鱼雷耦合非线性系统的线性控制方法

给出了鱼雷空间运动的数学模型;在流形上研究了非线性系统的线性化系统可控时的镇定问题,给出了线性控制规律使非线性控制系统镇定于原平衡点的条件;基于线性化拓扑等价性定理,将鱼雷三通道的非线性模型进行等价变换,利用传统的线性设计方法和多变量控制方法分别去处理鱼雷耦合非线性系统的控制问题,从而降低了多通道耦合控制设计问题的难度和复杂性。     

A model to design recreational boat mooring fields

This article develops a mathematical model and heuristic algorithm to design recreational boating mooring fields. The boating industry is important to the Florida economy, and boat storage is becoming a concern among those in the industry. The mooring field design problem is formulated to maximize the total number of boat feet moored in the mooring field. In the model, we allow two adjacent moorings to overlap, which introduces a risk that under certain conditions the boats on these moorings could contact each other. We identify the conditions when contact is possible and quantify the probability of contact. The mooring field design problem is formulated as a nonlinear mixed‐integer programming problem. To solve the problem, we decompose it into two separate models, a mooring radii assignment model and a mooring layout model, which are solved sequentially. The first is solved via exhaustive enumeration and the second via a depth‐first search algorithm. Two actual mooring fields are evaluated, and in both cases our model leads to better layouts than ones experts developed manually. The mooring field design model rationalizes the mooring field design and shows that in one case by increasing the risk from 0 to 1%, the mooring efficiency increases from 74.8% to 96.2%. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

滚动轴承外圈缺陷非线性动力学分析

为揭示故障轴承系统复杂的非线性动力学特征,建立了基于轴承外圈缺陷、接触非线性和间隙非线性的轴承系统非线性动力学微分方程,并采用数值方法对其求解,得到转子系统在不同转速、不同缺陷程度、不同阻尼下的相图、庞加莱图、分岔图等。研究结果表明,转速和缺陷程度是影响轴承系统非线性动力学特性的重要因素,随着转速和缺陷程度的不同,系统会产生周期、拟周期和混沌等多种非线性行为。     

基于状态观测器的混沌系统鲁棒同步设计

研究了在有界干扰情况下一类非线性反馈混沌系统的鲁棒同步状态观测器设计问题。基于Sylvester矩阵方程的参数化解,将非线性反馈混沌系统的鲁棒同步状态观测器设计问题转化为带有约束条件的优化问题,通过解决该优化问题得到鲁棒同步状态观测器的增益矩阵,从而达到了干扰信号解耦目的。数值算例及其仿真结果表明:该非线性反馈混沌系统的鲁棒同步状态观测器的设计方法是简单有效的。     

Dynamic evacuation routes for personnel on a naval ship

We propose a dynamic escape route system for emergency evacuation of a naval ship. The system employs signals that adapt to the causative contingency and the crew's physical distribution about the ship. A mixed‐integer nonlinear programming model, with underlying network structure, optimizes the evacuation process. The network's nodes represent compartments, closures (e.g., doors and hatches) and intersections, while arcs represent various types of passageways. The objective function integrates two potentially conflicting factors: average evacuation time and the watertight and airtight integrity of the ship after evacuation. A heuristic solves the model approximately using a sequence of mixed‐integer linear approximating problems. Using data for a Spanish frigate, with standard static routes specified by the ship's designers, computational tests show that the dynamic system can reduce average evacuation times, nearly 23%, and can improve a combined measure of ship integrity by up to 50%. In addition, plausible design changes to the frigate yield further, substantial improvements. Published 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008     

坦克炮控伺服系统的滑模非线性摩擦补偿控制

坦克炮控伺服系统存在低速摩擦,摩擦环节不但造成系统的稳态误差,而且导致极限环振荡、低速爬行等现象.提出基于Lyapunov稳定理论的滑模控制方法,通过 Lyapunov稳定理论获得控制量,同时克服参数不确定性和补偿非线性摩擦力矩,从而保证跟踪误差渐进收敛.仿真结果表明该设计方法大大优于经典设计,为炮控伺服系统实际设计提供了一种可行的新方法.     

NORX算法中非线性组件的移位参数选取准则研究

NORX算法是进入凯撒竞赛第三轮的15个认证加密候选算法之一,该算法的唯一非线性组件由异或、与和移位操作组成.从非线性逼近和循环分析两个密码学性质研究移位参数的选取准则,证明了可变移位函数的非线性逼近概率为三值函数,并得到了移位参数取1时具有最佳的非线性逼近性质;给出了可变移位函数的循环概率表达式,并证明了对于任意非零...