The Flight Simulator Real-time Simulation Management System Research

The flight simulator is aviation experiment equipments which could be used to simulate the airplane's taxiing and flying. It is the typical applications of system simulation technology. Due to the merits such as economical, safety, efficiency and environmental, the flight simulator is widely used in the fields of new type airplane development, flight theory research, flight control research and flight training research. With the aviation industry's rapid development and the large airplane plane's start-up in our country, it is significient to carry out flight simulator key technologies research. It can speed up and perfect the development process of large airplane, narrows the gap between flight simulation technology and that of technologically advanced countries, cultivates the flight simulator development team and develops the high fidelity flight simulator with proprietary intellectual property rights.As the dispatching control center of the flight simulator, the Real-Time simulation Management System (RTMS) controls and manages subsystem simulation softwares' real-time execution and data exchange through the real-time dispatching mechanism and the real-time communication technology. Meanwhile, as the key technology for flight simulator research, it can maximize the functions and performance of flight simulation software. This essay elaborates an efficient and flexible real-time simulation management system though the deeply research in the flight simulator software architecture, the real-time dispatching theory, the real-time communication technology and the flight simulator integration technology.According to the functional analysis of flight simulation software such as the flight training, enviroment simulation and malfunction simulation requirements, the functional requirements and system compositions of the real-time simulation management system are given. On the basis of Model-View-Controller (MVC) design pattern and through the software quality requirement analysis, the platform independent and extensible flight simulation architecture is proposed. The software architecture elements are also elaborated.Based on the software architecture, an improved layered simulation tasks dispatching structure is devised according to the simulation tasks' tightly sequence relationship. The periodic dispatching algothrim with binary tree is builded for the periodic tasks, aperiodic and the background tasks. Meanwhile, the mixture task set dispatching algothrim is devised based on the earliest deadline first dispatching algothrim. It not only faciliates the real-time scheduling, but also easies modification and extension of complex task set.Data communication has an important role in flight simulator, the simulation parameters distribution technology and the integrity and consistency technology of the shared data are deeply and systematically studied with the focus study of the global data space and parameters distribution services. On the basis of the publish/subscribe communication paradigm, the flight simulation parameters sharing methods are proposed. The principles of minimum parameters publication area are given. And by the utilization these principles, the construction algothrim for the shared parameters' publication/subscription is proposed. With the bottom-up method, the controlled shared data accession in the layer of simulation models, subsystems and simulation computing nodes are described which meets the data integrity requirements. The data sharing method with double buffers is proposed which meets the data consistency requirements. The flexible network communication module is devised through the communication class factory which fulfills the data exchange requirement of the distributed system. All of these methods fulfill the integrity and consistency requirement of data sharing. Meanwhile, the simulation network's communication efficiency is improved.In order to verify efficiency and flexibility of RTMS, reduce the development period and improve the development efficiency of flight simulator, an experimental flight simulator is developed by the method of COTS (Commercial-Off-The-Shelf) which includes the simulation hardware and software. On the basis of Ethernet, IEEE 1394 bus and CAN bus, a mixture real-time simulation network is constructed. The flight simulation software development is facilitated by the COTS software. And tests of the simulation tasks' execution time, the occupancy factor of frame period, software architecture evaluation, and integrated performance verification are carried out in the constructed flight simulator. The test show that flight simulation software architecture is reasonable and the RTMS fulfill the real-time scheduling and communication requirements of flight simulator.