Finite-time Attitude Stabilization Research Articles

A thrust inversion method for small satellite electric propulsion based on a momentum wheel

Electric propulsion, which is an advanced form of thrust production, is widely used in small satellites. Measuring the thrust of electric propulsion in an orbit is difficult because it is very small (μN∼mN). However, the thrust of electric propulsion can be determined by evaluating the change in the speed of a momentum wheel. The contributions of this paper mainly include two aspects: 1) a robust PID controller and 2) a thrust inversion method. The torque of the electric propulsion is regarded as the disturbance torque in this paper. To achieve finite-time attitude stabilization of a satellite during electric propulsion, a robust PID controller is designed. Furthermore, the thrust of the electric propulsion can be determined in the stable attitude of the satellite by only measuring the speed derivative of the momentum wheel. Compared with the traditional thrust inversion method, the designed thrust inversion method is simple and effective and does not use a filtering algorithm. In the HIL experiment, the error rate between the inverted thrust (31.287 μN) and the designed thrust (30 μN) is 4.29%. Most importantly, the thrust inversion method is verified in orbit based on the small satellite APSCO SSS-1, which is consistent with the HIL experimental results and ground test results.

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.

Global finite-time set stabilization of spacecraft attitude with disturbances using second-order sliding mode control

The performance of attitude stabilization control algorithms for rigid spacecraft can be limited by disturbances. In this paper, the global finite-time attitude stabilization problem with disturbances is investigated and handled by constructing a second-order sliding mode controller. Firstly, a virtual controller based on set stabilization idea is constructed to globally finite-time stabilize the system. Then, a relay polynomial second-order sliding mode controller is constructed to guarantee that the tracking error toward the virtual controller will converge to zero in finite-time. Finite-time Lyapunov theory is applied to support the proof and stability analysis. The global finite-time stability holds even with bounded disturbances. The effectiveness and feasibility of the controller are illustrated by the numerical simulations.

Learning‐based robust control methodologies under information constraints

Learning‐based robust control methodologies under information constraints

Robust finite-time control design for attitude stabilization of spacecraft under measurement uncertainties

This paper investigates the finite-time attitude stabilization of spacecraft under multiple uncertainties. Besides inertia uncertainties, external disturbances, and actuator faults, the measurement uncertainties are particularly considered. When including the measurement uncertainties, the spacecraft attitude control system becomes a mismatching system, which brings a great challenge to the control design. To resolve this problem, a novel robust finite-time attitude control approach is proposed by using a dual-disturbance-observer-based structure. First, two finite-time disturbance observers are developed to estimate the mismatched and matched lumped disturbances in the spacecraft attitude kinematics and dynamics, respectively. Then, the robust finite-time attitude controller is synthesized by incorporating the two finite-time disturbance observers into the adding a power integrator technique. It is strictly proved that the proposed robust finite-time attitude controller can ensure the actual attitude and angular velocity stabilize to the small neighborhoods around the origin in finite time even subject to multiple uncertainties. Benefiting from the feedforward disturbance compensation, the proposed controller is not only robust against inertia uncertainties, external disturbances, and actuator faults, but also insensitive to measurement uncertainties. Lastly, the effectiveness and advantages of the proposed control approach are validated through simulations and comparisons.

Neural network-based robust finite-time attitude stabilization for rigid spacecraft under angular velocity constraint

In this paper, the problem of attitude stabilization control of spacecraft under angular velocity constraint is investigated. A state-constrained finite-time attitude control scheme is designed by making full use of the model feature of the quaternion. Based on the homogeneous domination approach, the finite-time stability of the closed-loop system is proved. It proves that the angular velocity can be constrained within the limited range at any time. For the attitude loop dynamics subsystem with external disturbances, based on a radial basis function neural network, an integral terminal sliding mode controller is proposed. Finally, the validity and advantages of the proposed control scheme are demonstrated in the simulation section compared with the other two control methods.

Dynamic modeling and faster finite-time attitude stabilization of receiver aircraft for aerial refueling

This paper studies the faster attitude stabilization problem of receiver aircraft during the refueling phase. Dynamic models of receiver aircraft subject to practical uncertainties and disturbances are established, where the uncertain inertia, the wind disturbance, the time-varying inertia, and the shift of the center of mass are explicitly considered. A faster finite-time stable system is preliminarily proposed and proved rigorously in comparison with the conventional fast finite-time stable system. Then, a nonsingular terminal sliding mode surface is synthesized to ensure a fast convergence rate. An adaptive faster finite-time controller is finally developed with the aircraft attitude stabilized into a small neighborhood of the origin with a faster convergence rate. Simulations are conducted to validate that the proposed solution can accomplish attitude stabilization maneuvers in a faster way.

