arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1709.03421eess.SYcs.SY
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不确定输入系统的建模与识别

Modeling and identification of uncertain-input systems

ACCESS Linnaeus Center, KTH Royal Institute of Technology(ACCESS林奈中心,皇家理工学院);Department of Electrical Engineering, Eindhoven University of Technology(埃因霍温理工大学电气工程系)

Riccardo Sven Risuleo, Giulio Bottegal, Håkan Hjalmarsson

AI总结:

本文提出不确定输入模型,通过高斯过程模型处理部分未知输入信号的系统识别问题,结合经验贝叶斯方法和近似技术,适用于 Hammerstein 系统和级联线性系统识别。

摘要:

本文提出了一种新的模型类别,称为不确定输入模型,用于处理线性系统受部分未知输入信号影响的系统识别问题。为编码输入或线性系统之前的先验信息,我们使用高斯过程模型。通过经验贝叶斯方法从数据中估计模型:输入和线性系统的脉冲响应通过高斯过程模型的后验均值估计,而高斯过程模型的超参数通过数据的边际似然估计。我们提出了一种迭代算法来寻找超参数,该算法基于期望最大化方法,产生简单的更新步骤。在最一般的情况下,边际似然或未知变量的后验分布不可行。因此,我们提出两种近似方法,一种基于马尔可夫链蒙特卡罗技术,另一种基于变分贝叶斯近似。我们还展示了某些特殊模型结构,其中分布可以精确处理。通过数值模拟,我们研究了不确定输入模型在 Hammerstein 系统和级联线性系统识别中的应用。作为本文的贡献,我们展示了该模型结构涵盖了系统识别中的许多经典问题,如经典 PEM、Hammerstein 模型、误差变量问题、盲系统识别和级联线性系统。这使我们能够构建一个系统的方法,将本文提出的算法应用于广泛的经典问题。

英文摘要:

In this work, we present a new class of models, called uncertain-input models, that allows us to treat system-identification problems in which a linear system is subject to a partially unknown input signal. To encode prior information about the input or the linear system, we use Gaussian-process models. We estimate the model from data using the empirical Bayes approach: the input and the impulse responses of the linear system are estimated using the posterior means of the Gaussian-process models given the data, and the hyperparameters that characterize the Gaussian-process models are estimated from the marginal likelihood of the data. We propose an iterative algorithm to find the hyperparameters that relies on the EM method and results in simple update steps. In the most general formulation, neither the marginal likelihood nor the posterior distribution of the unknowns is tractable. Therefore, we propose two approximation approaches, one based on Markov-chain Monte Carlo techniques and one based on variational Bayes approximation. We also show special model structures for which the distributions are treatable exactly. Through numerical simulations, we study the application of the uncertain-input model to the identification of Hammerstein systems and cascaded linear systems. As part of the contribution of the paper, we show that this model structure encompasses many classical problems in system identification such as classical PEM, Hammerstein models, errors-in-variables problems, blind system identification, and cascaded linear systems. This allows us to build a systematic procedure to apply the algorithms proposed in this work to a wide class of classical problems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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