航天器自适应快速非奇异终端滑模容错控制

针对存在外部干扰、转动惯量矩阵不确定以及执行器故障的航天器姿态跟踪控制问题,本文提出了基于自适应快速非奇异终端滑模的有限时间收敛故障容错控制方案.通过引入能够避免奇异点,且具有有限时间收敛特性的快速非奇异终端滑模面,设计了满足多约束条件有限时间收敛的姿态跟踪容错控制律,利用参数自适应方法使控制器不依赖转动惯量和外部干扰的上界信息.Lyapunov稳定性分析表明:在存在外部干扰、转动惯量矩阵不确定以及执行器故障等约束条件下,本文设计的控制律能够保证闭环系统的快速收敛性,而且对执行器故障具有良好的容错性能.数值仿真校验了该控制律在姿态跟踪控制中的优良性能.     

Global finite-time attitude consensus tracking control for a group of rigid spacecraft

The problem of finite-time attitude consensus for multiple rigid spacecraft with a leader–follower architecture is investigated in this paper. To achieve the finite-time attitude consensus, at the first step, a distributed finite-time convergent observer is proposed for each follower to estimate the leader's attitude in a finite time. Then based on the terminal sliding mode control method, a new finite-time attitude tracking controller is designed such that the leader's attitude can be tracked in a finite time. Finally, a finite-time observer-based distributed control strategy is proposed. It is shown that the attitude consensus can be achieved in a finite time under the proposed controller. Simulation results are given to show the effectiveness of the proposed method.     

Nonsingular terminal sliding mode based finite-time control for spacecraft attitude tracking

This paper studies finite-time attitude tracking control problem of a rigid spacecraft system with external disturbances and inertia uncertainties. Firstly, a new finite-time attitude tracking control law is designed using nonsingular terminal sliding mode concepts. In the absence and presence of external disturbances and inertia uncertainties, this controller can drive the attitude and angular velocity tracking errors to reach zero in finite time. Secondly, a finite-time disturbance observer is introduced to estimate the disturbance, and a composite controller is developed which consists of a feedback control based on nonsingular terminal sliding mode method and compensation term based on finite-time disturbance observer. Finite-time convergence of attitude tracking errors and the stability of the closed-loop system is ensured by the Lyapunov approach. Numerical simulations on attitude control of spacecraft are also given to demonstrate the performance of the proposed controllers.     

输入饱和受限下的刚体飞行器姿态系统的有限时间镇定

研究存在输入饱和受限下的飞行器姿态控制问题, 提出一种有限时间姿态镇定方案. 针对基于修改的Rodriguez 参数模型的飞行器姿态控制系统, 基于齐次性理论和饱和控制器设计方法, 并充分利用系统的模型结构特征, 设计一类饱和的有限时间姿态控制器, 使得姿态可以在有限时间内被镇定到平衡点. 仿真结果验证了所设计姿态控制器的有效性.

     

Velocity-free adaptive nonsingular fast terminal sliding mode finite-time attitude tracking control for spacecraft

Aiming at the attitude tracking control problem of rigid spacecraft under the condition of unmeasurable angular velocity information, a velocity-free adaptive nonsingular fast terminal sliding mode finite-time tracking control method is proposed. The finite-time extended-state observer is used to estimate the attitude tracking speed errors and the integrated disturbances. Combined with the above control method, a fast nonsingular terminal sliding mode controller with attitude measurement is designed and the adaptive technology is introduced to compensate for the influence of observation errors on the controller. The finite-time convergence of the observer and the control method was demonstrated based on Lyapunov theory, and the effectiveness of the proposed method is verified by numerical simulations.     

Output feedback second order sliding mode control for spacecraft attitude and translation motion

This paper studies an output feedback control problem for spacecraft position and attitude control when uncertainties related to system parameters and external disturbances are present. Firstly, a new finite-time control law is designed using second order sliding mode concepts. In the presence of external disturbances and inertia uncertainties, the new control law provides finite-time convergence and high tracking precision. Secondly, a new sliding-mode-based filter is developed to estimate the first time derivatives of attitude and position in finite time. Instead of the translational and angular velocity variables, the estimated derivative values are used for the controller design. The proposed controller with this filter is an output feedback controller since translational and angular velocity measurements are not required. The closed-loop system under this controller is non-homogeneous and the stability is proven by using concepts of a strong Lyapunov function and Lyapunov stability theory. The trajectories of the closed-loop system can be controlled to converge to a ball centered at the origin that can be made as small as desired. Numerical simulations of position and attitude control of spacecraft are given to demonstrate the performance of the proposed controller and filter.     