Saturated output feedback control for finite-time attitude stabilization of spacecraft

The finite-time attitude stabilization of spacecraft subject to actuator constraints and attitude measurements only is investigated. A saturated output feedback finite-time proportional-derivative control is proposed. Lyapunov stability theory and homogeneous method are employed to show the finite-time stabilization. Advantages of the proposed control include the finite-time stabilization featuring faster transient and higher precision and the absence of the modelling information and the velocity measurements in the control law formulation, and thus, it offers an easy-going solution for high-quality motion control of spacecraft. An additive feature is that the actuator saturation will not be reached by selecting the control gains a priori. Simulations are presented to illustrate the effectiveness of the proposed control.

Finite-time attitude stabilization of an output-constrained rigid spacecraft

This article concentrates on the study of finite-time attitude stabilization for a rigid spacecraft with output constraints. The dynamics of the spacecraft are expressed by modified Rodrigues parameters, so that the singularity of covariance matrix owing to quaternion’s redundancy is eliminated. Based on the backstepping technique in combination with adding a power integrator technique, the attitude stabilization control law is constructed. Rigorous mathematical proof shows that the closed-loop system is finite time stable and all the outputs remain bounded by using a barrier Lyapunov function technique. The effectiveness of the proposed finite-time stabilization scheme is verified by a simulation example.

Finite-Time Attitude Stabilization Adaptive Control for Spacecraft with Actuator Dynamics.

For the attitude stabilization of spacecraft with actuator dynamics, this paper proposed a finite-time control law. Firstly, the dynamic property of the actuator is analyzed by an example. Then, a basic control law is derived to achieve the finite-time stability using the double fast terminal sliding mode manifold. When there is no prior knowledge of time matrix of the actuator, an adaptive law is proposed to estimate the unknown information. An adaptive control law is derived to guarantee the finite-time convergence of the attitude, and a Lyapunov-based analysis is provided. Finally, simulations are carried out to demonstrate the effectiveness of the proposed control law to the attitude stabilization with the actuator dynamics. The results show that the high-precision attitude control performance can be achieved by the proposed scheme.

Adaptive Finite-Time Command Filtered Fault-Tolerant Control for Uncertain Spacecraft with Prescribed Performance

In this paper, an adaptive finite-time fault-tolerant control scheme is proposed for the attitude stabilization of rigid spacecrafts. A first-order command filter is presented at the second step of the backstepping design to approximate the derivative of the virtual control, such that the singularity problem caused by the differentiation of the virtual control is avoided. Then, an adaptive fuzzy finite-time backstepping controller is developed to achieve the finite-time attitude stabilization subject to inertia uncertainty, external disturbance, actuator saturation, and faults. Through using an error transformation, the prescribed performance boundary is incorporated into the controller design to guarantee the prescribed performance of the system output. Numerical simulations demonstrate the effectiveness of the proposed scheme.

Finite-Time Attitude Stabilization of Flexible Spacecrafts via Reduced-Order SMDO and NTSMC

AbstractAttitude control performance of spacecraft is inevitably affected by internal and external disturbances such as vibrations of flexible appendages, payload motions, actuator faults, and envi...

Observer-Based Terminal Sliding Mode Control for Attitude Stabilization of Flexible Spacecraft with Fuel Slosh

In this paper, an observer-based terminal sliding mode control approach is proposed and applied to the attitude control system of the flexible spacecraft with fuel slosh. The disturbances from the vibration of the flexible appendage and fuel slosh are modelled as derivative-bounded disturbances which can be estimated and rejected by the disturbance-observer-based-control (DOBC). Next, by combining the DOBC with terminal sliding mode controller (TSMC), a composite controller is proposed to realize the finite time convergence. Therefore, anti-disturbance and finite time attitude stabilization can be guaranteed by the proposed composite controller. Linear matrix inequality (LMI) -based algorithm is used to compute the observer parameters. Finally, theoretical analysis and simulation results are given to verify the effectiveness of the proposed method.

