压电分流阻尼电路设计的极点配置方法

针对作为被动控制的压电分流阻尼电路提出极点配置方法。对压电分流阻尼系统建立机电耦合方程,考虑模态位移为输出量,得到系统极点的特征方程。运用主导极点与虚轴的距离对系统动态响应衰减有着关键作用这一特性,确立优化目标,然后求解出压电分流阻尼电路参数的最优值。最后通过数值仿真对所设计的优化方法进行检验,并与传统传递函数优化法进行比较。仿真结果表明,运用极点配置方法设计的压电分流电路有着良好的抑制振动的效果,这验证了极点配置方法的有效性。     

基于T-S模糊模型的倒立摆

用牛顿力学方法建立了直线一级倒立摆的非线性数学模型,并基于倒立摆系统的状态方程,用Matlab对系统进行定性分析。采用极点配置法、LQR设计了控制器,并分析了参数对系统控制的影响。针对倒立摆的非线性,研究了非线性控制方法中变结构控制的基本思想,并设计了控制器。     

线性微分多项式的零点与极点

对Frank-Weissenborn不等式中导数f~((k))能否被替换成一般的线性微分多项式a_0f+a_1f′+…+a_kf~((k))进行了研究,并彻底解决了这一问题.作为此结果的应用,Hayman-Yang不等式等几个已有的定理也得到了推广.例子表明,本文所得到的几个不等式的条件是基本的.     

亚纯函数的正规族

关于正规族的Hayman猜测目前已完全证实,本文考虑把Hayman猜测中的 f′换为一般的f∧（k）,得到一个更为一般的结果,由此改进和推广了陈怀惠,顾永兴、华歆厚,庞学诚与W.Schwick的相应结果。     

Tachyon Pole in σ Meson Propagator in Nuclear Matter in the Relativistic σ—ω Model

The conditions that the tachyon pole of the σ meson propagator in nuclear matter appears are studied in the one-loop approximation in the relativistic σ-ω model.Different from the results of the previous paper,we find that the effect of the constant a in the self-interaction,U(σ)=aσ 1/2! bσ^2 1/3!cσ^3 1/4!dσ^4,of the σ meson cannot be neglected.It determines the critical density where techyon appears.The smaller the a,the larger the critical density.The binding energy,pressure,incompressibility coefficient,nucleon effective mass are calculated and the relation between parameters to the tachyon pole is also studied.     

Partial pole placement with time delay in structures using the receptance and the system matrices

Datta et al. solved the partial pole placement problem for the symmetric definite quadratic eigenvalue problem where part of the spectrum is relocated to predetermined locations and the rest of the spectrum remains unchanged. In this paper, the problem is solved by a hybrid combination of this result and the method of receptances. This allows for the partial assignment of desired poles with no spillover when there is time delay between the measured or estimated state and actuation of the control.     

倒立摆状态反馈极点配置与LQR控制Matlab实现

为了实现对绝对不稳定的非线性多变量倒立摆系统的控制,采用了状态反馈极点配置和LQR控制2种方法。状态反馈极点配置是将多变量系统的闭环系统极点配置在期望的位置上,从而使系统满足瞬态和稳态性能指标。LQR算法是在一定的性能指标下,利用最少的控制能量,来达到最小的状态误差。通过Matlab软件仿真实验,发现2种控制方法对于倒立摆这种不稳定的系统有一定的控制作用,证明了两种控制方案的可行性和有效性。仿真表明二次型最优控制有较小的振荡和超调量,对系统有更好的控制效果。     

碳化硅凸非球面反射镜的加工与检测

为了满足凸非球面反射镜加工中的全频段质量控制及光学参数的高精度检验,提出了应用双摆轴极坐标快速非球面加工技术及测杆法控制Hindle法检测光学参数。首先,描述了双摆轴极坐标快速非球面加工技术及设备;然后,介绍了应用测杆法控制Hindle检测法中标准球面镜顶点分别与被检非球面镜顶点及其焦点的光学间隔,并对其控制精度进行了分析;最后,针对Φ158mm的凸非球面,给出了双摆轴加工的检验结果,并对检测精度进行了分析。实验结果表明：应用双摆轴加工工艺在使低频误差快速收敛的同时,可以有效抑制中频误差,其低频误差的控制精度可以稳定地达到λ/30（λ=633 nm）;应用测杆装调Hindle检测光路的控制极限误差为±0.065 mm,两个光学间隔参数的公差分别为±0.22 mm和±0.30 mm。应用双摆轴加工技术实现了凸非球面的快速加工与全频段质量控制,采用Hindle检测凸非球面得到面形精度为0.022λ（RMS,@633 nm）,满足光学设计技术指标要求。     

On the q-Bernstein polynomials of rational functions with real poles

The paper aims to investigate the convergence of the q  -Bernstein polynomials _Bn,q(f;x)$B_{n,q}(f;x)$ attached to rational functions in the case q>1$q>1$. The problem reduces to that for the partial fractions (x−α)^−j${(x-\alpha )}^{-j}$, j∈N$j\in \mathbb{N}$. The already available results deal with cases, where either the pole α   is simple or α≠q^−m$\alpha \ne q^{-m}$, m∈_N0$m\in {\mathbb{N}}_0$. Consequently, the present work is focused on the polynomials _Bn,q(f;x)$B_{n,q}(f;x)$ for the functions of the form f(x)=(x−q^−m)^−j$f(x)={(x-q^{-m})}^{-j}$ with j?2$j?2$. For such functions, it is proved that the interval of convergence of {_Bn,q(f;x)}$\{B_{n,q}(f;x)\}$ depends not only on the location, but also on the multiplicity of the pole – a phenomenon which has not been considered previously.