Large Angle Attitude Maneuver Research Articles

Design of anti-unwinding attitude coupling controller for flexible spacecraft using positive position feedback control

Flexible vibration has a great impact on flexible spacecraft attitude control, which will reduce the pointing accuracy of the spacecraft platform and bring severe challenges to the design of a high-precision attitude control system for flexible spacecraft. Aiming at the problem of attitude and vibration coupling control of flexible spacecraft, an anti-unwinding attitude coupling controller using the positive position feedback (PPF) control is proposed in this paper. The model compensation control term is constructed based on the prior information to improve the tracking performance. The proposed attitude coupling control method can effectively suppress the flexible vibration while achieving more accurate attitude control. The obtained closed-loop system under the proposed control scheme is asymptotically stable, which is proved by the Lyapunov stability theory. The numerical simulation illustrates that the proposed method can effectively improve the attitude control accuracy of the flexible spacecraft and is capable of large-angle attitude maneuver control because of its prominent performance in attitude tracking and its unwinding-free performance.

Finite-Time Attitude Optimization Maneuver Control for Coupled Spacecraft Under Attitude Measurement Errors and Actuator Faults

The large-angle attitude maneuver trajectory design and tracking control for flexible spacecraft with slosh structure under attitude measurement errors and actuator faults are investigated in this article. Considering that rapid attitude maneuvers can lead to severe flexible vibrations and liquid sloshing, which in turn affects system stability. Therefore, under the requirement of fast maneuvering, the attitude trajectory is optimized to maximize the system’s stability by establishing a new indicator function, while satisfying multiple physical constraints. Furthermore, the novel adaptive multivariable command filtering backstepping fault-tolerant controller is proposed for the coupled spacecraft, to achieve the finite-time attitude tracking to the optimized trajectory, despite the measurement errors and actuator faults. The merits lie in the modified auxiliary signals and virtual commands design, which can compensate the filter errors, caused by the applied filters to deal with the “explosion of terms” of conventional backstepping control, in finite time with better control performance. The numerical simulations are performed to verify the effectiveness of the proposed method.

Singularity avoidance controller design for spacecraft attitude control using double-gimbal variable-speed control moment gyro

A sub-optimal singularity avoidance large angle rest-to-rest attitude maneuver control of a rigid spacecraft actuated using a double-gimbal variable-speed control moment gyro (DGVSCMG) is proposed for avoiding the control torque saturation and the gimbal lock singularity. To achieve this objective, a modified model predictive static programming (MPSP) algorithm subject to control and state constraints is proposed and developed. A cuboid rigid spacecraft equipped with a single DGVSCMG device for the attitude control is considered to validate the proposed control algorithm. A new MPSP based control architecture for the attitude control of a spacecraft using a DGVSCMG is developed, wherein the desired gimbal angle rates and rotor spin acceleration are taken as the control input and computed directly using the MPSP algorithm without requiring the steering law. The control law ensures attitude stabilization of the spacecraft-DGVSCMG system while successfully avoiding the control input saturation and the gimbal lock singularity of the DGVSCMG, thereby enabling large angle attitude maneuvers. Multiple test cases of rest-to-rest attitude maneuvers are simulated to show the efficacy of the proposed control.

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.

Adaptive Robust Control and Active Vibration Suppression of Dumbbell-Shaped Spacecraft

In this paper, the dynamic modelling of a new configuration spacecraft is investigated. The significance of dumbbell-shaped spacecraft to deep space exploration and the configuration of dumbbell-shaped spacecraft are introduced firstly. Then, the vibration problem of the dumbbell-shaped spacecraft of large-angle attitude maneuver is investigated, and a control program based on the combination of adaptive robust control (ARC) and component synthesis vibration suppression method-seven-section path planning (CSVS-SPP) is proposed. The large-angle attitude maneuver route of the spacecraft, which serves as the reference path, is planned using the CSVS-SPP approach, and the attitude controller is designed using the ARC. This program can effectively reduce the influence of external disturbance and parameter uncertainty on the system performance while completing attitude maneuver and suppress the vibration of the flexible beam during large-angle attitude maneuver. The numerical simulations show the superiority and effectiveness of the proposed ARC+CSVS-SPP.

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.

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.

Finite-Time Controller for Flexible Satellite Attitude Fast and Large-Angle Maneuver

In order to deal with the fast, large-angle attitude maneuver with flexible appendages, a finite-time attitude controller is proposed in this paper. The finite-time sliding mode is constructed by implementing the dynamic sliding mode method; the sliding mode parameter is constructed to be time-varying; hence, the system could have a better convergence rate. The updated law of the sliding mode parameter is designed, and the performance of the standard sliding mode is largely improved; meanwhile, the inherent robustness could be maintained. In order to ensure the system’s state could converge along the proposed sliding mode, a finite-time controller is designed, and an auxiliary term is designed to deal with the torque caused by flexible vibration; hence, the vibration caused by flexible appendages could be suppressed. System stability is analyzed by the Lyapunov method, and the superiority of the proposed controller is demonstrated by numerical simulation.

