电磁兼容技术在汽车嵌总线中的应用

用电磁兼容的设计理论分析了汽车中电子设备受电磁干扰的现象及危害性，对汽车嵌总线系统的PCB 板、总线进行了电磁兼容设计，并提出新的滤波电路及连接方法，能解决汽车嵌总线系统的抗干扰问题，达到良好的效果。     

Optimal and self‐tuning weighted measurement fusion Kalman filters and their asymptotic global optimality

For the multisensor linear discrete time‐invariant stochastic systems with unknown noise variances, using the correlation method, the information fusion noise variance estimators with consistency are given by taking the average of the local noise variance estimators. Substituting them into two optimal weighted measurement fusion steady‐state Kalman filters, two new self‐tuning weighted measurement fusion Kalman filters with a self‐tuning Riccati equation are presented. By the dynamic variance error system analysis (DVESA) method, it is rigorously proved that the self‐tuning Riccati equation converges to the steady‐state optimal Riccati equation. Further, by the dynamic error system analysis (DESA) method, it is proved that the steady‐state optimal and self‐tuning Kalman fusers converge to the global optimal centralized Kalman fuser, so that they have the asymptotic global optimality. Compared with the centralized Kalman fuser, they can significantly reduce the computational burden. A simulation example for the target tracking systems shows their effectiveness. Copyright © 2010 John Wiley & Sons, Ltd.     

A torque estimator-based control strategy for oil-well drill-string torsional vibrations active damping including an auto-tuning algorithm

Considerable compliance of the lengthy oil-well drill string combined with low tool inertia and stick-slip friction between the tool and the rock bed causes notable undesired torsional vibrations of the drill-string electrical drive. In order to attenuate the torsional vibrations and, thus, improve both the quality and the productivity of the drilling process, an automatically tuned active damping control strategy based on drill-string torque estimation is proposed in the paper. The core of the strategy includes a proportional-integral (PI) controller extended with estimator-based drill-string torque feedback loop. Furthermore, an appropriate algorithm that prevents drill-string back-spinning caused by the limited braking power of the power converter is presented. Finally, an auto-tuning algorithm is proposed, which is built around an adaptive Kalman filter-based estimator of drill-string drive natural frequencies. The drill-string control strategy is verified experimentally using a drill string hardware-in-the-loop setup under the laboratory conditions, as well as on an actual oil-drilling rig.     

Fabric filter bag investigation following field testing of sorbent injection for mercury control at TXU's Big Brown Station

Field testing of mercury control sorbent injection options with a TOXECON™ configuration has been completed at TXU's Big Brown Station. Mercury control results at Big Brown were promising and have been previously reported. However, the high air-to-cloth ratio of operations at this unit results in significant differential pressure, and thus there was little operating margin before differential pressure limits were encountered, especially at high loads. This limited the use of sorbent injection as the added material contributes to the overall differential pressure. After field testing, the residual differential pressure across the test fabric filter module had increased relative to baseline conditions to the point that the plant performed a filter change of the test module several months ahead of schedule. An investigation was conducted on pre- and posttest filter samples from the test module and a parallel nontest module to examine the effect of activated carbon injection. Analysis of the samples indicates an increase in residual dust embedded in the filters which appears to explain the low fabric permeabilities. The long-term increase in differential pressure did not appear to be associated with activated carbon injection, but instead was due to a gradual buildup of embedded material on the filters that was not cleaned away by the pulse cleaning system. The injected activated carbon appeared to behave like additional fly ash in terms of baghouse differential pressure but did not appear to accelerate the buildup of residual material.     