交会对接模拟系统姿态位置耦合有限时间控制

针对航天器交会对接模拟系统的姿态同步和位置跟踪控制问题,在存在外界扰动和系统不确定性的情况下,基于改进的快速非奇异终端滑模面和改进的自适应律,采用双闭环控制结构分别设计内环和外环有限时间姿态位置耦合控制器.所提出的自适应律不仅能有效地抑制扰动和不确定性且能保证控制器是连续的.李雅普诺夫理论推导和仿真结果表明,所提出的控制方法能保证系统内环和外环跟踪误差的有限时间稳定性和准确收敛性.     

Decentralised finite-time attitude synchronisation and tracking control for rigid spacecraft

The problem of finite-time attitude synchronisation and tracking for a group of rigid spacecraft nonlinear dynamics is investigated in this paper. First of all, in the presence of environmental disturbance, a novel decentralised control law is proposed to ensure that the spacecraft attitude error dynamics can converge to the sliding surface in finite time; then the final practical finite-time stability of the attitude error dynamics can be guaranteed in small regions. Furthermore, a modified finite-time control law is proposed to address the control chattering. The control law can guarantee a group of spacecraft to attain desired time-varying attitude and angular velocity while maintaining attitude synchronisation with other spacecraft in the formation. Simulation examples are provided to illustrate the feasibility of the control algorithm presented in this paper.     

基于积分滑模的航天器有限时间姿态容错控制

针对存在执行机构故障和外部干扰的刚体航天器姿态稳定系统,本文提出了基于积分滑模的容错控制策略,实现了姿态有限时间稳定.首先,利用齐次系统相关理论,设计了一类饱和有界的基础控制律,保证了不存在执行机构故障和干扰情况下的姿态有限时间稳定.在此基础上,利用积分滑模和自适应技术设计了一种有限时间姿态鲁棒容错控制方案,对执行机构故障和干扰进行有效的补偿;该方案能够快速地实现姿态高精度稳定,并抑制系统抖振现象.最后,将本文提出的姿态容错控制方案进行数值仿真与对比,验证了方案的有效性与优越性.     

Robust adaptive integrated translation and rotation finite-time control of a rigid spacecraft with actuator misalignment and unknown mass property

This paper tackles the problem of integrated translation and rotation finite-time control of a rigid spacecraft with actuator misalignment and unknown mass property. Due to the system natural couplings, the coupled translational and rotational dynamics of the spacecraft is developed, where a thruster configuration with installation misalignment and unknown mass property are taken into account. By solving an equivalent designated trajectory tracking problem via backstepping philosophy, a robust adaptive integrated finite-time control scheme is proposed to enable the spacecraft track command position and attitude in a pre-determined time, despite of external disturbance, unknown mass property and thruster misalignment. The finite-time closed-loop stability is guaranteed within the Lyapunov framework. Two scenario numerical simulations demonstrate the effect of the designed controller.     

Finite-time attitude quantised control for rigid spacecraft

This paper investigates the quantised finite-time attitude control for rigid spacecraft in the presence of external disturbance. First, a novel quantiser is designed with the combination and improvement of the traditional hysteresis logarithmic quantiser and hysteresis uniform quantiser, so that the innovative quantiser in this paper has the advantages of both hysteresis and uniform quantisers in ensuring chattering free and acceptable quantisation errors for better transient and steady-state performances. Second, a finite-time controller is synthesised even under disturbances and quantisation errors, and the closed-loop system/state converges to the region near zero in finite time. Finally, the attitude stabilisation and attitude tracking simulation results for the rigid spacecraft are presented to illustrate the effectiveness and feasibility of the proposed control strategy.     

PID control for global finite-time regulation of robotic manipulators

This paper addresses the global finite-time regulation problem of robotic manipulators. A simple nonlinear proportional-integral-derivative (PID) control is proposed by adding a nonlinear proportional and derivative term to the commonly used PID controller. Lyapunov's stability theory and geometric homogeneity technique are employed to prove global finite-time stability. Advantages of the proposed control include the absence of modelling information in the control law formulation and the global finite-time stability featuring fast transient and high-precision positioning. Explicit conditions on the controller parameters to ensure global finite-time regulation stability are obtained. Simulations are presented to demonstrate the effectiveness and the improved performances of the proposed approach.     

交会对接模拟系统姿态跟踪有限时间抗干扰控制

针对交会对接模拟系统的姿态同步问题,在存在扰动和系统不确定性的情况下,利用改进的快速非奇异终端滑模面和改进的自适应律设计两个有限时间抗干扰控制器.改进的自适应律保证了两个控制器的连续性和对干扰的鲁棒性,且第2个控制器能解决边界层理论存在的边界层内有限时间稳定性丢失的问题.李雅普诺夫理论推导和仿真结果表明,提出的两个控制器能保证系统的有限时间稳定性,系统能快速收敛到平衡点.     

SGCMGs驱动的挠性航天器有限时间自适应鲁棒控制

针对挠性航天器系统中同时存在单框架控制力矩陀螺群(Single gimbaled control moment gyroscopes,SGCMGs)摩擦非线性、电磁干扰力矩、惯量摄动以及外部干扰等问题,提出了一种有限时间自适应鲁棒控制(Finite-time adaptive robust control,FTARC)...     

