filter‐based velocity‐free finite‐time attitude control of spacecraft

AbstractThis brief presents a finite‐time output feedback control scheme for the velocity‐free attitude stabilization of rigid spacecraft under inertia uncertainties and disturbances. Note that either the finite‐time velocity observer or the finite‐time extended state observer contains the control torques, which makes the transient performance of the observer‐based output feedback control difficult to be regulated. Alternatively, the filter‐based output feedback control can overcome such problem naturally since the finite‐time velocity filter does not involve the control torques in its structure. Different from the existing finite‐time velocity filters, a finite‐time extended state filter is introduced in this work to estimate the pseudo angular velocity and total uncertain item simultaneously. Then, the developed controller is synthesized based on the recovered information, which does not require the angular velocity for feedback and has the excellent uncertainty and disturbance compensation capability. The global finite‐time stability of the resultant closed‐loop system is evaluated through the Lyapunov direct methodology and homogeneous system theory. Lastly, comparative simulations are carried out to examine the efficiency and superiority of the presented control scheme.

Optimization of body configuration and joint-driven attitude stabilization for transformable spacecraft under solar radiation pressure

Optimization of body configuration and joint-driven attitude stabilization for transformable spacecraft under solar radiation pressure

A novel output redefinition method for nonlinear H∞ attitude stabilization of a flexible spacecraft

AbstractThis paper addresses a novel output redefinition method for the nonlinear attitude stabilization problem of a flexible spacecraft. As an idea, the flexible appendage tip‐point can be selected as attitude output which may improve attitude pointing accuracy. However, it makes the system non‐minimum phase. The output redefinition method is an effective method to make the system minimum phase. In this paper, a novel output redefinition is proposed to overcome the non‐minimum phase property such that it improves the attitude control system performance. Then, a nonlinear controller is designed based on back‐stepping approach and a modal observer. The simulation results show the effectiveness of the proposed method in the presence of model uncertainties and environmental disturbances.

Convergence guaranteed attitude control of underactuated spacecraft using two control torques

In this paper, the convergence guaranteed attitude stabilization of underactuated spacecraft using two control torques is investigated. By introducing the (w,z) parameters to describe the attitude motion of the underactuated spacecraft, a unified integrated attitude kinematic and dynamic model is originally derived, based on which the controllers can be directly designed for the two actuated axes. Then, three types of controllers are designed to stabilize the attitude and angular velocity along the two actuated axes to zero in fixed time. After that, it is strictly evaluated that the attitude and angular velocity along the underactuated axis can eventually stabilize to the constant values. In this way, the convergence property of the designed controllers can be guaranteed. The utilized controllers are the fixed-time proportional-differential (PD)-like controller, the fixed-time nonsingular terminal sliding mode (NTSM) controller, and the fixed-time integral sliding mode (ISM) controller, respectively. Among them, the fixed-time ISM controller is best since it is strongly robust against disturbances and has no singularity problem naturally, which overcomes the drawbacks of the fixed-time PD-like controller and the fixed-time NTSM controller simultaneously. Lastly, simulated studies are executed to examine the derived results.

Spacecraft Attitude Stabilization Control with Fault-Tolerant Capability via a Mixed Learning Algorithm

The issue of active attitude fault-tolerant stabilization control for spacecrafts subject to actuator faults, inertia uncertainty, and external disturbances is investigated in this paper. To robustly and accurately reconstruct actuator faults, a novel mixed learning observer (MLO) is explored by combining the iterative learning algorithm and the repetitive learning algorithm. Moreover, to guarantee robust spacecraft attitude fault-tolerant stabilization, by synthesizing the mixed learning algorithm with the sliding mode controller, a novel mixed learning sliding-mode controller (MLSMC) is designed based on the separation principle, in which the mixed learning algorithm is used to update composite disturbances online, including fault errors, inertia uncertainty, and external disturbances. Finally, a numerical example is provided to demonstrate the effectiveness and superiority of our proposed spacecraft attitude fault-tolerant stabilization control approach.

Appointed‐time nonsingular sliding mode control of spacecraft attitude stabilization

AbstractThis paper investigates the appointed‐time attitude stabilization problem of a rigid spacecraft under disturbance and parametric uncertainty. A continuous appointed‐time sliding mode disturbance observer is presented to observe the synthetical disturbance term. To circumvent the singularity problem in terminal sliding mode control, a new nonsingular appointed‐time sliding mode surface is designed by employing the concept of switching control. Based on the observation information deriving from the proposed disturbance observer, an observer‐based nonsingular sliding mode control scheme is developed to stabilize the attitude control system within appointed time which is given by the user. And also, the undesired control chattering phenomenon can be attenuated. The appointed‐time stability of the controlled attitude system is proved by the Lyapunov criteria. The simulation results show that the proposed attitude stabilization control scheme is valid.

