Because of the presence of sporadic high-intensity measurement noise （outliers）, an adaptive algorithm for the robust estimation of parameters of linear dynamic discrete-time systems is proposed in this paper. First...Because of the presence of sporadic high-intensity measurement noise （outliers）, an adaptive algorithm for the robust estimation of parameters of linear dynamic discrete-time systems is proposed in this paper. First, the sorted data versus the normal quantiles is plotted, called QQ-plot. Next, the e-contaminated normal distribution of noise is adopted. Then, a data classification procedure based on the QQ-plot approach, combined with the robustified data winsorization technique, is developed; the estimation of the unknown noise statistical parameters is solved. Moreover, an iterative procedure for estimating the contamination degree ~＇, which originated from an ML classification, is also proposed. Thus, an ^-contaminated noise distribution is estimated and, the suboptimal maximum likelihood criterion is defined, and the system-parameter estimation problem is solved robustly, using the proposed recursive robust parameter estimation scheme. Finally, these parameters are used to estimate water level in the steam drum and residual of the steam-drum water level sensor.展开更多
Real-time and accurate fault detection is essential to enhance the aircraft navigation system’s reliability and safety. The existent detection methods based on analytical model draws back at simultaneously detecting ...Real-time and accurate fault detection is essential to enhance the aircraft navigation system’s reliability and safety. The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults. On account of this reason, we propose an online detection solution based on non-analytical model. In this article, the navigation system fault detection model is established based on belief rule base （BRB）, where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output. To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update, a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization （EM） algorithm. Furthermore, the proposed method is verified by navigation experiment. Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model. The output of the detection model can track the fault state very well, and the faults can be diagnosed in real time and accurately. In addition, the detection ability, especially in the probability of false detection, is superior to offline optimization method, and thus the system reliability has great improvement.展开更多
Accurate model identification and fault detection are necessary for reliable motor control. Motor-characterizing parameters experience substantial changes due to aging, motor operating conditions, and faults. Conseque...Accurate model identification and fault detection are necessary for reliable motor control. Motor-characterizing parameters experience substantial changes due to aging, motor operating conditions, and faults. Consequently, motor parameters must be estimated accurately and reliably during operation. Based on enhanced model structures of electric motors that accommodate both normal and faulty modes, this paper introduces bias-corrected least-squares （LS） estimation algorithms that incorporate functions for correcting estimation bias, forgetting factors for capturing sudden faults, and recursive structures for efficient real-time implementation. Permanent magnet motors are used as a benchmark type for concrete algorithm development and evaluation. Algorithms are presented, their properties are established, and their accuracy and robustness are evaluated by simulation case studies under both normal operations and inter-turn winding faults. Implementation issues from different motor control schemes are also discussed.展开更多
The faults in switched reluctance motors(SRMs) were detected and diagnosed in real time with the Kohonen neural network. When a fault happens, both financial losses and undesired situations may occur. For these reason...The faults in switched reluctance motors(SRMs) were detected and diagnosed in real time with the Kohonen neural network. When a fault happens, both financial losses and undesired situations may occur. For these reasons, it is important to detect the incipient faults of SRMs and to diagnose which faults have occurred. In this study, a test rig was realized to determine the healthy and faulty conditions of SRMs. A data set for the Kohonen neural network was created with implemented measurements. A graphical user interface(GUI) was created in Matlab to test the performance of the Kohonen artificial neural network in real time. The data of the SRM was transferred to this software with a data acquisition card. The condition of the motor was monitored by marking the data measured in real time on the weight position graph of the Kohonen neural network. This test rig is capable of real-time monitoring of the condition of SRMs, which are used with intermittent or continuous operation, and is capable of detecting and diagnosing the faults that may occur in the motor. The Kohonen neural network used for detection and diagnosis of faults of the SRM in real time with Matlab GUI was embedded in an STM32 processor. A prototype with the STM32 processor was developed to detect and diagnose the faults of SRMs independent of computers.展开更多