多航天器系统分布式有限时间姿态协同跟踪控制

基于一致性算法, 在有向通讯拓扑下, 研究存在状态约束的多航天器系统分布式有限时间姿态协同跟踪控制问题. 在仅有部分跟随航天器可以获取领航航天器状态, 并且跟随航天器之间存在不完全信息交互的情形下, 设计了分布式快速终端滑模面, 提出了不依赖于模型的分布式有限时间姿态协同跟踪控制律. 根据有限时间Lyapunov 稳定性定理, 证明了系统的状态在有限时间内收敛于领航航天器状态的小邻域内. 最后通过仿真算例验证了所提出算法的有效性.

     

Adaptive Dynamic Surface Control for Spacecraft Terminal Safe Approach with Input Saturation Based on Tracking Differentiator

This thesis studies the spacecraft terminal safe approach control problem considering input saturation. Based on the spacecraft relative motion model and sphere collision avoidance potential function, an anti-saturation controller and an adaptive finite-time anti-saturation controller using dynamic surface control(DSC) are presented for the situations of known and unknown upper bound of external disturbances respectively, which can guarantee that no collisions happen in the tracking process. The second-order tracking differentiator is introduced to design the controllers, which avoids the differential of the virtual control signal and ensures the tracking performance of system output signals. Meanwhile, the auxiliary system is introduced to handle input saturation. Lyapunov stability theory is adopted to prove that the states of system under the designed controllers are uniformly ultimately bounded and practical finite-time stable respectively, and the chaser spacecraft can approach to the desired position without collision. The numerical simulation results demonstrate that the chaser spacecraft using the designed controllers can realize terminal safe approach to target spacecraft, which further illustrate the effectiveness of the proposed controllers.     

飞轮安装偏差的过驱动航天器有限时间姿态控制

针对反作用飞轮安装存在偏差的过驱动航天器姿态跟踪问题, 提出一种有限时间姿态补偿控制策略. 通过设计自适应滑模控制器保证实现对不确定性转动惯量与外部干扰的鲁棒控制, 同时实现对飞轮安装偏差的补偿控制, 并应用Lyapunov 稳定性理论证明了该控制器能够在有限时间内实现姿态跟踪控制. 最后, 将该控制器应用于某型航天器的姿态跟踪控制, 仿真结果验证了所提出方法的有效性.     

考虑输入受限的航天器安全接近姿轨耦合控制

针对存在外部扰动和输入受限的航天器安全接近的问题,当扰动上界未知时,基于积分滑模控制理论设计了抗饱和的有限时间自适应姿轨耦合控制器.控制器的设计过程中采用了新型的避碰函数限制追踪航天器运动区域进而保证接近过程中航天器的安全性,同时通过辅助系统和自适应算法分别处理了输入受限和扰动上界未知.借助李雅普诺夫理论证明了在控制器的作用下系统状态在有限时间内收敛,且能够保证追踪航天器在实现航天器接近的过程中不与目标航天器发生碰撞.最后通过数字仿真进一步验证了所设计控制器的有效性.     

分布式航天器编队约定时间姿轨耦合协同控制

针对具有参数不确定性、外部扰动和预设性能需求的航天器编队约定时间姿轨耦合控制问题, 本文基于预设性能控制方法提出了一种低复杂度的约定时间编队姿轨耦合协同控制器, 使得航天器在设定时间内形成编队, 且编队误差满足预设的各种性能指标. 首先, 通过结合有限时间稳定概念引入一种约定时间性能函数, 其系统稳定时间可以由使用者任意设定; 然后, 把约定时间性能函数与预设性能控制方法结合起来, 提出了不依赖航天器质量和转动惯量等信息的约定时间编队协同控制器, 保证了编队状态量的收敛性能和收敛时间, 并使用李雅普诺夫理论证明了其稳定性. 最后, 通过仿真验证了该控制方案的有效性     

Attitude control of spacecraft simulator without angular velocity measurement

In this paper the attitude control of a spacecraft simulator using Reaction Wheels (RW) as the actuators is investigated. The main goal of the current study is to bring the RWs to the rest at the end of the maneuver without angular velocity measurement. A modified feedback linearization controller is applied by considering the Euler angles of the simulator as the output and the RWs angular momentums as the internal state variables. The stability of the proposed controller and the internal dynamics is analyzed using Lyapunov theory. Two modified sliding mode observers are designed to estimate the angular velocities of the spacecraft attitude control subsystem simulator. The proposed observers do not use the control input and the detailed knowledge of the model and thus it can be implemented easily. The global stability of the system is proved. The proposed controller and observers are finally evaluated numerically and experimentally on an attitude spacecraft simulator.