卡尔曼滤波焊缝跟踪控制

在视觉传感的电弧自动焊接过程中,需要根据视觉信息来控制电弧准确地跟踪焊缝.由于强烈的弧光干扰,使得从焊接区图像中直接提取电弧与焊缝的偏差信息十分困难.为此提出一种利用熔池图像质心和卡尔曼滤波来间接获取电弧与焊缝偏差的方法.选择熔池图像质心作为状态向量,建立基于图像质心的状态方程和焊缝位置测量方程.利用卡尔曼滤波消除过程噪声和测量噪声的影响,通过对熔池图像质心的状态估计,准确获取焊缝位置以及电弧与焊缝之间的偏差量,为自动焊接过程的焊缝跟踪控制提供准确信息.焊接试验结果表明,利用卡尔曼滤波方法可有效降低过程噪声和测量噪声的影响,从而提高焊缝跟踪控制精度.     

基于激光视觉检测的焊缝自动跟踪系统研究

旨在提高焊缝跟踪精度和焊接质量,提出一种基于激光检测自动焊缝跟踪系统。该系统由激光视觉部件、控制器、步进电机和十字滑架组成。当系统工作时,由激光视觉部件检测焊缝的当前位置与目标位置之间的偏差,控制器基于该偏差确定纠偏量,步进电机驱动十字滑架以纠正焊枪横向与纵向位置偏差。搭建出系统物理样机,进行了焊缝跟踪试验。试验结果表明,基于激光视觉检测的焊缝跟踪误差可控制在0. 5 mm 之内,其在精密焊接领域具有较大应用前景。     

基于示教与视觉纠偏的机器人自动焊接方法研究

给出了一种示教与纠偏相结合的焊缝跟踪方法,用于实现机器人的自动焊接．针对传统的示教再现机器人,由激光视觉传感器测量实际路径与示教路径之间的偏差．机器人控制器根据示教路径和偏差,对焊枪的运动方向和位置进行调整,实现焊缝跟踪．利用六自由度机器人和激光结构光视觉传感器设计了实验系统,对所提方法进行了实验．实验结果验证了该方法的有效性．     

含有有色噪声的非线性分数阶系统自适应扩展卡尔曼滤波器

研究了含有未知参数的情况下，分别含有分数阶有色过程噪声和有色测量噪声的连续时间非线性分数阶系统状态估计问题.采用Grünwald-Letnikov （G-L）差分方法和1阶泰勒展开公式，对描述连续时间非线性分数阶系统的状态方程进行离散化和线性化.构造由状态量、未知参数和分数阶有色噪声的增广向量，设计自适应分数阶扩展卡尔曼滤波算法实现对有色噪声情况下的连续时间非线性分数阶系统的状态和参数的估计.最后，通过分析两个仿真实例，验证了提出算法的有效性.     

去相关卡尔曼滤波算法在视频跟踪中的应用

针对测量噪声去相关下的卡尔曼滤波算法在视频目标跟踪中的应用问题展开了研究,首先分析了图像目标质心测量噪声的统计特性,指出测量误差是具有较强相关性的有色噪声;通过提出一种噪声白化方法,将测醋噪声视为在高斯自噪声激励下所产生的一阶马尔科夫序列,并对系统测量模型进行了改进;最后借助噪声去相关虑义下的卡尔曼滤波算法对所拍摄的航模飞机视频图像进行了跟踪仿真测试.仿真实验结果证明所给出的滤波算法可以明显提高目标位置的估计精度,并有效抑制了背景的干扰.     

含有分数阶有色关联噪声的分数阶系统的卡尔曼滤波器设计

提出基于Tustin生成函数的分数阶卡尔曼滤波器设计方法,以解决含有相互关联的分数阶有色过程噪声和分数阶有色测量噪声的连续时间线性分数阶系统的状态估计问题.通过Tustin生成函数方法,对连续时间线性分数阶系统进行离散化,将分数阶系统的微分方程转化为差分方程.利用增广向量法,将分数阶状态方程和分数阶有色噪声作为新的增广状态向量,从而将分数阶有色噪声转化为高斯白噪声.然后,提出一种基于Tustin生成函数的分数阶卡尔曼滤波算法,有效地实现对含有相互关联的分数阶有色过程噪声和分数阶有色测量噪声的连续时间线性分数阶系统的状态估计.与基于Grddotunwald-Letnikov差分的离散化方法相比,所提出的基于Tustin生成函数的卡尔曼滤波算法得到的状态估计精度更高,状态估计效果更好.最后,通过仿真结果验证所提出算法的有效性.     

