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131.
对一类模有界的参数不确定T-S模糊系统的保性能控制问题进行了分析研究。一个二次指标函数表征了闭环系统的性能。采用分段二次Lyapunov函数(Piecewise quadratic Lyapunov function,PQLF)方法,在使闭环系统渐近稳定的前提下以线性矩阵不等式(Linear matrix inequality,LMI)的形式给出了一种鲁棒最优保性能控制律。同时提出了一种新型分段并行补偿(Parallel distributed compensation,PDC)控制策略。该PDC控制器同样反映了模糊系统前提变量的规则结构信息。数值仿真显示,采用该设计方法所得到的闭环保性能值优于传统二次Lyapunov函数(Common quadratic Lyapunov function,CQLF)方法下的闭环保性能值,且系统动态性能良好,鲁棒性强。 相似文献
132.
Target-enclosing affine formation control of two-layer networked spacecraft with collision avoidance
《中国航空学报》2019,32(12):2679-2693
This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods, the adopted two-layer network structure in this paper is generally directed, which is suitable for practical space missions. Firstly, distributed finite-time sliding-mode estimators and formation controllers in both layers are designed separately to improve the flexibility of the formation control system. By introducing the properties of affine transformation into formation control protocol design, the controllers can be used to track different time-varying target formation patterns. Besides, multi-layer time-varying encirclements can be achieved with particular shapes to surround the moving target. In the sequel, by integrating adaptive neural networks and specialized artificial potential functions into backstepping controllers, the problems of uncertain Euler-Lagrange models, collision avoidance as well as formation reconfiguration are solved simultaneously. The stability of the proposed controllers is verified by the Lyapunov direct method. Finally, two simulation examples of triangle formation and more complex hexagon formation are presented to illustrate the feasibility of the theoretical results. 相似文献
133.
航材消耗的时间序列分析 总被引:2,自引:0,他引:2
本文采用时间序列分析法对某种航材故障率进行预测,用移动平均法消除时间序列的长期趋势和周期变动,然后按月平均法求出季节指数,并对季节指数进行调整,然后根据拟合的趋势方程对此种航材的故障率进行预测.其结果能为航材的可靠性保障提供理论依据. 相似文献
134.
Chaotic characteristics of traffic flow time series is analyzed to further investigate nonlinear characteristics of air traffic system. Phase space is reconstructed both by time delay which is built through mutual information, and by embedding dimension which is based on false nearest neighbors method. In order to analyze chaotic characteristics of time series, correlation dimensions and the largest Lyapunov exponents are calculated through Grassberger-Procaccia (G-P) algorithm and small-data method. Five-day radar data from the control center in Guangzhou area are analyzed and the results show that saturated correlation dimensions with self-similar structures exist in time series, and the largest Lyapunov exponents are all equal to zero and not sensitive to initial conditions. Air traffic system is affected hy multiple factors, containing inherent randomness, which lead to chaos. Only grasping chaotic characteristics can air traffic be predicted and controlled accurately. 相似文献
135.
首先,给出弹目距离与视线角控制的二阶欠驱动系统的标准形式,选取这两个相关的系统状态分别构造滑模平面,滑模面能够保证系统状态的跟踪;然后,选取李雅普诺夫函数,采用李雅普诺夫稳定定理求取最终的控制量,保证两个滑模面渐近稳定,实现对撞击时间与撞击角度的同时控制;最后,在时间控制基本完成后,切换为角度精确控制。 相似文献
136.
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138.
The problem of designing passive fault-tolerant flight controller is addressed when the normal and faulty cases are prescribed. First of all, the considered fault and fault-free cases are formed by polytopes. As considering that the safety of a post-fault system is directly related to the maximum values of physical variables in the system, peak-to-peak gain is selected to represent the relationships among the amplitudes of actuator outputs, system outputs, and reference commands. Based on the parameter dependent Lyapunov and slack methods, the passive fault-tolerant flight controllers in the absence/presence of system uncertainty for actuator failure cases are designed, respectively. Case studies of an airplane under actuator failures are carried out to validate the effectiveness of the proposed approach 相似文献
139.
针对高超声速飞行器的角度与角速度子系统间的耦合控制问题,提出了一种基于耦合特性评价的有限时间模糊控制方案。首先,针对高超声速飞行器的动力学模型,并且考虑到与工程实际相结合,将舵系统引入到动力学模型中,建立了相对完善的动力学模型,通过引入期望指令,建立了面向控制的动力学误差模型。其次,在控制律设计上采用终端滑模设计了有限时间控制器,同时在耦合评价的基础上,为了解决系统对耦合的适应性以及耦合的抖振问题采用了模糊控制方法,并借助于干扰观测器解决外部干扰问题。采用李雅普诺夫稳定性理论证明了所设计的控制律是有限时间稳定性的。在数字仿真过程中,充分考虑了舵系统特性、气动拉偏、控制输入抖动等因素,仿真结果表明该方法是有效的。 相似文献
140.
Target Feedback Loop / Loop Transfer Recovery (TFL/LTR) synthesis and multiobjective optimization are combined to design robust and well performing controllers in a most general sense. A TFL/LTR synthesis based on quadratic stabilization is used to efficiently synthesize robustly stabilizing controllers. Multiobjective optimization is used to tune synthesis parameters for which the TFL/LTR controller yields good performance in addition to robust stability. The technique is demonstrated in the design of a lateral controller for a high performance aircraft in high incidence regime. 相似文献