最大类间方差法在寻北仪信号降噪中的应用

在分析了陀螺噪声信号的特点以及现有去除陀螺噪声方法的基础上,将最大类间方差法应用到陀螺寻北仪输出信号的滤波处理中,从而有效地减小了信号中的高频噪声,提高了信噪比,抑制了陀螺仪的漂移.介绍了该方法的原理与实现过程,并结合陀螺寻北仪的实地振动实验,对陀螺寻北仪的实测数据进行了分析研究,证明了使用该方法对陀螺寻北仪输出信号进行滤波处理的可行性和有效性.     

积分法在智能陀螺寻北系统中的应用研究

寻北方法是陀螺寻北仪的重要研究对象。在分析智能陀螺寻北系统的光路及采集系统基础上,对积分法进行了深入的理论分析,并讨论了其在智能寻北系统中的应用研究。利用JT—15型陀螺寻北仪,分别用中天法和积分法进行了寻北测量的对比实验,中天法测量的标准偏差不超过11,″积分法测量的标准偏差不超过9″。实验结果表明:积分法可以得到比中天法高的测量精度,在全自动智能寻北系统中可替代中天法进行寻北测量。     

3/4周期中天法的陀螺智能寻北

陀螺仪寻北的中天法一次测量需要一个完整的陀螺摆动周期,需时较长,已不能适应现代测量需要。在传统中天法的基础上,提出了3/4周期中天法,并给出了3/4周期中天法的原理和推导公式。完成了传统中天法与3/4周期中天法应用于JT15陀螺仪上的精度对比实验。实验表明:3/4周期中天法在基本保持中天法测量精度的情况下,可以有效地缩减中天法的寻北时间。说明了欠周期中天法寻北测量的可行性,从而为提高寻北效率找到了一条有效的途径。     

一种实用的激光陀螺寻北仪数据处理技术

本文针对车载环境下单位置激光陀螺寻北仪的输出信号进行了分析处理,设计了FIR低通数字滤波器抑制高频扰动,设计了一种利用加速度计进行陀螺误差补偿的低频扰动的抑制算法。Matlab仿真结果表明,本文的方法能够有效地抑制扰动,提高寻北仪寻北精度。     

旋转调制寻北方法的误差研究

采用一个陀螺和一个加速度计可以组成最简单的旋转调制式寻北仪.影响寻北仪寻北精度的误差源有很多,不同误差源对寻北精度有着不同程度的影响.为了研究引起寻北误差的主要误差源对寻北结果的影响,对提出的寻北仪三种方法(二位置、四位置、连续旋转)的公式进行了推导,并采用MATLAB进行了仿真.仿真结果表明,影响寻北仪寻北精度的主要误差源为:初始航向角、陀螺常值漂移、采样时间、转位误差、转台旋转速率(连续旋转方法)、台面倾斜角等.结果可为寻北仪的优化研制提供了理论依据.     

一种实用的激光陀螺寻北仪数据处理技术

本文针对车载环境下单位置激光陀螺寻北仪的输出信号进行了分析处理，设计了FIR低通数字滤波器抑制高频扰动，设计了一种利用加速度计进行陀螺误差补偿的低频扰动的抑制算法。Matlab仿真结果表明，本文的方法能够有效地抑制扰动．提高寻北仪寻北精度。     

基于FFT的陀螺寻北仪误差补偿

传统提高陀螺寻北仪精度的方法主要是选用高精度陀螺、提高转位精度、增加转位数、通过数字滤波消除外界干扰等,这些方法大多针对寻北仪的某方面误差因素进行改进,而对寻北仪整体的误差特性研究较少。通过对陀螺寻北仪综合误差特性的分析,提出了基于快速傅立叶变换(FFT)的寻北仪误差补偿方法。该方法首先测量出寻北仪的整周误差,然后通过求取FFT系数完成对寻北仪的系统级误差补偿,该方法尤其对寻北仪制造过程中的结构误差和测量元件的常值漂移残差具有良好的补偿效果。经产品验证可以在保持现有陀螺和转位精度不变的情况下,提高寻北精度3倍以上,具有良好的工程实用价值。     

光纤陀螺动态寻北转位控制系统设计

针对光纤陀螺动态寻北仪实际应用中存在的转位误差以及高频测量噪声问题,对寻北仪转位机构引入低通滤波和反馈回路,设计出了一种新的转位控制系统,有效地减小了由于光纤陀螺和转位机构的误差带来的系统误差,从而提高了动态寻北仪的寻北精度;实验结果表明,相同条件下该控制系统能有效缩短寻北时间,提高定位精度至4″,具有较好工程实用前景。     

