论文标题
基于相对错误的时间限制的H2模型订单通过倾斜投影降低
Relative Error-based Time-limited H2 Model Order Reduction via Oblique Projection
论文作者
论文摘要
在时间限制的模型降低中,获得原始高阶模型的减小近似值,该模型可准确地近似于所需的有限时间间隔内的原始模型。在此时间间隔之外的准确性并不重要。当将还原模型用作原始模型的替代物时,可能会以绝对或相对项来访问模型还原算法的性能。相对误差通常比绝对误差更有意义,因为如果原始系统的响应和减少的响应幅度很小,则绝对误差的幅度也很小。但是,这并不一定意味着还原模型是准确的。在这种情况下,相对误差是有用且有意义的,因为它可以量化百分比误差,而与系统响应的幅度无关。在本文中,得出了相对误差系统的时限H2规范的局部最佳条件。受这些条件的启发,提出了一种倾斜投影算法,以确保所需时间间隔内的小H2-norm相对误差。与现有的基于相对错误的模型还原算法不同,该算法不需要大规模Lyapunov和Riccati方程的解决方案。将所提出的算法与时间限制的平衡截断,时间限制的平衡随机截断以及时限的迭代理性Krylov算法进行比较。数值结果证实了所提出的算法比这些现有算法的优越性。
In time-limited model order reduction, a reduced-order approximation of the original high-order model is obtained that accurately approximates the original model within the desired limited time interval. Accuracy outside that time interval is not that important. The error incurred when a reduced-order model is used as a surrogate for the original model can be quantified in absolute or relative terms to access the performance of the model reduction algorithm. The relative error is generally more meaningful than an absolute error because if the original and reduced systems' responses are of small magnitude, the absolute error is small in magnitude as well. However, this does not necessarily mean that the reduced model is accurate. The relative error in such scenarios is useful and meaningful as it quantifies percentage error irrespective of the magnitude of the system's response. In this paper, the necessary conditions for a local optimum of the time-limited H2 norm of the relative error system are derived. Inspired by these conditions, an oblique projection algorithm is proposed that ensures small H2-norm relative error within the desired time interval. Unlike the existing relative error-based model reduction algorithms, the proposed algorithm does not require solutions of large-scale Lyapunov and Riccati equations. The proposed algorithm is compared with time-limited balanced truncation, time-limited balanced stochastic truncation, and time-limited iterative Rational Krylov algorithm. Numerical results confirm the superiority of the proposed algorithm over these existing algorithms.