Advanced Control of Flight Vehicle Maneuver and Operation

Anti-disturbance, continuous fixed-time controller is designed for faulted airbreathing hypersonic vehicle, including a fast fixed-time integral sliding surface (FFIS), a continuous fixed-time super-twisting-like reaching law (CFSTL) and a uniformly convergent observer. Firstly, the model of a hypersonic vehicle is established. Secondly, an FFIS is designed based on a newly presented fast fixed-time high-order regulator (FFTR). Then, a CFSTL is applied to drive the sliding mode vector and its derivative to achieve fixed-time convergence. Finally, lumped disturbances are estimated by a uniformly convergent observer.

This chapter provides a simple Adaptive Local Variational Iteration Method (ALVIM) that can efficiently solve nonlinear differential equations and orbital problems of spacecrafts. Based on a general first-order form of nonlinear differential equations, the iteration formula is analytically derived and then discretized using Chebyshev polynomials as basis functions in the time domain. It leads to an iterative numerical algorithm that only involves the addition and multiplication of sparse matrices. Moreover, the Jacobian matrix is free from inversing. Apart from that, a straightforward adaptive scheme is proposed to refine the configuration of the algorithm, involving the length of time steps and the number of collocation nodes in a time step. With the adaptive scheme, the prescribed accuracy can be guaranteed without manually tuning the configuration of the algorithm. Since the refinement is adjusted automatically, our algorithm reduces overcalculation for smooth and slowly changing problems. Examples such as large amplitude pendulum and perturbed two-body problem are used to verify this easy-to-use adaptive method's high accuracy and efficiency.

The spacecraft attitude tracking control problem with limited communication is addressed by employing event-triggered based sliding mode control theory. The attitude dynamics are directly developed on the Special Orthogonal Group SO(3), and singularities and ambiguities associated with other attitude representations are avoided successfully, taking model uncertainties and external disturbances into consideration. Based on the developed model, an adaptive eventtriggered sliding mode controller is designed to ensure the closed-loop system that is uniformly ultimately bounded, by using fuzzy logic theory to deal with the disturbance. Due to the application of the event-triggered theory, the control signal is only updated and transmitted at some discrete instants. Therefore, the communication burden is decreased significantly. Finally, numerical simulations are conducted to demonstrate the effectiveness of the proposed control method.

A robust adaptive finite-time controller for satellite fast attitude maneuver is proposed in this paper. The standard sliding mode is robust to some typical disturbances, but the convergence speed is slow and often could not meet the system requirements. The finite-time sliding mode not only has the robustness of the classical sliding mode, but also could greatly improve the terminal convergence speed. In order to deal with inertia matrix uncertainty, a finite-time adaptive law for inertia matrix estimation variables is proposed. A new method to deal with the singularity problem is proposed,based on the properties of Euler rotations. Considering that the variable estimation system has no direct feedback, an auxiliary state that converges slower than the system is designed to achieve finite-time stability. The Lyapunov method is used to demonstrate the global finite-time stability of the ensemble, and the numerical simulation results demonstrate the performance of the controller.

Spacecraft in space may have some certain non-cooperative characteristics due to the service life limit, fuel exhaustion, component fault, structural fatigue damage, or after performing certain space tasks such as capturing non-cooperative targets. In modeling, these non-cooperative characteristics are often manifested in uncertain and unknown inertia, model parameters uncertainty, actuator faults, etc. In this paper, aiming at the attitude stability control problem of such 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 (SOF) controller is applied to model the closed-loop attitude control system a stable negative imaginary (NI) system with H∞ performance constraints according to NI theory. As long as the optimization variables approach zero, the LMI-based iterative algorithm can find such the static output feedback controller to stabilize the flexible spacecraft. It is worth mentioning that an event-trigger mechanism is introduced into the control scheme to reduce communication pressure. Finally, the numerical simulation is carried out in the presence of controller gain perturbations and model parameter uncertainty. The results of the simulation demonstrate the effectiveness, robustness and non-fragility of the control method.

The fact that spacecraft faces a rich and complex dynamic environment makes the development of vibration control and energy harvesting techniques a special concern in space engineering. Nonlinear Energy Sink is such a technique that has developed recently. It generally refers to a lightweight nonlinear device, that is attached to a primary system with essential nonlinear couplings. A special one-way energy transfer called targeted energy transfer (TET) could be observed for passive energy localization into itself. By taking advantage of such essential nonlinearities and the TET phenomenon, NES could be designed as smart and lightweight vibration absorbers or energy harvesters, in a broadband manner, which is especially suitable for the need in aerospace engineering. This chapter is thus devoted to the nonlinear dynamics of vibrational systems with coupled NESs and their applications in the field of passive vibration suppression and vibration energy harvesting.

The partial space elevator (PSE) is a space transportation system that consists of one main satellite and one end body connected to a piece of tether. A climber can move along the tether conveying the cargo. This chapter studies a new configure-keeping technology for the stable cargo transportation of the PSE. The new technology contains two control modules. Module I predicts the optimal climber speed as a reference and suppresses the libration motions using the actuators on the climber. The control law of Module I is designed based on an analytical climber speed function, PPC control is used to compensate for system error. Module II further stabilizes the system by eliminating the possible disturbances in real-time acting on the end body. Two control modes are used given to further ensure the system configuration keeping. To test the validity of the proposed technology, two cases are simulated. The numerical results show that the proposed configuration keeping technology is very effective in dealing with the configuration keeping problems for the partial space elevators and other complex nonlinear dynamic systems in the aerospace engineering area.

In this paper, the fixed-time coordinated control problem is investigated for multiple spacecraft formation flying (SFF) system based on six-degrees-of-freedom (6-DOF) dynamic model. The system under consideration involves input quantization, external disturbance, and directed communication topology. By utilizing the neighborhood state information, a novel multi-spacecraft nonsingular fixed-time terminal sliding mode function is designed. To reduce the required communication rate, a hysteretic quantizer is employed to quantify the control torque and force. The problem addressed is the design of 6-DOF fixed-time coordinated controller such that, the controlled system is practical fixed-time stable and also ensures the relative attitude and position tracking errors can converge into the regions in fixed time. A numerical example is provided to illustrate the usefulness of the proposed control scheme.

In this paper, a prescribed time control strategy for satellite cluster formation reconstruction with multiple environmental disturbances and thruster constraints is proposed. Firstly, a finite time convergent extended state observer (FTCESO) is used to eliminate the effects of external disturbances. And it has been proved to be able to accurately estimate the total disturbances of the satellite cluster in a short time. Secondly, based on the sliding mode, a prescribed time controller with piecewise control law is designed for satellite cluster reconstruction which can ensure that the satellites move to the specified configuration at a prescribed time. Then, the convergence of the controller is proved by Lyapunov stability theory. Finally, compared with a sliding mode controller, a numerical simulation is performed to demonstrate the effectiveness of the proposed method.