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.

     

带两控制器刚体飞行器的姿态镇定

已知带两控制器的刚体飞行器系统不能被连续的纯状态反馈局部渐近镇定.有效的解决方法包括时变反馈镇定方法和非连续反馈镇定方法.现有的时变反馈镇定方法设计均较为复杂.已有的光滑时变反馈方法是非指数收敛的.本文通过引入辅助变量以及采用反馈线性化技术设计出光滑时变的控制器.该方法设计简单且保证闭环系统状态是指数收敛的.仿真结果证明了本文方法的有效性.     

一类不确定非线性系统的全局鲁棒有限时间镇定

对一类不确定非线性系统提出了一种连续的全局鲁棒有限时间控制律．首先,针对标称系统设计出了一种状态反馈控制律,应用Lyapunov直接稳定性理论和Lasalle不变性原理证明了闭环标称系统的全局渐近稳定性,同时具有负的齐次度;其次,引入辅助变量和采用有限时间收敛的二阶滑模Super—twisting算法,设计出了对不确定性和干扰进行抑制的补偿控制项,并根据有限时间Lyapunov函数给出了补偿控制项参数的取值范围;最后,综合得到一种连续的使实际闭环系统有限时间收敛到平衡点的鲁棒镇定控制律．仿真结果表明了所提控制律的有效性．     

变体飞行器的非脆弱有限时间鲁棒控制器设计

针对存在有界干扰和控制器参数不确定性的变体飞行器,研究非脆弱有限时间鲁棒控制器的设计问题.首先建立变体飞行器纵向运动的切换系统模型.考虑到每个子系统具有不同的特性,基于多Lyapunov函数方法和模态依赖驻留时间方法分析了飞行器系统有限时间有界性能及满足$H_{\infty     

不确定广义大系统有限时间鲁棒分散控制

研究不确定连续广义大系统的有限时间鲁棒分散控制问题,设计系统的有限时间鲁棒分散状态反馈控制器.首先应用广义Lyapunov 函数法,给出不确定广义大系统有限时间鲁棒稳定的充分条件;其次,给出不确定广义大系统应用分散状态反馈控制器鲁棒镇定的充分条件和有限时间鲁棒分散控制器的设计方法;最后,通过仿真例子验证所提出方法的有效性.     

一类二阶非线性系统的有限时间状态反馈镇定方法

针对一类二阶非线性系统的有限时间状态反馈镇定问题进行了讨论. 给出了三种基于连续状态反馈的全局有限时间状态反馈镇定方法. 首先,利用非线性齐次系统性质,设计出一种状态反馈控制器,使得闭环系统渐近稳定并且具有负的齐次度;其次,基于有限时间Lyapunov函数的反步构造法,给出了一种有限时间控制器;最后,利用非奇异终端滑模控制技术,得到了一种使闭环系统有限时间收敛到平衡点的反馈镇定控制器. 仿真结果表明了这些方法的有效性.     

输入饱和下的非线性积分系统的全局有限时间镇定

针对一类非线性积分系统, 利用有限时间控制技术, 提出了一种输入饱和情况下的全局有限时间控制方案. 首先, 基于有限时间 Lyapunov 稳定性理论, 设计镇定系统的全局有限时间递归控制器. 然后,将该递归控制器与饱和函数结合得到饱和控制器. 数学上严格证明了在该饱和控制器的作用下, 闭环系统满足全局有限时间稳定性. 仿真结果验证了该方法的有效性.     

约束不确定非线性系统的鲁棒优化镇定

针对状态和输入约束不确定非线性仿射系统,提出一种鲁棒镇定的优化控制器设计方法.基于弱鲁棒控制Lyapunov函数概念,构造一个参数可调控制器.再利用LaSalle定理和逆优化理论,验证该控制器的鲁棒镇定性和逆最优性.进一步,采用滚动优化原理在线计算控制器的可调参数,实现闭环系统的鲁棒优化镇定.最后对一个开环不稳定振荡器系统进行鲁棒优化镇定,其结果验证了文中方法的有效性.     

全状态受限飞行器的自适应有限时间姿态控制

针对全状态受限飞行器系统的姿态跟踪,构建了一种新的自适应有限时间跟踪控制器,以消除经典反步法中由于对虚拟信号求导所导致的计算复杂性问题,并保证飞行器姿态系统中所有状态均限制在设计区域内。对于飞行器系统非线性模型中的未知部分,采用神经网络进行逼近。在此基础上,设计了误差补偿机制用于补偿滤波误差,并使用障碍李雅普诺夫函数证明了尽管存在输入饱和,但是飞行器的姿态仍然可以在有限时间内以一定的精度跟踪期望信号。最后,对该控制方法进行了仿真验证。     

一类扩展结构大系统的分散有限时间鲁棒关联镇定

研究一类扩展结构大系统分散有限时间鲁棒关联镇定问题. 扩展结构大系统是在原结构系统上增加新子系统而构成的, 在原系统分散控制律确定不变的情况下, 设计新加入子系统的鲁棒分散控制律, 使扩展后的系统仍能保持有限时间关联稳定. 利用LMI 方法推导此类系统基于状态反馈和输出反馈的分散有限时间关联镇定的充分条件, 并给出扩展子系统的相应控制器的设计方法. 最后通过仿真实验表明了所提出方法的可行性和有效性.

