Oriented Simulation Of Real-time Operating System Technology Research

Along with the expansion of the simulation system applications, more and more systems need to be constructed with HIL(Hardware In Loop),which strongly calls for real-time simulation.Real-time simulation,must provide better real-time characteristic and faster response characteristic^ support the complexity and large-size of nowaday simulation systems. Then, operating system of the computers, as the infrastructure for the simulation systems, is very important to give us a steady, unfluctuating and expedite feature.Even a good real-time OS can't satisfy all requirements of every real-time simulation system. Then the better way is to develop a special real-time OS which meets our special needs. And the special OS should provide easy parameters-reconfiguration ability to adapt to different kinds of simulation systems.With a pretty good real-time performance and the open-source feature of the kernel codes, Linux OS helps us realize "simulation real-time OS" easily. Although Linux is a time-shared OS, its new edition kernel has a much better real-time characteristic .we can convert Linux to real-time OS by modifying kernel source codes according to our special requirments.Firstly, in this paper, we study the source codes of all kernel subsystems which are related to the real-time characteristics, and sum up the key kernel elements that affect the real-time characteristics, which include processes and process scheduling, interrupts and system calls, net management, timing measurement. At the same time we offer some methods for the improvements of every kernel elements.Secondly, we compile kernel source codes which has been modified, build a new neat root-file-system, combine the two parts above to get a new KD-Linux that is prepared for latter examination.In the end, we design a series of real-time simulation programs for different running conditions, analyze the means to realize real-time simulation and the accuracy of timing measurement in Linux OS step by step, and then test the programs in KD-Linux to validate above theories. What's more, we design network data transfer programs to research the effects of network communications in real-time simulation.