【作者】 谢勇；

【导师】 李仁发；

【作者基本信息】 湖南大学 ， 计算机科学与技术， 2010， 硕士

【摘要】 近年来,随着嵌入式计算、通信技术等信息技术在汽车中的应用,汽车制造技术产生了深刻的变革。现代汽车的性能提升已经发展到以采用先进的电子控制技术进行综合控制的阶段,以嵌入式软件为主要载体的各种控制技术的应用将成为未来汽车技术发展的重点之一软件是汽车电子控制系统的核心,因汽车电子软件的复杂性日益攀升,且汽车本身在成本上非常敏感,所以实时、成本控制等问题变得日益严峻。任务的周期和总线的访问配置是系统实时性、ECU内CPU利用率等的关键影响因素。通过对任务周期和总线访问配置进行调整,可以在保障实时性的情况下,优化ECU内的CPU利用率。这能提升ECU单元对新功能的容纳能力,缓解ECU的增加,从而对汽车系统的成本控制具有一定意义。任务的周期分配和总线访问配置是基于平台的汽车电子软件设计中的关键部分,所以本文从基于平台的汽车电子软件设计入手,提出一种基于几何规划算法的周期分配和总线访问配置算法。本文的工作主要集中在以下三个方面：1,首先介绍了传统汽车电子软件设计,并对其存在的不足进行了分析。在此基础之上,对汽车电子软件设计面临的挑战和发展趋势进行概括。然后,对基于平台的汽车电子软件设计进行了介绍,并就设计中的周期分配、总线访问配置及相关的问题进行了综述。2,经过上述分析我们发现：现有的面向嵌入式实时系统的周期分配和总线访问配置方法主要以时间相关的属性作为优化目标,很少对与汽车成本控制相关的CPU利用率问题进行研究。本文提出了一种基于几何规划算法的周期分配和总线访问配置算法,在满足实时性要求、总线时隙利用率、可调度性等限制条件的情况下,对ECU内CPU利用率进行优化。3,上述问题是一个典型的几何规划问题,所以本文在能解决几何规划问题的GPPOSY工具箱和Matlab的仿真平台上对本文提出的算法进行了实验仿真。实验结果表明该算法在满足实时性要求,优化CPU利用率方面的有效性。更多还原

【Abstract】 In recent years, as the application of embedded computing technology, communication technology and other information technologies in automobiles,it has seen great evolutions in automotive fabricaton.The increase of automotive system’s capability has entered a new era to apply the advanced electronic control technology, and all kinds of control technology’s applications based on embedded software will be one of the development priorities of automotive technology.Software is the core of automotive electronics control systems,for the complexity of automotive electronics software is on the rise and the automobiles is sensitive to the cost,real-time and cost control problems are becoming more and more severe in it. Task’s period and the Bus Access Configuration are decisive factors of the system’s real-time property, CPU utilization,so through the adjustment of it,we can optimize the CPU utilization under the premise of guaranteeing real-time requirements.It can enhance the ECU’s ability to accommodate the new applications and slow down the ECU’s increasing,so it is meaningful to the cost control of automobiles.Task’s period assignment and Bus Access Configuration are key parts of platform-based automotive electronics software design method,so we started from it and propsed the period assignment and bus access configuration algorithm.The main contributions of this thesis are as followes:1,we firstly introduce traditional automotive electronics software design,and give an analysis about its deficits.Based upon it we summarize the key challenges and trends of automotive electronics software design.And then we describe the platform-based automotive electronics software design and its design flow, and give a survey about the period assignment, bus access configuration and the relevant problems of that design flow.2,Based on the analysis mentioned before,we found that the current research about period assignment and Bus Access Configuration in embedded real-time systems are mostly about how to optimize the time-related properties,and there is little work related with CPU utilization optimization.So based on Geometric Programming, we propose a period assignment and Bus Access Configuration algorithm which can meet the requirements of real-time, bus slot utilization and schedulability constraints,and realize the optimization of CPU utilization.3,The problem mentioned before is a typical GP problem, so we combine GPPOSY toolbox,which can solve the GP problem,with matlab to simulate our algorithm.The simulation results shown this algorithm is effective in optimizing the CPU utilization while meeting the real-time property constraints.更多还原