     

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

Neural Computing and Applications - In this paper, the problem of attitude stabilization control of spacecraft under angular velocity constraint is investigated. A state-constrained finite-time...     

Robust stabilization of the angular velocity of a rigid body

The problem of robust control for the angular velocity of a rigid body subject to external disturbances is addressed. It is shown that if the disturbances are matched there exists a control law attenuating the effect of the disturbances, whereas in the case of non-matched disturbances no such a feedback law generically exists. Hence, a new concept of disturbance attenuation is introduced and it is proved that the aforementioned problem is solvable in this weaker sense. Explicit expressions of the control laws solving the proposed robust stabilization problems are given.     

Robust output feedback stabilization of the angular velocity of a rigid body

The problem of semi-global stabilization of the angular velocity of an underactuated rigid body in the presence of model errors is addressed and solved using a smooth, time-varying, dynamic, output feedback control law. The proposed scheme improves some of the existing results and provides guidelines for a general stabilization strategy applicable to systems which are not exponentially stabilizable. Simulations results are included.     

Output feedback stabilization of the angular velocity of a rigid body

The problem of stabilization of the angular velocity of a rigid body using only two control signals and partial state information is addressed. It is shown that if any two (out of three) states are measured the system is not asymptotically stabilizable with (continuous) dynamic output feedback. Nevertheless, we prove that practical stability is achievable if the measurable states fulfill a certain structural property, and that, under the same structural condition, a hybrid control law yielding exponential convergence can be constructed. Finally, we also study some geometric features of the Euler’s equations and the connection between local strong accessibility and local observability.     

考虑执行器性能约束的刚体航天器鲁棒姿态跟踪控制

针对存在模型不确定性、外界干扰力矩和执行器性能受限等约束条件下的刚体航天器姿态跟踪控制问题进行研究,并基于滑模控制、反步控制、自适应控制、辅助系统和动态面控制等方法设计相应的鲁棒姿态跟踪控制算法.利用自适应控制实现了对具有多项式形式上界函数的系统未知不确定性进行在线估计和补偿;通过建立描述执行器动态特性的低通滤波模型,并结合辅助系统方法,以确保执行器输出控制力矩的幅值及其变化率均满足一定的饱和约束;通过引入动态面控制法,避免期望虚拟控制信号的一阶导数项直接出现在控制器中,简化了闭环姿态跟踪控制器的设计形式.最后,通过数值仿真验证了所提出控制算法的有效性和可行性.     

Robust PID controller for flexible satellite attitude control under angular velocity and control torque constraint

A PID controller for flexible satellite attitude control with unknown perturbation is proposed in this paper. System inertia uncertainty, stochastic disturbance torque, and perturbation of flexible deformation are discussed, and the controller proposed in this paper is robust to these perturbations. A novel integral term is designed; hence the Lyapunov function structure is modified and the stability proof is simplified. The angular velocity constraint is discussed and a novel method to solve the angular velocity saturation issue is given. The control torque saturation issue is also taken into consideration. Stability for all conditions considered in this paper is proved by the Lyapunov method. The performance of the controller is demonstrated by numerical simulation.     

Global feedback stabilization of the angular velocity of a symmetric rigid body

In this paper we prove that the angular velocity equations of a symmetric rigid body can be globally stabilized by means of linear feedback when two control torques act on the body.     

Distributed finite-time attitude containment control for multiple rigid bodies

Distributed finite-time attitude containment control for multiple rigid bodies is addressed in this paper. When there exist multiple stationary leaders, we propose a model-independent control law to guarantee that the attitudes of the followers converge to the stationary convex hull formed by those of the leaders in finite time by using both the one-hop and two-hop neighbors’ information. We also discuss the special case of a single stationary leader and propose a control law using only the one-hop neighbors’ information to guarantee cooperative attitude regulation in finite time. When there exist multiple dynamic leaders, a distributed sliding-mode estimator and a non-singular sliding surface were given to guarantee that the attitudes and angular velocities of the followers converge, respectively, to the dynamic convex hull formed by those of the leaders in finite time. We also explicitly show the finite settling time.