When a state changes as a result of some discrete event, the continuous behavior may also change. In turn, a condition specified on continuously changing variables could trigger a state machine transition-so-called change event. State machines run within objects that communicate in discrete way, e.g. by message passing, as well as by sharing continuous time variables over unidirectional connections. Developed simulation should interoperate with other components, possibly created with different tools.Ĭomplex hybrid system modeling may require distributed simulation due to system complexity, performance and interoperability requirements, etc. This could be achieved by using some M&S standard. This would also allow creation of distributed simulations, where components are run on different machines and different platforms. We believe that high level architecture (HLA) for modeling and simulation developed by US Department of Defense (DoD),, is the most suitable for this purpose. In the paper we present AnyLogic, a tool for modeling and simulation of hybrid systems and a way of HLA support integration in the tool simulation engine. To demonstrate AnyLogic ability to model and simulate hybrid systems, we present a simple example of two tanks system. We examine problems aroused with distributed simulation of this system in AnyLogic using HLA. Section 2 presents AnyLogic tool and its modeling language. A hybrid system example and its modeling in AnyLogic environment is described in Section 3. Section 4 gives an overview of AnyLogic simulation engine integration into HLA. Distributed model of two tanks system designed in HLA is also described here together with problems of hybrid system simulation in distributed environment. Section snippets AnyLogic and its modeling languageĪnyLogic architecture is shown in Fig. Windows-based development environment includes graphical model editor and code generator that maps the model into Java code. The model runs on any Java platform on the top of AnyLogic hybrid engine. A running model exposes an interface to control its execution and to retrieve information via a text-based protocol over TCP/IP. That interface is used by Viewer and Debugger that runs on Java platform as well. The model supports connection of multiple Hybrid system exampleĬonsider a system consisting of two tanks and a controller (Fig. Three valves controls water injection in tank 1 (v 1), water flow from tank 1 to tank 2 (v 2), and water flow from tank 2 outside the system (v 3). Controller tracks water level in both tanks ( h 1 and h 2) and generates commands to open or close valves. The main task is to avoid droughts or overflows of tank 2. )Īs we can see from the system Distributed simulation with HLA support (AnyLogic demo with this and other examples is available from. The HLA is a standard framework that supports simulations composed of different distributed simulation components. The HLA was developed by the Defense Modeling and Simulation Office (DMSO) of DoD to meet the needs of defense-related projects, but it is now increasingly being used in other application areas. Recent adoption of the HLA as an IEEE Detecting conditions defined over continuously changing interface variables: RPE technique The primary goal of such architecture is to facilitate simulation interoperability and reuse across a broad range of applications. Polling and sampling update methods are good enough when we need to monitor behavior of components, e.g. for building external viewers, statistic collecting, tracking objects, and other situation awareness needs. However, these update methods are not very good for detecting conditions defined over continuously changing interface variables (like h 2 in the distributed two tanks system).
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