QSS and multi-rate simulation of object-oriented models
QSS and multi-rate simulation of object-oriented models
复制标题
面向对象模型的 QSS 和多速率仿真
DOI：
10.1145/2904081.2904091
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
F. Casella
中科院分区：
文献类型：
--
作者：
Federico Bergero;Akshay Ranade;F. Casella
面向对象（O-O）语言，如Modelica允许描述多域动态模型。这些模型表示微分代数方程（DAE），通常转换为常微分方程（ODE）公式，并使用数值积分方法进行模拟。大多数Modelica工具包括基于时间离散化的单速率积分方法。最近开发的ODE数值积分方法，如量化状态系统（QSS）和多速率算法具有一些功能（稀疏性开发，有效的刚度处理，有效的松散耦合方程组的集成），使它们适合于许多应用。就其本质而言，这些方法的有效实现需要从与经典方法不同的角度来看待模型，因此在Modelica工具中实现它们并不是一项简单的任务。FMI（Functional Mock-up Interface）是一个独立于工具的模型交换和协同仿真标准。模型作为编译的二进制文件（功能模型单元-FMU）与允许模型评估和模拟的API交换。FMU将该模型表示为混合常微分方程，在其上应用数值积分方法（如欧拉、龙格-库塔）进行模拟。在这篇文章中，我们提出了一个扩展的FMU API，允许QSS和多速率模拟的O-O面向模型的FMI模型交换。这种扩展开辟了在广泛的系统模型上测试和微调QSS和多速率算法的可能性。两个示例情况下的原型实现所获得的一些结果进行了报告。
Object-Oriented (O--O) languages like Modelica allow the description of multi-domain dynamical models. These models represent a Differential Algebraic Equation (DAE) that is usually converted to an Ordinary Differential Equation (ODE) formulation and simulated using numerical integration methods. Most Modelica tools include Single-Rate integration methods based on time discretization. Recently developed ODE numerical integration methods like Quantized State Systems (QSS) and Multi-Rate algorithms have some features (sparsity exploitation, efficient stiffness handling, efficient integration of loosely coupled systems of equations) that makes them suitable for many applications. By their nature, efficient implementation of these methods requires a different perspective on the model than classical methods, thus it is not a trivial task to implement them in Modelica tools. The Functional Mock-up Interface (FMI) is a tool independent standard for model exchange and co-simulation. Models are exchanged as compiled binaries (Functional Mockup Unit - FMU) with an API that allows the evaluation and simulation of the model. The FMU presents the model as a hybrid ODE on which numerical integration methods (such as Euler, Runge-Kutta) are applied for simulation. In this article we propose an extension to the FMU API to allow QSS and Multi-Rate simulation of O--O oriented models by means of FMI Model-Exchange. This extension opens up the possibility of testing and fine tuning QSS and Multi-Rate algorithms on a wide range of system models. Some results obtained with a prototype implementation on two example cases are reported.