毕业论文外文翻译_CAN总线系统的实时对象调用.doc

大连交通大学2009届本科生毕业设计外文翻译 PAGE 1 Invocation of Real-Time Objects in a CAN Bus-System Abstract The paper focuses on method invocation of real-time objects in a CAN-based distributed real-time system. A simple object model is introduced, which allows the convenient modelling of hardware and software components. Related to the object model, two issues are discussed. Firstly, a model is introduced which allows to form and address object groups. This reflects a basic need in a real-time system to distribute information to multiple clients efficiently. Secondly, we discuss an approach to express timing requirements for object invocations. To achieve distributed consensus on communication resource access, an EDF-like approach is introduced, which takes advantage of knowledge about deadlines, the number of remaining communication activities, and the remaining worst-case execution time for the invoked method at each point of time. 1. Introduction Future computer systems will, to a large extent, monitor and control real-world processes. This results in an inevitable demand for timeliness and reliability. Distributed systems which inherently provide immunity against single failures are an adequate architecture to meet the goal of reliability. Additionally, because realworld applications often require the spatially distributed control of electromechanical components, a distributed system architecture brings computing power to the points where it is needed. The availability of inexpensive yet powerful microcontrollers supports a distributed solution. This results in a system model which is composed from smart components implementing the instrumentation interface to the real world comprising sensors and actuators. A convenient way to model such an environment is to use an object-based approach where objects encapsulate all kinds of entities necessary to control a physical process. We can identify at least two layers in systems interacting with the real world. A lower responsive