Spacecraft Attitude Maneuver Research Articles

Robust flexible spacecraft attitude tracking under measurement errors, actuator nonlinearities, and faults

Reliable spacecraft attitude maneuver is one of the core research areas of the space industry due to the need for sustainable space exploration and advancements in the space technology. The paper presents an observer-based adaptive backstepping (OB-ABST) fault-tolerant control scheme for a flexible spacecraft attitude tracking under the effect of state measurement errors, inertial uncertainties, external disturbances, multiple actuator faults, and input nonlinear saturation (INS) while suppressing vibrations due to flexible modes. Initially, we design an adaptive backstepping controller to mitigate the system’s unwanted nonlinearities and observers to get estimates of the attitude dynamics in a recursive design framework. Later, the control structure incorporates a simple actuator saturation compensator to tackle input torque saturation in the system. The critical feature of the proposed OB-ABST control structure is to ensure precise attitude-tracking maneuvers and vibration suppression without intelligent materials such as shape memory alloys (SMA) and piezoelectric material (PZT). Lyapunov stability analysis proves practical finite-time convergence of the system state errors, observation errors, and actuator saturation compensators. Moreover, we provide specific conditions to tune design parameters. Finally, comparative simulation experiments validate the control performance of the proposed controller in the presence of multiple challenges.

Anti-unwinding adaptive robust backstepping attitude maneuver control for rigid spacecraft

In this paper, an anti-unwinding adaptive robust backstepping control law is proposed to solve the attitude control problem of rigid spacecraft with external disturbances and inertia uncertainties. A new variable based on hyperbolic sine functions is designed to prevent the unwinding phenomenon, and then a novel robust backstepping controller is developed. Initially, a nonlinear tracking law is designed to obtain the desired angular velocity and to ensure that the attitude maneuvering system could have two equilibrium points. Subsequently, an adaptive robust control law is devised, which incorporates the adaptive estimation method to update the inertial parameters in real-time. Moreover, the bounded external disturbances are taken into account in the design of the control law, and thus the robustness of the attitude control system is improved. Furthermore, the global asymptotic stability of the attitude control system is verified by the Lyapunov-Krasovskii theorem. Finally, numerical simulations are carried out to demonstrate the effectiveness and robustness of the proposed control law, as well as the anti-unwinding characteristics are perfectly validated during the attitude maneuver of rigid spacecraft.

Underactuated Steering Control Law for Spacecraft Attitude Maneuver using Two Skewed Control Moment Gyroscopes under Path Constraint

Underactuated Steering Control Law for Spacecraft Attitude Maneuver using Two Skewed Control Moment Gyroscopes under Path Constraint

Nonlinear attitude maneuvering of a flexible spacecraft for space debris tracking and collision avoidance

This work addresses the problem of attitude maneuvering of a spacecraft equipped with two flexible solar panels, in response to an alert in two distinct operational scenarios: (a) detection of an approaching debris, and (b) collision avoidance of an impacting debris. In scenario (a) the approaching debris is assumed to be off a collision course with the satellite. As a result, the latter can track the debris, to provide supplementary observations (in addition to those given by ground stations) that allow improving the estimation of its trajectory. Instead, in scenario (b) an impact is predicted, therefore the satellite shall perform a collision avoidance maneuver. This is designed with the objective of minimizing propellant consumption, while ensuring a miss distance greater than a specified threshold value. This research considers the overall dynamics by modeling the spacecraft as a multibody structure, with the use of the Kane's method, which simplifies the process of deriving all the governing equations, while identifying their minimum number. Flexibility is introduced using a modal decomposition technique, under the assumption of small amplitude oscillations. In the two scenarios of interest, efficient strategies are introduced to rotate the solar panels, for the purpose of either maximizing their irradiation or minimizing their oscillations. A new nonlinear reduced-attitude control law, which enjoys global stability properties, is proposed, and is shown to improve the performance of attitude maneuvers when only a single axis must be driven toward a desired direction. Actuation is modeled as well, by assuming the use of a pyramidal array of four single-gimbal control momentum gyroscopes. Their steering law includes singularity avoidance, based on the singular value decomposition of the actuation matrix. Numerical simulations demonstrate that the agile attitude maneuvering strategies proposed in this study allow achieving the operational objectives in the two scenarios of interest, with limited elastic oscillations.

Spacecraft attitude maneuver planning with multi–sensor pointing constraints using improved RRT–star algorithm

During the spacecraft attitude maneuvers for the observation of mission targets, multiple instruments may face different pointing constraints, and they are rarely considered by the current attitude maneuver planning methods. In this case, this paper proposes an improved rapidly–exploring random trees star (RRT*) algorithm to obtain discrete quaternion path nodes while satisfying the pointing constraints of multiple sensors. Next, the temporal properties of these path nodes are defined by a trapezoidal path planning method, and bounded constraints on the angular velocity and control moment during the attitude maneuver are introduced. Then, the continuous quaternion curves through the discrete quaternion path nodes are calculated by a segmented cubic spline interpolation function. Finally, the angular velocity and control moment are calculated through the inverse dynamics. The simulation results verify the feasibility of the method. It can satisfy complex constraints and obtain the attitude optimization path, and alleviate the large control moment variations in the start and stop phases of the rest–to–rest maneuver.