Global Finite-Time Stabilization of Spacecraft Attitude With Disturbances via Continuous Nonlinear Controller

In this paper, a robust continuous controller is investigated to solve the global finite-time attitude stabilization problem of rigid spacecraft system subject to multiple disturbances. The system order is firstly increased by derivation and the derivative of the actual torque is regarded as the virtual control law to be designed. Then, a super-twisting differentiator is constructed to provide finite-time angular acceleration estimations. Finally, based on the estimated angular accelerations, a discontinuous set stabilization control law is designed as the virtual controller. The actual continuous controller is obtained by integrating the discontinuous one. Rigorous proof and stability analysis are presented based on Lyapunov analysis. Compared with most of the existing finite-time control approaches in spacecraft systems, the proposed continuous control scheme guarantees the finite-time set stability of the closed-loop system. Moreover, the system states can converge to the equilibria even in the presence of derivative-bounded disturbances. Simulation studies of the proposed controller are illustrated to demonstrate the strong disturbance rejection ability, fast convergence rate, and high steady-state precision.

Fault-tolerant model predictive sliding mode control with fixed-time attitude stabilization and vibration suppression of flexible spacecraft

This brief proposes two novel double-loop fault-tolerant controllers to tackle the problems of stabilizing the attitude and nullifying appendages' vibration of flexible spacecraft by integrating the advantages of model predictive control (MPC) and sliding mode control (SMC). The structure of the first method is as follows: First in the external loop, by using terminal sliding mode (TSM), the attitude of the spacecraft is derived to its reference value, and the proper angular velocity of the interior part is generated. Then, by employing the preciseness and constrained attributes of MPC, an optimal fault-tolerant controller is suggested in the internal part. Constrained fault-tolerant MPC tracks the angular velocity to the set value while guaranteeing appendages' passive vibration suppression. In another method, as opposed to the first technique, in the inner loop fault-tolerant finite-time TSM, and in the outer loop MPC are designed. The unified double-layer nonlinear controller schemes guarantee good dynamics and robustness against external torques and actuator faults. The closed-loop system's stability of the controllers is precisely proved using the Lyapunov theorem in the presence of actuator faults and external disturbances and in the absence of the damping matrix to study the advantages of the proposed methods. The performance of the proposed methods has been compared with each other. Moreover, the simulation results substantiate that the proposed method outperforms faster fixed-time sliding model control significantly.

Non-fragile negative imaginary output feedback control for attitude stabilization of flexible spacecraft

The robust non-fragile attitude stabilization controller for flexible spacecraft with model parameters uncertainty is difficult to be synthesized with negative imaginary system which is widely applicable for the vibration control of flexible structures. To address this issue, this paper proposes a negative imaginary output feedback H∞ synthesis strategy, in which the model parameters uncertainty, controller gain perturbations, unknown inertia and actuator faults are considered simultaneously. This strategy can guarantee that the closed-loop attitude control system has asymptotical stability with H∞ performance and approximates to negative imaginary. The iterative algorithm under linear matrix inequality constraints gives the conditions for the existence of such controller. In addition, external disturbance and input saturation are also taken into account. Compared with the general non-fragile H∞ controller, the numerical simulations demonstrate the superiority of the proposed controller in attitude stabilization and vibration suppression of flexible spacecraft.

Practical prescribed time attitude stabilization of combined spacecraft with measurement uncertainties

This paper investigates a novel practical prescribed time attitude control method for post-capture combined spacecraft with the prescribed performance for attitude and angular velocity in the presence of external disturbances, unknown inertia, measurement uncertainties, and input saturation. Control design faces a significant challenge in ensuring the control performance of the attitude and angular velocity at the same time. To solve this problem, a novel practical prescribed time attitude controller is proposed. First, a performance constraint function is used to achieve the desired performance for attitude and angular velocity. Second, a nonlinear transformed function is employed to cope with full-state constraints. Then, a prescribed time attitude controller is designed based on the dynamic surface control technique, where an auxiliary system is used to deal with input saturation. Analysis based on the Lyapunov stability theory proves that the closed-loop system is stable, and both the attitude and angular velocity converge to a specified region around the desired values within a prescribed time. Compared with the previous works, the proposed control method can simultaneously ensure the desired performance for attitude and angular velocity and has a smaller overshoot and a faster convergence rate. Numerical simulations and comparison results with other controllers validate the effectiveness and superiority of the proposed control approach.

Constrained reaction wheel desaturation and attitude control of spacecraft with four reaction wheels

The paper addresses a problem of constrained spacecraft attitude stabilization with simultaneous reaction wheel (RW) desaturation. The spacecraft has a reaction wheel array (RWA) consisting of four RWs in a pyramidal configuration. The developments exploit a spacecraft dynamics model with gravity gradient torques. The linearized dynamics are shown to be controllable at almost all RWA configurations. Configurations that result in the highest Degree of Controllability are elucidated. A strategy that combines an incremental reference governor and time-distributed model predictive control is proposed to perform constrained RW desaturation at low computational cost. Simulation results of successful RW desaturation maneuvers subject to spacecraft pointing constraints, RW zero-speed crossing avoidance and limits on control moments are reported.