陀螺灵敏部的精密升降定位控制

设计了基于微型旋转步进电机的陀螺灵敏部精密定位测量控制的结构,采用最优化升降速原则,实时精确定位,实现步进电机的稳态运行控制,并实现陀螺灵敏部下放时精确的位置和速度控制,时间短,效率高,克服了人工下放、托起陀螺房带来的耗时和不稳定性.实验结果表明:应用步进电机自动精确定位可以控制陀螺灵敏部摆幅为53′～139′,陀螺仪实现精密的寻北特性,寻北重复性定位精度达到8″.     

基于抗差估计的快速动态寻北算法

陀螺寻北仪是一种精确、快速测定真北方位的仪器.主要特点是:定向精度高、测量时间短、在任何时间和地点(高纬度地区除外)都可以自主定向.然而,陀螺寻北仪易受异常因素影响,而使定向观测值产生异常.采用旋转调制方法,研究了以动调陀螺为角速率传感器的全姿态寻北仪.为了削弱动调陀螺的噪声对寻北精度的影响,基于抗差估计原理构造了高崩溃污染率的初值辅以IGGⅢ方案迭代解算的混合算法.计算结果表明:基于可靠初值和稳定均方差因子估值的抗差估计可以有效削弱异常干扰的影响.测试结果显示,在4 min之内系统的寻北精度优于1.5 ',远高于最小二乘估计得到的精度.     

Overview of damped least-squares methods for inverse kinematics of robot manipulators

In this paper, we present a tutorial report of the literature on the damped-least squares method which has been used for computing velocity inverse kinematics of robotic manipulators. This is a local optimization method that can prevent infeasible joint velocities near singular configurations by using a damping factor to control the norm of the joint velocity vector. However, the exactness of the inverse kinematic solution has to be sacrificed in order to achieve feasibility.The damping factor is an important parameter in this technique since it determines the trade-off between the accuracy and feasibility of the inverse kinematic solution. Various methods that have been proposed to compute an appropriate damping factor are described.Redundant manipulators, possessing extra degrees of freedom, afford more choice of inverse kinematic solutions than do non-redundant ones. The damped least-squares method has been used in conjunction with redundancy resolution schemes to compute feasible joint velocities for redundant arms while performing an additional subtask. We outline the different techniques that have been proposed to achieve this objective. In addition, we introduce an iterative method to compute the optimal damping factor for one of the redundancy resolution techniques.     

球极平面逆投影迭代谱聚类算法

提出一种相似矩阵迭代修正并聚类算法, 分为偏振定理的谱分离数据和球极平面逆投影的几何分离数据两步. 首先将数据谱分解, 得到低维距离矩阵; 然后投影到双随机矩阵, 隐式进行一次球极平面逆投影, 几何对称分离数据; 最后解算投影后坐标, 得到新相似矩阵. 实验在人工合成数据和自然数据上进行, 结果表明所提出算法修正了数据的相似度, 并获得了正确的聚类个数, 对尺度参数变化有较强的鲁棒性, 聚类性能比修正前有较大提升.

     

一类离散时间代数Riccati矩阵方程对称解的双迭代算法

利用逆矩阵的Neumann级数形式,将在线性二次优化问题中遇到的含未知矩阵之逆的离散时间代数Riccati矩阵方程(DTARME)转化为高次多项式矩阵方程,然后采用牛顿算法求高次多项式矩阵方程的对称解,并采用修正共轭梯度法求由牛顿算法每一步迭代计算导出的线性矩阵方程的对称解或者对称最小二乘解,建立求DTARME的对称解的双迭代算法。双迭代算法仅要求DTARME有对称解,不要求它的对称解唯一,也不对它的系数矩阵做附加限定。数值算例表明双迭代算法是有效的。     

Predicting audio step feedback for real walking in virtual environments

When navigating in virtual environments by using real walking, the correct auditory step feedback is usually ignored, although this could give more information to the user about the ground he is walking on. One reason for this is time constraints that hinder a replay of a walking sound synchronous to the haptic step feedback when walking. In order to add a matching step feedback to virtual environments, this paper introduces a calibration‐free system, which can predict the occurrence time of a step‐down event based on an analysis of the user's gait. For detecting reliable characteristics of the gait, accelerometers and gyroscopes are used, which are mounted on the user's foot. Because the proposed system is capable of detecting the characteristic events in the foot's swing phase, it allows a prediction that gives enough time to replay sound synchronous to the haptic sensation of walking. In order to find the best prediction regarding prediction time and accuracy, data gathered in an experiment is analyzed regarding reliably occurring characteristics in the human gait. Based on this, a suitable prediction algorithm is proposed. Copyright © 2014 John Wiley & Sons, Ltd.     