Hybrid Control of Fixed-Wing UAVs for Large-Angle Attitude Maneuvers on the Two-Sphere

We propose the design of a hybrid controller for fixed-wing unmanned aerial vehicles which guarantees global exponential tracking of attitude references on the two-sphere. The chosen attitude representation is singularity-free and can be exploited to apply proportional feedback along the shortest path in the natural configuration space, giving it an advantage to conventional design methods based on Euler angle reprentations. The design includes the concept of synergistic potential functions to overcome the problem of a vanishing potential at the additional undesired equilibrium on the compact manifold. It employs proportional-derivative feedback with the relative velocity as an exogeneous input and allows for integration into conventional autopilot architectures. The controller is well-suited for the recovery from large attitude disturbances and the performance is demonstrated in a numerical example.

Agile Attitude Control and Singularity Avoidance/Escape by the SDRE Method Using a Biased State-Dependent Weighting Matrix

In recent years there has been an increasing need to improve satellite attitude control performance in terms of agility and attitude accuracy in large-angle attitude maneuvers. To achieve such control performance, single-gimbal control moment gyros (SGCMGs) should be mounted as modern-type actuators. Conventionally, based on the torque command calculated by the attitude control system of the satellite, SGCMGs were controlled by solving inverse kinematics through a pseudo inverse matrix steering law. However, in such a control system structure, it may be difficult to obtain the desired torque required by the attitude control system because of the singularity problem of SGCMGs. Furthermore, with respect to implementation, since the condition number of the Jacobian matrix of SGCMG becomes extremely large in the singularity, the numerical calculation error of the pseudo inverse matrix increases greatly. Therefore, we propose an overall control system that can solve above-described problems and the state-dependent Riccati equation (SDRE) control system that integrates the satellite and SGCMG system. The proposed optimal control system, which does not solve the pseudo inverse matrix, can realize gimbal angle guidance by gimbal angle feedback and singularity avoidance/escape using the biased weighting matrix. In the numerical simulation, the usefulness of proposed system is shown in comparison with the conventional system.

Time-optimal spacecraft attitude maneuver path planning under boundary and pointing constraints

The rapid large angle attitude maneuver capability of spacecraft is required during many space missions. This paper addresses the challenge of time-optimal spacecraft attitude maneuver under boundary and pointing constraints. From the perspective of the optimal time, the constrained attitude maneuver problem is summarized as an optimum path-planning problem. To address this problem, a metaheuristic maneuver path planning method is proposed, Angular velocity-Time Coding Differential Evolution (ATDE). In the ATDE method, the angular velocity and time are coded for attitude maneuver modeling, which increases the number of variables and results in a high-dimensional problem. In order to deal with this problem, differential evolution is employed to perform variation and evolution. The boundary and pointing constraints are constructed into the fitness function for path evaluation. Finally, numerical simulations for the different cases were performed to validate the feasibility and effectiveness of the proposed method.

A Hybrid Scheme of Synthesized Sliding Mode/Strain Rate Feedback Control Design for Flexible Spacecraft Attitude Maneuver Using Time Scale Decomposition

Presented herein is a new control approach for large angle attitude maneuver of flexible spacecraft. The singular perturbation theory (SPT) provides a useful tool for two time rate scale separation (mapping) of rigid and flexible body dynamics. The resulting slow and fast subsystems, enabling the use of two control approach for attitude (Modified Sliding Mode) and vibration Strain Rate Feedback (SRF) control of flexible spacecraft, respectively. An attractive feature of the present control approach is that the global stability of the entire system has been guaranteed while the controllers accomplished their tasks in coupled rigid/flexible dynamic domain without parasitic parameter interactions. Numerical simulations show the effectiveness of the present approach.

非線形モデル予測制御を用いた宇宙機の姿勢制御（スラスタとホイールによる閉ループ系の安定性と最適性）

This paper studies model predictive control (MPC) for spacecraft nonlinear attitude control with actuator input nonlinearities. This technology is important to achieve high-rate large angle attitude maneuver problems of recent spacecraft missions. To this end, we first derive linear matrix inequality (LMI) conditions to ensure input-to-state stability (ISS) or asymptotic stability (AS) of MPC closed-loop systems for standard actuators such as reaction control systems (RCS) and reaction wheels (RW). After providing optimization algorithms based on branch and bound methods, we evaluate and compare the control performance of each case using RW, RCS and both RCS and RW in combination through numerical simulations for astronomical observation satellite.

Rapid Path Planning for Zero-Propellant Maneuvers

AbstractThe zero-propellant maneuver (ZPM) is an advanced space station large-angle attitude maneuver technique using control momentum gyroscopes (CMGs), and rapid path planning (RPP) enhances its performance. This paper proposes a novel trajectory optimization technique—the RPP method—to generate the ZPM path. The core of the RPP method is the reconstruction of a continuous-time feasible solution upon the rapid computation of the nonlinear programming (NLP) problem. The method maintains the sparsity of the transcribed NLP and achieves the continuous-time feasibility of the solution with a small number of discretization points. Thus, rapid acquisition of a suboptimal solution may be achieved. The performance of the RPP method is demonstrated by showing that continuous-time feasible ZPM paths with high performance index may be obtained rapidly.

