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.     

Finite-time attitude tracking control for a rigid spacecraft using time-varying terminal sliding mode techniques

This paper investigates the finite-time attitude tracking control for a rigid spacecraft in the presence of inertia uncertainties and external disturbances. Two novel time-varying terminal sliding mode control algorithms are derived for attitude tracking control system. The proposed two control algorithms not only eliminate the reaching phase of the conventional sliding mode control but also guarantee the tracking errors converge to zero in finite time. Moreover, the singularity problem can be avoided. Simulation results are provided to demonstrate the effectiveness of the proposed design methods.     

航天器平移及姿态机动自适应终端滑模控制

研究了用于航天器平移及姿态机动的自适应终端滑模控制方法.通过在广义准坐标下建立拉格朗日方程得到了刚体航天器平移及姿态耦合运动的动力学方程.能对存在模型不确定性和环境扰动下的航天器实现平移和姿态机动.该自适应过程包括对不确定性和干扰的估计、有效抑制传统滑模控制的抖振现象.利用李雅普诺夫稳定性理论证明了控制器的可达性和稳定性.通过航天器的位置以及姿态跟踪的数值仿真,验证了所设计控制器的有效性和准确性.     

Adaptive attitude tracking control for rigid spacecraft with finite-time convergence

In this paper, the finite-time attitude tracking control problem for rigid spacecraft with external disturbances and inertia uncertainties is addressed. First, a novel fast nonsingular terminal sliding mode surface (FNTSMS) without any constraint is designed, which not only avoids the singularity problem, but also contains the advantages of the nonsingular terminal sliding mode (NTSM) and the conventional sliding-mode together. Second, the proposed FNTSM control laws (FNTSMCLs) by employing FNTSMS associated with adaptation provide finite-time convergence, robustness, faster, higher control precision. The proposed FNTSMCLs in light of novel adaptive control architecture are continuous. Thus, they are chattering-free. Finally, simulation results are presented to illustrate effectiveness of the control strategies. In addition, digital simulations of satellite Hubble Space Telescope (HST) are presented to verify the practical feasibility of the reorientation/ slew maneuvers mission.     

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ESO 的复合滑模面非奇异terminal 滑模控制

针对传统非奇异terminal 滑模控制存在的收敛缓慢和控制输入抖振的问题, 提出采用复合滑模面函数和扩张状态观测器的控制器设计方法. 首先, 结合复合滑模面, 采用分阶段控制律提高系统收敛速度; 然后, 在此基础上使用扩张状态观测器在线估计并补偿系统的不确定量, 以有效削弱系统未建模动力学导致的抖振; 最后, 分别证明了以上两种方法的有限时间收敛特性. 仿真结果验证了所提出方法的有效性, 体现了系统的快速收敛和强鲁棒性等特点.     

基于动态滑模控制的挠性航天器姿态控制

本文采用滑动模态控制方法对挠性航天器设计了姿态镇定控制律.首先,建立了挠性航天器的数学模型.其中,挠性航天器的运动学方程采用姿态四元数描述.然后,通过引入动态切换函数,设计挠性航天器的动态滑模姿态控制律.该控制律能对滑模姿态控制律中由符号函数项引起的抖振进行抑制.采用Lyapunov方法证明了所设计的动态滑模姿态控制律能使闭环航天器姿态系统稳定.最后,通过数值仿真例子验证了所提出方法的有效性.     

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.     

一种改进的自适应滑模控制及其在航天器姿态控制中的应用

针对刚体航天器的鲁棒姿态控制问题,提出一种改进的自适应滑模控制(ASMC)算法.该算法除了不需要事先知道扰动及系统参数不确定性的上界外,还有效地解决了现有ASMC设计中对切换增益的过度适应问题.该算法具有以下优点:1)自适应的切换增益更接近扰动及参数不确定性的上界,能够产生低抖振的控制信号;2)控制力矩更为平滑,适于工程应用.仿真结果验证了所提出算法的有效性.     

输入饱和的充液航天器抗干扰有限时间滑模控制

研究三轴稳定充液航天器姿态控制过程中存在外部未知干扰、参数不确定和输入饱和的问题,提出一种抗干扰有限时间滑模控制的姿态机动控制方法.将部分充液贮箱内液体燃料晃动等效为球摆模型,采用动量矩守恒定律推导出充液航天器耦合动力学方程.首先,设计有限时间积分滑模干扰观测器,保证控制系统中集总干扰可以在有限时间内被估计;然后,基于...     

Continuous finite-time control for robotic manipulators with terminal sliding mode

A continuous finite-time control scheme for rigid robotic manipulators is proposed using a new form of terminal sliding modes. The robustness of the controller is established using the Lyapunov stability theory. Theoretical analysis and simulation results show that faster and high-precision tracking performance is obtained compared with the conventional continuous sliding mode control method.     

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.     

