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张友安

Bio: 张友安 is an academic researcher. The author has an hindex of 1, co-authored 1 publications receiving 70 citations.

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Journal ArticleDOI
TL;DR: The article concludes by presenting applications in which different state of the art simulation programs are linked for run-time data exchange, and allows the use of the simulation program best suited for the particular problem to model building heat transfer, HVAC system dynamics and control algorithms, and to compute a solution to the coupled problem using co-simulation.
Abstract: This article describes the implementation of the Building Controls Virtual Test Bed (BCVTB). The BCVTB is a software environment that allows connecting different simulation programs to exchange data during the time integration, and that allows conducting hardware in the loop simulation. The software architecture is a modular design based on Ptolemy II, a software environment for design and analysis of heterogeneous systems. Ptolemy II provides a graphical model building environment, synchronizes the exchanged data and visualizes the system evolution during run-time. The BCVTB provides additions to Ptolemy II that allow the run-time coupling of different simulation programs for data exchange, including EnergyPlus, MATLAB, Simulink and the Modelica modelling and simulation environment Dymola. The additions also allow executing system commands, such as a script that executes a Radiance simulation. In this article, the software architecture is presented and the mathematical model used to implement the co-simulation is discussed. The simulation program interface that the BCVTB provides is explained. The article concludes by presenting applications in which different state of the art simulation programs are linked for run-time data exchange. This link allows the use of the simulation program that is best suited for the particular problem to model building heat transfer, HVAC system dynamics and control algorithms, and to compute a solution to the coupled problem using co-simulation.

408 citations

Journal ArticleDOI
TL;DR: This article introduces the concept of combining both form (CAD models) and behavior (simulation models) of mechatronic system components into component objects by connecting these component objects through their ports, and introduces a port-based modeling paradigm.
Abstract: This article introduces the concept of combining both form (CAD models) and behavior (simulation models) of mechatronic system components into component objects. By connecting these component objects to each other through their ports, designers can create both a system-level design description and a virtual prototype of the system. This virtual prototype, in turn, can provide immediate feedback about design decisions by evaluating whether the functional requirements are met in simulation. To achieve the composition of behavioral models, we introduce a port-based modeling paradigm. The port-based models are reconfigurable, so that the same physical component can be simulated at multiple levels of detail without having to modify the system-level model description. This allows the virtual prototype to evolve during the design process, and to achieve the accuracy required for the simulation experiments at each design stage. To maintain the consistency between the form and behavior of component objects, we introduce parametric relations between these two descriptions. In addition, we develop algorithms that determine the type and parameter values of the lower pair interaction models; these models depend on the form of both components that are interacting. This article presents the initial results of our approach. The discussion is limited to high-level system models consisting of components and lumped component interactions described by differential algebraic equations. Expanding these concepts to finite element models and distributed interactions is left for future research. Our composable simulation and design environment has been implemented as a distributed system in Java and C11, enabling multiple users to collaborate on the design of a single system. Our current implementation has been applied to a variety of systems ranging from consumer electronics to electrical train systems. We illustrate its functionality and use with a design scenario.

127 citations

Journal ArticleDOI
TL;DR: This paper describes the architecture for a system consisting of a robotic manipulator controlled by a digital controller over a wireless network and shows that the system is stable even in the presence of time-varying delays and is insensitive to network uncertainties.
Abstract: Real-life cyber physical systems, such as automotive vehicles, building automation systems, and groups of unmanned vehicles are monitored and controlled by networked control systems (NCS). The overall system dynamics emerges from the interaction among physical dynamics, computational dynamics, and communication networks. Network uncertainties such as time-varying delay and packet loss cause significant challenges. This paper proposes a passive control architecture for designing NCS that are insensitive to network uncertainties. We describe the architecture for a system consisting of a robotic manipulator controlled by a digital controller over a wireless network and show that the system is stable even in the presence of time-varying delays. Experimental results demonstrate the advantages of the passivity-based architecture with respect to stability and performance and show that the system is insensitive to network uncertainties.

51 citations

Proceedings ArticleDOI
01 Jan 2011
TL;DR: It is shown that some inconsistencies cannot be detected and it is impossible to say whether or not a system is fully consistent, so the ontology of inconsistencies is constructed.
Abstract: Developing complex engineering systems requires the consolidation of models from a variety of domains such as economics, mechanics and software engineering. These models are typically created using differing formalisms and by stakeholders that have varying views on the same problem statement. The challenging question is: what is needed to make sure that all of these different models remain consistent during the design process? A review of the related literature reveals that this is still an open challenge and has not yet been investigated at a fundamental level within the context of Model-Based Systems Engineering (MBSE). Therefore, this paper specifically focuses on examining the fundamentals of consistency management. We show that some inconsistencies cannot be detected and come to the conclusion that it is impossible to say whether or not a system is fully consistent. In this paper, we first introduce a mathematical foundation to define consistency in a formal manner. A decision-based approach to design is then studied and applied to the development of a real-world example. The research reveals several distinct types of inconsistencies that can occur during the design and development of a system. We show that these inconsistencies can be further classified into two groups: internal and external consistency. From these insights, the ontology of inconsistencies is constructed. Finally, requirements for possible tool support and methods to identify and manage specific types of consistency issues are proposed.Copyright © 2011 by ASME

47 citations

Proceedings ArticleDOI
30 Oct 2013
TL;DR: This work describes a framework for distributed simulation of cyber-physical systems (CPS) and leverages existing frameworks to facilitate the integration of components in a systematic, well-defined manner and demonstrates the approach on a flight control system simulation.
Abstract: This work describes a framework for distributed simulation of cyber-physical systems (CPS). Modern CPS comprise large numbers of heterogeneous components, typically designed in very different tools and languages that are not or not easily compose able. Evaluating such large systems requires tools that integrate all components in a systematic, well-defined manner. This work leverages existing frameworks to facilitate the integration offers validation by simulation. A framework for distributed simulation is the IEEE High-Level Architecture (HLA) compliant tool CERTI, which provides the infrastructure for co-simulation of models in various simulation environments as well as hardware components. We use CERTI in combination with Ptolemy II, an environment for modeling and simulating heterogeneous systems. In particular, we focus on models of a CPS, including the physical dynamics of a plant, the software that controls the plant, and the network that enables the communication between controllers. We describe the Ptolemy extensions for the interaction with HLA and demonstrate the approach on a flight control system simulation.

44 citations