Finite-Time Fuzzy Sampled-Data Control for Nonlinear Flexible Spacecraft With Stochastic Actuator Failures

This paper deals with the problem of finite-time sampled-data control for nonlinear flexible spacecraft described by Takagi–Sugeno (T–S) fuzzy model with stochastic actuator failures. Different from the existing literatures, T–S fuzzy approach is used to model the nonlinear behaviors of flexible spacecraft for its good approximation performance. A novel and general input model related to Markovian variables is developed to depict the stochastic actuator failures, which is capable of covering various faulty modes. With the aid of stochastic analysis and convex optimization techniques, a novel fault-tolerant fuzzy switching controller is designed to carry out the finite-time attitude stabilization for flexible spacecraft with the existence of stochastic failures and sampled-data inputs, and an optimal $H_\infty$ performance level is ensured simultaneously. Finally, a practical example with simulation results are provided to validate the effectiveness of the developed control strategy.

Global finite-time attitude stabilization for rigid spacecraft in the exponential coordinates

ABSTRACTThis paper addresses the global finite-time attitude stabilisation problem on the special orthogonal group (SO(3)) for a rigid spacecraft via homogeneous feedback approach. Considering the topological and geometric properties of SO(3), the logarithm map is utilised to transform the stabilisation problem on SO(3) into the one on its associated Lie algebra (). A model-independent discontinuous state feedback plus dynamics compensation scheme is constructed to achieve the global finite-time attitude stabilisation in a coordinate-invariant way. In addition, to address the absence of angular velocity measurements, a sliding mode observer is proposed to reconstruct the unknown angular velocity information within finite time. Then, an observer-based finite-time output feedback control strategy is obtained. Numerical simulations are finally performed to demonstrate the effectiveness of the proposed finite-time controllers.

Simple finite-time attitude stabilization laws for rigid spacecraft with bounded inputs

The problem of finite-time attitude stabilization of a rigid spacecraft is investigated. Homogeneous system theory is utilized to design a simple nonlinear proportional-derivative-type (PD-type) saturated finite-time controller (SFTC), which can accommodate its form to different attitude parameterizations, such as quaternion, Rodrigues parameters (RP) and modified Rodrigues parameters (MRP). The proposed SFTC is inertia-independent and yields bounded control torques, in addition to finite-time convergence. Specially, the quaternion-based SFTC avoids the unwinding phenomenon associated with traditional continuous quaternion-based control laws and achieves, as shown by the Monte Carlo analysis, a faster convergence than a previous quaternion-based finite-time attitude stabilization law. Numerical examples are presented to verify the efficacy of the proposed method.

Robust Saturated Finite Time Output Feedback Attitude Stabilization for Rigid Spacecraft

This paper investigates the velocity-free feedback control problem associated with finite time attitude stabilization of a rigid spacecraft subject to external disturbance and input saturation. First of all, to address the lack of angular velocity measurement, a novel, fast, finite time convergent observer is proposed to recover the unknown angular velocity information in a finite time under external disturbance. Then, a finite time output feedback controller is proposed using the designed finite time observer, in which the control input saturation nonlinearity is explicitly considered in the proposed finite time stabilizer. Rigorous proofs show that the proposed observer can achieve finite time stability, the controller rigorously enforces actuator-magnitude constraints, and the attitude of the rigid spacecraft will converge to the equilibrium in a finite time. Numerical simulations illustrate the spacecraft performance obtained using the proposed controllers.

Finite-Time Stabilization Control for a Rigid Spacecraft under Parameter Uncertainties

A novel finite-time control scheme is investigated for a rigid spacecraft in present of parameter uncertainties and external disturbances. Firstly, the spacecraft mathematical model is transformed into a cascading system by introducing an adaptive variable. Then a novel finite-time attitude stabilization control scheme for a rigid spacecraft is proposed based on the homogeneous method. Lyapunov stability analysis shows that the resulting closed-loop attitude system is proven to be stable in finite time without parameter uncertainties and asymptotically stable with parameter uncertainties. Finally, numerical simulation examples are also presented to demonstrate that the control strategy developed is feasible and effective for spacecraft attitude stabilization mission.

Semi-global finite-time attitude stabilization by output feedback for a rigid spacecraft

This article investigates the finite-time attitude stabilization problem by output feedback for a rigid spacecraft without angular velocity measurement. First of all, by employing the finite-time c...

Finite-Time Attitude Stabilization for a Spacecraft Using Homogeneous Method

Finite-Time Attitude Stabilization for a Spacecraft Using Homogeneous Method