Finite‐time attitude control of multiple rigid spacecraft using terminal sliding mode

This paper investigates the control problem of finite‐time attitude synchronization and tracking for a group of rigid spacecraft in the presence of environmental disturbances. A new fast terminal sliding manifold is developed for multiple spacecraft formation flying under the undirected graph topology. On the basis of the finite‐time control and adaptive control strategies, two novel decentralized finite‐time control laws are proposed to force the spacecraft attitude error dynamics to converge to small regions in finite time, and adaptive control is applied to reject the disturbance. The finite‐time convergence and stability of the closed‐loop system can be guaranteed by Lyapunov theory. Simulation examples are provided to illustrate the feasibility of the control algorithm. Copyright © 2014 John Wiley & Sons, Ltd.     

刚体航天器姿态跟踪的高阶滑模控制器设计

针对存在参数不确定性和外加干扰的刚体航天器的姿态跟踪控制问题,提出一种基于高阶滑模的姿态跟踪控制方法．首先介绍高阶滑模控制的基本原理,并建立基于修正罗德里格参数描述的航天器数学模型;然后采用李雅普诺夫第２法推导出高阶滑模姿态控制律．理论分析和仿真结果均表明,该方法能够有效消除系统抖振,实现航天器姿态跟踪的精确定位,并且系统具有全局稳定性和鲁棒性．     

飞翼无人机复合连续非奇异终端滑模姿态跟踪容错控制

本文针对受多源干扰和舵面故障影响的飞翼无人机系统姿态跟踪控制问题进行研究, 提出了一种基于高阶滑模观测器的复合连续非奇异终端滑模主动抗干扰容错控制算法, 在实现姿态跟踪误差有限时间收敛的同时, 保证了控制量的连续. 并且针对控制力矩的具体实现问题, 结合飞翼无人机气动舵面冗余特性, 给出了基于加权伪逆算法的舵面分配方案, 该方案在满足舵面约束的情况下, 保证了舵面偏转角度的最优. 仿真结果表明, 所提控制方案显著提升了飞翼无人机姿态跟踪精度和跟踪误差的收敛速度, 并且保证了所有舵面满足偏角约束.     

Adaptive fault‐tolerant spacecraft attitude control using a novel integral terminal sliding mode

The attitude tracking of a rigid spacecraft is approached in the presence of uncertain inertias, unknown disturbances, and sudden actuator faults. First, a novel integral terminal sliding mode (ITSM) is designed such that the sliding motion realizes the action of a quaternion‐based nonlinear proportional‐derivative controller. More precisely, on the ITSM, the attitude dynamics behave equivalently to an uncertainty‐free system, and finite‐time convergence of the tracking error is achieved almost globally. A basic ITSM controller is then designed to ensure the ITSM from onset when an upper bound on the system uncertainties is known. Further, to remove this requirement, adaptive techniques are employed to compensate for the uncertainties, and the resultant adaptive ITSM controller stabilizes the system states to a small neighborhood around the sliding surface in finite time. The proposed schemes avoid the singularity intrinsic to terminal sliding mode‐based controllers and the unwinding phenomenon associated with some quaternion‐based controllers. Numerical examples demonstrate the advantageous features of the proposed algorithm. Copyright © 2017 John Wiley & Sons, Ltd.     

基于扩张状态观测器的二质量系统非奇异快速终端滑模控制

针对含未知负载信息的二质量伺服系统,提出一种基于有限时间扩张状态观测器的非奇异快速终端滑模控制方法.首先,利用电机侧位置信息设计有限时间扩张状态观测器估计系统的扰动,并将估计值融入到控制器中作为前馈项对系统的未知扰动进行补偿;然后,引入一种新型的滑模趋近律,该趋近律能够避免传统滑模控制中存在的奇异性问题,据此设计非奇异快速终端滑模控制器,保证系统状态在有限时间内收敛到原点,并根据李雅普诺夫稳定性理论分析闭环系统的稳定性;最后,通过仿真和实验验证所提出方法的优越性.结果表明,与传统的PID等控制相比较,所提出的基于扩张状态观测器的有限时间滑模控制方法能够提高系统的跟踪性能,并有效增强二质量伺服系统的抗扰动能力.     

挠性航天器鲁棒后步滑模姿态跟踪及主动振动控制

针对挠性航天器姿态跟踪及振动抑制问题,提出一种双回路鲁棒控制方法.首先,采用滑模控制与后步法设,计了姿态跟踪控制器,基于Lyapunov方法分析系统的渐近稳定性,并从实际应用角度考虑了反作用飞轮的动态特性;其次,为抑制挠性结构的振动,采用压电智能材料作为敏感器和作动器,设计了应变速率反馈补偿器.仿真结果表明,所提方法在保证完成姿态跟踪任务的同时,能有效抑制挠性附件的振动.     

基于扰动观测器的不确定非线性系统非奇异终端滑模控制

针对一类SISO 非线性不确定系统, 提出一种基于扰动观测器的非奇异终端滑模(NTSM) 控制策略. 在保证控制器非奇异性的情况下, 设计了一种改进的NTSM函数, 理论分析证明了到达滑模面的时间小于传统NTSM控制算法的到达时间. 同时为了消除系统扰动量对控制器抖振的影响, 设计了一种线性扰动观测器以降低滑模切换项的增益, 并采用Sigmoid 函数来替代传统的符号函数. 仿真结果表明了所得结论的正确性和有效性.