Fault-tolerant attitude control for liquid-filled flexible spacecraft without angular velocity measurements based on disturbance observer

The problem of robust, angular velocity-free control and fault-tolerant control for liquid-filled flexible spacecraft attitude maneuver subject to unknown external disturbances is investigated. Moreover, state variables measurement uncertainty and actuator failures are explored. The liquid sloshing effect of spacecraft fuel is equivalent to a two-order spring-mass model, and the flexible attachments are equivalent to the Euler–Bernoulli beams. The external disturbance, multiple failures of the output actuator, and the coupled interference caused by liquid sloshing and vibrations of flexible attachments are distinguished as continuous and percussive disturbances. First, a fault-tolerant control method against the percussive disturbances is proposed, and the robustness performance and characteristics of this method are analyzed. Then, both continuous and percussive disturbances are considered to propose a new fault-tolerant control method based on a nonlinear disturbance observer, which is used to estimate the integrated disturbance. The Lyapunov stability theory proves that the proposed control strategy can make the state variables converge to a small neighborhood of the origin in finite time. Finally, the numerical simulation is used to verify the effectiveness and robustness of the proposed control strategy.

Predictive Control for Large Angle Attitude Tracking Maneuver of Spacecraft with Reaction Control System and Reaction Wheel

Missions involving rapid and large angle attitude maneuvers have been conceived in astronomical and earth observation satellites in recent years. As an actuator capable of generating a large torque is also going to be required, it will also be necessary to consider characteristics of an actuator in designing a control system. Actuators capable of generating a large torque include reaction control system (RCS). RCS gives an on/off input as it uses the reaction force from fuel injection by thrusters, it can generate a large moment. In addition, the control system of current application satellites normally uses both RCS and reaction wheel (RW) conventionally used for attitude control. This paper considers large angle attitude maneuver of spacecraft by a combination of RCS and RW. To this end, characteristics of RCS and RW are defined, and a discrete-time model (Euler approximation model) for the control system design is derived. Next, we design a discrete-time nonlinear tracking controller so that the closed-loop system consisting of the Euler approximation model becomes input-to-state stable (ISS) using the concept of backstepping approach. Then, we propose a method to appropriately change the threshold of RCS injection corresponding to the attitude of spacecraft by model predictive control. Finally, the effectiveness of proposed control method is verified by numerical simulations.

Wave-based attitude control of in-orbit spacecraft with large-amplitude slosh

This paper aims to reach high-quality attitude control and large-amplitude slosh suppression when a typical liquid-filled spacecraft executes three-axial large-angle maneuvers, by applying a wave-based attitude controller (WBAC). First, the sloshing dynamics is modeled by using a spherical pendulum, whose motion is expressed by splitting its coordinates. Thus, the large-amplitude lateral sloshing and the rotary sloshing as well as the over-all rigid motion of a liquid with respect to the tank in spacecraft can be approximately described. Second, the dynamics equations of system in terms of hybrid coordinate for the liquid-filled spacecraft are derived via the Lagrangian formulation. Third, an improved WBAC for three-axial large-angle maneuvers of in-orbit liquid-filled spacecraft is designed by adding a derivative control law and a gravity-gradient-torque compensation law to a wave-based control law. Simulations of three-axial large-angle maneuver demonstrate good performance of the WBAC in shortening completion time of attitude maneuvering, suppressing the jitter in the angular velocity of spacecraft, and accelerating the large-amplitude slosh suppression, simultaneously. The results indicate the potential applications of the proposed WBAC in the large-angle attitude maneuvering of liquid-filled spacecraft when there exists large-amplitude liquid slosh.

Adaptive connected hierarchical optimization algorithm for minimum energy spacecraft attitude maneuver path planning

Adaptive connected hierarchical optimization algorithm for minimum energy spacecraft attitude maneuver path planning

Correction: New Minimum InfnityNorm Solution and Rapid Eigenaxis Attitude Maneuvering of Spacecraft

Correction: New Minimum InfnityNorm Solution and Rapid Eigenaxis Attitude Maneuvering of Spacecraft

Parametric control for flexible spacecraft attitude maneuver based on disturbance observer

This paper considers the problems of control performance degradation caused by the vibration of flexible accessories and external disturbance during the attitude maneuvering process of flexible spacecraft. A parametric design method for attitude maneuver control (AMC) of flexible spacecraft based on disturbance observer is proposed to improve the anti-interference ability and control accuracy of the control system. Firstly, considering the spacecraft kinematics model for quasi-linear system modeling then design a disturbance observer to solve the external disturbance and vibration generated by the flexible attachment during maneuvering. Further, a controller designed using direct parametric method is proposed that can transform the nonlinear closed-loop system into a second-order linear constant system with the desired characteristic structure and provide all degrees of freedom in the control system design. Finally, numerical examples are given to evaluate the efficacy of the proposed approach.