利用滤波理论建立设备预测维修的优化模型

利用滤波理论建立设备预测维修的优化模型，通过状态空间模型建立状态监测信息和元件的剩余寿命之间的关系，然后，根据卡尔曼滤波预测和更新设备剩余珠概率分布函数。在此基础上，建立了一个费用模型，确定出合理的维修时机，使得单位时间内设备维修费用的期望值最小。     

Maximum likelihood estimation via the extended covariance and combined square-root filters

The method of maximum likelihood is a general method for parameter estimation and is often used in system identification. To implement it, it is necessary to maximize the likelihood function, which is usually done using the gradient approach. It involves the computation of the likelihood gradient with respect to unknown system parameters. For linear stochastic system models this leads to the implementation of the Kalman filter, which is known to be numerically unstable. The aim of this work is to present new efficient algorithms for likelihood gradient evaluation. They are more reliable in practice and improve robustness of computations against roundoff errors. All algorithms are derived in measurement and time updates form. The comparison with the conventional Kalman filter approach and results of numerical experiments are given.     

Two‐stage Kalman filter‐based actuator/surface fault identification and reconfigurable control applied to F‐16 fighter dynamics

In this study, an active fault‐tolerant control technique with reconfiguration against actuator/surface failures is presented. A two‐stage Kalman filter is designed in order to identify the control distribution matrix elements that correspond to the faulty actuator/surface; thus, the control reconfiguration is carried out using this identified control distribution matrix. The actuator/surface fault identification problem is solved through two jointly operating Kalman filters: the first one is for the estimation of the control distribution matrix elements that correspond to the faulty actuator/surface, and the second one is for the estimation of the state variables of the aircraft model. A structure for the active fault‐tolerant aircraft flight control system with reconfiguration against actuator/surface failures is presented. A control reconfiguration action is taken in order to keep the performance of the impaired aircraft the same as that of the unimpaired aircraft. In simulations, the nonlinear flight dynamics of an AFTI/F‐16 fighter model is considered, and the performance of the proposed actuator/surface failure identification and reconfigurable control schemes are examined for this model. Copyright © 2012 John Wiley & Sons, Ltd.     

Filter approach to the stochastic analysis of MDOF wind-excited structures

In this paper, an approach useful for stochastic analysis of the Gaussian and non-Gaussian behavior of the response of multi-degree-of-freedom (MDOF) wind-excited structures is presented. This approach is based on a particular model of the multivariate stochastic wind field based upon a particular diagonalization of the power spectral density (PSD) matrix of the fluctuating part of wind velocity. This diagonalization is performed in the space of eigenvectors and eigenvalues that are called here wind-eigenvalues and wind-eigenvectors, respectively. From the examination of these quantities it can be recognized that the wind-eigenvectors change slowly with frequency while the first wind-eigenvalue dominates all the others in the low-frequency range. It is shown that the wind field can be modeled in a satisfactory way by taking the first wind-eigenvector as constant and by retaining only the first eigenvalue in the calculations. The described model is then used for stochastic analysis in the time domain of MDOF wind-excited structures. This is accomplished by modeling each element of the diagonalized wind-PSD matrix as the velocity PSD function of a set of second-order digital filters with viscous damping driven by white noise of selected intensity. This approach makes it easy to obtain in closed form the statistical moments of every order of the structural response, taking full advantage of the Itô calculus. Moreover, in the proposed approach, it is possible to reduce the computational effort by appropriately selecting the number of wind modes retained in the calculation.     

清梳联合机工艺技术与设备创新探讨

通过利用AFis纤维检验仪对清梳联各单机在制品的测试结果 ,得出了清梳联工程中棉结、杂质的变化规律 ,并对清梳联工程中清棉打手的组合结构、清梳除杂分配、清梳联短绒控制、生条定量控制、排尘、滤尘与空调系统等重要问题进行了讨论。     

运用自组织神经网络进行多目标跟踪的算法

总结了自组织神经网络的结构、训练方法；分析了在多目标跟踪问题中数据关联的重要性及传统的数据关联方法的局限性；研究了在多目标环境下运用自组织神经网络解决数据关联的问题。提出了一种基于自组织神经网络对多个目标实施跟踪的算法，此算法采用自组织神经网络的聚类功能对目标进行数据关联处理，并将经过卡尔曼滤波后的数据信息结合到神经网络的学习训练中。仿真实验结果表明此算法能在多目标环境下取得较好的跟踪效果。