Multi-objective optimization of zero propellant maneuver using hybrid programming

Zero-propellant maneuver is an advanced concept of attitude control. The multi-objective optimization of zero-propellant maneuver using single gimbal control momentum gyroscopes is investigated in this paper. First, the multi-objective optimization model of zero-propellant maneuver is established. Then, a hybrid approach combining pseudospectral method and physical programming is proposed. Finally, the effectiveness of this proposed hybrid method has been validated. It is shown that, using the hybrid programming method, the indexes of the trade-off solution are all desirable. Moreover, the pareto-solution set can be obtained when changing the structure of the preference functions of physical programming, which is examined by 90° and 180° attitude maneuver mission examples. This hybrid programming method provides an effective approach for multi-objective optimal large angle attitude maneuver mission to meet different engineering requirement.

Optimization of Control Parameters Based on Multi-Objective Genetic Algorithms for Spacecraft Large Angle Attitude

Based on multi-objective generic algorithms, a novel approach to optimizing control parameters for large angle spacecraft attitude was proposed. The large angle attitude maneuver controller was designed by taking the spacecraft nonlinear dynamics model and Lyapunov method. To optimize the controller parameters, the alterable weight coefficient method was adopted. Optimal value of time and power consumption acted as fitness goals of the algorithm. Simulation results showed that the algorithm proposed in this paper was superior to the traditional single-objective optimization design method.

Multi-objective Optimization of Zero Propellant Spacecraft Attitude Maneuvers

The zero propellant maneuver (ZPM) is an advanced space station, large angle attitude maneuver technique, using only control momentum gyroscopes (CMGs). Path planning is the key to success, and this paper studies the associated multi-objective optimization problem. Three types of maneuver optimal control problem are formulated: (i) momentum-optimal, (ii) time-optimal, and (iii) energy-optimal. A sensitivity analysis approach is used to study the Pareto optimal front and allows the tradeoffs between the performance indices to be investigated. For example, it is proved that the minimum peak momentum decreases as the maneuver time increases, and the minimum maneuver energy decreases if a larger momentum is available from the CMGs. The analysis is verified and complemented by the numerical computations. Among the three types of ZPM paths, the momentum-optimal solution and the time-optimal solution generally possess the same structure, and they are singular. The energy-optimal solution saves significant energy, while generally maintaining a smooth control profile.

Agile Attitude Control and Vibration Suppression of Flexible Spacecraft Using Control Moment Gyros

Because control moment gyroscopes (CMGs) are capable of generating a much larger control torque for attitude maneuvers than can reaction wheels (RWs), vibration becomes a significant issue for flexible structures such as solar paddles. It is important to address this issue for the agile attitude maneuver control of flexible spacecraft using CMGs. This paper presents an integrated feedback/feedforward control system for reducing the vibration of flexible structures, as well as for completing a rapid, large-angle attitude maneuver of the spacecraft. The proposed Lyapunov control integrated with the Nil-Mode-Exciting profiler and an extended Input Shaping technique effectively improved the transient vibration of the modal response.

Nonlinear Attitude Control of Flexible Spacecraft With Scissored Pairs of Control Moment Gyros

Dynamic equations describing the attitude motion of flexible spacecraft with scissored pairs of control moment gyroscopes are established. A nonlinear controller is designed to drive the flexible spacecraft to implement three-axis large-angle attitude maneuvers with the vibration suppression. Singularity analysis for three orthogonally mounted scissored pairs of control moment gyros shows that there exists no internal singularity in this configuration. A new pseudo-inverse steering law is designed based on the synchronization of gimbal angles of the twin gyros in each pair. To improve the synchronization performance, an adaptive nonlinear feedback controller is designed for each pairs of control moment gyros by using the stability theory of Lyapunov. Simulation results are provided to show the validity of the controllers and the steering law.

Exponential Time-varying Sliding Mode Control for Large Angle Attitude Eigenaxis Maneuver of Rigid Spacecraft

An eigenaxis maneuver strategy with global robustness is studied for large angle attitude maneuver of rigid spacecraft. A sliding mode attitude control algorithm with an exponential time-varying sliding surface is designed, which guarantees the sliding mode occurrence at the beginning and eliminates the reaching phase of time-invariant sliding mode control. The proposed control law is global robust against matched external disturbances and system uncertainties, and ensures the eigenaxis rotation in the presence of disturbances and parametric uncertainties. The stability of the control law and the existence of global siding mode are proved by Lyapunov method. Furthermore, the system states can be fully predicted by the analytical solution of state equations, which indicates that the attitude error does not exhibit any overshoots and the system has a good dynamic response. A control torque command regulator is introduced to ensure the eigenaxis rotation under the actuator saturation. Finally, a numerical simulation is employed to illustrate the advantages of the proposed control law.