核主元分析方法（Kernel Principal Component Analysis,KPCA）能有效地捕捉数据的非线性特征,其故障检测能力很大程度上取决于核参数的选择。常用的核函数有多项式核函数和高斯径向基核函数等。该方法将多项式核函数和高斯径向基核函...核主元分析方法（Kernel Principal Component Analysis,KPCA）能有效地捕捉数据的非线性特征,其故障检测能力很大程度上取决于核参数的选择。常用的核函数有多项式核函数和高斯径向基核函数等。该方法将多项式核函数和高斯径向基核函数进行线性组合,结合两者优点得到混合核函数,使用故障检测率作为优化目标的适应度函数,通过人工蜂群（Artificial Bee Colony Algorithm,ABC）优化算法对KPCA核参数的选取进行优化。将该方法应用到电主轴的转子不平衡故障分析中,对信号进行时域分析,利用KPCA对样本数据进行非线性特征提取,根据主元特征计算出的T2和SPE统计量实现故障检测。经过对实验数据分析表明,ABC优化算法较二分法、粒子群等优化算法能更有效地提高故障检测率。展开更多
文摘Because of the presence of sporadic high-intensity measurement noise （outliers）, an adaptive algorithm for the robust estimation of parameters of linear dynamic discrete-time systems is proposed in this paper. First, the sorted data versus the normal quantiles is plotted, called QQ-plot. Next, the e-contaminated normal distribution of noise is adopted. Then, a data classification procedure based on the QQ-plot approach, combined with the robustified data winsorization technique, is developed; the estimation of the unknown noise statistical parameters is solved. Moreover, an iterative procedure for estimating the contamination degree ~＇, which originated from an ML classification, is also proposed. Thus, an ^-contaminated noise distribution is estimated and, the suboptimal maximum likelihood criterion is defined, and the system-parameter estimation problem is solved robustly, using the proposed recursive robust parameter estimation scheme. Finally, these parameters are used to estimate water level in the steam drum and residual of the steam-drum water level sensor.
基金the National High-tech Research and Development Program of China(No.2011AA7053016)National Natural Science Foundation of China(No.61174030)
文摘Real-time and accurate fault detection is essential to enhance the aircraft navigation system’s reliability and safety. The existent detection methods based on analytical model draws back at simultaneously detecting gradual and sudden faults. On account of this reason, we propose an online detection solution based on non-analytical model. In this article, the navigation system fault detection model is established based on belief rule base （BRB）, where the system measuring residual and its changing rate are used as the inputs of BRB model and the fault detection function as the output. To overcome the drawbacks of current parameter optimization algorithms for BRB and achieve online update, a parameter recursive estimation algorithm is presented for online BRB detection model based on expectation maximization （EM） algorithm. Furthermore, the proposed method is verified by navigation experiment. Experimental results show that the proposed method is able to effectively realize online parameter evaluation in navigation system fault detection model. The output of the detection model can track the fault state very well, and the faults can be diagnosed in real time and accurately. In addition, the detection ability, especially in the probability of false detection, is superior to offline optimization method, and thus the system reliability has great improvement.
文摘Accurate model identification and fault detection are necessary for reliable motor control. Motor-characterizing parameters experience substantial changes due to aging, motor operating conditions, and faults. Consequently, motor parameters must be estimated accurately and reliably during operation. Based on enhanced model structures of electric motors that accommodate both normal and faulty modes, this paper introduces bias-corrected least-squares （LS） estimation algorithms that incorporate functions for correcting estimation bias, forgetting factors for capturing sudden faults, and recursive structures for efficient real-time implementation. Permanent magnet motors are used as a benchmark type for concrete algorithm development and evaluation. Algorithms are presented, their properties are established, and their accuracy and robustness are evaluated by simulation case studies under both normal operations and inter-turn winding faults. Implementation issues from different motor control schemes are also discussed.
基金Project(No.KBü-BAP-C-11-D-003)supported by the Karabük University BAP Unit,Turkey
文摘The faults in switched reluctance motors(SRMs) were detected and diagnosed in real time with the Kohonen neural network. When a fault happens, both financial losses and undesired situations may occur. For these reasons, it is important to detect the incipient faults of SRMs and to diagnose which faults have occurred. In this study, a test rig was realized to determine the healthy and faulty conditions of SRMs. A data set for the Kohonen neural network was created with implemented measurements. A graphical user interface(GUI) was created in Matlab to test the performance of the Kohonen artificial neural network in real time. The data of the SRM was transferred to this software with a data acquisition card. The condition of the motor was monitored by marking the data measured in real time on the weight position graph of the Kohonen neural network. This test rig is capable of real-time monitoring of the condition of SRMs, which are used with intermittent or continuous operation, and is capable of detecting and diagnosing the faults that may occur in the motor. The Kohonen neural network used for detection and diagnosis of faults of the SRM in real time with Matlab GUI was embedded in an STM32 processor. A prototype with the STM32 processor was developed to detect and diagnose the faults of SRMs independent of computers.