焊接机器人焊缝自动跟踪系统

本文提出了一种焊接机器人焊缝自动跟踪系统用以实现焊枪对焊缝的实时自动跟踪。系统中应用激光焊缝传感器测量焊缝的位置,并采用Fuzzy-P双模分段控制进行焊缝的纠偏。DSP作为系统的核心控制器产生控制信号,驱动焊枪横向步进电机和纵向步进电机动作,调整焊枪实时跟踪焊缝。实验证明,基于双模控制的焊缝自动跟踪系统可以实现焊接机器人焊枪对焊缝的实时自动跟踪。该系统完全满足实际焊接工程的需要。     

基于鲁棒H∞滤波的蓄电池荷电状态估计

针对蓄电池系统的荷电状态(SOC)受蓄电池材料及加工制作、工作温度、充放电大小及频率等因素的影响,是一个典型的非线性时变系统,相应的状态估计模型在测量过程中存在噪声干扰引起模型参数不确定性的特征。以安时法为基础,建立SOC的状态方程并应用鲁棒H∞滤波算法预测SOC估计值。仿真研究表明,提出的鲁棒H∞滤波算法在有色噪声干扰下比卡尔曼滤波(Kalman filter)有更好的估计精度;在白噪声情况下,鲁棒H∞滤波算法可通过调节其参数达到和卡尔曼滤波器相同的估计精度。     

基于双模控制的焊接机器人焊缝自动跟踪系统

该文提出了一种基于双模控制的焊接机器人焊缝自动跟踪系统.系统中应用新一代激光焊缝传感器测量焊缝的位置,并采用Fuzzy-P双模分段控制进行焊缝的纠偏.系统中采用DSP作为核心控制器产生控制信号,驱动焊枪横向步进电机和纵向步进电机动作,实现焊接机器人焊枪对焊缝的实时自动跟踪.实验证明,基于双模控制的焊缝自动跟踪系统可以实现焊接机器人焊枪对焊缝的实时自动跟踪.该系统完全满足实际焊接工程的需要.     

利用混合卡尔曼滤波的混沌信号盲估计

针对混沌动力学系统时变参数未知的混沌信号,在含有状态噪声的情况下,利用混合卡尔曼滤波提出一种盲估计算法.对未知参数和混沌状态构成的高维状态进行估计,先利用卡尔曼滤波给出线性高斯部分的最优精确估计,剩余部分利用粒子滤波方法给出次优估计,文中详细研究了高斯噪声以及非高斯噪声下的最优重要性函数选取并推导了重要性权重的计算公式,最终基于有效粒子的最小均方误差准则实现了信号的盲估计.仿真结果表明该算法能有效实现含有状态噪声混沌信号的盲估计,并取得了比基本粒子滤波算法更优的性能.     

Kalman Filters for Continuous-time Fractional-order Systems Involving Fractional-order Colored Noises Using Tustin Generating Function

This study presents fractional-order Kalman filers for linear fractional-order systems with colored noises using Tustin generating function. A continuous-time fractional-order system with the fractional-order colored process noise is discretized by Tustin generating function. The augmented vector consists of the state and the colored noise is offered to construct an augmented system based on the discretized state equation of a fractional-order system and the colored process noise. The Tustin fractional-order Kalman filter is designed based on the augmented system to obtain the state estimation, effectively. Besides, the colored noise involved in the measurement of a continuous-time fractional-order system is also discussed, and the corresponding Tustin fractional-order Kalman filter is provided in this study. Two illustrative examples are given to verify the effectiveness of Tustin fractional-order Kalman filters for the colored process and measurement noises.     

Critical Issues on Kalman Filter with Colored and Correlated System Noises

The Kalman filtering (KF) is optimal under the assumption that both process and observation noises are independent white Gaussian noise. However, this assumption is not always satisfied in real‐world navigation campaigns. In this paper, two types of KF methods are investigated, i.e. augmented KF (AKF) and the second moment information based KF (SMIKF) with colored system noises, including process and observation noises. As a popular noise‐whitening method, the principle of AKF is briefly reviewed for dealing with the colored system noises. The SMIKF method is developed for the colored and correlated system noises, which directly compensates for the covariance through stochastic model in the sense of minimum mean square error. To accurately implement the SMIKF, a refined SMIKF is further derived regarding the continuous‐time dynamic model rather than the discrete one. The computational burdens of the proposed SMIKF along with representative methods are analyzed and compared. The simulation results demonstrate the performances of proposed methods.     

