分层近似粒子滤波及其在陀螺寻北中的应用

针对粒子滤波的粒子退化和匮乏等问题,在粒子滤波和网格近似的基础上,提出了一种采用分层近似策略的粒子滤波改进算法.改进算法利用高斯分布对后验概率密度进行近似,并在连续分布的后验概率密度上进行分层近似,从而获得更具效率的粒子,提高了粒子滤波的精度.光纤陀螺的寻北精度主要取决于光纤陀螺自身的性能以及所采用的寻北方案,将采用分层近似策略的改进粒子滤波算法应用于光纤陀螺的寻北方案中,能够有效地解决光纤陀螺寻北中的非线性状态估计问题,提高光纤陀螺的寻北精度.     

机器人姿态解算算法研究

在机器人惯性导航研究中,针对传统滤波方法在非线性系统模型下误差大的问题,提出了一种基于改进粒子滤波的机器人姿态解算方法。粒子滤波精度较高且不受系统模型非线性程度的影响,与扩展卡尔曼滤波算法相比在非线性系统应用中有巨大的优势。使用扩展卡尔曼滤波对系统状态进行预测,使粒子分布向高似然区移动。对粒子滤波算法的重采样过程进行了改进,提升了算法的效率。不同的地面环境下系统噪声有较大变化,将地面环境信息作为观测信息融合到系统中,对算法参数进行实时修正能够获得更高的精度。实验结果表明,应用此算法进行姿态解算精度较高,且性能优异。     

基于MCMC方法的正则粒子滤波算法及其应用

粒子退化现象是一般粒子滤波无法避免的问题.通过分析该现象产生的原因.提出了将MCMC(马尔可夫链蒙特卡罗)方法应用于正则粒子滤波算法(RPF),与采样重要重采样(SIR)粒子滤波算法比较.此算法不仅克服了粒子退化现象,而且解决了重采样带来的采样枯竭的影响.仿真和实验结果表明:该算法在滤波精度和自适应调整粒子个数方面比SIR粒子滤波有很大的提高.     

微纳卫星陀螺阵列系统信息融合

为了实现微纳卫星MEMS陀螺动态在线滤波,对MEMS陀螺阵列建模,设计可应用于动态过程的最优在线数据融合算法,建立陀螺阵列测试系统,并对融合滤波的陀螺系统的性能对比分析。首先,建立多个陀螺的量测模型。接着基于信息融合模型,使用Kalman滤波算法,对预测的协方差矩阵进无求逆运算迭代;然后,基于误差估计,对动态时变信号滤波模型建模,并给出了融合滤波方法;最后,搭建6个MEMS陀螺在线滤波系统,验证该算法的有效性。实验结果表明：滤波误差可降低为单陀螺采样误差的1/15,精度提高一个数量级;运算量相比层序式滤波减少为1/4,计算时间减少为1/3。本文所提算法在提高精度的基础上,显著提高了MEMS陀螺系统的性能指标,拓展了MEMS陀螺在微纳卫星的应用范围。     

基于智能陀螺经纬仪实现快速初寻北

机械陀螺经纬仪初寻北时间的长短是决定其寻北效率的关键因素.从陀螺仪寻北的原理出发,在智能寻北系统中引入了一种快速寻北新方法--加速度判定法.该方法通过计算光标运动的速度与加速度值,能够在陀螺开始寻北数秒后即测量出真北值,并且能够弥补电子罗盘初寻北精度过低的问题,是全自动寻北策略的重要组成部分.以JT-15陀螺仪为样机的寻北实验表明,将加速度判定法应用于智能寻北系统中,仪器初寻北测量精度优于3′54″,满足了JT-15陀螺仪精寻北的条件要求,保证了全自动寻北的速度和精度,对于机械陀螺的快速及智能化寻北具有现实意义.     

基于改进粒子滤波算法的人眼跟踪方法

针对粒子滤波计算量大、粒子匮乏等问题,提出了2种策略来改进粒子滤波算法,一方面基于Galerkin投影法产生良好的粒子滤波参考分布函数;另一方面将BP神经网络引入粒子滤波,提出了一种提高粒子多样性的重采样策略。在此基础上,将改进的粒子滤波算法应用于人眼跟踪问题,运用颜色和纹理复合的观测模型,实现了人眼的准确跟踪。实验结果表明,改进算法有效提高了粒子滤波的估计精度和运算速度,避免了粒子退化和样本匮乏现象。     

基于动调陀螺的多位置捷联寻北仪研制

为了提高大型光电跟踪设备和惯性导航设备自主定向的性能,根据动调陀螺的工作原理,设计了一种多位置捷联寻北仪。针对多位置捷联寻北系统的数学模型,采用改进的最小二乘拟合算法,对正弦曲线进行参数估计,解算出北向方位角。寻北仪主要由精密位置转台及转位控制系统、惯性测量系统、温度控制系统、数据采集与处理系统及其它配套部件组成。综合考虑寻北时间和寻北精度两个技术指标,进行了时间模式和精度模式的研究和实验。在时间模式下,当寻北精度为35.4″时,寻北时间仅为4.5 min;在精度模式下,当寻北时间为9 min时,寻北精度可达到23.9″。这两项指标均高于国内同类产品。     

一种改进的交互式多模型粒子滤波算法

在实际的目标跟踪与识别的过程中,机动目标的跟踪不仅受非线性和非高斯现象的影响,而且它所采用的交互式多模型粒子滤波算法还存在着粒子权值退化和重要性密度函数选择的问题,导致跟踪误差较大。针对这一问题,提出了一种交互式的多模型的迭代容积粒子算法。该算法通过融合最新量测值产生更加接近系统的真实值,从而使粒子利用率得到进一步的提高。此外为了解决粒子的多样性减少的问题,还引入了MCMC重采样方法。仿真的结果表明,对于机动目标的跟踪与识别,改进的算法的精度要比IMM-PF算法的精度高、误差小,且通过改进的算法得到的重要性密度函数更加接近系统的后验概率分布。     

基于改进模糊推理的光纤陀螺温度漂移建模

光纤陀螺温度漂移建模是实现其温度补偿,提高测量精度的有效手段。通过实测数据分析,验证光纤陀螺的输出受温度和载体角速度的共同作用呈现复杂非线性。为准确描述这种复杂非线性关系以实现温度漂移高精度补偿,基于神经网络设计一种新型光纤陀螺温度漂移模糊系统结构,提出一种基于改进模糊推理的光纤陀螺温度漂移模型辨识新方法。由确定的模型结构设计模糊系统的模糊规则,并基于实测数据构建训练样本以被用于自适应调整变量隶属度函数的参数,从而建立基于误差方均根最小准则的光纤陀螺温度漂移补偿模型。试验结果表明,应用此方法得到的光纤陀螺温度漂移模型具有很高的精度、良好的适用性和预测性能。     

基于改进粒子滤波的非线性系统故障诊断

粒子滤波在非线性系统的故障诊断中,存在着粒子样本退化和突变状态难以跟踪的问题。为此提出一种基于无迹变换和遗传变异改进的粒子滤波算法,通过无迹变换将粒子转移到高似然区域,遗传算法代替重采样消除粒子多样性退化的问题,再利用对数似然函数和作为评价指标来进行故障诊断。仿真实验结果表明,改进的算法可有效提高滤波精度,在连续搅拌反应器变量发生突变时,能够有效、准确地诊断出故障。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.