An iterative design procedure for the synthesis of generalized dual‐bandpass filters

This article presents an iterative design technique to calculate the optimal position of transmission zeros in dual‐bandpass filters. In the proposed design technique, the characteristic function of the filter is linearized around the displacement of the transmission zeros. A linear system is then obtained and solved in combination with a damping technique used to guarantee the convergence. Design examples which demonstrate the efficiency of the proposed method are presented and an experimental verification at 4 GHz using open‐loop resonators validates the methodology. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

LTE-A系统中基于QoE能效的无线资源分配算法

针对无线通信网络能耗日益增加与用户体验质量(quality of experience,QoE)难以得到保证的问题,提出一种LTE-A系统基于QoE能效的资源分配算法。首先,给出联合优化QoE和能效的数学模型,特别的考虑了用户最小QoE要求;其次,根据约束条件提出了一种迭代算法进行用户资源块(resource block,RB)分配,然后利用分数规划的性质并采用凸优化方法求得最优的发射功率来优化目标函数。仿真结果表明,相较现有基于能效的资源分配算法,该算法在提高系统性能的同时有效的保证了用户QoE。     

Vibration sensitivity analysis of MEMS vibratory ring gyroscopes

This paper presents a detailed model for possible vibration effects on MEMS degenerate gyroscopes represented by vibratory ring gyroscopes. Ring gyroscopes are believed to be relatively vibration-insensitive because the vibration modes utilized during gyro operation are decoupled from the modes excited by environmental vibration. Our model incorporates four vibration modes needed to describe vibration-induced errors: two flexural modes (for gyro operation) and two translation modes (excited by external vibration). The four-mode dynamical model for ring gyroscopes is derived using Lagrange's equations. The model considers all elements comprising a ring gyroscope, namely the ring structure, the support-spring structures, and the electrodes that surround the ring structure. Inspection of this model demonstrates that the output of a ring gyroscope is fundamentally insensitive to vibration due to the decoupled dynamics governing ring translation versus ring flexure, however, becomes vibration-sensitive in the presence of non-proportional damping and/or capacitive nonlinearity at the sense electrodes.     

基于功率控制的大规模MIMO系统能效优化算法

能效优化是5 G通信领域的一个研究热点.首先针对单小区多用户上行大规模MIMO通信系统,在满足用户QoS需求和系统可容忍的信道有效噪声条件下,建立关于发射功率、导频序列长度、基站天线数的能效优化模型;其次,不同于传统利用迭代算法求解使系统能效最佳的基站天线数,提出了采用Lambert W函数分析得到最佳基站天线数的闭式表达式;最后根据分式规划理论,采用迭代优化算法联合优化系统导频序列长度、发射功率、基站天线数.仿真结果表明,该算法较现有算法能效提高了11.2％,说明该算法能有效提高系统性能.     

雅克比矩阵近似更新的三维装配约束求解研究

提出了三维装配约束求解中雅克比矩阵近似更新的方法。该方法通过对 迭代过程中满秩以及行秩秩亏雅克比矩阵进行近似更新,提高了约束求解的效率。首先在非 线性迭代求解过程中添加雅克比矩阵及其逆矩阵近似更新的公式;然后给出使用近似更新公 式需要满足的限制条件;最后通过对奇异点扰动算法的描述介绍迭代求解过程中雅克比矩阵 发生行秩秩亏的处理办法。文中提出的策略与算法已在三维装配约束求解引擎CBABench 中实现,给出的实例表明本文提出的方法效果显著。     

Schröder-like algorithms for multiple complex zeros of a polynomial

Using the iterative method of Newton's type in circular arithmetic, introduced in [14], a new iterative method for finding a multiple complex zero of a polynomial is derived. This method can be regarded as a version of classical Schröder's method. Initial conditions which guarantee a safe convergence of the proposed method are stated. The increase of the computational efficiency is achieved by a combination of the complex approximation methods of Schröder's type with some interval methods. The presented algorithms are analysed in view of their efficiency and illustrated numerically in the example of a polynomial equation.