基于无迹卡尔曼滤波的旋转倒立摆LQR控制

LQR控制器在含有系统噪声与量测噪声的旋转倒立摆系统应用中,难以获得精确的状态向量实现对系统的最优控制.为了提高LQR的控制精度,引入了无迹卡尔曼滤波(UKF)状态观测器,以获得系统的最优状态估计量,实现基于动态规划的自抗扰二次型最优反馈控策略.与卡尔曼滤波(KF)相比,UKF用于非线性系统的状态估计的主要优势是不需要线性化去计算状态转移矩阵,避免了系统线性化带来的模型误差.在含有系统噪声与量测噪声的旋转倒立摆仿真模型下,对基于KF和UKF的LQR控制器进行了仿真对比分析.仿真结果表明,UKF对系统响应时间、控制精度、鲁棒性的优化效果更好.     

双队列控制的激光视觉焊缝跟踪系统研究

设计与实现了一套激光视觉引导的焊缝自动跟踪系统,包括系统的整体硬件构成和关键算法。在工业机器人末端安装激光视觉传感器构成焊缝跟踪系统的硬件部分。采用小波变换滤除焊缝图像噪声,采用改进的Steger算法和Hough变换方法提取激光条纹中心直线,进一步提取出焊缝位置。提出一种双队列控制策略,在采集的焊缝特征点的基础上进一步插值,从而实现激光视觉引导的焊缝自动与平滑跟踪。实验结果表明,该系统具有较好的跟踪精度,能满足工业实际需求。     

Estimation of wiener nonlinear systems with measurement noises utilizing correlation analysis and Kalman filter

This paper is concerned with parameter estimation of Wiener systems with measurement noises employing correlation analysis method and adaptive Kalman filter. The presented Wiener system consists of two series blocks, that is, a dynamic block represented by auto-regressive moving average (ARMA) model, and static nonlinear block established by neural fuzzy model. Aim at estimating separately the two blocks, the separable signals are introduced. First, applying the separable signals to decouple the identification of linear dynamic block from that of static nonlinear block, then ARMA model parameters are estimated employing correlation function-based least squares principle. Moreover, aiming at handle with error caused by colored measurement noise, adaptive Kalman filter technique and cluster method are introduced to estimate parameter of the nonlinear block and noises model, enhancing parameter estimation precision. The accuracy and applicability of estimated scheme presented are verified through numerical simulation and nonlinear process, the results demonstrate that it is feasible for estimating the Wiener systems in the presence of colored measurement noises.     

Improved IMM Filter for Tracking a Highly Maneuvering Target with Mixed System Noises

We propose a method of improving tracking filter performance of a highly maneuvering target with mixed system noises in this paper. A case study of an off-road high speed moving target is considered. The system noises consist of white Gaussian noises generated from target motion models and additional colored noises arising from the effect of rough and uneven terrain profile. we design the colored noise first order discrete Markov dynamic system representing terrain conditions. Tracking is done by using an IMM filter with discrete white noise acceleration and horizontal coordinated turn models. The designed colored noise dynamic model is augmented with each of the motion models. We use Kalman filter for linear DWNA model while extended and unscented Kalman filters are used for nonlinear HCT model. A test scenario is setup and simulations are carried out. For filter performance comparison purposes, two more cases are considered i.e., systems with white noncorrelated system noises and the system correlated noise cases. Results show that the proposed method outperforms the traditional error treatment methods in terms of robustness, small mean square error, and acceptable computation load and data processing time.     

带未知有色观测噪声的自校正融合Kalman滤波器

对于带未知有色观测噪声的多传感器线性离散定常随机系统, 未知模型参数和噪声方差的一致的融合估值器用递推增广最小二乘法(RELS)和求解相关函数方程得到. 将这些估值器代入到最优解耦融合Kalman滤波器中, 得出了自校正解耦融合Kalman滤波器, 并用动态方差误差系统分析(DVESA)和动态误差分析(DESA)方法证明了它收敛于最优解耦融合Kalman滤波器, 因而具有渐近最优性. 一个带3传感器跟踪系统的仿真例子说明了其有效 性.