Adaptive predefined-time control for liquid-filled flexible spacecraft attitude stabilization during orbit maneuver

A predefined-time attitude stabilization for complex structure spacecraft with liquid sloshing and flexible vibration is investigated under input saturation during orbital maneuver. First, the attitude dynamics model of liquid-filled flexible spacecraft is constructed. Meanwhile, the influence of solar panel vibration and liquid sloshing is treated as a disturbance in the controller design. Next, an adaptive predefined-time control scheme is proposed by applying sliding mode control theory. A predefined-time convergent sliding surface and reaching law are designed to ensure the predefined-time fast convergence rate. Furthermore, a novel adaptive algorithm is developed to handle the disturbances from liquid sloshing and flexible vibration, ensuring that the system converges to a small neighborhood of the equilibrium. Additionally, a new auxiliary system is constructed to deal with the effects of input saturation. At last, one simulation case is performed to verify the feasibility and advantages of the proposed algorithm.

Two-channel optimal discrete law of control of spacecraft with aerodynamic and inertial asymmetry during descent in Mars atmosphere

At present, spacecraft attitude stability is of great importance for both state and private space companies and agencies. In this paper, we consider a mathematical model describing perturbed motion of spacecraft as a rigid body with significant aerodynamic and inertial asymmetry relative to the center of mass in the rarefied atmosphere of Mars. The aim of this work is to obtain an approximate discrete optimized law of controlling the spacecraft attitude using Bellman's dynamic programming and averaging methods. Discrete systems of equations used in the work were solved using the Z-transform method. The reliability of the obtained control laws was confirmed by the results of numerical integration by the numerical Euler method.

Hybrid nonfragile intermediate observer-based T-S fuzzy attitude control for flexible spacecraft with input saturation

This paper investigates a hybrid nonfragile intermediate observer-based T-S fuzzy attitude control strategy subject to multi-source complex disturbances to achieve integrated attitude stabilization and vibration suppression for the flexible spacecraft. A refined T-S fuzzy model for flexible spacecraft is introduced to represent the nonlinear characteristics in large-angle attitude maneuver. Then a hybrid nonfragile observer with coexisting additive and multiplicative perturbations is designed to estimate state information and disturbance simultaneously. Consequently, based on the closed-loop system, the quadratic stability and robust H∞ performance are proved via the Lyapunov stability analysis with corresponding conditions in terms of linear matrix inequalities (LMIs). It is worth mentioning that different from the limiter directly used in much literature, input saturation is disposed as a disturbance during the proof to satisfy the stability requirements. Finally, numerical simulations of a flexible spacecraft attitude control system are performed which demonstrate the effectiveness and superiority of the proposed control strategy.

A novel learning observer-based fault-tolerant attitude control for rigid spacecraft

This paper investigates a learning observer-based fault-tolerant control strategy for a rigid spacecraft attitude system with external disturbance, parameter uncertainty and actuator faults. An adaptive learning observer design approach, which does not require the upper bound information of generalized perturbation, is proposed to estimate the attitude angular velocities and reconstruct actuator faults accurately and quickly. On this basis, a fault tolerant attitude tracking control scheme is developed for spacecraft attitude stabilization by combining the estimation value and backstepping control technique. The stability of the faulty attitude system under the designed fault-tolerant control method is analyzed using Lyapunov framework. Finally, simulations are given to show the effectiveness of the proposed method.

NI-based static output feedback control for attitude stabilization of post-capture flexible spacecraft

This paper investigates the attitude stabilization problem of post-capture flexible spacecraft with non-cooperative target in the presence of input fault and saturation. In modeling, these non-cooperative characteristics are often manifested in uncertain and unknown inertia, model parameter uncertainty, input faults, etc. In this paper, aiming at the attitude stabilization problem of such post-capture flexible spacecraft, the attitude dynamics modeling is completed by introducing the nominal inertia to construct the comprehensive disturbance term including external disturbance, inertia uncertainty and actuator failure. Then, a static output feedback controller is applied to convert the closed-loop attitude control system to a stable negative imaginary system with H∞ performance constraints according to negative imaginary theory. As long as the optimization variables approach zero, the iterative algorithm can find such a static output feedback controller to achieve attitude stabilization of post-capture flexible spacecraft. It is worth mentioning that an event-triggered mechanism is introduced into the control scheme to reduce the communication pressure. Finally, the numerical simulation is performed in the presence of model parameter uncertainty and controller gain perturbations. Simulation results demonstrate the effectiveness, robustness and non-fragility of the control method.