Finite-Time Prescribed Performance Control for Spacecraft Attitude Tracking

The problem of finite-time prescribed performance control (PPC) for spacecraft attitude maneuvering is researched. To the best of the authors’ knowledge, limited results have been reported. How to achieve the prescribed performance attitude tracking within a preset time interval is still an open problem, especially in the presence of inertia perturbations, external disturbances, actuator saturations, and faults. On account of this, a finite-time performance function is first constructed as the predefined boundary of tracking errors. Second, Chebyshev neural network is utilized to approximate the lumped uncertainties. Then, the Nussbaum gain technique compensating for actuator saturations and faults is incorporated into the backstepping design to develop a new fault-tolerant attitude controller. Both transient and steady-state performances (e.g., the maximum overshoot, steady-state error, and settling time) are guaranteed. Compared with the common PPC or finite-time control achievements on spacecraft attitude tracking, the setting time herein can be set in advance without relying on initial states. Finally, experiments are performed to verify the effectiveness of the solution and comparisons with related works are displayed.

A spacecraft attitude maneuvering path planning method based on PIO-improved reinforcement learning

<p indent="0mm">Aiming at the problem of spacecraft attitude maneuver planning under multiple mandatory pointing constraints and prohibited pointing constraints, based on pigeon-inspired optimization (PIO), we proposed an improved policy gradient reinforcement learning (RL) algorithm (PIOPGRL). First, we establish an angle-based attitude constraint model, and then, we establish the reward function of RL based on the model. Then, the fitness function is used to replace the policy evaluation function, so PIOPGRL is integrated with RL. The PIOPGRL algorithm uses the PIO algorithm to solve the policy gradient, significantly reduces the amount of calculation and accelerating the convergence speed. The simulation results show that the spacecraft attitude maneuvering path planning method based on PIO-improved RL (PIOPGRL) has better planning results and lower cost of maneuver than the classical PGRL algorithm, which can solve the problem of spacecraft attitude maneuver planning under multiple pointing constraints perfectly.

Agile rest-to-rest attitude maneuvering of spacecraft using pyramid-type SGCMG based on iteratively recalculated optimal trajectory

This paper is concerned with the agile rest-to-rest attitude maneuvering of spacecraft using pyramid-type single-gimbal control moment gyroscopes (SGCMGs). In this method, the gimbal rate command to the SGCMGs is determined by calculating the pair of optimal trajectories of the attitude and the gimbal angles without any “steering law”. Thus, the proposed method does not suffer from the singularity problem causing the increase in control error and settling time. Before maneuvering, the pair of the initial optimal trajectories of the attitude and the gimbal angles is calculated by the minimum-time problem. Then, to compensate for errors in maneuvering caused by disturbances and/or modeling errors, the trajectories of the attitude and the gimbal angles are recalculated and updated frequently during the control. In this paper, optimization problems for generating and updating the trajectories are formulated, and specific control algorithms are provided. Finally, numerical simulations and ground experiments with an air floating table are performed to verify the feasibility and effectiveness of the proposed control method. For the rest-to-rest attitude maneuver, the proposed method can be adapted not only to the presence of modeling error in the inertia tensor, but also to the failure of one or two CMGs in the SGCMG system, without changing the control algorithm. These demonstrate the high robustness and practicality of the proposed method.

A pointing-based method for spacecraft attitude maneuver path planning under time-varying pointing constraints

The requirement to observe moving targets raises the time-varying pointing constraint for spacecraft attitude maneuver, which is seldom considered in existing attitude maneuver path planning methods. Therefore, a pointing-based method for attitude maneuver path planning under time-varying pointing constraints is proposed. Considering that pointing constraints are exerted on the perceptional sensor of spacecraft, an improved rapidly-exploration random tree method is designed to obtain the rotational pointing nodes while satisfying the pointing constraints. To this end, the key point is to define the time property of sampled nodes to determine their relations with time-varying constraints. Subsequently, the attitude quaternion nodes are generated according to pointing nodes. Finally, to find a continuous quaternion curve passing through quaternion nodes, component-wise and piecewise quaternion interpolation functions are adopted to calculate the angular velocity and control torque by the inverse dynamics method. The attitude motion spherical shell is designed by using the radial component to represent the timeline to visually display the satisfaction of time-varying constraints. Simulation results are used to validate the feasibility of the proposed method.

