平台稳定回路H_∞鲁棒控制设计

平台是一个耦合系统 ,表现在转动惯量耦合和力矩耦合。在设计稳定回路时平台模型与实际物理模型有差别 ,因此要求所设计的控制器具有鲁棒稳定性。 H∞ 控制理论是目前解决鲁棒控制问题比较成功且比较完善的理论体系 ,本文利用 H∞ 控制理论 ,研究了平台稳定回路多输入多输出 ( MIMO)控制器的设计。最后通过计算机仿真 ,验证了控制器的正确性。     

Design and ARM-embedded implementation of a chaotic secure communication scheme based on H.264 selective encryption

Nonlinear Dynamics - In this paper, a novel video chaotic secure communication scheme and its ARM-embedded hardware implementation are investigated, based on the H.264 selective encryption and...     

封闭空间有源弹性壁振动声辐射的鲁棒H∞控制研究

应用H∞控制原理,设计了封闭空间有源弹性壁声辐射有源力控制系统,折衷考虑了系统对外扰力噪声衰减问题和系统参数摄动的鲁棒问题,并对流体声速摄动这一常见情况进行了数值仿真,结果表明,系统对参数摄动具有较强的鲁棒性,同时能有效抑制外扰,与目前较先进的基于自适应滤波的前馈系统相比,具有不需要参考信号,系统相对简单,易于工程实现等优点。∞     

The Design of Structural Design Norms

Abstract

This paper deals with the analysis of prismatic and nonprismatic members with axial restraints, where their material is permitted to be stressed well beyond its elastic limit. This loading on the members causes the modulus of elasticity of the material to vary along their length. The mathematical formulation of this problem, as well as its analysis, is based on the method of equivalent systems that was developed by the first author. This method permits replacement of the original nonlinear member of variable stiffness E^xI^x, with one of uniform stiffness E¹I^l, that has the same length, boundary conditions, and elastic line as the original variable stiffness member. It is proven mathematically that this equivalency exists and that the solution of the equivalent system using linear analysis yields the same results as the solution of the original nonlinear variable stiffness member. Deflections and rotations may be easily obtained using equivalent systems, and the member can be analyzed in both elastic and inelastic ranges, all the way to failure, thus permitting observation of progressive deterioration of the ability of the member to resist load, stress, and de-formation. In this manner, practical critical limits regarding these modes of behavior can be established.     

H13钢氧化磨损行为的研究

采用销盘式磨损试验机,对H13钢在室温、200和400℃和不同载荷条件下进行干滑动磨损试验,研究了钢的磨损行为及磨损机制.结果表明：在室温至400℃之间,200℃时钢的磨损率最低,其次为室温下的磨损率,400℃时磨损率最高.室温下钢的磨损率随载荷的提高而增加,磨损表面氧化物较少,其磨损机制主要为黏着磨损;200℃时的磨损行为极为特殊,随载荷从50增至100 N时,磨损表面出现较厚的氧化物层,故磨损率降低,载荷从100增至200 N时磨损率略提高,且显著低于室温和400℃时的磨损率,呈轻微氧化磨损特征.当环境温度达到400℃时,虽然磨损表面发生了明显的氧化,但随载荷的提高,导致基体塑性变形和热软化,导致磨损表面氧化物层剥落量增大,磨损率提高;当载荷超过150 N后材料的磨损机制由轻微氧化磨损转变为氧化磨损和塑性挤出磨损,磨损率迅速提高,为严重磨损.     

In memory of Professor Ali H. Nayfeh

Nonlinear Dynamics - In this paper, we propose and numerically study a nonlinear, asymmetric, passive metamaterial that achieves giant non-reciprocity with (i) broadband frequency operation and...     

简化杂交应力元H阵的一种方法

本文建议一种简化杂交应力元H阵的方法,可以有效地减少H阵的生成和求逆的计算时间。     

H^∞鲁棒滤波在惯导初始对准中的应用

本给出了惯导系统初始对准的非线性模型,针对一般非线性滤波线性化所引起的模型误差,提出了H^∞鲁棒滤波方法,并与卡尔曼滤波器、二次滤波等方法进行了比较。仿真结果表明,该方法比二次滤波等方法计算量大大减小,精度要高;对于非线性模型,在存在模型误差或噪声不确定情况时,其滤波性能远优于扩展卡尔曼滤波及其它非线性滤波算法。     

惯导系统初始对准的H∞滤波器设计

在对系统的噪声统计特性的了解并不确切的情况下，将H∞滤波技术应用于惯导系统初始对准，对失准角和仪表误差进行估计，克服了传统Kalman滤波器的性能恶化问题。通过对系统频域特性进行整形，有效地抑制了低频干扰对系统误差传播特性的影响，效果优于Kalman滤波。     

Design of a steering control law for an autonomous underwater vehicle using nonlinear $$\mathscr {H}_{\infty }$$ state feedback technique

This paper proposes a new robust nonlinear \(\mathscr {H}_{\infty }\) state feedback (NHSF) controller for an autonomous underwater vehicle (AUV) in steering plane. A three-degree-of-freedom nonlinear model of an AUV has considered for developing a steering control law. In this, the energy dissipative theory is used which leads to form a Hamilton–Jacobi–Isaacs (HJI) inequality. The nonlinear \(\mathscr {H}_{\infty }\) control algorithm has been developed by solving HJI equation such that the AUV tracks the desired yaw angle accurately. Furthermore, a path following control has been implemented using the NHSF control algorithm for various paths in steering plane. Simulation studies have been carried out using MATLAB/Simulink environment to verify the efficacies of the proposed control algorithm for AUV. From the results obtained, it is concluded that the proposed robust control algorithm exhibits a good tracking performance ensuring internal stability and significant disturbance attenuation.