Spacecraft attitude control and vibration suppression using magnetically suspended control &amp; sensitive gyroscope and radial basis function network adaptive sliding mode control

For the sake of improving the agility and super-static performance of spacecraft under external disturbances, this paper puts forward an idea for using pyramid configuration of the Magnetically Suspended Control &amp; Sensitive Gyroscope to realize dual control of attitude maneuver and vibration suppression of spacecraft. The RBF neural network is used to reduce the chattering in sliding mode control through adaptively learning the non-linear part of the system. A band-pass filter is designed to divide the attitude deviation signal fed back by the sensors into high-frequency and low-frequency parts. The control laws of gyro gimbal and magnetic suspension rotor are designed, respectively, to realize the attitude maneuver and vibration suppression simultaneously. The adaptive laws of parameters avoid the saturation of rotor deflection angle while speeding up the attitude maneuver process of spacecraft. Compared with the traditional sliding mode control methods, the proposed one not only improves the accuracy and speed of attitude control but also improves the robustness of the spacecraft attitude control and vibration suppression system. Semi-physical simulation results show the effectiveness and superiority of the proposed method.

Rigid-flexible coupling identification and attitude control based on deep neural networks

Rigid-flexible coupling significantly affects the attitude control accuracy during attitude maneuvering of spacecraft with large flexible appendages. On-orbit identification of flexible parameters such as modal frequency is very important for attitude control. However, large errors could exist in current identification methods, especially for extreme scenarios such as large deformation or configuration transformation of spacecraft. Unlike previous studies that identified natural frequencies or modal shapes, this paper proposes a method of directly estimating the rigid-flexible coupling term based on deep neural networks (DNNs). By using the neural network (NN), the proposed identification method is independent of the specific dynamic model and has better adaptability. We establish a rigid-flexible dynamic model considering uncertainties and analyze the possibility of identifying the rigid-flexible coupling term in the attitude dynamic equation through selected system states. To verify the feasibility of training the neural networks mapping from system states to the coupling term, we design a numerical experiment. Five attitude maneuvers with different target attitude angles are conducted with the data collected for training. The experimental results show that all estimation errors of neural networks are relatively small. Based on this, we further propose an improved PD controller. We assume that the DNNs can be well trained offline, followed by online prediction of the rigid-flexible coupling term to improve attitude control accuracy. Five random attitude maneuvers are performed for offline training, and a large angle attitude maneuver under the proposed improved PD controller is simulated. The experiment proves that the improved PD controller is effective and can improve system performance. The Elman neural network appears the best choice for rigid-flexible estimation and the improved PD controller.

Application of the Improved Grey Wolf Algorithm in Spacecraft Maneuvering Path Planning

In many space missions, spacecraft are required to have the ability to avoid various obstacles and finally reach the target point. In this paper, the path planning of spacecraft attitude maneuver under boundary constraints and pointing constraints is studied. The boundary constraints and orientation constraints are constructed as finite functions of path evaluation. From the point of view of optimal time and shortest path, the constrained attitude maneuver problem is reduced to optimal time and path solving problem. To address this problem, a metaheuristic maneuver path planning method is proposed (cross-mutation grey wolf algorithm (CMGWO)). In the CMGWO method, we use angular velocity and control torque coding to model attitude maneuver, which increases the difficulty of solving the problem. In order to deal with this problem, the grey wolf algorithm is used for mutation and evolution, so as to reduce the difficulty of solving the problem and shorten the convergence time. Finally, simulation analysis is carried out under different conditions, and the feasibility and effectiveness of the method are verified by numerical simulation.

Selecting Initial Gimbal Angles of Roof-type CMG System for Avoiding Singularities in Spacecraft Attitude Maneuver

Selecting Initial Gimbal Angles of Roof-type CMG System for Avoiding Singularities in Spacecraft Attitude Maneuver

Quantum-inspired diffusion Monte Carlo optimization algorithm applied to space trajectories and attitude maneuvers

In this work, an algorithm for solving optimization problems is proposed, inspired by a computational method employed in Quantum Mechanics: the Diffusion Monte Carlo method, commonly used for the computation of ground states of many-particle systems. The optimization problem is re-formulated as the problem of sampling the ground state wave function of a particle subject to a potential based on the function to be minimized. The algorithm is applied to problems in space trajectory and spacecraft attitude maneuvers optimization, the first application is to the problem of transfer between circular orbits, the results obtained are compared to the results from the literature, then it is applied to the problem of rendezvous with the asteroid Pallas, and finally to the optimization of an attitude maneuver in the presence of several constraints, and the obtained results are compared to two widely used methods: Particle Swarm Optimization and Differential Evolution algorithms. The algorithm is of simple implementation, and the numerical results show better performance than the comparison methods in the considered problems.